[PATCH v2 2/5] powerpc: Fix vDSO clock_getres()

Christophe Leroy christophe.leroy at c-s.fr
Wed May 22 03:03:12 AEST 2019



Le 21/05/2019 à 18:46, Christophe Leroy a écrit :
> 
> 
> Le 21/05/2019 à 18:08, Vincenzo Frascino a écrit :
>> Hi Christophe,
>>
>> I did not see this patch in 5.2-rc1 and I was wondering if there is 
>> anything I
>> can do to help with upstraming it.
> 
> As far as I can see you series still has status 'new' in patchwork so I 
> guess Michael didn't have time to look at it 
> (https://patchwork.ozlabs.org/patch/1086410/)

Maybe you should also provide a Fixes: tag. What about:

Fixes: a7f290dad32e ("[PATCH] powerpc: Merge vdso's and add vdso support 
to 32 bits kernel")
Cc: stable at vger.kernel.org

Christophe

> 
>>
>> Please let me know.
> 
> 
> You series involves several arches, how do you plan to handle it ? Do 
> you expect each arch maintainer to take each patch independentely, or do 
> you expect acks from arch maintainers in order to merge the entire 
> series in a given tree (which one ?)
> 
> Christophe
> 
> 
>>
>> Thanks,
>> Vincenzo
>>
>> On 23/04/2019 17:33, Christophe Leroy wrote:
>>>
>>>
>>> Le 16/04/2019 à 18:14, Vincenzo Frascino a écrit :
>>>> 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>
>>>
>>> Reviewed-by: Christophe Leroy <christophe.leroy at c-s.fr>
>>>
>>>> ---
>>>>    arch/powerpc/include/asm/vdso_datapage.h  | 2 ++
>>>>    arch/powerpc/kernel/asm-offsets.c         | 2 +-
>>>>    arch/powerpc/kernel/time.c                | 1 +
>>>>    arch/powerpc/kernel/vdso32/gettimeofday.S | 7 +++++--
>>>>    arch/powerpc/kernel/vdso64/gettimeofday.S | 7 +++++--
>>>>    5 files changed, 14 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/include/asm/vdso_datapage.h 
>>>> b/arch/powerpc/include/asm/vdso_datapage.h
>>>> index bbc06bd72b1f..4333b9a473dc 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;            /* Wall to monotonic clock 
>>>> nsec */
>>>>        __s64 wtom_clock_sec;            /* Wall to monotonic clock 
>>>> sec */
>>>>        struct timespec stamp_xtime;        /* xtime as at 
>>>> tb_orig_stamp */
>>>> +    __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 afd516b572f8..2b5f9e83c610 100644
>>>> --- a/arch/powerpc/kernel/vdso32/gettimeofday.S
>>>> +++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
>>>> @@ -160,12 +160,15 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
>>>>        cror    cr0*4+eq,cr0*4+eq,cr1*4+eq
>>>>        bne    cr0,99f
>>>> +    mflr    r12
>>>> +  .cfi_register lr,r12
>>>> +    bl    __get_datapage at local
>>>> +    lwz    r5,CLOCK_REALTIME_RES(r3)
>>>> +    mtlr    r12
>>>>        li    r3,0
>>>>        cmpli    cr0,r4,0
>>>>        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)
>>>>        blr
>>>> diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S 
>>>> b/arch/powerpc/kernel/vdso64/gettimeofday.S
>>>> index 1f324c28705b..f07730f73d5e 100644
>>>> --- a/arch/powerpc/kernel/vdso64/gettimeofday.S
>>>> +++ b/arch/powerpc/kernel/vdso64/gettimeofday.S
>>>> @@ -190,12 +190,15 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
>>>>        cror    cr0*4+eq,cr0*4+eq,cr1*4+eq
>>>>        bne    cr0,99f
>>>> +    mflr    r12
>>>> +  .cfi_register lr,r12
>>>> +    bl    V_LOCAL_FUNC(__get_datapage)
>>>> +    lwz    r5,CLOCK_REALTIME_RES(r3)
>>>> +    mtlr    r12
>>>>        li    r3,0
>>>>        cmpldi    cr0,r4,0
>>>>        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)
>>>>        blr
>>>>
>>


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