From bbffdd2fc743bdc529f9a8264bdb5d3491f58c95 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 9 May 2022 07:36:05 +0200 Subject: powerpc/ftrace: Use patch_instruction() return directly 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 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 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 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 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 30: 7f e3 fb 78 mr r3,r31 34: 48 00 00 01 bl 34 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%. Modify patch_instruction() return on failure to -EPERM in order to match with ftrace expectations. Other users of patch_instruction() do not care about the exact error value returned. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/49a8597230713e2633e7d9d7b56140787c4a7e20.1652074503.git.christophe.leroy@csgroup.eu --- arch/powerpc/kernel/trace/ftrace.c | 5 +---- arch/powerpc/lib/code-patching.c | 2 +- 2 files changed, 2 insertions(+), 5 deletions(-) (limited to 'arch/powerpc') 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); } /* diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 46ffce27135e..6edf0697a526 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -33,7 +33,7 @@ static int __patch_instruction(u32 *exec_addr, ppc_inst_t instr, u32 *patch_addr return 0; failed: - return -EFAULT; + return -EPERM; } int raw_patch_instruction(u32 *addr, ppc_inst_t instr) -- cgit v1.2.3