ppc64: Fix v_regs pointer setup

During some signal test, we found that v_regs pointer was not setup correctly. v_regs was made to point to itself, as a result of which the pointer was corrupted when vec registers were copied over. When the signal handler returned, restore_sigcontext tried derefering the invalid pointer and in the process killed the app with SIGSEGV.

Following patch should fix it. Please review and apply:

---

 linux-2.6.8.1-vatsa/arch/ppc64/kernel/signal.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff -puN arch/ppc64/kernel/signal.c~signal_fix arch/ppc64/kernel/signal.c
@@ -127,7 +127,7 @@ static long setup_sigcontext(struct sigc
 	 * v_regs pointer or not
 	 */
 #ifdef CONFIG_ALTIVEC
-	elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve) & ~0xful);
+	elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 16) & ~0xful);
 #endif
 	long err = 0;
 

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Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017