Robustify ARM's die() handling with improvements from x86:
- Fix for a deadlock (before panic in the case of panic_on_oops) if we
oops under a spinlock which is also used from interrupt handler,
since the old code was unconditionally enabling interrupts.
- Usage of arch spinlock so lockdep etc doesn't get involved while
we're trying to dump out oopses.
- Deadlock prevention in the unlikely event that die() recurses.
The changes all touch the same few lines of code, so they're done
together in one patch.
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The cacheflush syscall can fail for two reasons:
(1) The arguments are invalid (nonsensical address range or no VMA)
(2) The region generates a translation fault on a VIPT or PIPT cache
This patch allows do_cache_op to return an error code to userspace in
the case of the above. The various coherent_user_range implementations
are modified to return 0 in the case of VIVT caches or -EFAULT in the
case of an abort on v6/v7 cores.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We can't be holding the mmap_sem while calling flush_cache_user_range
because the flush can fault. If we fault on a user address, the
page fault handler will try to take mmap_sem again. Since both places
acquire the read lock, most of the time it succeeds. However, if another
thread tries to acquire the write lock on the mmap_sem (e.g. mmap) in
between the call to flush_cache_user_range and the fault, the down_read
in do_page_fault will deadlock.
[will: removed drop of vma parameter as already queued by rmk (7365/1)]
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dima Zavin <dima@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
vma isn't used and flush_cache_user_range isn't a standard macro that
is used on several archs with the same prototype. In fact only unicore32
has a macro with the same name (with an identical implementation and no
in-tree users).
This is a part of a patch proposed by Dima Zavin (with Message-id:
1272439931-12795-1-git-send-email-dima@android.com) that didn't get
accepted.
Cc: Dima Zavin <dima@android.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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
Add the compiled ISA to oops dumps, along side the preempt/smp
configuration. This allows us to see immediately whether the kernel
was compiled for Thumb-2 or not.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The ARM kernel uses undefined instructions to implement
BUG/BUG_ON(). This leads to problems where people don't read one
line above the Oops message and see the "kernel BUG at ..."
message and so they wrongly assume the kernel has hit an
undefined instruction.
Instead of printing:
Internal error: Oops - undefined instruction: 0 [#1] PREEMPT SMP
print
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
This should prevent people from thinking the BUG_ON was an
undefined instruction when it was actually intentional.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Initialize the contents of the vectors page immediately after we
allocate the page, but before we map it. This avoids any possible
aliases with other mappings which may need to be flushed after the
page has been mapped irrespective of the cache type.
We follow this later with a flush_cache_all() after all static memory
mappings have been initialized, which ensures that this is safe from
any cache effects.
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
rtmutex: Add missing rcu_read_unlock() in debug_rt_mutex_print_deadlock()
lockdep: Comment all warnings
lib: atomic64: Change the type of local lock to raw_spinlock_t
locking, lib/atomic64: Annotate atomic64_lock::lock as raw
locking, x86, iommu: Annotate qi->q_lock as raw
locking, x86, iommu: Annotate irq_2_ir_lock as raw
locking, x86, iommu: Annotate iommu->register_lock as raw
locking, dma, ipu: Annotate bank_lock as raw
locking, ARM: Annotate low level hw locks as raw
locking, drivers/dca: Annotate dca_lock as raw
locking, powerpc: Annotate uic->lock as raw
locking, x86: mce: Annotate cmci_discover_lock as raw
locking, ACPI: Annotate c3_lock as raw
locking, oprofile: Annotate oprofilefs lock as raw
locking, video: Annotate vga console lock as raw
locking, latencytop: Annotate latency_lock as raw
locking, timer_stats: Annotate table_lock as raw
locking, rwsem: Annotate inner lock as raw
locking, semaphores: Annotate inner lock as raw
locking, sched: Annotate thread_group_cputimer as raw
...
Fix up conflicts in kernel/posix-cpu-timers.c manually: making
cputimer->cputime a raw lock conflicted with the ABBA fix in commit
bcd5cff721 ("cputimer: Cure lock inversion").
ARM uses its own BUG() handler which makes its output slightly different
from other archtectures.
One of the problems is that the ARM implementation doesn't report the function
with the BUG() in it, but always reports the PC being in __bug(). The generic
implementation doesn't have this problem.
Currently we get something like:
kernel BUG at fs/proc/breakme.c:35!
Unable to handle kernel NULL pointer dereference at virtual address 00000000
...
PC is at __bug+0x20/0x2c
With this patch it displays:
kernel BUG at fs/proc/breakme.c:35!
Internal error: Oops - undefined instruction: 0 [#1] PREEMPT SMP
...
