Hi Gustavo,
Thanks for fixing that TM issue.
On 01/16/2020 07:05 PM, Gustavo Luiz Duarte wrote:
Fixes: 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context")
Cc: stable@xxxxxxxxxxxxxxx # v3.9
Signed-off-by: Gustavo Luiz Duarte <gustavold@xxxxxxxxxxxxx>
---
arch/powerpc/kernel/signal.c | 17 +++++++++++++++--
arch/powerpc/kernel/signal_32.c | 24 ++++++++++--------------
arch/powerpc/kernel/signal_64.c | 20 ++++++++------------
3 files changed, 33 insertions(+), 28 deletions(-)
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index e6c30cee6abf..1660be1061ac 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -200,14 +200,27 @@ unsigned long get_tm_stackpointer(struct task_struct *tsk)
* normal/non-checkpointed stack pointer.
*/
+ unsigned long ret = tsk->thread.regs->gpr[1];
+
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
BUG_ON(tsk != current);
if (MSR_TM_ACTIVE(tsk->thread.regs->msr)) {
+ preempt_disable();
tm_reclaim_current(TM_CAUSE_SIGNAL);
if (MSR_TM_TRANSACTIONAL(tsk->thread.regs->msr))
- return tsk->thread.ckpt_regs.gpr[1];
+ ret = tsk->thread.ckpt_regs.gpr[1];
+
+ /* If we treclaim, we must immediately clear the current
+ * thread's TM bits. Otherwise we might be preempted and have
+ * the live MSR[TS] changed behind our back
+ * (tm_recheckpoint_new_task() would recheckpoint).
+ * Besides, we enter the signal handler in non-transactional
+ * state.
+ */
+ tsk->thread.regs->msr &= ~MSR_TS_MASK;
+ preempt_enable();
}
#endif
- return tsk->thread.regs->gpr[1];
+ return ret;
}
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 98600b276f76..132a092cd170 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -489,19 +489,11 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
*/
static int save_tm_user_regs(struct pt_regs *regs,
struct mcontext __user *frame,
- struct mcontext __user *tm_frame, int sigret)
+ struct mcontext __user *tm_frame, int sigret,
+ unsigned long msr)
{
- unsigned long msr = regs->msr;
-
WARN_ON(tm_suspend_disabled);
- /* Remove TM bits from thread's MSR. The MSR in the sigcontext
- * just indicates to userland that we were doing a transaction, but we
- * don't want to return in transactional state. This also ensures
- * that flush_fp_to_thread won't set TIF_RESTORE_TM again.
- */
- regs->msr &= ~MSR_TS_MASK;
-
/* Save both sets of general registers */
if (save_general_regs(¤t->thread.ckpt_regs, frame)
|| save_general_regs(regs, tm_frame))
@@ -912,6 +904,8 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
int sigret;
unsigned long tramp;
struct pt_regs *regs = tsk->thread.regs;
+ /* Save the thread's msr before get_tm_stackpointer() changes it */
+ unsigned long msr = regs->msr;
BUG_ON(tsk != current);
@@ -944,13 +938,13 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
tm_frame = &rt_sf->uc_transact.uc_mcontext;
- if (MSR_TM_ACTIVE(regs->msr)) {
+ if (MSR_TM_ACTIVE(msr)) {
if (__put_user((unsigned long)&rt_sf->uc_transact,
&rt_sf->uc.uc_link) ||
__put_user((unsigned long)tm_frame,
&rt_sf->uc_transact.uc_regs))
goto badframe;
- if (save_tm_user_regs(regs, frame, tm_frame, sigret))
+ if (save_tm_user_regs(regs, frame, tm_frame, sigret, msr))
goto badframe;
}
else
@@ -1369,6 +1363,8 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
int sigret;
unsigned long tramp;
struct pt_regs *regs = tsk->thread.regs;
+ /* Save the thread's msr before get_tm_stackpointer() changes it */
+ unsigned long msr = regs->msr;
BUG_ON(tsk != current);
@@ -1402,9 +1398,9 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
tm_mctx = &frame->mctx_transact;
- if (MSR_TM_ACTIVE(regs->msr)) {
+ if (MSR_TM_ACTIVE(msr)) {
if (save_tm_user_regs(regs, &frame->mctx, &frame->mctx_transact,
- sigret))
+ sigret, msr))
goto badframe;
}
else
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 117515564ec7..e5b5f9738056 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -192,7 +192,8 @@ static long setup_sigcontext(struct sigcontext __user *sc,
static long setup_tm_sigcontexts(struct sigcontext __user *sc,
struct sigcontext __user *tm_sc,
struct task_struct *tsk,
