Both rt_sigreturn() and handle_rt_signal_64() contain TM-related ifdefs
which break-up an if/else block. Provide stubs for the ifdef-guarded TM
functions and remove the need for an ifdef in rt_sigreturn().
Rework the remaining TM ifdef in handle_rt_signal64() similar to
commit f1cf4f93de2f ("powerpc/signal32: Remove ifdefery in middle of if/else").
Unlike in the commit for ppc32, the ifdef can't be removed entirely
since uc_transact in sigframe depends on CONFIG_PPC_TRANSACTIONAL_MEM.
Signed-off-by: Christopher M. Riedl <c...@codefail.de>
---
arch/powerpc/kernel/process.c | 3 +-
arch/powerpc/kernel/signal_64.c | 102 ++++++++++++++++----------------
2 files changed, 54 insertions(+), 51 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 924d023dad0a..08c3fbe45921 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1117,9 +1117,10 @@ void restore_tm_state(struct pt_regs *regs)
regs->msr |= msr_diff;
}
-#else
+#else /* !CONFIG_PPC_TRANSACTIONAL_MEM */
#define tm_recheckpoint_new_task(new)
#define __switch_to_tm(prev, new)
+void tm_reclaim_current(uint8_t cause) {}
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
static inline void save_sprs(struct thread_struct *t)
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 6ca546192cbf..bd8d210c9115 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -594,6 +594,12 @@ static long restore_tm_sigcontexts(struct task_struct *tsk,
return err;
}
+#else /* !CONFIG_PPC_TRANSACTIONAL_MEM */
+static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext
__user *sc,
+ struct sigcontext __user *tm_sc)
+{
+ return -EINVAL;
+}
#endif
/*
@@ -710,9 +716,7 @@ SYSCALL_DEFINE0(rt_sigreturn)
struct pt_regs *regs = current_pt_regs();
struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
sigset_t set;
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
unsigned long msr;
-#endif
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
@@ -724,48 +728,50 @@ SYSCALL_DEFINE0(rt_sigreturn)
goto badframe;
set_current_blocked(&set);
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
- /*
- * If there is a transactional state then throw it away.
- * The purpose of a sigreturn is to destroy all traces of the
- * signal frame, this includes any transactional state created
- * within in. We only check for suspended as we can never be
- * active in the kernel, we are active, there is nothing better to
- * do than go ahead and Bad Thing later.
- * The cause is not important as there will never be a
- * recheckpoint so it's not user visible.
- */
- if (MSR_TM_SUSPENDED(mfmsr()))
- tm_reclaim_current(0);
+ if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM)) {
+ /*
+ * If there is a transactional state then throw it away.
+ * The purpose of a sigreturn is to destroy all traces of the
+ * signal frame, this includes any transactional state created
+ * within in. We only check for suspended as we can never be
+ * active in the kernel, we are active, there is nothing better
to
+ * do than go ahead and Bad Thing later.
+ * The cause is not important as there will never be a
+ * recheckpoint so it's not user visible.
+ */
+ if (MSR_TM_SUSPENDED(mfmsr()))
+ tm_reclaim_current(0);
- /*
- * Disable MSR[TS] bit also, so, if there is an exception in the
- * code below (as a page fault in copy_ckvsx_to_user()), it does
- * not recheckpoint this task if there was a context switch inside
- * the exception.
- *
- * A major page fault can indirectly call schedule(). A reschedule
- * process in the middle of an exception can have a side effect
- * (Changing the CPU MSR[TS] state), since schedule() is called
- * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended
- * (switch_to() calls tm_recheckpoint() for the 'new' process). In
- * this case, the process continues to be the same in the CPU, but
- * the CPU state just changed.
- *
- * This can cause a TM Bad Thing, since the MSR in the stack will
- * have the MSR[TS]=0, and this is what will be used to RFID.
- *
- * Clearing MSR[TS] state here will avoid a recheckpoint if there
- * is any process reschedule in kernel space. The MSR[TS] state
- * does not need to be saved also, since it will be replaced with
- * the MSR[TS] that came from user context later, at
- * restore_tm_sigcontexts.
- */
- regs->msr &= ~MSR_TS_MASK;
+ /*
+ * Disable MSR[TS] bit also, so, if there is an exception in the
+ * code below (as a page fault in copy_ckvsx_to_user()), it does
+ * not recheckpoint this task if there was a context switch
inside
+ * the exception.
+ *
+ * A major page fault can indirectly call schedule(). A
reschedule
+ * process in the middle of an exception can have a side effect
+ * (Changing the CPU MSR[TS] state), since schedule() is called
+ * with the CPU MSR[TS] disable and returns with
MSR[TS]=Suspended
+ * (switch_to() calls tm_recheckpoint() for the 'new' process).
In
+ * this case, the process continues to be the same in the CPU,
but
+ * the CPU state just changed.
+ *
+ * This can cause a TM Bad Thing, since the MSR in the stack
will
+ * have the MSR[TS]=0, and this is what will be used to RFID.
+ *
+ * Clearing MSR[TS] state here will avoid a recheckpoint if
there
+ * is any process reschedule in kernel space. The MSR[TS] state
+ * does not need to be saved also, since it will be replaced
with
+ * the MSR[TS] that came from user context later, at
+ * restore_tm_sigcontexts.
+ */
+ regs->msr &= ~MSR_TS_MASK;
- if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
- goto badframe;
- if (MSR_TM_ACTIVE(msr)) {
+ if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
+ goto badframe;
+ }
+
+ if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && MSR_TM_ACTIVE(msr)) {
/* We recheckpoint on return. */
struct ucontext __user *uc_transact;
@@ -778,9 +784,7 @@ SYSCALL_DEFINE0(rt_sigreturn)
if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
&uc_transact->uc_mcontext))
goto badframe;
- } else
-#endif
- {
+ } else {
/*
* Fall through, for non-TM restore
*
@@ -818,10 +822,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
unsigned long newsp = 0;
long err = 0;
struct pt_regs *regs = tsk->thread.regs;
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/* Save the thread's msr before get_tm_stackpointer() changes it */
unsigned long msr = regs->msr;
-#endif
frame = get_sigframe(ksig, tsk, sizeof(*frame), 0);
if (!access_ok(frame, sizeof(*frame)))
@@ -836,8 +838,9 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
/* Create the ucontext. */
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(msr)) {
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/* The ucontext_t passed to userland points to the second
* ucontext_t (for transactional state) with its uc_link ptr.
*/
@@ -847,9 +850,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
tsk, ksig->sig, NULL,
(unsigned
long)ksig->ka.sa.sa_handler,
msr);
- } else
#endif
- {
+ } else {
err |= __put_user(0, &frame->uc.uc_link);
prepare_setup_sigcontext(tsk);
err |= setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
--
2.26.1
