[PATCH v2] Fix VDSO gettimeofday() when called with NULL struct timeval.
Tony Breeds
tony at bakeyournoodle.com
Tue Jun 26 09:50:32 EST 2007
Updated to include feedback from Ben and Segher, also reposition the
compare in the 64bit VDSO to catch all the references to tv.
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>
---
Also fixes some whitespace damage at the top of vdso64/gettimeofday.S
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
+++ working/arch/powerpc/kernel/vdso32/gettimeofday.S
@@ -32,6 +32,8 @@ 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 */
+ cmplwi r10,0 /* check if tv is NULL */
+ beq 3f
bl __do_get_xsec at local /* get xsec from tb & kernel */
bne- 2f /* out of line -> do syscall */
@@ -50,7 +52,7 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
mulhwu r5,r5,r6
stw r5,TVAL32_TV_USEC(r10)
- cmpli cr0,r11,0 /* check if tz is NULL */
+3: cmplwi r11,0 /* check if tz is NULL */
beq 1f
lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */
lwz r5,CFG_TZ_DSTTIME(r9)
Index: working/arch/powerpc/kernel/vdso64/gettimeofday.S
===================================================================
--- working.orig/arch/powerpc/kernel/vdso64/gettimeofday.S
+++ working/arch/powerpc/kernel/vdso64/gettimeofday.S
@@ -1,5 +1,4 @@
-
- /*
+/*
* Userland implementation of gettimeofday() for 64 bits processes in a
* ppc64 kernel for use in the vDSO
*
@@ -32,6 +31,8 @@ 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 r10,0 /* check if tv is NULL */
+ beq 2f
bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */
lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */
ori r7,r7,16960
@@ -43,8 +44,8 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
* XSEC_PER_SEC
*/
rldicl r0,r0,44,20
- cmpldi cr0,r10,0 /* check if tz is NULL */
std r0,TVAL64_TV_USEC(r11) /* store usec in tv */
+2: cmpldi r10,0 /* check if tz is NULL */
beq 1f
lwz r4,CFG_TZ_MINUTEWEST(r3)/* fill tz */
lwz r5,CFG_TZ_DSTTIME(r3)
Yours Tony
linux.conf.au http://linux.conf.au/ || http://lca2008.linux.org.au/
Jan 28 - Feb 02 2008 The Australian Linux Technical Conference!
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