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-rw-r--r--arch/powerpc/kernel/entry_32.S39
1 files changed, 21 insertions, 18 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 3e57a00b8cba..ba3aeb4bc06a 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -206,40 +206,43 @@ reenable_mmu: /* re-enable mmu so we can */
andi. r10,r10,MSR_EE /* Did EE change? */
beq 1f
- /* Save handler and return address into the 2 unused words
- * of the STACK_FRAME_OVERHEAD (sneak sneak sneak). Everything
- * else can be recovered from the pt_regs except r3 which for
- * normal interrupts has been set to pt_regs and for syscalls
- * is an argument, so we temporarily use ORIG_GPR3 to save it
- */
- stw r9,8(r1)
- stw r11,12(r1)
- stw r3,ORIG_GPR3(r1)
/*
* The trace_hardirqs_off will use CALLER_ADDR0 and CALLER_ADDR1.
* If from user mode there is only one stack frame on the stack, and
* accessing CALLER_ADDR1 will cause oops. So we need create a dummy
* stack frame to make trace_hardirqs_off happy.
+ *
+ * This is handy because we also need to save a bunch of GPRs,
+ * r3 can be different from GPR3(r1) at this point, r9 and r11
+ * contains the old MSR and handler address respectively,
+ * r4 & r5 can contain page fault arguments that need to be passed
+ * along as well. r12, CCR, CTR, XER etc... are left clobbered as
+ * they aren't useful past this point (aren't syscall arguments),
+ * the rest is restored from the exception frame.
*/
+ stwu r1,-32(r1)
+ stw r9,8(r1)
+ stw r11,12(r1)
+ stw r3,16(r1)
+ stw r4,20(r1)
+ stw r5,24(r1)
andi. r12,r12,MSR_PR
- beq 11f
- stwu r1,-16(r1)
+ b 11f
bl trace_hardirqs_off
- addi r1,r1,16
b 12f
-
11:
bl trace_hardirqs_off
12:
+ lwz r5,24(r1)
+ lwz r4,20(r1)
+ lwz r3,16(r1)
+ lwz r11,12(r1)
+ lwz r9,8(r1)
+ addi r1,r1,32
lwz r0,GPR0(r1)
- lwz r3,ORIG_GPR3(r1)
- lwz r4,GPR4(r1)
- lwz r5,GPR5(r1)
lwz r6,GPR6(r1)
lwz r7,GPR7(r1)
lwz r8,GPR8(r1)
- lwz r9,8(r1)
- lwz r11,12(r1)
1: mtctr r11
mtlr r9
bctr /* jump to handler */