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linux/include/asm-generic
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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
..
bitops bitops: Do not default to __clear_bit() for __clear_bit_unlock() 2016-03-21 10:50:48 +01:00
4level-fixup.h asm-generic: introduce 5level-fixup.h 2017-03-09 11:48:47 -08:00
5level-fixup.h asm-generic: introduce 5level-fixup.h 2017-03-09 11:48:47 -08:00
asm-offsets.h asm-generic: Add common asm-offsets.h 2015-06-23 13:35:49 +09:00
asm-prototypes.h asm-prototypes: Clear any CPP defines before declaring the functions 2017-01-05 12:57:42 +01:00
atomic64.h locking/atomic: Fix atomic_set_release() for 'funny' architectures 2017-08-10 12:28:54 +02:00
atomic-long.h locking/atomic: Introduce inc/dec variants for the atomic_fetch_$op() API 2016-07-07 09:16:20 +02:00
atomic.h openrisc: add optimized atomic operations 2017-02-25 04:14:06 +09:00
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 locking/spinlock, arch: Update and fix spin_unlock_wait() implementations 2016-06-14 11:55:15 +02:00
bitops.h arch: Prepare for smp_mb__{before,after}_atomic() 2014-04-18 11:40:30 +02:00
bitsperlong.h
bug.h asm-generic/bug.h: declare struct pt_regs; before function prototype 2017-07-10 16:32:34 -07:00
bugs.h
cache.h
cacheflush.h
checksum.h ipv4: Update parameters for csum_tcpudp_magic to their original types 2016-03-13 23:55:13 -04:00
clkdev.h asm-generic: COMMON_CLK defines __clk_{get,put} 2014-09-25 18:00:45 -07:00
cmpxchg-local.h LLVMLinux: Remove warning about returning an uninitialized variable 2014-04-09 13:44:35 -07:00
cmpxchg.h asm-generic: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations 2015-10-15 00:21:13 +02:00
current.h
delay.h
device.h
div64.h __div64_32(): make it overridable at compile time 2015-11-16 14:42:12 -05:00
dma-contiguous.h asm-generic: Add dma-contiguous.h 2014-09-22 13:35:51 +02:00
dma.h
early_ioremap.h x86/mm: Extend early_memremap() support with additional attrs 2017-07-18 11:38:00 +02:00
emergency-restart.h
exec.h
export.h modversions: treat symbol CRCs as 32 bit quantities 2017-02-03 08:28:25 -08:00
extable.h add asm-generic/extable.h 2017-03-27 20:27:28 -04:00
fb.h
fixmap.h asm-generic: Fix local variable shadow in __set_fixmap_offset 2016-02-16 15:10:44 +00:00
ftrace.h
futex.h futex: Remove duplicated code and fix undefined behaviour 2017-08-25 22:49:59 +02:00
getorder.h
gpio.h gpio: allow setting ARCH_NR_GPIOS from Kconfig 2016-02-19 00:22:54 +01:00
hardirq.h
hugetlb.h mm/hugetlb: allow architectures to override huge_pte_clear() 2017-07-06 16:24:34 -07:00
hw_irq.h
ide_iops.h
int-ll64.h
io.h x86/io: Remove xlate_dev_kmem_ptr() duplication 2017-07-24 11:18:21 +02:00
ioctl.h include/asm-generic/ioctl.h: fix _IOC_TYPECHECK sparse error 2014-06-06 16:08:13 -07:00
iomap.h asm-generic/io.h: add io{read,write}64 accessors 2016-05-31 16:41:50 +08:00
irq_regs.h
irq_work.h irq_work: Introduce arch_irq_work_has_interrupt() 2014-09-13 18:38:07 +02:00
irq.h
irqflags.h
kdebug.h
kmap_types.h
kprobes.h kprobes: move kprobe declarations to asm-generic/kprobes.h 2017-02-27 18:43:45 -08:00
kvm_para.h
