Instead of returning -EPERM when patch_instruction() fails,
just return what patch_instruction returns.
That simplifies ftrace_modify_code():
0: 94 21 ff c0 stwu r1,-64(r1)
4: 93 e1 00 3c stw r31,60(r1)
8: 7c 7f 1b 79 mr. r31,r3
c: 40 80 00 30 bge 3c <ftrace_modify_code+0x3c>
10: 93 c1 00 38 stw r30,56(r1)
14: 7c 9e 23 78 mr r30,r4
18: 7c a4 2b 78 mr r4,r5
1c: 80 bf 00 00 lwz r5,0(r31)
20: 7c 1e 28 40 cmplw r30,r5
24: 40 82 00 34 bne 58 <ftrace_modify_code+0x58>
28: 83 c1 00 38 lwz r30,56(r1)
2c: 7f e3 fb 78 mr r3,r31
30: 83 e1 00 3c lwz r31,60(r1)
34: 38 21 00 40 addi r1,r1,64
38: 48 00 00 00 b 38 <ftrace_modify_code+0x38>
38: R_PPC_REL24 patch_instruction
Before:
0: 94 21 ff c0 stwu r1,-64(r1)
4: 93 e1 00 3c stw r31,60(r1)
8: 7c 7f 1b 79 mr. r31,r3
c: 40 80 00 4c bge 58 <ftrace_modify_code+0x58>
10: 93 c1 00 38 stw r30,56(r1)
14: 7c 9e 23 78 mr r30,r4
18: 7c a4 2b 78 mr r4,r5
1c: 80 bf 00 00 lwz r5,0(r31)
20: 7c 08 02 a6 mflr r0
24: 90 01 00 44 stw r0,68(r1)
28: 7c 1e 28 40 cmplw r30,r5
2c: 40 82 00 48 bne 74 <ftrace_modify_code+0x74>
30: 7f e3 fb 78 mr r3,r31
34: 48 00 00 01 bl 34 <ftrace_modify_code+0x34>
34: R_PPC_REL24 patch_instruction
38: 80 01 00 44 lwz r0,68(r1)
3c: 20 63 00 00 subfic r3,r3,0
40: 83 c1 00 38 lwz r30,56(r1)
44: 7c 63 19 10 subfe r3,r3,r3
48: 7c 08 03 a6 mtlr r0
4c: 83 e1 00 3c lwz r31,60(r1)
50: 38 21 00 40 addi r1,r1,64
54: 4e 80 00 20 blr
It improves ftrace activation/deactivation duration by about 3%.
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
arch/powerpc/kernel/trace/ftrace.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/trace/ftrace.c
b/arch/powerpc/kernel/trace/ftrace.c
index 98e82fa4980f..1b05d33f96c6 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -78,10 +78,7 @@ ftrace_modify_code(unsigned long ip, ppc_inst_t old,
ppc_inst_t new)
}
/* replace the text with the new text */
- if (patch_instruction((u32 *)ip, new))
- return -EPERM;
-
- return 0;
+ return patch_instruction((u32 *)ip, new);
}
/*
--
2.35.1
