[PATCH] Save NVGPRS in 32-bit signal frame

[David Woodhouse]

Somehow this one slipped through the cracks; when we ended up in
do_signal() on a 32-bit kernel but without having the caller-saved
registers into the regs, we didn't set the TIF_SAVE_NVGPRS flag to
ensure they got saved later.

Signed-off-by: David Woodhouse <dwmw2 at infradead.org>

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -219,6 +218,15 @@ static inline int get_old_sigaction(stru
 static inline int save_general_regs(struct pt_regs *regs,
 		struct mcontext __user *frame)
 {
+	if (!FULL_REGS(regs)) {
+		/* Zero out the unsaved GPRs to avoid information
+		   leak, and set TIF_SAVE_NVGPRS to ensure that the
+		   registers do actually get saved later. */
+		memset(&regs->gpr[14], 0, 18 * sizeof(unsigned long));
+		current_thread_info()->nvgprs_frame = &frame->mc_gregs;
+		set_thread_flag(TIF_SAVE_NVGPRS);
+	}
+
 	return __copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE);
 }
 

-- 
dwmw2