On cheetahplus chips we take the ctx_alloc_lock in order to
modify the TLB lookup parameters for the indexed TLBs, which
are stored in the context register.
This is called with interrupts disabled, however ctx_alloc_lock
is an IRQ safe lock, therefore we must take acquire/release it
properly with spin_{lock,unlock}_irq().
Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>
During hugepage map/unmap, TSB and TLB flushes are currently
issued at every PAGE_SIZE'd boundary which is unnecessary.
We now issue the flush at REAL_HPAGE_SIZE boundaries only.
Without this patch workloads which unmap a large hugepage
backed VMA region get CPU lockups due to excessive TLB
flush calls.
Orabug: 22365539, 22643230, 22995196
Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Based on recent thread on linux-arch (some weeks ago) I
decided to check how much work was required to build sparc32
with STRICT_MM_TYPECHECKS enabled.
The resulting binary (checked srmmu.o) was to my suprise smaller with
STRICT_MM_TYPECHECKS defined, than without.
As I have no working gear to test sparc32 bits at for the moment,
I did not enable STRICT_MM_TYPECHECKS - but was tempeted to do so.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add code to recognize SPARC-Sonoma cpu correctly and update cpu hardware
caps and cpu distribution map. SPARC-Sonoma is based upon SPARC-M7 core
along with additional PCI functions added on and is reported by firmware
as "SPARC-SN".
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Acked-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull sparc fixes from David Miller:
"Minor typing cleanup from Joe Perches, and some comment typo fixes
from Adam Buchbinder"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
sparc: Convert naked unsigned uses to unsigned int
sparc: Fix misspellings in comments.
Use the more normal kernel definition/declaration style.
Done via:
$ git ls-files arch/sparc | \
xargs ./scripts/checkpatch.pl -f --fix-inplace --types=unspecified_int
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull x86 protection key support from Ingo Molnar:
"This tree adds support for a new memory protection hardware feature
that is available in upcoming Intel CPUs: 'protection keys' (pkeys).
There's a background article at LWN.net:
https://lwn.net/Articles/643797/
The gist is that protection keys allow the encoding of
user-controllable permission masks in the pte. So instead of having a
fixed protection mask in the pte (which needs a system call to change
and works on a per page basis), the user can map a (handful of)
protection mask variants and can change the masks runtime relatively
cheaply, without having to change every single page in the affected
virtual memory range.
This allows the dynamic switching of the protection bits of large
amounts of virtual memory, via user-space instructions. It also
allows more precise control of MMU permission bits: for example the
executable bit is separate from the read bit (see more about that
below).
This tree adds the MM infrastructure and low level x86 glue needed for
that, plus it adds a high level API to make use of protection keys -
if a user-space application calls:
mmap(..., PROT_EXEC);
or
mprotect(ptr, sz, PROT_EXEC);
(note PROT_EXEC-only, without PROT_READ/WRITE), the kernel will notice
this special case, and will set a special protection key on this
memory range. It also sets the appropriate bits in the Protection
Keys User Rights (PKRU) register so that the memory becomes unreadable
and unwritable.
So using protection keys the kernel is able to implement 'true'
PROT_EXEC on x86 CPUs: without protection keys PROT_EXEC implies
PROT_READ as well. Unreadable executable mappings have security
advantages: they cannot be read via information leaks to figure out
ASLR details, nor can they be scanned for ROP gadgets - and they
cannot be used by exploits for data purposes either.
We know about no user-space code that relies on pure PROT_EXEC
mappings today, but binary loaders could start making use of this new
feature to map binaries and libraries in a more secure fashion.
There is other pending pkeys work that offers more high level system
call APIs to manage protection keys - but those are not part of this
pull request.
Right now there's a Kconfig that controls this feature
(CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) that is default enabled
(like most x86 CPU feature enablement code that has no runtime
overhead), but it's not user-configurable at the moment. If there's
any serious problem with this then we can make it configurable and/or
flip the default"
* 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits)
x86/mm/pkeys: Fix mismerge of protection keys CPUID bits
mm/pkeys: Fix siginfo ABI breakage caused by new u64 field
x86/mm/pkeys: Fix access_error() denial of writes to write-only VMA
mm/core, x86/mm/pkeys: Add execute-only protection keys support
x86/mm/pkeys: Create an x86 arch_calc_vm_prot_bits() for VMA flags
x86/mm/pkeys: Allow kernel to modify user pkey rights register
x86/fpu: Allow setting of XSAVE state
x86/mm: Factor out LDT init from context init
mm/core, x86/mm/pkeys: Add arch_validate_pkey()
mm/core, arch, powerpc: Pass a protection key in to calc_vm_flag_bits()
x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU
x86/mm/pkeys: Add Kconfig prompt to existing config option
x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps
x86/mm/pkeys: Dump PKRU with other kernel registers
mm/core, x86/mm/pkeys: Differentiate instruction fetches
x86/mm/pkeys: Optimize fault handling in access_error()
mm/core: Do not enforce PKEY permissions on remote mm access
um, pkeys: Add UML arch_*_access_permitted() methods
mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys
x86/mm/gup: Simplify get_user_pages() PTE bit handling
...
