linux-kernel - Re: [PATCH v2] powerpc/vdso: fix clock_gettime

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Message-ID: <87v9c3j6u5.fsf@mpe.ellerman.id.au>
Date:   Tue, 12 Jan 2021 12:13:06 +1100
From:   Michael Ellerman <mpe@...erman.id.au>
To:     Christophe Leroy <christophe.leroy@...roup.eu>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>, schwab@...ux-m68k.org
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v2] powerpc/vdso: fix clock_gettime_fallback for vdso32

Christophe Leroy <christophe.leroy@...roup.eu> writes:
> From: Andreas Schwab <schwab@...ux-m68k.org>
>
> 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@...ux-m68k.org>
> [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@...roup.eu>
> ---
>  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