Translation faults arising from cache maintenance instructions are
rather unhelpfully reported with an FSR value where the WnR field is set
to 1, indicating that the faulting access was a write. Since cache
maintenance instructions on 32-bit ARM do not require any particular
permissions, this can cause our private 'cacheflush' system call to fail
spuriously if a translation fault is generated due to page aging when
targetting a read-only VMA.
In this situation, we will return -EFAULT to userspace, although this is
unfortunately suppressed by the popular '__builtin___clear_cache()'
intrinsic provided by GCC, which returns void.
Although it's tempting to write this off as a userspace issue, we can
actually do a little bit better on CPUs that support LPAE, even if the
short-descriptor format is in use. On these CPUs, cache maintenance
faults additionally set the CM field in the FSR, which we can use to
suppress the write permission checks in the page fault handler and
succeed in performing cache maintenance to read-only areas even in the
presence of a translation fault.
Reported-by: Orion Hodson <oth@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Architectures which support kprobes have very similar boilerplate around
calling kprobe_fault_handler(). Use a helper function in kprobes.h to
unify them, based on the x86 code.
This changes the behaviour for other architectures when preemption is
enabled. Previously, they would have disabled preemption while calling
the kprobe handler. However, preemption would be disabled if this fault
was due to a kprobe, so we know the fault was not due to a kprobe
handler and can simply return failure.
This behaviour was introduced in commit a980c0ef9f ("x86/kprobes:
Refactor kprobes_fault() like kprobe_exceptions_notify()")
[anshuman.khandual@arm.com: export kprobe_fault_handler()]
Link: http://lkml.kernel.org/r/1561133358-8876-1-git-send-email-anshuman.khandual@arm.com
Link: http://lkml.kernel.org/r/1560420444-25737-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull force_sig() argument change from Eric Biederman:
"A source of error over the years has been that force_sig has taken a
task parameter when it is only safe to use force_sig with the current
task.
The force_sig function is built for delivering synchronous signals
such as SIGSEGV where the userspace application caused a synchronous
fault (such as a page fault) and the kernel responded with a signal.
Because the name force_sig does not make this clear, and because the
force_sig takes a task parameter the function force_sig has been
abused for sending other kinds of signals over the years. Slowly those
have been fixed when the oopses have been tracked down.
This set of changes fixes the remaining abusers of force_sig and
carefully rips out the task parameter from force_sig and friends
making this kind of error almost impossible in the future"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus
signal: Remove the signal number and task parameters from force_sig_info
signal: Factor force_sig_info_to_task out of force_sig_info
signal: Generate the siginfo in force_sig
signal: Move the computation of force into send_signal and correct it.
signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal
signal: Remove the task parameter from force_sig_fault
signal: Use force_sig_fault_to_task for the two calls that don't deliver to current
signal: Explicitly call force_sig_fault on current
signal/unicore32: Remove tsk parameter from __do_user_fault
signal/arm: Remove tsk parameter from __do_user_fault
signal/arm: Remove tsk parameter from ptrace_break
signal/nds32: Remove tsk parameter from send_sigtrap
signal/riscv: Remove tsk parameter from do_trap
signal/sh: Remove tsk parameter from force_sig_info_fault
signal/um: Remove task parameter from send_sigtrap
signal/x86: Remove task parameter from send_sigtrap
signal: Remove task parameter from force_sig_mceerr
signal: Remove task parameter from force_sig
signal: Remove task parameter from force_sigsegv
...
- Add a "cut here" to make it clearer where oops dumps should be cut
from - we already have a marker for the end of the dumps.
- Add logging severity to show_pte()
- Drop unnecessary common-page-size linker flag
- Errata workarounds for Cortex A12 857271, Cortex A17 857272 and
Cortex A7 814220.
- Remove some unused variables that had started to provoke a compiler
warning.
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Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King:
- Add a "cut here" to make it clearer where oops dumps should be cut
from - we already have a marker for the end of the dumps.
- Add logging severity to show_pte()
- Drop unnecessary common-page-size linker flag
- Errata workarounds for Cortex A12 857271, Cortex A17 857272 and
Cortex A7 814220.