There are few things about *pte_alloc*() helpers worth cleaning up:
- 'vma' argument is unused, let's drop it;
- most __pte_alloc() callers do speculative check for pmd_none(),
before taking ptl: let's introduce pte_alloc() macro which does
the check.
The only direct user of __pte_alloc left is userfaultfd, which has
different expectation about atomicity wrt pmd.
- pte_alloc_map() and pte_alloc_map_lock() are redefined using
pte_alloc().
[sudeep.holla@arm.com: fix build for arm64 hugetlbpage]
[sfr@canb.auug.org.au: fix arch/arm/mm/mmu.c some more]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We will soon modify the vanilla get_user_pages() so it can no
longer be used on mm/tasks other than 'current/current->mm',
which is by far the most common way it is called. For now,
we allow the old-style calls, but warn when they are used.
(implemented in previous patch)
This patch switches all callers of:
get_user_pages()
get_user_pages_unlocked()
get_user_pages_locked()
to stop passing tsk/mm so they will no longer see the warnings.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: jack@suse.cz
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210156.113E9407@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Set IORESOURCE_SYSTEM_RAM in flags of resource ranges with
"System RAM", "Kernel code", "Kernel data", and "Kernel bss".
Note that:
- IORESOURCE_SYSRAM (i.e. modifier bit) is set in flags when
IORESOURCE_MEM is already set. IORESOURCE_SYSTEM_RAM is defined
as (IORESOURCE_MEM|IORESOURCE_SYSRAM).
- Some archs do not set 'flags' for children nodes, such as
"Kernel code". This patch does not change 'flags' in this
case.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@linux-mips.org
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-parisc@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1453841853-11383-7-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tail page refcounting is utterly complicated and painful to support.
It uses ->_mapcount on tail pages to store how many times this page is
pinned. get_page() bumps ->_mapcount on tail page in addition to
->_count on head. This information is required by split_huge_page() to
be able to distribute pins from head of compound page to tails during
the split.
We will need ->_mapcount to account PTE mappings of subpages of the
compound page. We eliminate need in current meaning of ->_mapcount in
tail pages by forbidding split entirely if the page is pinned.
The only user of tail page refcounting is THP which is marked BROKEN for
now.
Let's drop all this mess. It makes get_page() and put_page() much
simpler.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Orabug: 22495713
Currently, NUMA node distance matrix is initialized only
when a machine descriptor (MD) exists. However, sun4u
machines (e.g. Sun Blade 2500) do not have an MD and thus
distance values were left uninitialized. The initialization
is now moved such that it happens on both sun4u and sun4v.
Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Tested-by: Mikael Pettersson <mikpelinux@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pagefault handling has a BUG_ON path that panics the system. Convert it to
a warning instead. There is no need to bring down the system for this kind
of failure.
The following was hit while running:
perf sched record -g -- make -j 16
[3609412.782801] kernel BUG at /opt/dahern/linux.git/arch/sparc/mm/fault_64.c:416!
