[PATCH v2 2/8] powerpc/signal64: Untangle setup_tm_sigcontexts() and user_access_begin()

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

Call setup_tm_sigcontexts() before opening user access to avoid
having to close and open again.

Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
---
v2: Add a stub setup_tm_sigcontexts() for when CONFIG_PPC_TRANSACTIONAL_MEM is not set
---
 arch/powerpc/kernel/signal_64.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 86bb5bb4c143..9b4cd0bbf4a7 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -203,8 +203,7 @@ static long notrace __unsafe_setup_sigcontext(struct sigcontext __user *sc,
  * examine the transactional registers in the 2nd sigcontext to determine the
  * real origin of the signal.
  */
-static long setup_tm_sigcontexts(struct sigcontext __user *sc,
-				 struct sigcontext __user *tm_sc,
+static long setup_tm_sigcontexts(struct rt_sigframe __user *frame,
 				 struct task_struct *tsk,
 				 int signr, sigset_t *set, unsigned long handler,
 				 unsigned long msr)
@@ -217,6 +216,8 @@ static long setup_tm_sigcontexts(struct sigcontext __user *sc,
 	 * Userland shall check AT_HWCAP to know wether it can rely on the
 	 * v_regs pointer or not.
 	 */
+	struct sigcontext __user *sc = &frame->uc.uc_mcontext;
+	struct sigcontext __user *tm_sc = &frame->uc_transact.uc_mcontext;
 #ifdef CONFIG_ALTIVEC
 	elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
 	elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
@@ -325,6 +326,15 @@ static long setup_tm_sigcontexts(struct sigcontext __user *sc,
 
 	return err;
 }
+#else
+static long setup_tm_sigcontexts(struct rt_sigframe __user *frame,
+				 struct task_struct *tsk,
+				 int signr, sigset_t *set, unsigned long handler,
+				 unsigned long msr)
+{
+	BUILD_BUG();
+	return -EINVAL;
+}
 #endif
 
 /*
@@ -872,6 +882,9 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 	 */
 	if (!MSR_TM_ACTIVE(msr))
 		prepare_setup_sigcontext(tsk);
+	else
+		err |= setup_tm_sigcontexts(frame, tsk, ksig->sig, NULL,
+					    (unsigned long)ksig->ka.sa.sa_handler, msr);
 
 	if (!user_write_access_begin(frame, sizeof(*frame)))
 		goto badframe;
@@ -889,19 +902,6 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 		 * ucontext_t (for transactional state) with its uc_link ptr.
 		 */
 		unsafe_put_user(&frame->uc_transact, &frame->uc.uc_link, badframe_block);
-
-		user_write_access_end();
-
-		err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
-					    &frame->uc_transact.uc_mcontext,
-					    tsk, ksig->sig, NULL,
-					    (unsigned long)ksig->ka.sa.sa_handler,
-					    msr);
-
-		if (!user_write_access_begin(&frame->uc.uc_sigmask,
-					     sizeof(frame->uc.uc_sigmask)))
-			goto badframe;
-
 #endif
 	} else {
 		unsafe_put_user(0, &frame->uc.uc_link, badframe_block);
-- 
2.54.0