[PATCH 2/5] powerpc: Fix vDSO clock_getres()
Christophe Leroy
christophe.leroy at c-s.fr
Tue Apr 2 16:54:47 AEDT 2019
On 04/01/2019 11:51 AM, Vincenzo Frascino wrote:
> clock_getres in the vDSO library has to preserve the same behaviour
> of posix_get_hrtimer_res().
>
> In particular, posix_get_hrtimer_res() does:
> sec = 0;
> ns = hrtimer_resolution;
> and hrtimer_resolution depends on the enablement of the high
> resolution timers that can happen either at compile or at run time.
>
> Fix the powerpc vdso implementation of clock_getres keeping a copy of
> hrtimer_resolution in vdso data and using that directly.
>
> Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Cc: Paul Mackerras <paulus at samba.org>
> Cc: Michael Ellerman <mpe at ellerman.id.au>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino at arm.com>
> ---
> arch/powerpc/include/asm/vdso_datapage.h | 2 ++
Conflicts with commit b5b4453e7912 ("powerpc/vdso64: Fix CLOCK_MONOTONIC
inconsistencies across Y2038")
Christophe
> arch/powerpc/kernel/asm-offsets.c | 2 +-
> arch/powerpc/kernel/time.c | 1 +
> arch/powerpc/kernel/vdso32/gettimeofday.S | 22 +++++++++++++++-------
> arch/powerpc/kernel/vdso64/gettimeofday.S | 22 +++++++++++++++-------
> 5 files changed, 34 insertions(+), 15 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h
> index 1afe90ade595..4ae43fc77fe9 100644
> --- a/arch/powerpc/include/asm/vdso_datapage.h
> +++ b/arch/powerpc/include/asm/vdso_datapage.h
> @@ -86,6 +86,7 @@ struct vdso_data {
> __s32 wtom_clock_nsec;
> struct timespec stamp_xtime; /* xtime as at tb_orig_stamp */
> __u32 stamp_sec_fraction; /* fractional seconds of stamp_xtime */
> + __u32 hrtimer_res; /* hrtimer resolution */
> __u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls */
> __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
> };
> @@ -107,6 +108,7 @@ struct vdso_data {
> __s32 wtom_clock_nsec;
> struct timespec stamp_xtime; /* xtime as at tb_orig_stamp */
> __u32 stamp_sec_fraction; /* fractional seconds of stamp_xtime */
> + __u32 hrtimer_res; /* hrtimer resolution */
> __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
> __u32 dcache_block_size; /* L1 d-cache block size */
> __u32 icache_block_size; /* L1 i-cache block size */
> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
> index 86a61e5f8285..52e4b98a8492 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -383,6 +383,7 @@ int main(void)
> OFFSET(WTOM_CLOCK_NSEC, vdso_data, wtom_clock_nsec);
> OFFSET(STAMP_XTIME, vdso_data, stamp_xtime);
> OFFSET(STAMP_SEC_FRAC, vdso_data, stamp_sec_fraction);
> + OFFSET(CLOCK_REALTIME_RES, vdso_data, hrtimer_res);
> OFFSET(CFG_ICACHE_BLOCKSZ, vdso_data, icache_block_size);
> OFFSET(CFG_DCACHE_BLOCKSZ, vdso_data, dcache_block_size);
> OFFSET(CFG_ICACHE_LOGBLOCKSZ, vdso_data, icache_log_block_size);
> @@ -413,7 +414,6 @@ int main(void)
> DEFINE(CLOCK_REALTIME_COARSE, CLOCK_REALTIME_COARSE);
> DEFINE(CLOCK_MONOTONIC_COARSE, CLOCK_MONOTONIC_COARSE);
> DEFINE(NSEC_PER_SEC, NSEC_PER_SEC);
> - DEFINE(CLOCK_REALTIME_RES, MONOTONIC_RES_NSEC);
>
> #ifdef CONFIG_BUG
> DEFINE(BUG_ENTRY_SIZE, sizeof(struct bug_entry));
> diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
> index bc0503ef9c9c..62c04a6746d8 100644
> --- a/arch/powerpc/kernel/time.c
> +++ b/arch/powerpc/kernel/time.c
> @@ -955,6 +955,7 @@ void update_vsyscall(struct timekeeper *tk)
> vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec;
> vdso_data->stamp_xtime = xt;
> vdso_data->stamp_sec_fraction = frac_sec;
> + vdso_data->hrtimer_res = hrtimer_resolution;
> smp_wmb();
> ++(vdso_data->tb_update_count);
> }
> diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
> index 1e0bc5955a40..b21630079496 100644
> --- a/arch/powerpc/kernel/vdso32/gettimeofday.S
> +++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
> @@ -160,14 +160,21 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
> cror cr0*4+eq,cr0*4+eq,cr1*4+eq
> bne cr0,99f
>
> - li r3,0
> - cmpli cr0,r4,0
> + mflr r12
> + .cfi_register lr,r12
> + mr r11,r4
> + bl __get_datapage at local
> + lwz r5,CLOCK_REALTIME_RES(r3)
> + li r4,0
> + cmplwi r11,0 /* check if res is NULL */
> + beq 1f
> +
> + stw r4,TSPC32_TV_SEC(r11)
> + stw r5,TSPC32_TV_NSEC(r11)
> +
> +1: mtlr r12
> crclr cr0*4+so
> - beqlr
> - lis r5,CLOCK_REALTIME_RES at h
> - ori r5,r5,CLOCK_REALTIME_RES at l
> - stw r3,TSPC32_TV_SEC(r4)
> - stw r5,TSPC32_TV_NSEC(r4)
> + li r3,0
> blr
>
> /*
> @@ -175,6 +182,7 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
> */
> 99:
> li r0,__NR_clock_getres
> + .cfi_restore lr
> sc
> blr
> .cfi_endproc
> diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S
> index a4ed9edfd5f0..a7e49bddd475 100644
> --- a/arch/powerpc/kernel/vdso64/gettimeofday.S
> +++ b/arch/powerpc/kernel/vdso64/gettimeofday.S
> @@ -190,14 +190,21 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
> cror cr0*4+eq,cr0*4+eq,cr1*4+eq
> bne cr0,99f
>
> - li r3,0
> - cmpldi cr0,r4,0
> + mflr r12
> + .cfi_register lr,r12
> + mr r11, r4
> + bl V_LOCAL_FUNC(__get_datapage)
> + lwz r5,CLOCK_REALTIME_RES(r3)
> + li r4,0
> + cmpldi r11,0 /* check if res is NULL */
> + beq 1f
> +
> + std r4,TSPC64_TV_SEC(r11)
> + std r5,TSPC64_TV_NSEC(r11)
> +
> +1: mtlr r12
> crclr cr0*4+so
> - beqlr
> - lis r5,CLOCK_REALTIME_RES at h
> - ori r5,r5,CLOCK_REALTIME_RES at l
> - std r3,TSPC64_TV_SEC(r4)
> - std r5,TSPC64_TV_NSEC(r4)
> + li r3,0
> blr
>
> /*
> @@ -205,6 +212,7 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
> */
> 99:
> li r0,__NR_clock_getres
> + .cfi_restore lr
> sc
> blr
> .cfi_endproc
>
More information about the Linuxppc-dev
mailing list