summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/kernel/entry_32.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
-rw-r--r--arch/powerpc/kernel/entry_32.S40
1 files changed, 9 insertions, 31 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 7ecc0d1855c..6f7eb7e00c7 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -1162,39 +1162,17 @@ machine_check_in_rtas:
#ifdef CONFIG_DYNAMIC_FTRACE
_GLOBAL(mcount)
_GLOBAL(_mcount)
- stwu r1,-48(r1)
- stw r3, 12(r1)
- stw r4, 16(r1)
- stw r5, 20(r1)
- stw r6, 24(r1)
- mflr r3
- stw r7, 28(r1)
- mfcr r5
- stw r8, 32(r1)
- stw r9, 36(r1)
- stw r10,40(r1)
- stw r3, 44(r1)
- stw r5, 8(r1)
- subi r3, r3, MCOUNT_INSN_SIZE
- .globl mcount_call
-mcount_call:
- bl ftrace_stub
- nop
- lwz r6, 8(r1)
- lwz r0, 44(r1)
- lwz r3, 12(r1)
+ /*
+ * It is required that _mcount on PPC32 must preserve the
+ * link register. But we have r0 to play with. We use r0
+ * to push the return address back to the caller of mcount
+ * into the ctr register, restore the link register and
+ * then jump back using the ctr register.
+ */
+ mflr r0
mtctr r0
- lwz r4, 16(r1)
- mtcr r6
- lwz r5, 20(r1)
- lwz r6, 24(r1)
- lwz r0, 52(r1)
- lwz r7, 28(r1)
- lwz r8, 32(r1)
+ lwz r0, 4(r1)
mtlr r0
- lwz r9, 36(r1)
- lwz r10,40(r1)
- addi r1, r1, 48
bctr
_GLOBAL(ftrace_caller)