[PATCH] Fix VDSO gettimeofday() when called with NULL struct timeval.
Tony Breeds
tony at bakeyournoodle.com
Mon Jun 25 20:58:36 EST 2007
Hi Paul,
It'd be nice if this made it into 2.6.22, esp. now that more
distros are shipping glibc's that will use the VDSO.
I think I got the asm right, it works on pSerie, either way feedback
welcome.
From: Tony Breeds <tony at bakeyournoodle.com>
Fix VDSO gettimeofday() when called with NULL struct timeval.
Consider the prototype for gettimeofday():
int gettimofday(struct timeval *tv, struct timezone *tz);
AFAICT it is valid to call with /either/ tv or tz being NULL, the C version
of sys_gettimeofday() supports this, the current version of gettimeofday() in
the VDSO will SEGV if called with a NULL tv.
This patch fixes this.
Signed-off-by: Tony Breeds <tony at bakeyournoodle.com>
CC: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---
arch/powerpc/kernel/vdso32/gettimeofday.S | 13 +++++++------
arch/powerpc/kernel/vdso64/gettimeofday.S | 8 +++++---
2 files changed, 12 insertions(+), 9 deletions(-)
Index: working/arch/powerpc/kernel/vdso32/gettimeofday.S
===================================================================
--- working.orig/arch/powerpc/kernel/vdso32/gettimeofday.S 2007-06-25 19:35:47.000000000 +1000
+++ working/arch/powerpc/kernel/vdso32/gettimeofday.S 2007-06-25 19:40:34.000000000 +1000
@@ -32,8 +32,10 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
mr r11,r4 /* r11 saves tz */
bl __get_datapage at local /* get data page */
mr r9, r3 /* datapage ptr in r9 */
+ cmpli cr0,r10,0 /* check if tv is NULL */
+ beq 1f
bl __do_get_xsec at local /* get xsec from tb & kernel */
- bne- 2f /* out of line -> do syscall */
+ bne- 3f /* out of line -> do syscall */
/* seconds are xsec >> 20 */
rlwinm r5,r4,12,20,31
@@ -50,20 +52,19 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
mulhwu r5,r5,r6
stw r5,TVAL32_TV_USEC(r10)
- cmpli cr0,r11,0 /* check if tz is NULL */
- beq 1f
+1: cmpli cr0,r11,0 /* check if tz is NULL */
+ beq 2f
lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */
lwz r5,CFG_TZ_DSTTIME(r9)
stw r4,TZONE_TZ_MINWEST(r11)
stw r5,TZONE_TZ_DSTTIME(r11)
-1: mtlr r12
+2: mtlr r12
crclr cr0*4+so
li r3,0
blr
-2:
- mtlr r12
+3: mtlr r12
mr r3,r10
mr r4,r11
li r0,__NR_gettimeofday
Index: working/arch/powerpc/kernel/vdso64/gettimeofday.S
===================================================================
--- working.orig/arch/powerpc/kernel/vdso64/gettimeofday.S 2007-06-25 19:35:52.000000000 +1000
+++ working/arch/powerpc/kernel/vdso64/gettimeofday.S 2007-06-25 19:42:45.000000000 +1000
@@ -32,6 +32,8 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
mr r11,r3 /* r11 holds tv */
mr r10,r4 /* r10 holds tz */
bl V_LOCAL_FUNC(__get_datapage) /* get data page */
+ cmpldi cr0,r11,0 /* check if tv is NULL */
+ beq 1f
bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */
lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */
ori r7,r7,16960
@@ -43,14 +45,14 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
* XSEC_PER_SEC
*/
rldicl r0,r0,44,20
- cmpldi cr0,r10,0 /* check if tz is NULL */
+1: cmpldi cr0,r10,0 /* check if tz is NULL */
std r0,TVAL64_TV_USEC(r11) /* store usec in tv */
- beq 1f
+ beq 2f
lwz r4,CFG_TZ_MINUTEWEST(r3)/* fill tz */
lwz r5,CFG_TZ_DSTTIME(r3)
stw r4,TZONE_TZ_MINWEST(r10)
stw r5,TZONE_TZ_DSTTIME(r10)
-1: mtlr r12
+2: mtlr r12
crclr cr0*4+so
li r3,0 /* always success */
blr
Yours Tony
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