[PATCH v2] Fix VDSO gettimeofday() when called with NULL struct timeval.
From: Tony Breeds <hidden>
Date: 2007-06-25 23:50:33
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 <redacted> 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 <redacted> CC: Benjamin Herrenschmidt <benh@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@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@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!