- Remove some unused variables that had started to provoke a compiler
warning.
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8863/1: stm32: select ARM errata 814220
ARM: 8862/1: errata: 814220-B-Cache maintenance by set/way operations can execute out of order
ARM: 8865/1: mm: remove unused variables
ARM: 8864/1: Add workaround for I-Cache line size mismatch between CPU cores
ARM: 8861/1: errata: Workaround errata A12 857271 / A17 857272
ARM: 8860/1: VDSO: Drop implicit common-page-size linker flag
ARM: arrange show_pte() to issue severity-based messages
ARM: add "8<--- cut here ---" to kernel dumps
show_pte() is used to print information after various other kernel
messages, which themselves are printed at different severities.
Include the severity in the show_pte() information so that associated
messages are printed with the same severity.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Add a "8<--- cut here ---" marker to kernel dumps to help users cut
the dump at the right place when emailing list, rather than cutting
off the first line which gives the reason for the dump.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As synchronous exceptions really only make sense against the current
task (otherwise how are you synchronous) remove the task parameter
from from force_sig_fault to make it explicit that is what is going
on.
The two known exceptions that deliver a synchronous exception to a
stopped ptraced task have already been changed to
force_sig_fault_to_task.
The callers have been changed with the following emacs regular expression
(with obvious variations on the architectures that take more arguments)
to avoid typos:
force_sig_fault[(]\([^,]+\)[,]\([^,]+\)[,]\([^,]+\)[,]\W+current[)]
->
force_sig_fault(\1,\2,\3)
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Update the calls of force_sig_fault that pass in a variable that is
set to current earlier to explicitly use current.
This is to make the next change that removes the task parameter
from force_sig_fault easier to verify.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The __do_user_fault function is always called with tsk == current.
Make that obvious by removing the tsk parameter.
This makes it clear that __do_user_fault calls force_sig_fault
on the current task.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Some software such as perf makes unconditional use of the special
[vectors] page which is only provided when CONFIG_KUSER_HELPERS is
enabled in the kernel.
Facilitate the debugging of such situations by printing a debug message
to the kernel log showing the task name and the faulting address.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Suggested-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
In arm_notify_die call force_sig_fault to let the generic
code handle siginfo generation.
This removes some boiler plate making the code easier to
maintain in the long run.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Use new return type vm_fault_t for fault handler. For now, this is just
documenting that the function returns a VM_FAULT value rather than an
errno. Once all instances are converted, vm_fault_t will become a
distinct type.
Ref-> commit 1c8f422059 ("mm: change return type to vm_fault_t")
In this patch all the caller of handle_mm_fault() are changed to return
vm_fault_t type.
Link: http://lkml.kernel.org/r/20180617084810.GA6730@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: David S. Miller <davem@davemloft.net>
Cc: Richard Weinberger <richard@nod.at>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull ARM updates from Russell King:
- Initial round of Spectre variant 1 and variant 2 fixes for 32-bit ARM
- Clang support improvements
- nommu updates for v8 MPU
- enable ARM_MODULE_PLTS by default to avoid problems loading modules
with larger kernels
- vmlinux.lds and dma-mapping cleanups
* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (31 commits)
ARM: spectre-v1: fix syscall entry
ARM: spectre-v1: add array_index_mask_nospec() implementation
ARM: spectre-v1: add speculation barrier (csdb) macros
ARM: KVM: report support for SMCCC_ARCH_WORKAROUND_1
ARM: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling
ARM: spectre-v2: KVM: invalidate icache on guest exit for Brahma B15
ARM: KVM: invalidate icache on guest exit for Cortex-A15
ARM: KVM: invalidate BTB on guest exit for Cortex-A12/A17
ARM: spectre-v2: warn about incorrect context switching functions
ARM: spectre-v2: add firmware based hardening
ARM: spectre-v2: harden user aborts in kernel space
ARM: spectre-v2: add Cortex A8 and A15 validation of the IBE bit
ARM: spectre-v2: harden branch predictor on context switches
ARM: spectre: add Kconfig symbol for CPUs vulnerable to Spectre
ARM: bugs: add support for per-processor bug checking
ARM: bugs: hook processor bug checking into SMP and suspend paths
ARM: bugs: prepare processor bug infrastructure
ARM: add more CPU part numbers for Cortex and Brahma B15 CPUs
ARM: 8774/1: remove no-op macro VMLINUX_SYMBOL()
ARM: 8773/1: amba: Export amba_bustype
...
