mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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e88d62cd4b
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> |
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.. | ||
bitops | ||
4level-fixup.h | ||
5level-fixup.h | ||
asm-offsets.h | ||
asm-prototypes.h | ||
atomic64.h | ||
atomic-long.h | ||
atomic.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_regs.h | ||
irq_work.h | ||
irq.h | ||
irqflags.h | ||
kdebug.h | ||
kmap_types.h | ||
kprobes.h | ||
kvm_para.h | ||
linkage.h | ||
local64.h | ||
local.h | ||
mcs_spinlock.h | ||
memory_model.h | ||
mm_hooks.h | ||
mm-arch-hooks.h | ||
mmu_context.h | ||
mmu.h | ||
module.h | ||
msi.h | ||
page.h | ||
param.h | ||
parport.h | ||
pci_iomap.h | ||
pci.h | ||
percpu.h | ||
pgalloc.h | ||
pgtable-nop4d-hack.h | ||
pgtable-nop4d.h | ||
pgtable-nopmd.h | ||
pgtable-nopud.h | ||
pgtable.h | ||
preempt.h | ||
ptrace.h | ||
qrwlock_types.h | ||
qrwlock.h | ||
qspinlock_types.h | ||
qspinlock.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 | ||
vtime.h | ||
word-at-a-time.h | ||
xor.h |