The DYNAMIC_FTRACE_WITH_REGS configuration makes it possible for a
ftrace operation to specify if registers need to saved/restored by
the ftrace handler. This is needed by kgraft and possibly other
ftrace-based tools, and the ARM architecture is currently lacking
this feature. It would also be the first step to support the
"Kprobes-on-ftrace" optimization on ARM.
This patch introduces a new ftrace handler that stores the registers
on the stack before calling the next stage. The registers are restored
from the stack before going back to the instrumented function.
A side-effect of this patch is to activate the support for
ftrace_modify_call() as it defines ARCH_SUPPORTS_FTRACE_OPS for the
ARM architecture.
Signed-off-by: Abel Vesa <abelvesa@linux.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Merge more updates from Andrew Morton:
- the rest of MM
- various misc things
- procfs updates
- lib/ updates
- checkpatch updates
- kdump/kexec updates
- add kvmalloc helpers, use them
- time helper updates for Y2038 issues. We're almost ready to remove
current_fs_time() but that awaits a btrfs merge.
- add tracepoints to DAX
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (114 commits)
drivers/staging/ccree/ssi_hash.c: fix build with gcc-4.4.4
selftests/vm: add a test for virtual address range mapping
dax: add tracepoint to dax_insert_mapping()
dax: add tracepoint to dax_writeback_one()
dax: add tracepoints to dax_writeback_mapping_range()
dax: add tracepoints to dax_load_hole()
dax: add tracepoints to dax_pfn_mkwrite()
dax: add tracepoints to dax_iomap_pte_fault()
mtd: nand: nandsim: convert to memalloc_noreclaim_*()
treewide: convert PF_MEMALLOC manipulations to new helpers
mm: introduce memalloc_noreclaim_{save,restore}
mm: prevent potential recursive reclaim due to clearing PF_MEMALLOC
mm/huge_memory.c: deposit a pgtable for DAX PMD faults when required
mm/huge_memory.c: use zap_deposited_table() more
time: delete CURRENT_TIME_SEC and CURRENT_TIME
gfs2: replace CURRENT_TIME with current_time
apparmorfs: replace CURRENT_TIME with current_time()
lustre: replace CURRENT_TIME macro
fs: ubifs: replace CURRENT_TIME_SEC with current_time
fs: ufs: use ktime_get_real_ts64() for birthtime
...
set_memory_* functions have moved to set_memory.h. Switch to this
explicitly
Link: http://lkml.kernel.org/r/1488920133-27229-3-git-send-email-labbott@redhat.com
Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The support for dynamic ftrace with CONFIG_DEBUG_RODATA involves
overriding the weak arch_ftrace_update_code() with a variant which makes
the kernel text writable around the patching.
This override was however added under the CONFIG_OLD_MCOUNT ifdef, and
CONFIG_OLD_MCOUNT is only enabled if frame pointers are enabled.
This leads to non-functional dynamic ftrace (ftrace triggers a
WARN_ON()) when CONFIG_DEBUG_RODATA is enabled and CONFIG_FRAME_POINTER
is not.
Move the override out of that ifdef and into the CONFIG_DYNAMIC_FTRACE
ifdef where it belongs.
Fixes: 80d6b0c2ee ("ARM: mm: allow text and rodata sections to be read-only")
Suggested-by: Nicolai Stange <nicstange@gmail.com>
Suggested-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Abel Vesa <abelvesa@gmail.com>
Acked-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Storing this value will help prevent unwinders from getting out of sync
with the function graph tracer ret_stack. Now instead of needing a
stateful iterator, they can compare the return address pointer to find
the right ret_stack entry.
Note that an array of 50 ftrace_ret_stack structs is allocated for every
task. So when an arch implements this, it will add either 200 or 400
bytes of memory usage per task (depending on whether it's a 32-bit or
64-bit platform).
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a95cfcc39e8f26b89a430c56926af0bb217bc0a1.1471607358.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch introduce kprobeopt for ARM 32.
Limitations:
- Currently only kernel compiled with ARM ISA is supported.
- Offset between probe point and optinsn slot must not larger than
32MiB. Masami Hiramatsu suggests replacing 2 words, it will make
things complex. Futher patch can make such optimization.
Kprobe opt on ARM is relatively simpler than kprobe opt on x86 because
ARM instruction is always 4 bytes aligned and 4 bytes long. This patch
replace probed instruction by a 'b', branch to trampoline code and then
calls optimized_callback(). optimized_callback() calls opt_pre_handler()
to execute kprobe handler. It also emulate/simulate replaced instruction.