[3609412.782833] \|/ ____ \|/
[3609412.782833] "@'/ .. \`@"
[3609412.782833] /_| \__/ |_\
[3609412.782833] \__U_/
[3609412.782870] cat(4516): Kernel bad sw trap 5 [#1]
[3609412.782889] CPU: 0 PID: 4516 Comm: cat Tainted: G E 4.1.0-rc8+ #6
[3609412.782909] task: fff8000126e31f80 ti: fff8000110d90000 task.ti: fff8000110d90000
[3609412.782931] TSTATE: 0000004411001603 TPC: 000000000096b164 TNPC: 000000000096b168 Y: 0000004e Tainted: G E
[3609412.782964] TPC: <do_sparc64_fault+0x5e4/0x6a0>
[3609412.782979] g0: 000000000096abe0 g1: 0000000000d314c4 g2: 0000000000000000 g3: 0000000000000001
[3609412.783009] g4: fff8000126e31f80 g5: fff80001302d2000 g6: fff8000110d90000 g7: 00000000000000ff
[3609412.783045] o0: 0000000000aff6a8 o1: 00000000000001a0 o2: 0000000000000001 o3: 0000000000000054
[3609412.783080] o4: fff8000100026820 o5: 0000000000000001 sp: fff8000110d935f1 ret_pc: 000000000096b15c
[3609412.783117] RPC: <do_sparc64_fault+0x5dc/0x6a0>
[3609412.783137] l0: 000007feff996000 l1: 0000000000030001 l2: 0000000000000004 l3: fff8000127bd0120
[3609412.783174] l4: 0000000000000054 l5: fff8000127bd0188 l6: 0000000000000000 l7: fff8000110d9dba8
[3609412.783210] i0: fff8000110d93f60 i1: fff8000110ca5530 i2: 000000000000003f i3: 0000000000000054
[3609412.783244] i4: fff800010000081a i5: fff8000100000398 i6: fff8000110d936a1 i7: 0000000000407c6c
[3609412.783286] I7: <sparc64_realfault_common+0x10/0x20>
[3609412.783308] Call Trace:
[3609412.783329] [0000000000407c6c] sparc64_realfault_common+0x10/0x20
[3609412.783353] Disabling lock debugging due to kernel taint
[3609412.783379] Caller[0000000000407c6c]: sparc64_realfault_common+0x10/0x20
[3609412.783449] Caller[fff80001002283e4]: 0xfff80001002283e4
[3609412.783471] Instruction DUMP: 921021a0 7feaff91 901222a8 <91d02005> 82086100 02f87f7b 808a2873 81cfe008 01000000
[3609412.783542] Kernel panic - not syncing: Fatal exception
[3609412.784605] Press Stop-A (L1-A) to return to the boot prom
[3609412.784615] ---[ end Kernel panic - not syncing: Fatal exception
With this patch rather than a panic I occasionally get something like this:
perf sched record -g -m 1024 -- make -j N
where N is based on number of cpus (128 to 1024 for a T7-4 and 8 for an 8 cpu
VM on a T5-2).
WARNING: CPU: 211 PID: 52565 at /opt/dahern/linux.git/arch/sparc/mm/fault_64.c:417 do_sparc64_fault+0x340/0x70c()
address (7feffcd6000) != regs->tpc (fff80001004873c0)
Modules linked in: ipt_REJECT nf_reject_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_reject_ipv6 xt_tcpudp nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables x_tables ipv6 cdc_ether usbnet mii ixgbe mdio igb i2c_algo_bit i2c_core ptp crc32c_sparc64 camellia_sparc64 des_sparc64 des_generic md5_sparc64 sha512_sparc64 sha1_sparc64 uio_pdrv_genirq uio usb_storage mpt3sas scsi_transport_sas raid_class aes_sparc64 sunvnet sunvdc sha256_sparc64(E) sha256_generic(E)
CPU: 211 PID: 52565 Comm: ld Tainted: G W E 4.1.0-rc8+ #19
Call Trace:
[000000000045ce30] warn_slowpath_common+0x7c/0xa0
[000000000045ceec] warn_slowpath_fmt+0x30/0x40
[000000000098ad64] do_sparc64_fault+0x340/0x70c
[0000000000407c2c] sparc64_realfault_common+0x10/0x20
---[ end trace 62ee02065a01a049 ]---
ld[52565]: segfault at fff80001004873c0 ip fff80001004873c0 (rpc fff8000100158868) sp 000007feffcd70e1 error 30002 in libc-2.12.so[fff8000100410000+184000]
The segfault is horrible, but better than a system panic.
An 8-cpu VM on a T5-2 also showed the above traces from time to time,
so it is a general problem and not specific to the T7 or baremetal.
Signed-off-by: David Ahern <david.ahern@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some high end Intel Xeon systems report uncorrectable memory errors as a
recoverable machine check. Linux has included code for some time to
process these and just signal the affected processes (or even recover
completely if the error was in a read only page that can be replaced by
reading from disk).
But we have no recovery path for errors encountered during kernel code
execution. Except for some very specific cases were are unlikely to ever
be able to recover.
Enter memory mirroring. Actually 3rd generation of memory mirroing.
Gen1: All memory is mirrored
Pro: No s/w enabling - h/w just gets good data from other side of the
mirror
Con: Halves effective memory capacity available to OS/applications
Gen2: Partial memory mirror - just mirror memory begind some memory controllers
Pro: Keep more of the capacity
Con: Nightmare to enable. Have to choose between allocating from
mirrored memory for safety vs. NUMA local memory for performance
Gen3: Address range partial memory mirror - some mirror on each memory
controller
Pro: Can tune the amount of mirror and keep NUMA performance
Con: I have to write memory management code to implement
The current plan is just to use mirrored memory for kernel allocations.
This has been broken into two phases:
1) This patch series - find the mirrored memory, use it for boot time
allocations
2) Wade into mm/page_alloc.c and define a ZONE_MIRROR to pick up the
unused mirrored memory from mm/memblock.c and only give it out to
select kernel allocations (this is still being scoped because
page_alloc.c is scary).
