linux-sg2042/arch/sparc/kernel/kprobes.c

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 22:07:57 +08:00
// SPDX-License-Identifier: GPL-2.0
/* arch/sparc64/kernel/kprobes.c
*
* Copyright (C) 2004 David S. Miller <davem@davemloft.net>
*/
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/extable.h>
#include <linux/kdebug.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <linux/context_tracking.h>
#include <asm/signal.h>
#include <asm/cacheflush.h>
#include <linux/uaccess.h>
/* We do not have hardware single-stepping on sparc64.
* So we implement software single-stepping with breakpoint
* traps. The top-level scheme is similar to that used
* in the x86 kprobes implementation.
*
* In the kprobe->ainsn.insn[] array we store the original
* instruction at index zero and a break instruction at
* index one.
*
* When we hit a kprobe we:
* - Run the pre-handler
* - Remember "regs->tnpc" and interrupt level stored in
* "regs->tstate" so we can restore them later
* - Disable PIL interrupts
* - Set regs->tpc to point to kprobe->ainsn.insn[0]
* - Set regs->tnpc to point to kprobe->ainsn.insn[1]
* - Mark that we are actively in a kprobe
*
* At this point we wait for the second breakpoint at
* kprobe->ainsn.insn[1] to hit. When it does we:
* - Run the post-handler
* - Set regs->tpc to "remembered" regs->tnpc stored above,
* restore the PIL interrupt level in "regs->tstate" as well
* - Make any adjustments necessary to regs->tnpc in order
* to handle relative branches correctly. See below.
* - Mark that we are no longer actively in a kprobe.
*/
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
if ((unsigned long) p->addr & 0x3UL)
return -EILSEQ;
p->ainsn.insn[0] = *p->addr;
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
flushi(&p->ainsn.insn[0]);
p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2;
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
flushi(&p->ainsn.insn[1]);
[PATCH] Move kprobe [dis]arming into arch specific code The architecture independent code of the current kprobes implementation is arming and disarming kprobes at registration time. The problem is that the code is assuming that arming and disarming is a just done by a simple write of some magic value to an address. This is problematic for ia64 where our instructions look more like structures, and we can not insert break points by just doing something like: *p->addr = BREAKPOINT_INSTRUCTION; The following patch to 2.6.12-rc4-mm2 adds two new architecture dependent functions: * void arch_arm_kprobe(struct kprobe *p) * void arch_disarm_kprobe(struct kprobe *p) and then adds the new functions for each of the architectures that already implement kprobes (spar64/ppc64/i386/x86_64). I thought arch_[dis]arm_kprobe was the most descriptive of what was really happening, but each of the architectures already had a disarm_kprobe() function that was really a "disarm and do some other clean-up items as needed when you stumble across a recursive kprobe." So... I took the liberty of changing the code that was calling disarm_kprobe() to call arch_disarm_kprobe(), and then do the cleanup in the block of code dealing with the recursive kprobe case. So far this patch as been tested on i386, x86_64, and ppc64, but still needs to be tested in sparc64. Signed-off-by: Rusty Lynch <rusty.lynch@intel.com> Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 15:09:25 +08:00
p->opcode = *p->addr;
return 0;
[PATCH] Move kprobe [dis]arming into arch specific code The architecture independent code of the current kprobes implementation is arming and disarming kprobes at registration time. The problem is that the code is assuming that arming and disarming is a just done by a simple write of some magic value to an address. This is problematic for ia64 where our instructions look more like structures, and we can not insert break points by just doing something like: *p->addr = BREAKPOINT_INSTRUCTION; The following patch to 2.6.12-rc4-mm2 adds two new architecture dependent functions: * void arch_arm_kprobe(struct kprobe *p) * void arch_disarm_kprobe(struct kprobe *p) and then adds the new functions for each of the architectures that already implement kprobes (spar64/ppc64/i386/x86_64). I thought arch_[dis]arm_kprobe was the most descriptive of what was really happening, but each of the architectures already had a disarm_kprobe() function that was really a "disarm and do some other clean-up items as needed when you stumble across a recursive kprobe." So... I took the liberty of changing the code that was calling disarm_kprobe() to call arch_disarm_kprobe(), and then do the cleanup in the block of code dealing with the recursive kprobe case. So far this patch as been tested on i386, x86_64, and ppc64, but still needs to be tested in sparc64. Signed-off-by: Rusty Lynch <rusty.lynch@intel.com> Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 15:09:25 +08:00
