[POWERPC] Fix VDSO gettimeofday() when called with NULL struct timeval

Consider the prototype for gettimeofday():
	int gettimofday(struct timeval *tv, struct timezone *tz);

Although it is valid to call with /either/ tv or tz being NULL, and
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 adds a check for tv being NULL so that it doesn't SEGV.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index 05909f754307..72ca26df457e 100644
--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/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)