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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-02-02 23:22:20 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-02-02 23:22:20 -0300
commit5c545e1fb127a4b11ddc5f1a5ed066b853dd1a1a (patch)
treed4cd913bc79d37d32756a9bffbeedabf93e32579 /arch/powerpc/kernel/process.c
parentb4b7ff4b08e691656c9d77c758fc355833128ac0 (diff)
Linux-libre 4.4.1-gnupck-4.4.1-gnu
Diffstat (limited to 'arch/powerpc/kernel/process.c')
-rw-r--r--arch/powerpc/kernel/process.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 646bf4d22..ef2ad2d68 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -569,6 +569,24 @@ static void tm_reclaim_thread(struct thread_struct *thr,
if (!MSR_TM_SUSPENDED(mfmsr()))
return;
+ /*
+ * Use the current MSR TM suspended bit to track if we have
+ * checkpointed state outstanding.
+ * On signal delivery, we'd normally reclaim the checkpointed
+ * state to obtain stack pointer (see:get_tm_stackpointer()).
+ * This will then directly return to userspace without going
+ * through __switch_to(). However, if the stack frame is bad,
+ * we need to exit this thread which calls __switch_to() which
+ * will again attempt to reclaim the already saved tm state.
+ * Hence we need to check that we've not already reclaimed
+ * this state.
+ * We do this using the current MSR, rather tracking it in
+ * some specific thread_struct bit, as it has the additional
+ * benifit of checking for a potential TM bad thing exception.
+ */
+ if (!MSR_TM_SUSPENDED(mfmsr()))
+ return;
+
tm_reclaim(thr, thr->regs->msr, cause);
/* Having done the reclaim, we now have the checkpointed