}
void __kprobes arch_arm_kprobe(struct kprobe *p)
[PATCH] Move kprobe [dis]arming into arch specific code The architecture independent code of the current kprobes implementation is arming and disarming kprobes at registration time. The problem is that the code is assuming that arming and disarming is a just done by a simple write of some magic value to an address. This is problematic for ia64 where our instructions look more like structures, and we can not insert break points by just doing something like: *p->addr = BREAKPOINT_INSTRUCTION; The following patch to 2.6.12-rc4-mm2 adds two new architecture dependent functions: * void arch_arm_kprobe(struct kprobe *p) * void arch_disarm_kprobe(struct kprobe *p) and then adds the new functions for each of the architectures that already implement kprobes (spar64/ppc64/i386/x86_64). I thought arch_[dis]arm_kprobe was the most descriptive of what was really happening, but each of the architectures already had a disarm_kprobe() function that was really a "disarm and do some other clean-up items as needed when you stumble across a recursive kprobe." So... I took the liberty of changing the code that was calling disarm_kprobe() to call arch_disarm_kprobe(), and then do the cleanup in the block of code dealing with the recursive kprobe case. So far this patch as been tested on i386, x86_64, and ppc64, but still needs to be tested in sparc64. Signed-off-by: Rusty Lynch <rusty.lynch@intel.com> Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 15:09:25 +08:00
{
*p->addr = BREAKPOINT_INSTRUCTION;
flushi(p->addr);
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
[PATCH] Move kprobe [dis]arming into arch specific code The architecture independent code of the current kprobes implementation is arming and disarming kprobes at registration time. The problem is that the code is assuming that arming and disarming is a just done by a simple write of some magic value to an address. This is problematic for ia64 where our instructions look more like structures, and we can not insert break points by just doing something like: *p->addr = BREAKPOINT_INSTRUCTION; The following patch to 2.6.12-rc4-mm2 adds two new architecture dependent functions: * void arch_arm_kprobe(struct kprobe *p) * void arch_disarm_kprobe(struct kprobe *p) and then adds the new functions for each of the architectures that already implement kprobes (spar64/ppc64/i386/x86_64). I thought arch_[dis]arm_kprobe was the most descriptive of what was really happening, but each of the architectures already had a disarm_kprobe() function that was really a "disarm and do some other clean-up items as needed when you stumble across a recursive kprobe." So... I took the liberty of changing the code that was calling disarm_kprobe() to call arch_disarm_kprobe(), and then do the cleanup in the block of code dealing with the recursive kprobe case. So far this patch as been tested on i386, x86_64, and ppc64, but still needs to be tested in sparc64. Signed-off-by: Rusty Lynch <rusty.lynch@intel.com> Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 15:09:25 +08:00
{
*p->addr = p->opcode;
flushi(p->addr);
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
kcb->prev_kprobe.kp = kprobe_running();
kcb->prev_kprobe.status = kcb->kprobe_status;
kcb->prev_kprobe.orig_tnpc = kcb->kprobe_orig_tnpc;
kcb->prev_kprobe.orig_tstate_pil = kcb->kprobe_orig_tstate_pil;
}
static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
{
sparc: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: sparclinux@vger.kernel.org Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-18 01:30:54 +08:00
