On 02/04/2019 07:14, Christophe Leroy wrote: > > > 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 <b...@kernel.crashing.org> >> Cc: Paul Mackerras <pau...@samba.org> >> Cc: Michael Ellerman <m...@ellerman.id.au> >> Signed-off-by: Vincenzo Frascino <vincenzo.frasc...@arm.com> >> --- >> 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 | 22 +++++++++++++++------- >> arch/powerpc/kernel/vdso64/gettimeofday.S | 22 +++++++++++++++------- >> 5 files changed, 34 insertions(+), 15 deletions(-) >> > > [...] > >> 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@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@h >> - ori r5,r5,CLOCK_REALTIME_RES@l >> - stw r3,TSPC32_TV_SEC(r4) >> - stw r5,TSPC32_TV_NSEC(r4) >> + li r3,0 >> blr > > The above can be done simpler, see below > > @@ -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@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@h > - ori r5,r5,CLOCK_REALTIME_RES@l > stw r3,TSPC32_TV_SEC(r4) > stw r5,TSPC32_TV_NSEC(r4) > blr >
Thank you for this, I will update my code accordingly before posting v2. > Christophe > >> >> /* >> @@ -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@h >> - ori r5,r5,CLOCK_REALTIME_RES@l >> - std r3,TSPC64_TV_SEC(r4) >> - std r5,TSPC64_TV_NSEC(r4) >> + li r3,0 >> blr > > The same type of simplification applies here too. > > Christophe > > >> >> /* >> @@ -205,6 +212,7 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) >> */ >> 99: >> li r0,__NR_clock_getres >> + .cfi_restore lr >> sc >> blr >> .cfi_endproc >> -- Regards, Vincenzo