In order to prevent aliasing attacks on the branch predictor,
invalidate the BTB or instruction cache on CPUs that are known to be
affected when taking an abort on a address that is outside of a user
task limit:
Cortex A8, A9, A12, A17, A73, A75: flush BTB.
Cortex A15, Brahma B15: invalidate icache.
If the IBE bit is not set, then there is little point to enabling the
workaround.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.
Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.
The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.
In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.
Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Avoid adding kprobes to any of the kernel entry/exit or startup
assembly code, or code in the identity-mapped region. This code does
not conform to the standard C conventions, which means that the
expectations of the kprobes code is not forfilled.
Placing kprobes at some of these locations results in the kernel trying
to return to userspace addresses while retaining the CPU in kernel mode.
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
When there's a fatal signal pending, arm's do_page_fault()
implementation returns 0. The intent is that we'll return to the
faulting userspace instruction, delivering the signal on the way.
However, if we take a fatal signal during fixing up a uaccess, this
results in a return to the faulting kernel instruction, which will be
instantly retried, resulting in the same fault being taken forever. As
the task never reaches userspace, the signal is not delivered, and the
task is left unkillable. While the task is stuck in this state, it can
inhibit the forward progress of the system.
To avoid this, we must ensure that when a fatal signal is pending, we
apply any necessary fixup for a faulting kernel instruction. Thus we
will return to an error path, and it is up to that code to make forward
progress towards delivering the fatal signal.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/debug.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'extable-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
Pull exception table module split from Paul Gortmaker:
"Final extable.h related changes.
This completes the separation of exception table content from the
module.h header file. This is achieved with the final commit that
removes the one line back compatible change that sourced extable.h
into the module.h file.
The commits are unchanged since January, with the exception of a
couple Acks that came in for the last two commits a bit later. The
changes have been in linux-next for quite some time[1] and have got
widespread arch coverage via toolchains I have and also from
additional ones the kbuild bot has.
Maintaners of the various arch were Cc'd during the postings to
lkml[2] and informed that the intention was to take the remaining arch
specific changes and lump them together with the final two non-arch
specific changes and submit for this merge window.
The ia64 diffstat stands out and probably warrants a mention. In an
earlier review, Al Viro made a valid comment that the original header
separation of content left something to be desired, and that it get
fixed as a part of this change, hence the larger diffstat"
* tag 'extable-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (21 commits)
module.h: remove extable.h include now users have migrated
core: migrate exception table users off module.h and onto extable.h
cris: migrate exception table users off module.h and onto extable.h
hexagon: migrate exception table users off module.h and onto extable.h
microblaze: migrate exception table users off module.h and onto extable.h
unicore32: migrate exception table users off module.h and onto extable.h
score: migrate exception table users off module.h and onto extable.h
metag: migrate exception table users off module.h and onto extable.h
arc: migrate exception table users off module.h and onto extable.h
nios2: migrate exception table users off module.h and onto extable.h
sparc: migrate exception table users onto extable.h
openrisc: migrate exception table users off module.h and onto extable.h
frv: migrate exception table users off module.h and onto extable.h
sh: migrate exception table users off module.h and onto extable.h
xtensa: migrate exception table users off module.h and onto extable.h
mn10300: migrate exception table users off module.h and onto extable.h
alpha: migrate exception table users off module.h and onto extable.h
arm: migrate exception table users off module.h and onto extable.h
m32r: migrate exception table users off module.h and onto extable.h
ia64: ensure exception table search users include extable.h
...
Asynchronous external abort is coded differently in DFSR with LPAE enabled.
Fixes: 9254970c "ARM: 8447/1: catch pending imprecise abort on unmask".
