diff options
Diffstat (limited to 'arch/arm64/include/asm/barrier.h')
| -rw-r--r-- | arch/arm64/include/asm/barrier.h | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h index c3009b0e5239..065ba482daf0 100644 --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -25,10 +25,6 @@ #define psb_csync() asm volatile("hint #17" : : : "memory") #define csdb() asm volatile("hint #20" : : : "memory") -#define spec_bar() asm volatile(ALTERNATIVE("dsb nsh\nisb\n", \ - SB_BARRIER_INSN"nop\n", \ - ARM64_HAS_SB)) - #ifdef CONFIG_ARM64_PSEUDO_NMI #define pmr_sync() \ do { \ @@ -70,6 +66,25 @@ static inline unsigned long array_index_mask_nospec(unsigned long idx, return mask; } +/* + * Ensure that reads of the counter are treated the same as memory reads + * for the purposes of ordering by subsequent memory barriers. + * + * This insanity brought to you by speculative system register reads, + * out-of-order memory accesses, sequence locks and Thomas Gleixner. + * + * http://lists.infradead.org/pipermail/linux-arm-kernel/2019-February/631195.html + */ +#define arch_counter_enforce_ordering(val) do { \ + u64 tmp, _val = (val); \ + \ + asm volatile( \ + " eor %0, %1, %1\n" \ + " add %0, sp, %0\n" \ + " ldr xzr, [%0]" \ + : "=r" (tmp) : "r" (_val)); \ +} while (0) + #define __smp_mb() dmb(ish) #define __smp_rmb() dmb(ishld) #define __smp_wmb() dmb(ishst) |