[POWERPC] Make sure interrupt enable gets restored properly
The lazy IRQ disable patch missed a couple of places where the
interrupt enable flags need to be restored correctly. First, we
weren't restoring the paca->hard_enabled flag on interrupt exit.
Instead of saving it on entry, we compute it from the MSR_EE bit
in the MSR we are restoring at exit. Secondly, the MMU hash miss
code was clearing both paca->soft_enabled and paca->hard_enabled
but not restoring them in the case where hash_page was able to
resolve the miss from the Linux page tables.
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index efda487..86e2bdd 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -489,6 +489,10 @@
andi. r0,r3,MSR_RI
beq- unrecov_restore
+ /* extract EE bit and use it to restore paca->hard_enabled */
+ rldicl r4,r3,49,63 /* r0 = (r3 >> 15) & 1 */
+ stb r4,PACAHARDIRQEN(r13)
+
andi. r0,r3,MSR_PR
/*
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index c93d9f3..d289005 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -961,10 +961,18 @@
* any task or sent any task a signal, you should use
* ret_from_except or ret_from_except_lite instead of this.
*/
+fast_exc_return_irq: /* restores irq state too */
+ ld r3,SOFTE(r1)
+ ld r12,_MSR(r1)
+ stb r3,PACASOFTIRQEN(r13) /* restore paca->soft_enabled */
+ rldicl r4,r12,49,63 /* get MSR_EE to LSB */
+ stb r4,PACAHARDIRQEN(r13) /* restore paca->hard_enabled */
+ b 1f
+
.globl fast_exception_return
fast_exception_return:
ld r12,_MSR(r1)
- ld r11,_NIP(r1)
+1: ld r11,_NIP(r1)
andi. r3,r12,MSR_RI /* check if RI is set */
beq- unrecov_fer
@@ -1361,6 +1369,16 @@
* interrupts if necessary.
*/
beq .ret_from_except_lite
+END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
+#endif
+BEGIN_FW_FTR_SECTION
+ /*
+ * Here we have interrupts hard-disabled, so it is sufficient
+ * to restore paca->{soft,hard}_enable and get out.
+ */
+ beq fast_exc_return_irq /* Return from exception on success */
+END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES)
+
/* For a hash failure, we don't bother re-enabling interrupts */
ble- 12f
@@ -1372,14 +1390,6 @@
ld r3,SOFTE(r1)
bl .local_irq_restore
b 11f
-END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
-#endif
-BEGIN_FW_FTR_SECTION
- beq fast_exception_return /* Return from exception on success */
- ble- 12f /* Failure return from hash_page */
-
- /* fall through */
-END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES)
/* Here we have a page fault that hash_page can't handle. */
_GLOBAL(handle_page_fault)