This patch (of 3):
Add extra "flags" to memblock to allow selection of memory based on
attribute. No functional changes
Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Xiexiuqi <xiexiuqi@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we have many duplicates in definitions of huge_pmd_unshare. In
all architectures this function just returns 0 when
CONFIG_ARCH_WANT_HUGE_PMD_SHARE is N.
This patch puts the default implementation in mm/hugetlb.c and lets these
architectures use the common code.
Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: David Rientjes <rientjes@google.com>
Cc: James Yang <James.Yang@freescale.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sparc: Resolve conflict between sparc v9 and M7 on usage of bit 9 of TTE
Bit 9 of TTE is CV (Cacheable in V-cache) on sparc v9 processor while
the same bit 9 is MCDE (Memory Corruption Detection Enable) on M7
processor. This creates a conflicting usage of the same bit. Kernel
sets TTE.cv bit on all pages for sun4v architecture which works well
for sparc v9 but enables memory corruption detection on M7 processor
which is not the intent. This patch adds code to determine if kernel
is running on M7 processor and takes steps to not enable memory
corruption detection in TTE erroneously.
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce faulthandler_disabled() and use it to check for irq context and
disabled pagefaults (via pagefault_disable()) in the pagefault handlers.
Please note that we keep the in_atomic() checks in place - to detect
whether in irq context (in which case preemption is always properly
disabled).
In contrast, preempt_disable() should never be used to disable pagefaults.
With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt
counter, and therefore the result of in_atomic() differs.
We validate that condition by using might_fault() checks when calling
might_sleep().
Therefore, add a comment to faulthandler_disabled(), describing why this
is needed.
faulthandler_disabled() and pagefault_disable() are defined in
linux/uaccess.h, so let's properly add that include to all relevant files.
This patch is based on a patch from Thomas Gleixner.
Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-7-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
/proc/kcore investigates the "System RAM" elements in /proc/iomem to
initialize it's memory tables. Therefore we have to register them
before it tries to do so. kcore uses device_initcall() so let's
use arch_initcall() for the registry.
Also we need ARCH_PROC_KCORE_TEXT to get the virtual addresses of
the kernel image correct.
Reported-by: David Ahern <david.ahern@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This allows the get_user_pages_fast slow path to release the mmap_sem
before blocking.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Peter Feiner <pfeiner@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we have many duplicates in definitions around
follow_huge_addr(), follow_huge_pmd(), and follow_huge_pud(), so this
patch tries to remove the m. The basic idea is to put the default
implementation for these functions in mm/hugetlb.c as weak symbols
(regardless of CONFIG_ARCH_WANT_GENERAL_HUGETL B), and to implement
arch-specific code only when the arch needs it.
For follow_huge_addr(), only powerpc and ia64 have their own
implementation, and in all other architectures this function just returns
ERR_PTR(-EINVAL). So this patch sets returning ERR_PTR(-EINVAL) as
default.
As for follow_huge_(pmd|pud)(), if (pmd|pud)_huge() is implemented to
always return 0 in your architecture (like in ia64 or sparc,) it's never
called (the callsite is optimized away) no matter how implemented it is.
So in such architectures, we don't need arch-specific implementation.
In some architecture (like mips, s390 and tile,) their current
arch-specific follow_huge_(pmd|pud)() are effectively identical with the
common code, so this patch lets these architecture use the common code.
One exception is metag, where pmd_huge() could return non-zero but it
expects follow_huge_pmd() to always return NULL. This means that we need
arch-specific implementation which returns NULL. This behavior looks
strange to me (because non-zero pmd_huge() implies that the architecture
supports PMD-based hugepage, so follow_huge_pmd() can/should return some
relevant value,) but that's beyond this cleanup patch, so let's keep it.
Justification of non-trivial changes:
- in s390, follow_huge_pmd() checks !MACHINE_HAS_HPAGE at first, and this
patch removes the check. This is OK because we can assume MACHINE_HAS_HPAGE
is true when follow_huge_pmd() can be called (note that pmd_huge() has
the same check and always returns 0 for !MACHINE_HAS_HPAGE.)
- in s390 and mips, we use HPAGE_MASK instead of PMD_MASK as done in common
code. This patch forces these archs use PMD_MASK, but it's OK because
they are identical in both archs.
In s390, both of HPAGE_SHIFT and PMD_SHIFT are 20.
In mips, HPAGE_SHIFT is defined as (PAGE_SHIFT + PAGE_SHIFT - 3) and
PMD_SHIFT is define as (PAGE_SHIFT + PAGE_SHIFT + PTE_ORDER - 3), but
PTE_ORDER is always 0, so these are identical.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.
That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works. However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.
In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV. And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.