- int signr, sigset_t *set, unsigned long handler)
+ int signr, sigset_t *set, unsigned long handler,
+ unsigned long msr)
{
/* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
* process never used altivec yet (MSR_VEC is zero in pt_regs of
@@ -207,12 +208,11 @@ static long setup_tm_sigcontexts(struct sigcontext __user *sc,
elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
#endif
struct pt_regs *regs = tsk->thread.regs;
- unsigned long msr = tsk->thread.regs->msr;
long err = 0;
BUG_ON(tsk != current);
- BUG_ON(!MSR_TM_ACTIVE(regs->msr));
+ BUG_ON(!MSR_TM_ACTIVE(msr));
WARN_ON(tm_suspend_disabled);
@@ -222,13 +222,6 @@ static long setup_tm_sigcontexts(struct sigcontext __user *sc,
*/
msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX);
- /* Remove TM bits from thread's MSR. The MSR in the sigcontext
- * just indicates to userland that we were doing a transaction, but we
- * don't want to return in transactional state. This also ensures
- * that flush_fp_to_thread won't set TIF_RESTORE_TM again.
- */
- regs->msr &= ~MSR_TS_MASK;
-
#ifdef CONFIG_ALTIVEC
err |= __put_user(v_regs, &sc->v_regs);
err |= __put_user(tm_v_regs, &tm_sc->v_regs);
@@ -824,6 +817,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
unsigned long newsp = 0;
long err = 0;
struct pt_regs *regs = tsk->thread.regs;
+ /* Save the thread's msr before get_tm_stackpointer() changes it */
+ unsigned long msr = regs->msr;
BUG_ON(tsk != current);
@@ -841,7 +836,7 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
err |= __put_user(0, &frame->uc.uc_flags);
err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]);
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
- if (MSR_TM_ACTIVE(regs->msr)) {
+ if (MSR_TM_ACTIVE(msr)) {
/* The ucontext_t passed to userland points to the second
* ucontext_t (for transactional state) with its uc_link ptr.
*/
@@ -849,7 +844,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
&frame->uc_transact.uc_mcontext,
tsk, ksig->sig, NULL,
- (unsigned long)ksig->ka.sa.sa_handler);
+ (unsigned long)ksig->ka.sa.sa_handler,
+ msr);
} else
#endif
{
The change needs to be improved in case CONFIG_PPC_TRANSACTIONAL_MEM=n, like:
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 132a092cd170..1b090a76b444 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -904,8 +904,10 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
int sigret;
unsigned long tramp;
struct pt_regs *regs = tsk->thread.regs;
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/* Save the thread's msr before get_tm_stackpointer() changes it */
unsigned long msr = regs->msr;
+#endif
BUG_ON(tsk != current);
@@ -1363,8 +1365,10 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
int sigret;
unsigned long tramp;
struct pt_regs *regs = tsk->thread.regs;
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/* Save the thread's msr before get_tm_stackpointer() changes it */
unsigned long msr = regs->msr;
+#endif
BUG_ON(tsk != current);
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index e5b5f9738056..84ed2e77ef9c 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -817,8 +817,10 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
unsigned long newsp = 0;
long err = 0;
struct pt_regs *regs = tsk->thread.regs;
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/* Save the thread's msr before get_tm_stackpointer() changes it */
unsigned long msr = regs->msr;
+#endif
BUG_ON(tsk != current);
or -Werror=unused-variable will catch it like:
/linux/arch/powerpc/kernel/signal_32.c: In function 'handle_rt_signal32':
/linux/arch/powerpc/kernel/signal_32.c:908:16: error: unused variable 'msr' [-Werror=unused-variable]
908 | unsigned long msr = regs->msr;
| ^~~
/linux/arch/powerpc/kernel/signal_32.c: In function 'handle_signal32':
/linux/arch/powerpc/kernel/signal_32.c:1367:16: error: unused variable 'msr' [-Werror=unused-variable]
1367 | unsigned long msr = regs->msr;
|
Feel free to send a v2 only after Mikey's review.
Otherwise, LGTM.
Reviewed-by: Gustavo Romero <gromero@xxxxxxxxxxxxx>
Best regards,
Gustavo
