Re: [PATCH v2] powerpc/vdso: fix clock_gettime_fallback for vdso32

From: Michael Ellerman
Date: Mon Jan 11 2021 - 20:14:20 EST


Christophe Leroy <christophe.leroy@xxxxxxxxxx> writes:
> From: Andreas Schwab <schwab@xxxxxxxxxxxxxx>
>
> The second argument of __kernel_clock_gettime64 points to a struct
> __kernel_timespec, with 64-bit time_t, so use the clock_gettime64 syscall
> in the fallback function for the 32-bit vdso. Similarily,
> clock_getres_fallback should use the clock_getres_time64 syscall, though
> it isn't yet called from the 32-bit vdso.
>
> Signed-off-by: Andreas Schwab <schwab@xxxxxxxxxxxxxx>
> [chleroy: Moved into the #ifdef CONFIG_VDSO32 block]

That doesn't build for 64-bit with compat VDSO. Should I just take
Andreas' version, or do you want to send a v3?

cheers

> Fixes: d0e3fc69d00d ("powerpc/vdso: Provide __kernel_clock_gettime64() on vdso32")
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> ---
> arch/powerpc/include/asm/vdso/gettimeofday.h | 27 +++++++++++++++-----
> 1 file changed, 21 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/vdso/gettimeofday.h b/arch/powerpc/include/asm/vdso/gettimeofday.h
> index 7a215cc5da77..3ecddd9c6302 100644
> --- a/arch/powerpc/include/asm/vdso/gettimeofday.h
> +++ b/arch/powerpc/include/asm/vdso/gettimeofday.h
> @@ -102,22 +102,22 @@ int gettimeofday_fallback(struct __kernel_old_timeval *_tv, struct timezone *_tz
> return do_syscall_2(__NR_gettimeofday, (unsigned long)_tv, (unsigned long)_tz);
> }
>
> +#ifdef CONFIG_VDSO32
> +
> +#define BUILD_VDSO32 1
> +
> static __always_inline
> int clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
> {
> - return do_syscall_2(__NR_clock_gettime, _clkid, (unsigned long)_ts);
> + return do_syscall_2(__NR_clock_gettime64, _clkid, (unsigned long)_ts);
> }
>
> static __always_inline
> int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
> {
> - return do_syscall_2(__NR_clock_getres, _clkid, (unsigned long)_ts);
> + return do_syscall_2(__NR_clock_getres_time64, _clkid, (unsigned long)_ts);
> }
>
> -#ifdef CONFIG_VDSO32
> -
> -#define BUILD_VDSO32 1
> -
> static __always_inline
> int clock_gettime32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
> {
> @@ -129,6 +129,21 @@ int clock_getres32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
> {
> return do_syscall_2(__NR_clock_getres, _clkid, (unsigned long)_ts);
> }
> +
> +#else
> +
> +static __always_inline
> +int clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
> +{
> + return do_syscall_2(__NR_clock_gettime, _clkid, (unsigned long)_ts);
> +}
> +
> +static __always_inline
> +int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
> +{
> + return do_syscall_2(__NR_clock_getres, _clkid, (unsigned long)_ts);
> +}
> +
> #endif
>
> static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
> --
> 2.25.0