However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d45 ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space. And user space really
expected SIGSEGV, not SIGBUS.
To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it. They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.
This is the mindless minimal patch to do this. A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.
Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.
Reported-and-tested-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Jan Engelhardt <jengelh@inai.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Load balancing can be triggered in the critical sections protected by
srmmu_context_spinlock in destroy_context() and switch_mm() and can hang
the cpu waiting for the rq lock of another cpu that in turn has called
switch_mm hangning on srmmu_context_spinlock leading to deadlock.
So, disable interrupt while taking srmmu_context_spinlock in
destroy_context() and switch_mm() so we don't deadlock.
See also commit 77b838fa1e ("[SPARC64]: destroy_context() needs to disable
interrupts.")
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now, we have prepared to avoid using debug-pagealloc in boottime. So
introduce new kernel-parameter to disable debug-pagealloc in boottime, and
makes related functions to be disabled in this case.
Only non-intuitive part is change of guard page functions. Because guard
page is effective only if debug-pagealloc is enabled, turning off
according to debug-pagealloc is reasonable thing to do.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is not sufficient to only implement get_user_pages_fast(), you
must also implement the atomic version __get_user_pages_fast()
otherwise you end up using the weak symbol fallback implementation
which simply returns zero.
This is dangerous, because it causes the futex code to loop forever
if transparent hugepages are supported (see get_futex_key()).
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull percpu consistent-ops changes from Tejun Heo:
"Way back, before the current percpu allocator was implemented, static
and dynamic percpu memory areas were allocated and handled separately
and had their own accessors. The distinction has been gone for many
years now; however, the now duplicate two sets of accessors remained
with the pointer based ones - this_cpu_*() - evolving various other
operations over time. During the process, we also accumulated other
inconsistent operations.
This pull request contains Christoph's patches to clean up the
duplicate accessor situation. __get_cpu_var() uses are replaced with
with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().
Unfortunately, the former sometimes is tricky thanks to C being a bit
messy with the distinction between lvalues and pointers, which led to
a rather ugly solution for cpumask_var_t involving the introduction of
this_cpu_cpumask_var_ptr().
This converts most of the uses but not all. Christoph will follow up
with the remaining conversions in this merge window and hopefully
remove the obsolete accessors"
* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
irqchip: Properly fetch the per cpu offset
percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
Revert "powerpc: Replace __get_cpu_var uses"
percpu: Remove __this_cpu_ptr
clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
sparc: Replace __get_cpu_var uses
avr32: Replace __get_cpu_var with __this_cpu_write
blackfin: Replace __get_cpu_var uses
tile: Use this_cpu_ptr() for hardware counters
tile: Replace __get_cpu_var uses
powerpc: Replace __get_cpu_var uses
alpha: Replace __get_cpu_var
ia64: Replace __get_cpu_var uses
s390: cio driver &__get_cpu_var replacements
s390: Replace __get_cpu_var uses
mips: Replace __get_cpu_var uses
MIPS: Replace __get_cpu_var uses in FPU emulator.
arm: Replace __this_cpu_ptr with raw_cpu_ptr
...
swapper_low_pmd_dir and swapper_pud_dir are actually completely
useless and unnecessary.
We just need swapper_pg_dir[]. Naturally the other page table chunks
will be allocated on an as-needed basis. Since the kernel actually
accesses these tables in the PAGE_OFFSET view, there is not even a TLB
locality advantage of placing them in the kernel image.
Use the hard coded vmlinux.ld.S slot for swapper_pg_dir which is
naturally page aligned.
Increase MAX_BANKS to 1024 in order to handle heavily fragmented
virtual guests.
Even with this MAX_BANKS increase, the kernel is 20K+ smaller.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
In order to accomodate embedded per-cpu allocation with large numbers
of cpus and numa nodes, we have to use as much virtual address space
as possible for the vmalloc region. Otherwise we can get things like:
PERCPU: max_distance=0x380001c10000 too large for vmalloc space 0xff00000000
So, once we select a value for PAGE_OFFSET, derive the size of the
vmalloc region based upon that.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
Make sure, at compile time, that the kernel can properly support
whatever MAX_PHYS_ADDRESS_BITS is defined to.
On M7 chips, use a max_phys_bits value of 49.
Based upon a patch by Bob Picco.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
For sparse memory configurations, the vmemmap array behaves terribly
and it takes up an inordinate amount of space in the BSS section of
the kernel image unconditionally.
Just build huge PMDs and look them up just like we do for TLB misses
in the vmalloc area.
Kernel BSS shrinks by about 2MB.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
If max_phys_bits needs to be > 43 (f.e. for T4 chips), things like
DEBUG_PAGEALLOC stop working because the 3-level page tables only
can cover up to 43 bits.