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
These files were only including module.h for exception table
related functions. We've now separated that content out into its
own file "extable.h" so now move over to that and avoid all the
extra header content in module.h that we don't really need to compile
these files.
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
The define has a comment from Nick Piggin from 2007:
/* For backwards compat. Remove me quickly. */
I guess 9 years should not be too hurried sense of 'quickly' even for
kernel measures.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Install a non-faulting handler just before unmasking imprecise aborts
and switch back to the regular one after unmasking is done.
This catches any pending imprecise abort that the firmware/bootloader
may have left behind that would normally crash the kernel at that point.
As there are apparently a lot of bootlaoders out there that do such a
thing it makes sense to handle it in the common startup code.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Tyler Baker <tyler.baker@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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>
It can be useful to dump the page table entries when an unhandled data
abort fault occurs. This can aid debugging of these situations, for
example, a STREX instruction causing an external abort on non-linefetch
fault, as has been reported recently.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Convert many (but not all) printk(KERN_* to pr_* to simplify the code.
We take the opportunity to join some printk lines together so we don't
split the message across several lines, and we also add a few levels
to some messages which were previously missing them.
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Unlike global OOM handling, memory cgroup code will invoke the OOM killer
in any OOM situation because it has no way of telling faults occuring in
kernel context - which could be handled more gracefully - from
user-triggered faults.
Pass a flag that identifies faults originating in user space from the
architecture-specific fault handlers to generic code so that memcg OOM
handling can be improved.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: azurIt <azurit@pobox.sk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kernel faults are expected to handle OOM conditions gracefully (gup,
uaccess etc.), so they should never invoke the OOM killer. Reserve this
for faults triggered in user context when it is the only option.
Most architectures already do this, fix up the remaining few.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: azurIt <azurit@pobox.sk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For LPAE, do_sect_fault used to be invoked as the second level access
flag handler. When transparent huge pages were introduced for LPAE,
do_page_fault was used instead.
Unfortunately, do_sect_fault remains defined but not used for LPAE code
resulting in a compile warning.
This patch surrounds do_sect_fault with #ifndef CONFIG_ARM_LPAE to fix
this warning.
Signed-off-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
.fault now can retry. The retry can break state machine of .fault. In
filemap_fault, if page is miss, ra->mmap_miss is increased. In the second
try, since the page is in page cache now, ra->mmap_miss is decreased. And
these are done in one fault, so we can't detect random mmap file access.
Add a new flag to indicate .fault is tried once. In the second try, skip
ra->mmap_miss decreasing. The filemap_fault state machine is ok with it.
I only tested x86, didn't test other archs, but looks the change for other
archs is obvious, but who knows :)
Signed-off-by: Shaohua Li <shaohua.li@fusionio.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch removes support for ARMv3 CPUs, which haven't worked properly
for quite some time (see the FIXME comment in arch/arm/mm/fault.c). The
only V3 parts left is the cache model for ARMv3, which is needed for some
odd reason by ARM740T CPUs, and being able to build with -march=armv3,
which is required for the RiscPC platform due to its bus structure.
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
commit 8878a539ff was done by me
to make the page fault handler retryable as well as interruptible.
Due to this commit, there is a mistake in the way in which
tsk->[maj|min]_flt counter gets incremented for VM_FAULT_ERROR:
If VM_FAULT_ERROR is returned in the fault flags by handle_mm_fault,
then either maj_flt or min_flt will get incremented. This is wrong
as in the case of a VM_FAULT_ERROR we need to be skip ahead to the
error handling code in do_page_fault.
Added a check after the call to __do_page_fault() to check for
(fault & VM_FAULT_ERROR).
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Pull more ARM updates from Russell King.
This got a fair number of conflicts with the <asm/system.h> split, but
also with some other sparse-irq and header file include cleanups. They
all looked pretty trivial, though.
