[PATCH 3.8 04/14] ftrace/x86: Load ftrace_ops in parameter not the variable holding it

From: Kamal Mostafa
Date: Fri Jan 31 2014 - 12:33:23 EST


3.8.13.17 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Steven Rostedt <rostedt@xxxxxxxxxxx>

commit 1739f09e33d8f66bf48ddbc3eca615574da6c4f6 upstream.

Function tracing callbacks expect to have the ftrace_ops that registered it
passed to them, not the address of the variable that holds the ftrace_ops
that registered it.

Use a mov instead of a lea to store the ftrace_ops into the parameter
of the function tracing callback.

Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20131113152004.459787f9@xxxxxxxxxxxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
arch/x86/kernel/entry_32.S | 4 ++--
arch/x86/kernel/entry_64.S | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 6ed91d9..1d7fdbe 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1113,7 +1113,7 @@ ENTRY(ftrace_caller)
pushl $0 /* Pass NULL as regs pointer */
movl 4*4(%esp), %eax
movl 0x4(%ebp), %edx
- leal function_trace_op, %ecx
+ movl function_trace_op, %ecx
subl $MCOUNT_INSN_SIZE, %eax

.globl ftrace_call
@@ -1171,7 +1171,7 @@ ENTRY(ftrace_regs_caller)
movl 12*4(%esp), %eax /* Load ip (1st parameter) */
subl $MCOUNT_INSN_SIZE, %eax /* Adjust ip */
movl 0x4(%ebp), %edx /* Load parent ip (2nd parameter) */
- leal function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */
+ movl function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */
pushl %esp /* Save pt_regs as 4th parameter */

GLOBAL(ftrace_regs_call)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index cb3c591..310b270 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -88,7 +88,7 @@ END(function_hook)
MCOUNT_SAVE_FRAME \skip

/* Load the ftrace_ops into the 3rd parameter */
- leaq function_trace_op, %rdx
+ movq function_trace_op(%rip), %rdx

/* Load ip into the first parameter */
movq RIP(%rsp), %rdi
--
1.8.3.2

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