Another problem is that when we increased MAX_PHYS_ADDRESS_BITS up to
47, several statically allocated tables became enormous.
Compounding this is that we will need to support up to 49 bits of
physical addressing for M7 chips.
The two tables in question are sparc64_valid_addr_bitmap and
kpte_linear_bitmap.
The first holds a bitmap, with 1 bit for each 4MB chunk of physical
memory, indicating whether that chunk actually exists in the machine
and is valid.
The second table is a set of 2-bit values which tell how large of a
mapping (4MB, 256MB, 2GB, 16GB, respectively) we can use at each 256MB
chunk of ram in the system.
These tables are huge and take up an enormous amount of the BSS
section of the sparc64 kernel image. Specifically, the
sparc64_valid_addr_bitmap is 4MB, and the kpte_linear_bitmap is 128K.
So let's solve the space wastage and the DEBUG_PAGEALLOC problem
at the same time, by using the kernel page tables (as designed) to
manage this information.
We have to keep using large mappings when DEBUG_PAGEALLOC is disabled,
and we do this by encoding huge PMDs and PUDs.
On a T4-2 with 256GB of ram the kernel page table takes up 16K with
DEBUG_PAGEALLOC disabled and 256MB with it enabled. Furthermore, this
memory is dynamically allocated at run time rather than coded
statically into the kernel image.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
As currently coded the KTSB accesses in the kernel only support up to
47 bits of physical addressing.
Adjust the instruction and patching sequence in order to support
arbitrary 64 bits addresses.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
Now that we use 4-level page tables, we can provide up to 53-bits of
virtual address space to the user.
Adjust the VA hole based upon the capabilities of the cpu type probed.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
This has become necessary with chips that support more than 43-bits
of physical addressing.
Based almost entirely upon a patch by Bob Picco.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
The "mem" boot option can result in many unexpected consequences. This patch
attempts to prevent boot hangs which have been experienced on T4-4 and T5-8.
Basically the boot loader allocates vmlinuz and initrd higher in available
OBP physical memory. For example, on a 2Tb T5-8 it isn't possible to boot
with mem=20G.
The patch utilizes memblock to avoid reserved regions and trim memory which
is only free. Other improvements are possible for a multi-node machine.
This is a snippet of the boot log with mem=20G on T5-8 with the patch applied:
MEMBLOCK configuration: <- before memory reduction
memory size = 0x1ffad6ce000 reserved size = 0xa1adf44
memory.cnt = 0xb
memory[0x0] [0x00000030400000-0x00003fdde47fff], 0x3fada48000 bytes
memory[0x1] [0x00003fdde4e000-0x00003fdde4ffff], 0x2000 bytes
memory[0x2] [0x00080000000000-0x00083fffffffff], 0x4000000000 bytes
memory[0x3] [0x00100000000000-0x00103fffffffff], 0x4000000000 bytes
memory[0x4] [0x00180000000000-0x00183fffffffff], 0x4000000000 bytes
memory[0x5] [0x00200000000000-0x00203fffffffff], 0x4000000000 bytes
memory[0x6] [0x00280000000000-0x00283fffffffff], 0x4000000000 bytes
memory[0x7] [0x00300000000000-0x00303fffffffff], 0x4000000000 bytes
memory[0x8] [0x00380000000000-0x00383fffc71fff], 0x3fffc72000 bytes
memory[0x9] [0x00383fffc92000-0x00383fffca1fff], 0x10000 bytes
memory[0xa] [0x00383fffcb4000-0x00383fffcb5fff], 0x2000 bytes
reserved.cnt = 0x2
reserved[0x0] [0x00380000000000-0x0038000117e7f8], 0x117e7f9 bytes
reserved[0x1] [0x00380004000000-0x0038000d02f74a], 0x902f74b bytes
...
MEMBLOCK configuration: <- after reduction of memory
memory size = 0x50a1adf44 reserved size = 0xa1adf44
memory.cnt = 0x4
memory[0x0] [0x00380000000000-0x0038000117e7f8], 0x117e7f9 bytes
memory[0x1] [0x00380004000000-0x0038050d01d74a], 0x50901d74b bytes
memory[0x2] [0x00383fffc92000-0x00383fffca1fff], 0x10000 bytes
memory[0x3] [0x00383fffcb4000-0x00383fffcb5fff], 0x2000 bytes
reserved.cnt = 0x2
reserved[0x0] [0x00380000000000-0x0038000117e7f8], 0x117e7f9 bytes
reserved[0x1] [0x00380004000000-0x0038000d02f74a], 0x902f74b bytes
...