__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
kcb->kprobe_status = kcb->prev_kprobe.status;
kcb->kprobe_orig_tnpc = kcb->prev_kprobe.orig_tnpc;
kcb->kprobe_orig_tstate_pil = kcb->prev_kprobe.orig_tstate_pil;
}
static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
sparc: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: sparclinux@vger.kernel.org Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-18 01:30:54 +08:00
__this_cpu_write(current_kprobe, p);
kcb->kprobe_orig_tnpc = regs->tnpc;
kcb->kprobe_orig_tstate_pil = (regs->tstate & TSTATE_PIL);
}
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
regs->tstate |= TSTATE_PIL;
/*single step inline, if it a breakpoint instruction*/
if (p->opcode == BREAKPOINT_INSTRUCTION) {
regs->tpc = (unsigned long) p->addr;
regs->tnpc = kcb->kprobe_orig_tnpc;
} else {
regs->tpc = (unsigned long) &p->ainsn.insn[0];
regs->tnpc = (unsigned long) &p->ainsn.insn[1];
}
}
static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
void *addr = (void *) regs->tpc;
int ret = 0;
struct kprobe_ctlblk *kcb;
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
*/
preempt_disable();
kcb = get_kprobe_ctlblk();
if (kprobe_running()) {
p = get_kprobe(addr);
if (p) {
if (kcb->kprobe_status == KPROBE_HIT_SS) {
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
kcb->kprobe_orig_tstate_pil);
goto no_kprobe;
}
/* We have reentered the kprobe_handler(), since
* another probe was hit while within the handler.
* We here save the original kprobes variables and
* just single step on the instruction of the new probe
* without calling any user handlers.
*/
save_previous_kprobe(kcb);
set_current_kprobe(p, regs, kcb);
kprobes_inc_nmissed_count(p);
kcb->kprobe_status = KPROBE_REENTER;
prepare_singlestep(p, regs, kcb);
return 1;
} else {
if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
/* The breakpoint instruction was removed by
* another cpu right after we hit, no further
* handling of this interrupt is appropriate
*/
ret = 1;
goto no_kprobe;
}
sparc: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: sparclinux@vger.kernel.org Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-18 01:30:54 +08:00
p = __this_cpu_read(current_kprobe);
if (p->break_handler && p->break_handler(p, regs))
goto ss_probe;
}
goto no_kprobe;
}
p = get_kprobe(addr);
if (!p) {
if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
* either a probepoint or a debugger breakpoint
* at this address. In either case, no further
* handling of this interrupt is appropriate.
*/
ret = 1;
}
/* Not one of ours: let kernel handle it */
goto no_kprobe;
}
set_current_kprobe(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (p->pre_handler && p->pre_handler(p, regs))
return 1;
ss_probe:
prepare_singlestep(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
no_kprobe:
preempt_enable_no_resched();
return ret;
}
/* If INSN is a relative control transfer instruction,
* return the corrected branch destination value.
*
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
* regs->tpc and regs->tnpc still hold the values of the
* program counters at the time of trap due to the execution
* of the BREAKPOINT_INSTRUCTION_2 at p->ainsn.insn[1]
*
*/
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
static unsigned long __kprobes relbranch_fixup(u32 insn, struct kprobe *p,
struct pt_regs *regs)
{
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
unsigned long real_pc = (unsigned long) p->addr;
/* Branch not taken, no mods necessary. */
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
if (regs->tnpc == regs->tpc + 0x4UL)
return real_pc + 0x8UL;
/* The three cases are call, branch w/prediction,
* and traditional branch.
*/
if ((insn & 0xc0000000) == 0x40000000 ||
(insn & 0xc1c00000) == 0x00400000 ||
(insn & 0xc1c00000) == 0x00800000) {
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
unsigned long ainsn_addr;
ainsn_addr = (unsigned long) &p->ainsn.insn[0];
/* The instruction did all the work for us
* already, just apply the offset to the correct
* instruction location.
*/
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
return (real_pc + (regs->tnpc - ainsn_addr));
}
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
/* It is jmpl or some other absolute PC modification instruction,
* leave NPC as-is.
