@@ -237,12 +237,7 @@ transfer_to_handler_cont:
reenable_mmu:
/*
- * 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,
+ * We 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
@@ -933,18 +928,11 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_47x)
*/
andi. r10,r9,MSR_EE
beq 1f
- /*
- * Since the ftrace irqsoff latency trace checks CALLER_ADDR1,
- * which is the stack frame here, we need to force a stack frame
- * in case we came from user space.
- */
stwu r1,-32(r1)
mflr r0
stw r0,4(r1)
- stwu r1,-32(r1)
bl trace_hardirqs_on
- lwz r1,0(r1)
- lwz r1,0(r1)
+ addi r1, r1, 32
lwz r9,_MSR(r1)
1:
#endif /* CONFIG_TRACE_IRQFLAGS */
No need to add dummy frames when calling trace_hardirqs_on or trace_hardirqs_off. GCC properly handles empty stacks. In addition, powerpc doesn't set CONFIG_FRAME_POINTER, therefore __builtin_return_address(1..) returns NULL at all time. So the dummy frames are definitely unneeded here. In the meantime, avoid reading memory for loading r1 with a value we already know. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/kernel/entry_32.S | 16 ++-------------- 1 file changed, 2 insertions(+), 14 deletions(-)