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alistair23-linux/include/asm-generic
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Will Deacon ec6931b281 word-at-a-time: avoid undefined behaviour in zero_bytemask macro 
The asm-generic, big-endian version of zero_bytemask creates a mask of
bytes preceding the first zero-byte by left shifting ~0ul based on the
position of the first zero byte.

Unfortunately, if the first (top) byte is zero, the output of
prep_zero_mask has only the top bit set, resulting in undefined C
behaviour as we shift left by an amount equal to the width of the type.
As it happens, GCC doesn't manage to spot this through the call to fls(),
but the issue remains if architectures choose to implement their shift
instructions differently.

An example would be arch/arm/ (AArch32), where LSL Rd, Rn, #32 results
in Rd == 0x0, whilst on arch/arm64 (AArch64) LSL Xd, Xn, #64 results in
Xd == Xn.

Rather than check explicitly for the problematic shift, this patch adds
an extra shift by 1, replacing fls with __fls. Since zero_bytemask is
never called with a zero argument (has_zero() is used to check the data
first), we don't need to worry about calling __fls(0), which is
undefined.

Cc: <stable@vger.kernel.org>
Cc: Victor Kamensky <victor.kamensky@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-27 15:20:05 -07:00
..
bitops bitops: Fix signedness of compile-time hweight implementations 2014-02-09 13:39:26 +01:00
4level-fixup.h
atomic-long.h
atomic.h asm-generic: move cmpxchg*_local defs to cmpxchg.h 2013-03-13 06:11:05 +01:00
atomic64.h
audit_change_attr.h audit: Modify a set of system calls in audit class definitions 2014-01-17 17:01:46 -05:00
audit_dir_write.h
audit_read.h
audit_signal.h
audit_write.h audit: Modify a set of system calls in audit class definitions 2014-01-17 17:01:46 -05:00
barrier.h arch: Introduce smp_load_acquire(), smp_store_release() 2014-01-12 10:37:17 +01:00
bitops.h
bitsperlong.h UAPI: (Scripted) Disintegrate include/asm-generic 2012-10-04 18:20:15 +01:00
bug.h bug: Make BUG() always stop the machine 2014-04-07 16:36:10 -07:00
bugs.h
cache.h
cacheflush.h
checksum.h asm-generic headers: Allow yet more arch overrides in checksum.h 2013-02-11 20:00:33 +05:30
clkdev.h asm-generic: Add default clkdev.h 2012-10-03 21:33:53 +02:00
cmpxchg-local.h LLVMLinux: Remove warning about returning an uninitialized variable 2014-04-09 13:44:35 -07:00
cmpxchg.h asm-generic: move cmpxchg*_local defs to cmpxchg.h 2013-03-13 06:11:05 +01:00
cputime.h cputime: Generic on-demand virtual cputime accounting 2013-01-27 19:23:27 +01:00
cputime_jiffies.h cputime: Bring cputime -> nsecs conversion 2014-03-13 15:56:44 +01:00
cputime_nsecs.h cputime: Bring cputime -> nsecs conversion 2014-03-13 15:56:44 +01:00
current.h
delay.h
device.h
div64.h
dma-coherent.h common: dma-mapping: add support for generic dma_mmap_* calls 2012-07-30 12:25:46 +02:00
dma-mapping-broken.h asm-generic/dma-mapping-broken.h: Provide dma_alloc_attrs()/dma_free_attrs() 2012-12-25 20:14:54 +01:00
dma-mapping-common.h common: dma-mapping: introduce dma_get_sgtable() function 2012-07-30 12:25:46 +02:00
dma.h
early_ioremap.h mm: create generic early_ioremap() support 2014-04-07 16:36:15 -07:00
emergency-restart.h
exec.h
fb.h
fixmap.h add generic fixmap.h 2014-01-23 16:36:54 -08:00
ftrace.h
futex.h
getorder.h
gpio.h gpio: make gpiod_direction_output take a logical value 2014-02-07 09:47:02 +01:00
hardirq.h
hash.h lib: hash: follow-up fixups for arch hash 2013-12-19 00:14:53 -05:00
hugetlb.h mm: Fix generic hugetlb pte check return type. 2013-10-02 20:02:35 -04:00
hw_irq.h
ide_iops.h
int-ll64.h UAPI: (Scripted) Disintegrate include/asm-generic 2012-10-04 18:20:15 +01:00