* 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (59 commits)
ARM: fix Kconfig warning for HAVE_BPF_JIT
ARM: 7361/1: provide XIP_VIRT_ADDR for no-MMU builds
ARM: 7349/1: integrator: convert to sparse irqs
ARM: 7259/3: net: JIT compiler for packet filters
ARM: 7334/1: add jump label support
ARM: 7333/2: jump label: detect %c support for ARM
ARM: 7338/1: add support for early console output via semihosting
ARM: use set_current_blocked() and block_sigmask()
ARM: exec: remove redundant set_fs(USER_DS)
ARM: 7332/1: extract out code patch function from kprobes
ARM: 7331/1: extract out insn generation code from ftrace
ARM: 7330/1: ftrace: use canonical Thumb-2 wide instruction format
ARM: 7351/1: ftrace: remove useless memory checks
ARM: 7316/1: kexec: EOI active and mask all interrupts in kexec crash path
ARM: Versatile Express: add NO_IOPORT
ARM: get rid of asm/irq.h in asm/prom.h
ARM: 7319/1: Print debug info for SIGBUS in user faults
ARM: 7318/1: gic: refactor irq_start assignment
ARM: 7317/1: irq: avoid NULL check in for_each_irq_desc loop
ARM: 7315/1: perf: add support for the Cortex-A7 PMU
...
Disintegrate asm/system.h for ARM.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Russell King <linux@arm.linux.org.uk>
cc: linux-arm-kernel@lists.infradead.org
Print debug information on user faults for SIGBUS if user_debug = 16
in the kernel command line.
Reference: <1327333344-26340-1-git-send-email-javi.merino@arm.com>
Signed-off-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The DFSR and IFSR register format is different when LPAE is enabled. In
addition, DFSR and IFSR have similar definitions for the fault type.
This modifies the fault code to correctly handle the new format.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The FSR structure is different with LPAE and this patch moves the
classic MMU specific definition to a separate fsr-2level.c file that is
included in fault.c. It also moves the fsr_fs and FSR bits to the
fault.h file.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit d065bd810b
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e0525
(x86,mm: make pagefault killable)
The above commits introduced changes into the x86 pagefault handler
for making the page fault handler retryable as well as killable.
These changes reduce the mmap_sem hold time, which is crucial
during OOM killer invocation.
Port these changes to ARM.
Without these changes, my ARM board encounters many hang and livelock
scenarios.
After applying this patch, OOM feature performance improves according to
my testing.
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The definition of __exception_irq_entry for
CONFIG_FUNCTION_GRAPH_TRACER=y needs linux/ftrace.h, but this creates a
circular dependency with it's current home in asm/system.h. Create
asm/exception.h and update all current users.
v4: - rebase to rmk/for-next
v3: - remove redundant includes of linux/ftrace.h
v2: - document the usage restricitions of __exception*
Cc: Zoltan Devai <zdevai@gmail.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (237 commits)
ARM: 7004/1: fix traps.h compile warnings
ARM: 6998/2: kernel: use proper memory barriers for bitops
ARM: 6997/1: ep93xx: increase NR_BANKS to 16 for support of 128MB RAM
ARM: Fix build errors caused by adding generic macros
ARM: CPU hotplug: ensure we migrate all IRQs off a downed CPU
ARM: CPU hotplug: pass in proper affinity mask on IRQ migration
ARM: GIC: avoid routing interrupts to offline CPUs
ARM: CPU hotplug: fix abuse of irqdesc->node
ARM: 6981/2: mmci: adjust calculation of f_min
ARM: 7000/1: LPAE: Use long long printk format for displaying the pud
ARM: 6999/1: head, zImage: Always Enter the kernel in ARM state
ARM: btc: avoid invalidating the branch target cache on kernel TLB maintanence
ARM: ARM_DMA_ZONE_SIZE is no more
ARM: mach-shark: move ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
ARM: mach-sa1100: move ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
ARM: mach-realview: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
ARM: mach-pxa: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
ARM: mach-ixp4xx: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
ARM: mach-h720x: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
ARM: mach-davinci: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
...
Currently using just long but this is not enough for the LPAE format
(64-bit entries).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Avoid enabling interrupts if the parent context had interrupts enabled
in the abort handler assembly code, and move this into the breakpoint/
page/alignment fault handlers instead.
This gets rid of some special-casing for the breakpoint fault handlers
from the low level abort handler path.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