Early memory node ranges
node 7: [mem 0x380000000000-0x38000117dfff]
node 7: [mem 0x380004000000-0x380f0d01bfff]
node 7: [mem 0x383fffc92000-0x383fffca1fff]
node 7: [mem 0x383fffcb4000-0x383fffcb5fff]
Could not find start_pfn for node 0
Could not find start_pfn for node 1
Could not find start_pfn for node 2
Could not find start_pfn for node 3
Could not find start_pfn for node 4
Could not find start_pfn for node 5
Could not find start_pfn for node 6
.
The patch was tested on T4-1, T5-8 and Jalap?no.
Cc: sparclinux@vger.kernel.org
Signed-off-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We have seen an issue with guest boot into LDOM that causes early boot failures
because of no matching rules for node identitity of the memory. I analyzed this
on my T4 and concluded there might not be a solution. I saw the issue in
mainline too when booting into the control/primary domain - with guests
configured. Note, this could be a firmware bug on some older machines.
I'll provide a full explanation of the issues below. Should we not find a
matching BEST latency group for a real address (RA) then we will assume node 0.
On the T4-2 here with the information provided I can't see an alternative.
Technically the LDOM shown below should match the MBLOCK to the
favorable latency group. However other factors must be considered too. Were
the memory controllers configured "fine" grained interleave or "coarse"
grain interleaved - T4. Also should a "group" MD node be considered a NUMA
node?
There has to be at least one Machine Description (MD) "group" and hence one
NUMA node. The group can have one or more latency groups (lg) - more than one
memory controller. The current code chooses the smallest latency as the most
favorable per group. The latency and lg information is in MLGROUP below.
MBLOCK is the base and size of the RAs for the machine as fetched from OBP
/memory "available" property. My machine has one MBLOCK but more would be
possible - with holes?
For a T4-2 the following information has been gathered:
with LDOM guest
MEMBLOCK configuration:
memory size = 0x27f870000
memory.cnt = 0x3
memory[0x0] [0x00000020400000-0x0000029fc67fff], 0x27f868000 bytes
memory[0x1] [0x0000029fd8a000-0x0000029fd8bfff], 0x2000 bytes
memory[0x2] [0x0000029fd92000-0x0000029fd97fff], 0x6000 bytes
reserved.cnt = 0x2
reserved[0x0] [0x00000020800000-0x000000216c15c0], 0xec15c1 bytes
reserved[0x1] [0x00000024800000-0x0000002c180c1e], 0x7980c1f bytes
MBLOCK[0]: base[20000000] size[280000000] offset[0]
(note: "base" and "size" reported in "MBLOCK" encompass the "memory[X]" values)
(note: (RA + offset) & mask = val is the formula to detect a match for the
memory controller. should there be no match for find_node node, a return
value of -1 resulted for the node - BAD)
There is one group. It has these forward links
MLGROUP[1]: node[545] latency[1f7e8] match[200000000] mask[200000000]
MLGROUP[2]: node[54d] latency[2de60] match[0] mask[200000000]
NUMA NODE[0]: node[545] mask[200000000] val[200000000] (latency[1f7e8])
(note: "val" is the best lg's (smallest latency) "match")
no LDOM guest - bare metal
MEMBLOCK configuration:
memory size = 0xfdf2d0000
memory.cnt = 0x3
memory[0x0] [0x00000020400000-0x00000fff6adfff], 0xfdf2ae000 bytes
memory[0x1] [0x00000fff6d2000-0x00000fff6e7fff], 0x16000 bytes
memory[0x2] [0x00000fff766000-0x00000fff771fff], 0xc000 bytes
reserved.cnt = 0x2
reserved[0x0] [0x00000020800000-0x00000021a04580], 0x1204581 bytes
reserved[0x1] [0x00000024800000-0x0000002c7d29fc], 0x7fd29fd bytes
MBLOCK[0]: base[20000000] size[fe0000000] offset[0]
there are two groups
group node[16d5]
MLGROUP[0]: node[1765] latency[1f7e8] match[0] mask[200000000]
MLGROUP[3]: node[177d] latency[2de60] match[200000000] mask[200000000]
NUMA NODE[0]: node[1765] mask[200000000] val[0] (latency[1f7e8])
group node[171d]
MLGROUP[2]: node[1775] latency[2de60] match[0] mask[200000000]
MLGROUP[1]: node[176d] latency[1f7e8] match[200000000] mask[200000000]
NUMA NODE[1]: node[176d] mask[200000000] val[200000000] (latency[1f7e8])
(note: for this two "group" bare metal machine, 1/2 memory is in group one's
lg and 1/2 memory is in group two's lg).
Cc: sparclinux@vger.kernel.org
Signed-off-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We've witnessed a few TLB events causing the machine to power off because
of prom_halt. In one case it was some nfs related area during rmmod. Another
was an mmapper of /dev/mem. A more recent one is an ITLB issue with
a bad pagesize which could be a hardware bug. Bugs happen but we should
attempt to not power off the machine and/or hang it when possible.