io-64-nonatomic-hi-lo.h
io-64-nonatomic-lo-hi.h
io.h Kconfig: rename HAS_IOPORT to HAS_IOPORT_MAP 2014-04-07 16:36:11 -07:00
ioctl.h UAPI: (Scripted) Disintegrate include/asm-generic 2012-10-04 18:20:15 +01:00
iomap.h Kconfig: rename HAS_IOPORT to HAS_IOPORT_MAP 2014-04-07 16:36:11 -07:00
irq.h
irq_regs.h
irqflags.h
Kbuild.asm UAPI: Set up uapi/asm/Kbuild.asm 2012-10-02 18:01:56 +01:00
kdebug.h
kmap_types.h asm-generic: remove km_type definitions 2012-07-24 15:27:30 +08:00
kvm_para.h KVM: add kvm_para_available to asm-generic/kvm_para.h 2013-06-05 13:21:29 +03:00
libata-portmap.h
linkage.h
local.h
local64.h
mcs_spinlock.h locking/mcs: Allow architecture specific asm files to be used for contended case 2014-02-09 21:18:52 +01:00
memory_model.h __page_to_pfn: Fix typo in comment 2013-10-14 15:28:29 +02:00
mm_hooks.h
mmu.h asm-generic/mmu.h: Add support for FDPIC 2012-12-09 23:14:14 +01:00
mmu_context.h
module.h Make most arch asm/module.h files use asm-generic/module.h 2012-09-28 14:31:03 +09:30
mutex-dec.h arch: Make __mutex_fastpath_lock_retval return whether fastpath succeeded or not 2013-06-26 12:10:55 +02:00
mutex-null.h arch: Make __mutex_fastpath_lock_retval return whether fastpath succeeded or not 2013-06-26 12:10:55 +02:00
mutex-xchg.h arch: Make __mutex_fastpath_lock_retval return whether fastpath succeeded or not 2013-06-26 12:10:55 +02:00
mutex.h
page.h
param.h UAPI: (Scripted) Disintegrate include/asm-generic 2012-10-04 18:20:15 +01:00
parport.h include: remove __dev* attributes. 2013-01-03 15:57:16 -08:00
pci-bridge.h
pci-dma-compat.h
pci.h
pci_iomap.h
percpu.h percpu: add raw_cpu_ops 2014-04-07 16:36:13 -07:00
pgalloc.h
pgtable-nopmd.h
pgtable-nopud.h
pgtable.h mm: use paravirt friendly ops for NUMA hinting ptes 2014-04-18 16:40:09 -07:00
preempt.h sched: Remove PREEMPT_NEED_RESCHED from generic code 2013-12-11 15:52:32 +01:00
ptrace.h
resource.h UAPI: (Scripted) Disintegrate include/asm-generic 2012-10-04 18:20:15 +01:00
rtc.h
rwsem.h asm-generic: rwsem: de-PPCify rwsem.h 2014-03-14 18:02:08 +00:00
scatterlist.h
sections.h vmlinux.lds: add comments for global variables and clean up useless declarations 2013-07-03 16:07:34 -07:00
segment.h
serial.h
siginfo.h constify copy_siginfo_to_user{,32}() 2013-11-09 00:16:29 -05:00
signal.h unify default ptrace_signal_deliver 2012-11-29 00:01:23 -05:00
simd.h crypto: create generic version of ablk_helper 2013-09-24 06:02:24 +10:00
sizes.h ARM: 7430/1: sizes.h: move from asm-generic to <linux/sizes.h> 2012-06-28 17:14:34 +01:00
spinlock.h
statfs.h UAPI: (Scripted) Disintegrate include/asm-generic 2012-10-04 18:20:15 +01:00
string.h
switch_to.h
syscall.h syscall_get_arch: remove useless function arguments 2014-03-20 10:11:59 -04:00
syscalls.h burying unused conditionals 2013-02-14 09:21:15 -05:00
termios-base.h
termios.h UAPI: (Scripted) Disintegrate include/asm-generic 2012-10-04 18:20:15 +01:00
timex.h
tlb.h Fix TLB gather virtual address range invalidation corner cases 2013-08-16 08:52:46 -07:00
tlbflush.h
topology.h
trace_clock.h tracing,x86: Add a TSC trace_clock 2012-11-13 15:48:27 -05:00
uaccess-unaligned.h
uaccess.h asm-generic: uaccess: Spelling s/a ny/any/ 2014-01-02 10:45:23 +01:00
unaligned.h
unistd.h We get rid of the general module prefix confusion with a binary config option, 2013-05-05 10:58:06 -07:00
user.h
vga.h
vmlinux.lds.h ARM: SoC specific changes 2014-04-05 14:19:54 -07:00
vtime.h include/asm-generic/vtime.h: avoid zero-length file 2013-09-30 14:31:02 -07:00
word-at-a-time.h word-at-a-time: avoid undefined behaviour in zero_bytemask macro 2014-04-27 15:20:05 -07:00
xor.h asm-generic: xor: mark static functions as __maybe_unused 2012-10-03 21:21:06 +02:00