*/
return regs->tnpc;
}
/* If INSN is an instruction which writes it's PC location
* into a destination register, fix that up.
*/
static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn,
unsigned long real_pc)
{
unsigned long *slot = NULL;
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
/* Simplest case is 'call', which always uses %o7 */
if ((insn & 0xc0000000) == 0x40000000) {
slot = &regs->u_regs[UREG_I7];
}
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
/* 'jmpl' encodes the register inside of the opcode */
if ((insn & 0xc1f80000) == 0x81c00000) {
unsigned long rd = ((insn >> 25) & 0x1f);
if (rd <= 15) {
slot = &regs->u_regs[rd];
} else {
/* Hard case, it goes onto the stack. */
flushw_all();
rd -= 16;
slot = (unsigned long *)
(regs->u_regs[UREG_FP] + STACK_BIAS);
slot += rd;
}
}
if (slot != NULL)
*slot = real_pc;
}
/*
* Called after single-stepping. p->addr is the address of the
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
* instruction which has been replaced by the breakpoint
* instruction. To avoid the SMP problems that can occur when we
* temporarily put back the original opcode to single-step, we
* single-stepped a copy of the instruction. The address of this
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
* copy is &p->ainsn.insn[0].
*
* This function prepares to return from the post-single-step
* breakpoint trap.
*/
static void __kprobes resume_execution(struct kprobe *p,
struct pt_regs *regs, struct kprobe_ctlblk *kcb)
{
u32 insn = p->ainsn.insn[0];
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
regs->tnpc = relbranch_fixup(insn, p, regs);
/* This assignment must occur after relbranch_fixup() */
regs->tpc = kcb->kprobe_orig_tnpc;
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
retpc_fixup(regs, insn, (unsigned long) p->addr);
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
kcb->kprobe_orig_tstate_pil);
}
static int __kprobes post_kprobe_handler(struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
if (!cur)
return 0;
if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
cur->post_handler(cur, regs, 0);
}
resume_execution(cur, regs, kcb);
/*Restore back the original saved kprobes variables and continue. */
if (kcb->kprobe_status == KPROBE_REENTER) {
restore_previous_kprobe(kcb);
goto out;
}
reset_current_kprobe();
out:
preempt_enable_no_resched();
return 1;
}
int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
const struct exception_table_entry *entry;
switch(kcb->kprobe_status) {
case KPROBE_HIT_SS:
case KPROBE_REENTER:
/*
* We are here because the instruction being single
* stepped caused a page fault. We reset the current
* kprobe and the tpc points back to the probe address
* and allow the page fault handler to continue as a
* normal page fault.
*/
regs->tpc = (unsigned long)cur->addr;
regs->tnpc = kcb->kprobe_orig_tnpc;
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
kcb->kprobe_orig_tstate_pil);
if (kcb->kprobe_status == KPROBE_REENTER)
restore_previous_kprobe(kcb);
else
reset_current_kprobe();
preempt_enable_no_resched();
break;
case KPROBE_HIT_ACTIVE:
case KPROBE_HIT_SSDONE:
/*
* We increment the nmissed count for accounting,
* we can also use npre/npostfault count for accounting
* these specific fault cases.
*/
kprobes_inc_nmissed_count(cur);
/*
* We come here because instructions in the pre/post
* handler caused the page_fault, this could happen
* if handler tries to access user space by
* copy_from_user(), get_user() etc. Let the
* user-specified handler try to fix it first.
*/
if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
return 1;
/*
* In case the user-specified fault handler returned
* zero, try to fix up.
*/
entry = search_exception_tables(regs->tpc);
if (entry) {
regs->tpc = entry->fixup;
regs->tnpc = regs->tpc + 4;
return 1;
}
/*
* fixup_exception() could not handle it,
* Let do_page_fault() fix it.