linkage.h
local64.h
local.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 mm: add PHYS_PFN, use it in __phys_to_pfn() 2016-01-14 16:00:49 -08:00
mm_hooks.h mm/gup: Drop the arch_pte_access_permitted() MMU callback 2017-03-18 09:48:01 +01:00
mm-arch-hooks.h mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
mmu_context.h asm-generic: Remove asm-generic arch_bprm_mm_init() 2014-11-22 21:52:08 +01:00
mmu.h
module.h
msi.h asm-generic: Add msi.h 2014-11-23 13:01:47 +01:00
page.h asm-generic: page.h: Remove useless get_user_page and free_user_page 2016-02-26 15:24:55 +01:00
param.h
parport.h
pci_iomap.h PCI: Add pci_iomap_wc() variants 2015-08-25 09:59:45 +02:00
pci.h PCI: Remove unused pcibios_select_root() (again) 2015-06-08 07:56:21 -05:00
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 asm-generic: introduce __ARCH_USE_5LEVEL_HACK 2017-03-09 11:48:47 -08:00
pgtable-nop4d.h asm-generic: introduce <asm-generic/pgtable-nop4d.h> 2017-03-09 11:48:47 -08:00
pgtable-nopmd.h
pgtable-nopud.h asm-generic: introduce <asm-generic/pgtable-nop4d.h> 2017-03-09 11:48:47 -08:00
pgtable.h mm: soft-dirty: keep soft-dirty bits over thp migration 2017-09-08 18:26:45 -07:00
preempt.h sched/preempt: Fix preempt_count manipulations 2016-05-17 12:24:21 +02:00
ptrace.h
qrwlock_types.h locking/qrwlock: Rename ->lock to ->wait_lock 2015-09-18 09:27:29 +02:00
qrwlock.h locking/qrwlock: Fix write unlock bug on big endian systems 2016-08-10 14:13:27 +02:00
qspinlock_types.h locking/qspinlock: Move __ARCH_SPIN_LOCK_UNLOCKED to qspinlock_types.h 2016-02-29 10:02:43 +01:00
qspinlock.h locking: Remove spin_unlock_wait() generic definitions 2017-08-17 08:08:58 -07:00
resource.h asm-generic: remove _STK_LIM_MAX 2014-05-15 00:32:09 +01:00
rwsem.h locking/rwsem: Remove unnecessary atomic_long_t casts 2017-01-20 09:46:44 +01:00
seccomp.h seccomp: Get compat syscalls from asm-generic header 2016-05-13 14:02:00 +02:00
sections.h irq: Make the irqentry text section unconditional 2017-08-10 16:28:53 +02:00
segment.h
serial.h
set_memory.h treewide: move set_memory_* functions away from cacheflush.h 2017-05-08 17:15:13 -07:00
signal.h
simd.h crypto: create generic version of ablk_helper 2013-09-24 06:02:24 +10:00
sizes.h
spinlock.h
statfs.h
string.h
switch_to.h
syscall.h syscall.h: fix doc text for syscall_get_arch() 2014-09-23 16:20:00 -04:00
syscalls.h
termios-base.h Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
termios.h Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
timex.h
tlb.h mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem 2017-08-10 15:54:07 -07:00
tlbflush.h
topology.h cpumask: fix spurious cpumask_of_node() on non-NUMA multi-node configs 2017-08-28 16:13:16 -07:00
trace_clock.h
uaccess.h fix the __user misannotations in asm-generic get_user/put_user 2017-09-04 12:07:24 -04:00
unaligned.h asm-generic: allow generic unaligned access if the arch supports it 2014-05-08 10:22:23 +02:00
unistd.h
user.h
vga.h
vmlinux.lds.h MTD changes for 4.14: 2017-09-09 14:48:21 -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 Make asm/word-at-a-time.h available on all architectures 2015-07-08 16:41:55 -04:00
xor.h