diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 01e3c08cb5503617318d05c38ee3f02862e83125..8fdeca2d4597c35295271ff9ea844a91ea856a4d 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -803,10 +803,13 @@ static int do_setcontext(struct ucontext __user *ucp, struct pt_regs *regs, int
 		if (__get_user(cmcp, &ucp->uc_regs))
 			return -EFAULT;
 		mcp = (struct mcontext __user *)(u64)cmcp;
+		/* no need to check access_ok(mcp), since mcp < 4GB */
 	}
 #else
 	if (__get_user(mcp, &ucp->uc_regs))
 		return -EFAULT;
+	if (!access_ok(VERIFY_READ, mcp, sizeof(*mcp)))
+		return -EFAULT;
 #endif
 	restore_sigmask(&set);
 	if (restore_user_regs(regs, mcp, sig))
@@ -908,13 +911,14 @@ int sys_debug_setcontext(struct ucontext __user *ctx,
 {
 	struct sig_dbg_op op;
 	int i;
+	unsigned char tmp;
 	unsigned long new_msr = regs->msr;
 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
 	unsigned long new_dbcr0 = current->thread.dbcr0;
 #endif
 
 	for (i=0; i<ndbg; i++) {
-		if (__copy_from_user(&op, dbg, sizeof(op)))
+		if (copy_from_user(&op, dbg + i, sizeof(op)))
 			return -EFAULT;
 		switch (op.dbg_type) {
 		case SIG_DBG_SINGLE_STEPPING:
@@ -959,6 +963,11 @@ int sys_debug_setcontext(struct ucontext __user *ctx,
 	current->thread.dbcr0 = new_dbcr0;
 #endif
 
+	if (!access_ok(VERIFY_READ, ctx, sizeof(*ctx))
+	    || __get_user(tmp, (u8 __user *) ctx)
+	    || __get_user(tmp, (u8 __user *) (ctx + 1) - 1))
+		return -EFAULT;
+
 	/*
 	 * If we get a fault copying the context into the kernel's
 	 * image of the user's registers, we can't just return -EFAULT
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 27f65b95184d39eadfae53a877afd3e1ba6caafe..c2db642f4cdd44c32695432b9622406204fdd866 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -182,6 +182,8 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
 	err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
 	if (err)
 		return err;
+	if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
+		return -EFAULT;
 	/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
 	if (v_regs != 0 && (msr & MSR_VEC) != 0)
 		err |= __copy_from_user(current->thread.vr, v_regs,