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@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
---
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
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
