From 76480a6a55a03d0fe5dd6290ccde7f78678ab85e Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 10 Dec 2015 19:20:22 -0800 Subject: [PATCH] x86/vdso: Enable vdso pvclock access on all vdso variants Now that pvclock doesn't require access to the fixmap, all vdso variants can use it. The kernel side isn't wired up for 32-bit kernels yet, but this covers 32-bit and x32 userspace on 64-bit kernels. Signed-off-by: Andy Lutomirski Reviewed-by: Paolo Bonzini Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/a7ef693b7a4c88dd2173dc1d4bf6bc27023626eb.1449702533.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/entry/vdso/vclock_gettime.c | 91 ++++++++++++---------------- 1 file changed, 40 insertions(+), 51 deletions(-) diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c index 59a98c25bde7..8602f06c759f 100644 --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -17,8 +17,10 @@ #include #include #include +#include #include #include +#include #define gtod (&VVAR(vsyscall_gtod_data)) @@ -43,10 +45,6 @@ extern u8 pvclock_page #ifndef BUILD_VDSO32 -#include -#include -#include - notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) { long ret; @@ -64,8 +62,42 @@ notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz) return ret; } -#ifdef CONFIG_PARAVIRT_CLOCK +#else + +notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) +{ + long ret; + + asm( + "mov %%ebx, %%edx \n" + "mov %2, %%ebx \n" + "call __kernel_vsyscall \n" + "mov %%edx, %%ebx \n" + : "=a" (ret) + : "0" (__NR_clock_gettime), "g" (clock), "c" (ts) + : "memory", "edx"); + return ret; +} + +notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz) +{ + long ret; + + asm( + "mov %%ebx, %%edx \n" + "mov %2, %%ebx \n" + "call __kernel_vsyscall \n" + "mov %%edx, %%ebx \n" + : "=a" (ret) + : "0" (__NR_gettimeofday), "g" (tv), "c" (tz) + : "memory", "edx"); + return ret; +} + +#endif + +#ifdef CONFIG_PARAVIRT_CLOCK static notrace const struct pvclock_vsyscall_time_info *get_pvti0(void) { return (const struct pvclock_vsyscall_time_info *)&pvclock_page; @@ -109,9 +141,9 @@ static notrace cycle_t vread_pvclock(int *mode) do { version = pvti->version; - /* This is also a read barrier, so we'll read version first. */ - tsc = rdtsc_ordered(); + smp_rmb(); + tsc = rdtsc_ordered(); pvti_tsc_to_system_mul = pvti->tsc_to_system_mul; pvti_tsc_shift = pvti->tsc_shift; pvti_system_time = pvti->system_time; @@ -126,7 +158,7 @@ static notrace cycle_t vread_pvclock(int *mode) pvclock_scale_delta(delta, pvti_tsc_to_system_mul, pvti_tsc_shift); - /* refer to tsc.c read_tsc() comment for rationale */ + /* refer to vread_tsc() comment for rationale */ last = gtod->cycle_last; if (likely(ret >= last)) @@ -136,49 +168,6 @@ static notrace cycle_t vread_pvclock(int *mode) } #endif -#else - -notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) -{ - long ret; - - asm( - "mov %%ebx, %%edx \n" - "mov %2, %%ebx \n" - "call __kernel_vsyscall \n" - "mov %%edx, %%ebx \n" - : "=a" (ret) - : "0" (__NR_clock_gettime), "g" (clock), "c" (ts) - : "memory", "edx"); - return ret; -} - -notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz) -{ - long ret; - - asm( - "mov %%ebx, %%edx \n" - "mov %2, %%ebx \n" - "call __kernel_vsyscall \n" - "mov %%edx, %%ebx \n" - : "=a" (ret) - : "0" (__NR_gettimeofday), "g" (tv), "c" (tz) - : "memory", "edx"); - return ret; -} - -#ifdef CONFIG_PARAVIRT_CLOCK - -static notrace cycle_t vread_pvclock(int *mode) -{ - *mode = VCLOCK_NONE; - return 0; -} -#endif - -#endif - notrace static cycle_t vread_tsc(void) { cycle_t ret = (cycle_t)rdtsc_ordered(); -- 2.20.1