*/
break;
default:
break;
}
return 0;
}
/*
* Wrapper routine to for handling exceptions.
*/
int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct die_args *args = (struct die_args *)data;
2005-11-07 17:00:07 +08:00
int ret = NOTIFY_DONE;
if (args->regs && user_mode(args->regs))
return ret;
switch (val) {
case DIE_DEBUG:
if (kprobe_handler(args->regs))
2005-11-07 17:00:07 +08:00
ret = NOTIFY_STOP;
break;
case DIE_DEBUG_2:
if (post_kprobe_handler(args->regs))
2005-11-07 17:00:07 +08:00
ret = NOTIFY_STOP;
break;
default:
break;
}
2005-11-07 17:00:07 +08:00
return ret;
}
asmlinkage void __kprobes kprobe_trap(unsigned long trap_level,
struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
BUG_ON(trap_level != 0x170 && trap_level != 0x171);
if (user_mode(regs)) {
local_irq_enable();
bad_trap(regs, trap_level);
goto out;
}
/* trap_level == 0x170 --> ta 0x70
* trap_level == 0x171 --> ta 0x71
*/
if (notify_die((trap_level == 0x170) ? DIE_DEBUG : DIE_DEBUG_2,
(trap_level == 0x170) ? "debug" : "debug_2",
regs, 0, trap_level, SIGTRAP) != NOTIFY_STOP)
bad_trap(regs, trap_level);
out:
exception_exit(prev_state);
}
/* Jprobes support. */
int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct jprobe *jp = container_of(p, struct jprobe, kp);
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
memcpy(&(kcb->jprobe_saved_regs), regs, sizeof(*regs));
regs->tpc = (unsigned long) jp->entry;
regs->tnpc = ((unsigned long) jp->entry) + 0x4UL;
regs->tstate |= TSTATE_PIL;
return 1;
}
void __kprobes jprobe_return(void)
{
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
register unsigned long orig_fp asm("g1");
orig_fp = kcb->jprobe_saved_regs.u_regs[UREG_FP];
__asm__ __volatile__("\n"
"1: cmp %%sp, %0\n\t"
"blu,a,pt %%xcc, 1b\n\t"
" restore\n\t"
".globl jprobe_return_trap_instruction\n"
"jprobe_return_trap_instruction:\n\t"
[SPARC64]: Fix several kprobes bugs. - relbranch_fixup(), for non-branches, would end up setting regs->tnpc incorrectly, in fact it would set it equal to regs->tpc which would cause that instruction to execute twice Also, if this is not a PC-relative branch, we should just leave regs->tnpc as-is. This covers cases like 'jmpl' which branch to absolute values. - To be absolutely %100 safe, we need to flush the instruction cache for all assignments to kprobe->ainsn.insn[], including cases like add_aggr_kprobe() - prev_kprobe's status field needs to be 'unsigned long' to match the type of the value it is saving - jprobes were totally broken: = jprobe_return() can run in the stack frame of the jprobe handler, or in an even deeper stack frame, thus we'll be in the wrong register window than the one from the original probe state. So unwind using 'restore' instructions, if necessary, right before we do the jprobe_return() breakpoint trap. = There is no reason to save/restore the register window saved at %sp at jprobe trigger time. Those registers cannot be modified by the jprobe handler. Also, this code was saving and restoring "sizeof (struct sparc_stackf)" bytes. Depending upon the caller, this could clobber unrelated stack frame pieces if there is only a basic 128-byte register window stored on the stack, without the argument save area. So just saving and restoring struct pt_regs is sufficient. = Kill the "jprobe_saved_esp", totally unused. Also, delete "jprobe_saved_regs_location", with the stack frame unwind now done explicitly by jprobe_return(), this check is superfluous. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 18:42:03 +08:00
"ta 0x70"
: /* no outputs */
: "r" (orig_fp));
}
extern void jprobe_return_trap_instruction(void);
int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
u32 *addr = (u32 *) regs->tpc;
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
if (addr == (u32 *) jprobe_return_trap_instruction) {
memcpy(regs, &(kcb->jprobe_saved_regs), sizeof(*regs));
preempt_enable_no_resched();
return 1;
}
return 0;
}
kprobes: improve kretprobe scalability with hashed locking Currently list of kretprobe instances are stored in kretprobe object (as used_instances,free_instances) and in kretprobe hash table. We have one global kretprobe lock to serialise the access to these lists. This causes only one kretprobe handler to execute at a time. Hence affects system performance, particularly on SMP systems and when return probe is set on lot of functions (like on all systemcalls). Solution proposed here gives fine-grain locks that performs better on SMP system compared to present kretprobe implementation. Solution: 1) Instead of having one global lock to protect kretprobe instances present in kretprobe object and kretprobe hash table. We will have two locks, one lock for protecting kretprobe hash table and another lock for kretporbe object. 