On 10/12/2015 00:12, Andy Lutomirski wrote:
> 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 <luto@xxxxxxxxxx>
> ---
> 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 <asm/vvar.h>
> #include <asm/unistd.h>
> #include <asm/msr.h>
> +#include <asm/pvclock.h>
> #include <linux/math64.h>
> #include <linux/time.h>
> +#include <linux/kernel.h>
>
> #define gtod (&VVAR(vsyscall_gtod_data))
>
> @@ -43,10 +45,6 @@ extern u8 pvclock_page
>
> #ifndef BUILD_VDSO32
>
> -#include <linux/kernel.h>
> -#include <asm/vsyscall.h>
> -#include <asm/pvclock.h>
> -
> 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();
>
Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
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