2 files changed, 29 insertions, 9 deletions

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 7484f43493d3..2d47cc79e5b3 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -1158,11 +1158,11 @@ SYSCALL_DEFINE0(rt_sigreturn)
 {
 	struct rt_sigframe __user *rt_sf;
 	struct pt_regs *regs = current_pt_regs();
+	int tm_restore = 0;
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 	struct ucontext __user *uc_transact;
 	unsigned long msr_hi;
 	unsigned long tmp;
-	int tm_restore = 0;
 #endif
 	/* Always make any pending restarted system calls return -EINTR */
 	current->restart_block.fn = do_no_restart_syscall;
@@ -1210,11 +1210,19 @@ SYSCALL_DEFINE0(rt_sigreturn)
 				goto bad;
 		}
 	}
-	if (!tm_restore)
-		/* Fall through, for non-TM restore */
+	if (!tm_restore) {
+		/*
+		 * Unset regs->msr because ucontext MSR TS is not
+		 * set, and recheckpoint was not called. This avoid
+		 * hitting a TM Bad thing at RFID
+		 */
+		regs->msr &= ~MSR_TS_MASK;
+	}
+	/* Fall through, for non-TM restore */
 #endif
-	if (do_setcontext(&rt_sf->uc, regs, 1))
-		goto bad;
+	if (!tm_restore)
+		if (do_setcontext(&rt_sf->uc, regs, 1))
+			goto bad;
 
 	/*
 	 * It's not clear whether or why it is desirable to save the
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index ba093ec5a21f..0935fe6c282a 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -757,11 +757,23 @@ SYSCALL_DEFINE0(rt_sigreturn)
 					   &uc_transact->uc_mcontext))
 			goto badframe;
 	}
-	else
-	/* Fall through, for non-TM restore */
 #endif
-	if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext))
-		goto badframe;
+	/* Fall through, for non-TM restore */
+	if (!MSR_TM_ACTIVE(msr)) {
+		/*
+		 * Unset MSR[TS] on the thread regs since MSR from user
+		 * context does not have MSR active, and recheckpoint was
+		 * not called since restore_tm_sigcontexts() was not called
+		 * also.
+		 *
+		 * If not unsetting it, the code can RFID to userspace with
+		 * MSR[TS] set, but without CPU in the proper state,
+		 * causing a TM bad thing.
+		 */
+		current->thread.regs->msr &= ~MSR_TS_MASK;
+		if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext))
+			goto badframe;
+	}
 
 	if (restore_altstack(&uc->uc_stack))
 		goto badframe;