When unregistering kprobe, the deferred manner of unoptimizer may leave
branch instruction before optimizer is called. Different from x86_64,
which only copy the probed insn after optprobe_template_end and
reexecute them, this patch call singlestep to emulate/simulate the insn
directly. Futher patch can optimize this behavior.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: Jon Medhurst (Tixy) <tixy@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This introduces CONFIG_DEBUG_RODATA, making kernel text and rodata
read-only. Additionally, this splits rodata from text so that rodata can
also be NX, which may lead to wasted memory when aligning to SECTION_SIZE.
The read-only areas are made writable during ftrace updates and kexec.
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Make ftrace work with CONFIG_DEBUG_SET_MODULE_RONX by making module text
writable around the place where ftrace does its work, like it is done on
x86 in the patch which introduced CONFIG_DEBUG_SET_MODULE_RONX,
84e1c6bb38 ("x86: Add RO/NX protection for loadable kernel modules").
Tested-by: Mitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
As the data parameter is not really used by any ftrace_dyn_arch_init,
remove that from ftrace_dyn_arch_init. This also removes the addr
local variable from ftrace_init which is now unused.
Note the documentation was imprecise as it did not suggest to set
(*data) to 0.
Link: http://lkml.kernel.org/r/1393268401-24379-4-git-send-email-jslaby@suse.cz
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
No architecture uses the "data" parameter in ftrace_dyn_arch_init() in any
way, it just sets the value to 0. And this is used as a return value
in the caller -- ftrace_init, which just checks the retval against
zero.
Note there is also "return 0" in every ftrace_dyn_arch_init. So it is
enough to check the retval and remove all the indirect sets of data on
all archs.
Link: http://lkml.kernel.org/r/1393268401-24379-3-git-send-email-jslaby@suse.cz
Cc: linux-arch@vger.kernel.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Commit 722b3c7469 modified x86 ftrace to
avoid tracing all functions called from irqs when function graph was
used with a filter. Port the same fix to ARM.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Extract out the instruction generation code so that it can be used
for jump labels too.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
As commit 592201a9f1 (ARM: Thumb-2: Support Thumb-2 in undefined
instruction handler) says:
32-bit Thumb instructions are specified in the form:
((first_half << 16 ) | second_half)
which matches the layout used by the ARM ARM.
Convert the ftrace code to use the same format to avoid the usage of
different formats in kernel code.
Acked-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Before replacing an instruction, the ftrace code determines what the old
instruction should be and verifies that that's what's really there in
memory before replacing it. This is useful if for example a bug in
mcountrecord causes it to record wrong locations.
However, in cases where we replace call sites in entry-common.S, these
checks are not needed. For these, we currently just memcpy() the memory
content and then "verify" it -- this is quite useless and can be
removed.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Tim Bird <tim.bird@am.sony.com>
[rabin@rab.in: rebase on top of latest code,
keep code in ftrace.c instead of separate file,
check for ftrace_graph_entry also]
Signed-off-by: Rabin Vincent <rabin@rab.in>
Handle the different nop and call instructions for Thumb-2. Also, we
need to adjust the recorded mcount_loc addresses because they have the
lsb set.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org> [recordmcount.pl change]
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This adds mcount recording and updates dynamic ftrace for ARM to work
with the new ftrace dyamic tracing implementation. It also adds support
for the mcount format used by newer ARM compilers.
With dynamic tracing, mcount() is implemented as a nop. Callsites are
patched on startup with nops, and dynamically patched to call to the
ftrace_caller() routine as needed.
Acked-by: Steven Rostedt <rostedt@goodmis.org> [recordmcount.pl change]
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
/tmp/ccJ3ssZW.s: Assembler messages:
/tmp/ccJ3ssZW.s:1952: Error: can't resolve `.text' {.text section} - `.LFB1077'
This is caused because:
.section .data
.section .text
.section .text
.previous
does not return us to the .text section, but the .data section; this
makes use of .previous dangerous if the ordering of previous sections
is not known.
Fix up the other users of .previous; .pushsection and .popsection are
a safer pairing to use than .section and .previous.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The arch dependent function ftrace_mcount_set was only used by the daemon
start up code. This patch removes it.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Record the address of the mcount call-site. Currently all archs except sparc64
record the address of the instruction following the mcount call-site. Some
general cleanups are entailed. Storing mcount addresses in rec->ip enables
looking them up in the kprobe hash table later on to check if they're kprobe'd.
Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com>
Cc: davem@davemloft.net
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Core ftrace support for the ARM architecture, which includes support
for dynamic function tracing.
Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Abel Vesa