This is a DTLB error from an mmapper of /dev/mem:
[root@sparcie ~]# SUN4V-DTLB: Error at TPC[fffff80100903e6c], tl 1
SUN4V-DTLB: TPC<0xfffff80100903e6c>
SUN4V-DTLB: O7[fffff801081979d0]
SUN4V-DTLB: O7<0xfffff801081979d0>
SUN4V-DTLB: vaddr[fffff80100000000] ctx[1250] pte[98000000000f0610] error[2]
.
This is recent mainline for ITLB:
[ 3708.179864] SUN4V-ITLB: TPC<0xfffffc010071cefc>
[ 3708.188866] SUN4V-ITLB: O7[fffffc010071cee8]
[ 3708.197377] SUN4V-ITLB: O7<0xfffffc010071cee8>
[ 3708.206539] SUN4V-ITLB: vaddr[e0003] ctx[1a3c] pte[2900000dcc800eeb] error[4]
.
Normally sun4v_itlb_error_report() and sun4v_dtlb_error_report() would call
prom_halt() and drop us to OF command prompt "ok". This isn't the case for
LDOMs and the machine powers off.
For the HV reported error of HV_ENORADDR for HV HV_MMU_MAP_ADDR_TRAP we cause
a SIGBUS error by qualifying it within do_sparc64_fault() for fault code mask
of FAULT_CODE_BAD_RA. This is done when trap level (%tl) is less or equal
one("1"). Otherwise, for %tl > 1, we proceed eventually to die_if_kernel().
The logic of this patch was partially inspired by David Miller's feedback.
Power off of large sparc64 machines is painful. Plus die_if_kernel provides
more context. A reset sequence isn't a brief period on large sparc64 but
better than power-off/power-on sequence.
Cc: sparclinux@vger.kernel.org
Signed-off-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
__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>
Based almost entirely upon a patch by Christopher Alexander Tobias
Schulze.
In commit db64fe0225 ("mm: rewrite vmap
layer") lazy VMAP tlb flushing was added to the vmalloc layer. This
causes problems on sparc64.
Sparc64 has two VMAP mapped regions and they are not contiguous with
eachother. First we have the malloc mapping area, then another
unrelated region, then the vmalloc region.
This "another unrelated region" is where the firmware is mapped.
If the lazy TLB flushing logic in the vmalloc code triggers after
we've had both a module unload and a vfree or similar, it will pass an
address range that goes from somewhere inside the malloc region to
somewhere inside the vmalloc region, and thus covering the
openfirmware area entirely.
The sparc64 kernel learns about openfirmware's dynamic mappings in
this region early in the boot, and then services TLB misses in this
area. But openfirmware has some locked TLB entries which are not
mentioned in those dynamic mappings and we should thus not disturb
them.
These huge lazy TLB flush ranges causes those openfirmware locked TLB
entries to be removed, resulting in all kinds of problems including
hard hangs and crashes during reboot/reset.
Besides causing problems like this, such huge TLB flush ranges are
also incredibly inefficient. A plea has been made with the author of
the VMAP lazy TLB flushing code, but for now we'll put a safety guard
into our flush_tlb_kernel_range() implementation.
Since the implementation has become non-trivial, stop defining it as a
macro and instead make it a function in a C source file.
Signed-off-by: David S. Miller <davem@davemloft.net>
The assumption was that update_mmu_cache() (and the equivalent for PMDs) would
only be called when the PTE being installed will be accessible by the user.
This is not true for code paths originating from remove_migration_pte().
There are dire consequences for placing a non-valid PTE into the TSB. The TLB
miss frramework assumes thatwhen a TSB entry matches we can just load it into
the TLB and return from the TLB miss trap.
So if a non-valid PTE is in there, we will deadlock taking the TLB miss over
and over, never satisfying the miss.
Just exit early from update_mmu_cache() and friends in this situation.
Based upon a report and patch from Christopher Alexander Tobias Schulze.
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds sparc RAM to /proc/iomem. It also identifies the
code, data and bss regions of the kernel.
Signed-off-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently hugepage migration is available for all archs which support
pmd-level hugepage, but testing is done only for x86_64 and there're
bugs for other archs. So to avoid breaking such archs, this patch
limits the availability strictly to x86_64 until developers of other
archs get interested in enabling this feature.
Simply disabling hugepage migration on non-x86_64 archs is not enough to
fix the reported problem where sys_move_pages() hits the BUG_ON() in
follow_page(FOLL_GET), so let's fix this by checking if hugepage
migration is supported in vma_migratable().
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: <stable@vger.kernel.org> [3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David S. Miller