2) We hold lock present in kretprobe object while we modify kretprobe instance in kretprobe object and we hold per-hash-list lock while modifying kretprobe instances present in that hash list. To prevent deadlock, we never grab a per-hash-list lock while holding a kretprobe lock. 3) We can remove used_instances from struct kretprobe, as we can track used instances of kretprobe instances using kretprobe hash table. Time duration for kernel compilation ("make -j 8") on a 8-way ppc64 system with return probes set on all systemcalls looks like this. cacheline non-cacheline Un-patched kernel aligned patch aligned patch =============================================================================== real 9m46.784s 9m54.412s 10m2.450s user 40m5.715s 40m7.142s 40m4.273s sys 2m57.754s 2m58.583s 3m17.430s =========================================================== Time duration for kernel compilation ("make -j 8) on the same system, when kernel is not probed. ========================= real 9m26.389s user 40m8.775s sys 2m7.283s ========================= Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com> Signed-off-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 16:46:04 +08:00
/* The value stored in the return address register is actually 2
* instructions before where the callee will return to.
* Sequences usually look something like this
*
* call some_function <--- return register points here
* nop <--- call delay slot
* whatever <--- where callee returns to
*
* To keep trampoline_probe_handler logic simpler, we normalize the
* value kept in ri->ret_addr so we don't need to keep adjusting it
* back and forth.
*/
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *)(regs->u_regs[UREG_RETPC] + 8);
/* Replace the return addr with trampoline addr */
regs->u_regs[UREG_RETPC] =
((unsigned long)kretprobe_trampoline) - 8;
}
/*
* Called when the probe at kretprobe trampoline is hit
*/
static int __kprobes trampoline_probe_handler(struct kprobe *p,
struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head, empty_rp;
hlist: drop the node parameter from iterators I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-28 09:06:00 +08:00
struct hlist_node *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
kprobes: improve kretprobe scalability with hashed locking Currently list of kretprobe instances are stored in kretprobe object (as used_instances,free_instances) and in kretprobe hash table. We have one global kretprobe lock to serialise the access to these lists. This causes only one kretprobe handler to execute at a time. Hence affects system performance, particularly on SMP systems and when return probe is set on lot of functions (like on all systemcalls). Solution proposed here gives fine-grain locks that performs better on SMP system compared to present kretprobe implementation. Solution: 1) Instead of having one global lock to protect kretprobe instances present in kretprobe object and kretprobe hash table. We will have two locks, one lock for protecting kretprobe hash table and another lock for kretporbe object. 2) We hold lock present in kretprobe object while we modify kretprobe instance in kretprobe object and we hold per-hash-list lock while modifying kretprobe instances present in that hash list. To prevent deadlock, we never grab a per-hash-list lock while holding a kretprobe lock. 3) We can remove used_instances from struct kretprobe, as we can track used instances of kretprobe instances using kretprobe hash table. Time duration for kernel compilation ("make -j 8") on a 8-way ppc64 system with return probes set on all systemcalls looks like this. cacheline non-cacheline Un-patched kernel aligned patch aligned patch =============================================================================== real 9m46.784s 9m54.412s 10m2.450s user 40m5.715s 40m7.142s 40m4.273s sys 2m57.754s 2m58.583s 3m17.430s =========================================================== Time duration for kernel compilation ("make -j 8) on the same system, when kernel is not probed. ========================= real 9m26.389s user 40m8.775s sys 2m7.283s ========================= Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com> Signed-off-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 16:46:04 +08:00
kretprobe_hash_lock(current, &head, &flags);
/*
* It is possible to have multiple instances associated with a given
* task either because an multiple functions in the call path
* have a return probe installed on them, and/or more than one return
* return probe was registered for a target function.
