diff options
Diffstat (limited to 'arch/arm64/include/asm/vdso/gettimeofday.h')
| -rw-r--r-- | arch/arm64/include/asm/vdso/gettimeofday.h | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/vdso/gettimeofday.h b/arch/arm64/include/asm/vdso/gettimeofday.h index 4f7a629df81f..764d13e2916c 100644 --- a/arch/arm64/include/asm/vdso/gettimeofday.h +++ b/arch/arm64/include/asm/vdso/gettimeofday.h @@ -7,8 +7,10 @@ #ifndef __ASSEMBLY__ +#include <asm/alternative.h> #include <asm/barrier.h> #include <asm/unistd.h> +#include <asm/sysreg.h> #define VDSO_HAS_CLOCK_GETRES 1 @@ -78,11 +80,20 @@ static __always_inline u64 __arch_get_hw_counter(s32 clock_mode, return 0; /* - * This isb() is required to prevent that the counter value + * If FEAT_ECV is available, use the self-synchronizing counter. + * Otherwise the isb is required to prevent that the counter value * is speculated. - */ - isb(); - asm volatile("mrs %0, cntvct_el0" : "=r" (res) :: "memory"); + */ + asm volatile( + ALTERNATIVE("isb\n" + "mrs %0, cntvct_el0", + "nop\n" + __mrs_s("%0", SYS_CNTVCTSS_EL0), + ARM64_HAS_ECV) + : "=r" (res) + : + : "memory"); + arch_counter_enforce_ordering(res); return res; |