Mark Rutland e88d62cd4b percpu: make this_cpu_generic_read() atomic w.r.t. interrupts ... As raw_cpu_generic_read() is a plain read from a raw_cpu_ptr() address, it's possible (albeit unlikely) that the compiler will split the access across multiple instructions. In this_cpu_generic_read() we disable preemption but not interrupts before calling raw_cpu_generic_read(). Thus, an interrupt could be taken in the middle of the split load instructions. If a this_cpu_write() or RMW this_cpu_*() op is made to the same variable in the interrupt handling path, this_cpu_read() will return a torn value. For native word types, we can avoid tearing using READ_ONCE(), but this won't work in all cases (e.g. 64-bit types on most 32-bit platforms). This patch reworks this_cpu_generic_read() to use READ_ONCE() where possible, otherwise falling back to disabling interrupts. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Lameter <cl@linux.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Tejun Heo <tj@kernel.org>		2017-09-26 07:37:33 -07:00
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bitops
4level-fixup.h
5level-fixup.h
asm-offsets.h
asm-prototypes.h
atomic-long.h
atomic.h
atomic64.h
audit_change_attr.h
audit_dir_write.h
audit_read.h
audit_signal.h
audit_write.h
barrier.h
bitops.h
bitsperlong.h
bug.h
bugs.h
cache.h
cacheflush.h
checksum.h
clkdev.h
cmpxchg-local.h
cmpxchg.h
current.h
delay.h
device.h
div64.h
dma-contiguous.h
dma.h
early_ioremap.h
emergency-restart.h
exec.h
export.h
extable.h
fb.h
fixmap.h
ftrace.h
futex.h
getorder.h
gpio.h
hardirq.h
hugetlb.h
hw_irq.h
ide_iops.h
int-ll64.h
io.h
ioctl.h
iomap.h
irq.h
irq_regs.h
irq_work.h
irqflags.h
kdebug.h
kmap_types.h
kprobes.h
kvm_para.h
linkage.h
local.h
local64.h
mcs_spinlock.h
memory_model.h
mm-arch-hooks.h
mm_hooks.h
mmu.h
mmu_context.h
module.h
msi.h
page.h
param.h
parport.h
pci.h
pci_iomap.h
percpu.h	percpu: make this_cpu_generic_read() atomic w.r.t. interrupts	2017-09-26 07:37:33 -07:00
pgalloc.h
pgtable-nop4d-hack.h
pgtable-nop4d.h
pgtable-nopmd.h
pgtable-nopud.h
pgtable.h
preempt.h
ptrace.h
qrwlock.h
qrwlock_types.h
qspinlock.h
qspinlock_types.h
resource.h
rwsem.h
seccomp.h
sections.h
segment.h
serial.h
set_memory.h
signal.h
simd.h
sizes.h
spinlock.h
statfs.h
string.h
switch_to.h
syscall.h
syscalls.h
termios-base.h
termios.h
timex.h
tlb.h
tlbflush.h
topology.h
trace_clock.h
uaccess.h
unaligned.h
unistd.h
user.h
vga.h
vmlinux.lds.h	MTD changes for 4.14:	2017-09-09 14:48:21 -07:00
vtime.h
word-at-a-time.h
xor.h