PC is at write_breakme+0xd0/0x1b4
This implementation uses an undefined instruction to implement BUG, and sets up
a bug table containing the relevant information. Many versions of gcc do not
support %c properly for ARM (inserting a # when they shouldn't) so we work
around this using distasteful macro magic.
v1: Initial version to replace existing ARM BUG() implementation with something
more similar to other architectures.
v2: Add Thumb support, remove backtrace whitespace output changes. Change to
use macros instead of requiring the asm %d flag to work (thanks to
Dave Martin <dave.martin@linaro.org>)
v3: Remove old BUG() implementation in favor of this one.
Remove the Backtrace: message (will submit this separately).
Use ARM_EXIT_KEEP() so that some architectures can dump exit text at link time
thanks to Stephen Boyd <sboyd@codeaurora.org> (although since we always
define GENERIC_BUG this might be academic.)
Rebase to linux-2.6.git master.
v4: Allow BUGS in modules (these were not reported correctly in v3)
(thanks to Stephen Boyd <sboyd@codeaurora.org> for suggesting that.)
Remove __bug() as this is no longer needed.
v5: Add %progbits as the section flags.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
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>
Annotate the low level hardware locks which must not be preempted.
In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>
Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch allows undef_hook's to be specified for 32-bit Thumb
instructions and also to be used for thumb kernel-side code.
32-bit Thumb instructions are specified in the form:
((first_half << 16 ) | second_half)
which matches the layout used by the ARM ARM.
ptrace was handling 32-bit Thumb instructions by hooking the first
halfword and manually checking the second half. This method would be
broken by this patch so it is migrated to make use of the new Thumb-2
support.
Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Dump out the following 16-bit instruction to the faulting instruction
in the Code: line. This allows Thumb-2 instructions to be properly
encoded.
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
If the page to cmpxchg is user mode read only (not write),
we should simulate a data abort first.
Signed-off-by: Po-Yu Chuang <ratbert@faraday-tech.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On some arches (x86, sh, arm, unicore, powerpc) the oops message would
print out the last sysfs file accessed.
This was very useful in finding a number of sysfs and driver core bugs
in the 2.5 and early 2.6 development days, but it has been a number of
years since this file has actually helped in debugging anything that
couldn't also be trivially determined from the stack traceback.
So it's time to delete the line. This is good as we need all the space
we can get for oops messages at times on consoles.
Acked-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There are optional bits that may complement a personality ID. It is
therefore wrong to simply test against the absolute current->personality
value to determine the effective personality. The PER_LINUX_32BIT is
itself just PER_LINUX with one of those optional bits set.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
PTRACE_SINGLESTEP is a ptrace request designed to offer single-stepping
support to userspace when the underlying architecture has hardware
support for this operation.
On ARM, we set arch_has_single_step() to 1 and attempt to emulate hardware
single-stepping by disassembling the current instruction to determine the
next pc and placing a software breakpoint on that location.
Unfortunately this has the following problems:
1.) Only a subset of ARMv7 instructions are supported
2.) Thumb-2 is unsupported
3.) The code is not SMP safe
We could try to fix this code, but it turns out that because of the above
issues it is rarely used in practice. GDB, for example, uses PTRACE_POKETEXT
and PTRACE_PEEKTEXT to manage breakpoints itself and does not require any
kernel assistance.
This patch removes the single-step emulation code from ptrace meaning that
the PTRACE_SINGLESTEP request will return -EIO on ARM. Portable code must
check the return value from a ptrace call and handle the failure gracefully.
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/kernel/return_address.c:37:6: warning: symbol 'return_address' was not declared. Should it be static?
arch/arm/kernel/setup.c:76:14: warning: symbol 'processor_id' was not declared. Should it be static?
arch/arm/kernel/traps.c:259:1: warning: symbol 'die_lock' was not declared. Should it be static?
arch/arm/vfp/vfpmodule.c:156:6: warning: symbol 'vfp_raise_sigfpe' was not declared. Should it be static?
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
For the Kernel to support 2 level and 3 level page tables, physical
addresses (and also page table entries) need to be 32 or 64-bits depending
upon the configuration.
This patch uses the %08llx conversion specifier for physical addresses
and page table entries, ensuring that they are cast to (long long) so
that common code can be used regardless of the datatype widths.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rather than passing the pte value to __pte_error, pass the raw pte_t
cookie instead. Do the same for pmd and pgd functions.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch removes the domain switching functionality via the set_fs and
__switch_to functions on cores that have a TLS register.
Currently, the ioremap and vmalloc areas share the same level 1 page
tables and therefore have the same domain (DOMAIN_KERNEL). When the
kernel domain is modified from Client to Manager (via the __set_fs or in
the __switch_to function), the XN (eXecute Never) bit is overridden and
newer CPUs can speculatively prefetch the ioremap'ed memory.