*
* We can handle this because:
* - instances are always inserted at the head of the list
* - when multiple return probes are registered for the same
* function, the first instance's ret_addr will point to the
* real return address, and all the rest will point to
* kretprobe_trampoline
*/
hlist: drop the node parameter from iterators I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-28 09:06:00 +08:00
hlist_for_each_entry_safe(ri, tmp, head, hlist) {
if (ri->task != current)
/* another task is sharing our hash bucket */
continue;
if (ri->rp && ri->rp->handler)
ri->rp->handler(ri, regs);
orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
/*
* This is the real return address. Any other
* instances associated with this task are for
* other calls deeper on the call stack
*/
break;
}
kretprobe_assert(ri, orig_ret_address, trampoline_address);
regs->tpc = orig_ret_address;
regs->tnpc = orig_ret_address + 4;
reset_current_kprobe();
kprobes: improve kretprobe scalability with hashed locking Currently list of kretprobe instances are stored in kretprobe object (as used_instances,free_instances) and in kretprobe hash table. We have one global kretprobe lock to serialise the access to these lists. This causes only one kretprobe handler to execute at a time. Hence affects system performance, particularly on SMP systems and when return probe is set on lot of functions (like on all systemcalls). Solution proposed here gives fine-grain locks that performs better on SMP system compared to present kretprobe implementation. Solution: 1) Instead of having one global lock to protect kretprobe instances present in kretprobe object and kretprobe hash table. We will have two locks, one lock for protecting kretprobe hash table and another lock for kretporbe object. 2) We hold lock present in kretprobe object while we modify kretprobe instance in kretprobe object and we hold per-hash-list lock while modifying kretprobe instances present in that hash list. To prevent deadlock, we never grab a per-hash-list lock while holding a kretprobe lock. 3) We can remove used_instances from struct kretprobe, as we can track used instances of kretprobe instances using kretprobe hash table. Time duration for kernel compilation ("make -j 8") on a 8-way ppc64 system with return probes set on all systemcalls looks like this. cacheline non-cacheline Un-patched kernel aligned patch aligned patch =============================================================================== real 9m46.784s 9m54.412s 10m2.450s user 40m5.715s 40m7.142s 40m4.273s sys 2m57.754s 2m58.583s 3m17.430s =========================================================== Time duration for kernel compilation ("make -j 8) on the same system, when kernel is not probed. ========================= real 9m26.389s user 40m8.775s sys 2m7.283s ========================= Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com> Signed-off-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 16:46:04 +08:00
kretprobe_hash_unlock(current, &flags);
preempt_enable_no_resched();
hlist: drop the node parameter from iterators I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-28 09:06:00 +08:00
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
* to run (and have re-enabled preemption)
*/
return 1;
}
static void __used kretprobe_trampoline_holder(void)
{
asm volatile(".global kretprobe_trampoline\n"
"kretprobe_trampoline:\n"
"\tnop\n"
"\tnop\n");
}
static struct kprobe trampoline_p = {
.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
.pre_handler = trampoline_probe_handler
};
int __init arch_init_kprobes(void)
{
return register_kprobe(&trampoline_p);
}
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
{
if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
return 1;
return 0;
}