Linux performs the kernel domain switching to allow user-specific
functions (copy_to/from_user, get/put_user etc.) to access kernel
memory. In order for these functions to work with the kernel domain set
to Client, the patch modifies the LDRT/STRT and related instructions to
the LDR/STR ones.
The user pages access rights are also modified for kernel read-only
access rather than read/write so that the copy-on-write mechanism still
works. CPU_USE_DOMAINS gets disabled only if the hardware has a TLS register
(CPU_32v6K is defined) since writing the TLS value to the high vectors page
isn't possible.
The user addresses passed to the kernel are checked by the access_ok()
function so that they do not point to the kernel space.
Tested-by: Anton Vorontsov <cbouatmailru@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The TLS register is only available on ARM1136 r1p0 and later.
Set HWCAP_TLS flags if hardware TLS is available and test for
it if CONFIG_CPU_32v6K is not set for V6.
Note that we set the TLS instruction in __kuser_get_tls
dynamically as suggested by Jamie Lokier <jamie@shareable.org>.
Also the __switch_to code is optimized out in most cases as
suggested by Nicolas Pitre <nico@fluxnic.net>.
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Kernel debuggers want to be informed of die() events, so that they
can take some action to allow the problem to be inspected. Provide
the hook in a similar manner to x86.
Note that we currently don't implement the individual trap hooks.
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Use a definition for the cmpxchg SWI instead of hard-coding the number.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
The signal restarting code was placed on the user stack when OABI
compatibility is enabled. Unfortunately, with an EABI NX executable,
this results in an attempt to run code from the non-executable stack,
which segfaults the application.
Fix this by placing the code in the vectors page, along side the
signal return code, and directing the application to that code.
Reported-by: saeed bishara <saeed.bishara@gmail.com>
Tested-by: saeed bishara <saeed.bishara@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Make die() better match x86:
- add printing of the last accessed sysfs file
- ensure console_verbose() is called under the lock
- ensure we panic outside of oops_exit()
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dump_mem and dump_backtrace were both using multiple printk statements
to print each line. With DEBUG_LL enabled, this causes OOPS to become
very difficult to read. Solve this by only using one printk per line.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
do_cache_op() uses find_vma() to validate its arguments without holding
any locking. This means that the VMA could vanish beneath us. Fix
this by taking a read lock on mmap_sem.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds the main functionality for parsing the stack unwinding
information generated by the ARM EABI toolchains. The unwinding
information consists of an index with a pair of words per function and a
table with unwinding instructions. For more information, see "Exception
Handling ABI for the ARM Architecture" at:
http://infocenter.arm.com/help/topic/com.arm.doc.subset.swdev.abi/index.html
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch moves code around in the arch/arm/kernel/traps.c file for
easier integration of the stack unwinding support.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/kernel/process.c:270:6: warning: symbol 'show_fpregs' was not declared. Should it be static?
This function isn't used, so can be removed.
arch/arm/kernel/setup.c:532:9: warning: symbol 'len' shadows an earlier one
arch/arm/kernel/setup.c:524:6: originally declared here
A function containing two 'len's.
arch/arm/mm/fault-armv.c:188:13: warning: symbol 'check_writebuffer_bugs' was not declared. Should it be static?
arch/arm/mm/mmap.c:122:5: warning: symbol 'valid_phys_addr_range' was not declared. Should it be static?
arch/arm/mm/mmap.c:137:5: warning: symbol 'valid_mmap_phys_addr_range' was not declared. Should it be static?
Missing includes.
arch/arm/kernel/traps.c:71:77: warning: Using plain integer as NULL pointer
arch/arm/mm/ioremap.c:355:46: error: incompatible types in comparison expression (different address spaces)
Sillies.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
As mentioned in commit 796969104c,
and because of commit b03a5b7559,
the direct calling of kprobe_trap_handler() can be removed.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Calling the undefined instruction handler functions with a
spinlock held is a recipe for must_sleep() warnings. Avoid it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds the ARCH=arm specific a kgdb backend, originally
written by Deepak Saxena <dsaxena@plexity.net> and George Davis
<gdavis@mvista.com>. Geoff Levand <geoffrey.levand@am.sony.com>,
Nicolas Pitre, Manish Lachwani, and Jason Wessel have contributed
various fixups here as well.
The KGDB patch makes one change to the core ARM architecture such that
the traps are initialized early for use with the debugger or other
subsystems.
[ mingo@elte.hu: small cleanups. ]
[ ben-linux@fluff.org: fixed early_trap_init ]
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Deepak Saxena <dsaxena@plexity.net>
The kprobes code is already able to cope with reentrant probes, so its
handler must be called outside of the region protected by undef_lock.
If ever this lock is released when handlers are called then this commit
could be reverted.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
