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Subject[PATCH 3/6] ARM: ftrace: use gas macros to avoid code duplication
Date
Use assembler macros to avoid copy/pasting code between the
implementations of the two variants of the mcount call.

Signed-off-by: Rabin Vincent <rabin@rab.in>
---
arch/arm/kernel/entry-common.S | 146 ++++++++++++++++++++++------------------
1 files changed, 80 insertions(+), 66 deletions(-)

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 8bfa987..fe1d586 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -141,98 +141,112 @@ ENDPROC(ret_from_fork)
#endif
#endif

-#ifdef CONFIG_DYNAMIC_FTRACE
-ENTRY(__gnu_mcount_nc)
- mov ip, lr
- ldmia sp!, {lr}
- mov pc, ip
-ENDPROC(__gnu_mcount_nc)
+.macro __mcount suffix
+ mcount_enter
+ ldr r0, =ftrace_trace_function
+ ldr r2, [r0]
+ adr r0, .Lftrace_stub
+ cmp r0, r2
+ bne 1f
+ mcount_exit

-ENTRY(ftrace_caller)
- stmdb sp!, {r0-r3, lr}
- mov r0, lr
+1: mcount_get_lr r1 @ lr of instrumented func
+ mov r0, lr @ instrumented function
+ sub r0, r0, #MCOUNT_INSN_SIZE
+ adr lr, BSYM(2f)
+ mov pc, r2
+2: mcount_exit
+.endm
+
+.macro __ftrace_caller suffix
+ mcount_enter
+
+ mcount_get_lr r1 @ lr of instrumented func
+ mov r0, lr @ instrumented function
sub r0, r0, #MCOUNT_INSN_SIZE
- ldr r1, [sp, #20]

- .global ftrace_call
-ftrace_call:
+ .globl ftrace_call\suffix
+ftrace_call\suffix:
bl ftrace_stub
- ldmia sp!, {r0-r3, ip, lr}
- mov pc, ip
-ENDPROC(ftrace_caller)
+
+ mcount_exit
+.endm

#ifdef CONFIG_OLD_MCOUNT
+/*
+ * mcount
+ */
+
+.macro mcount_enter
+ stmdb sp!, {r0-r3, lr}
+.endm
+
+.macro mcount_get_lr reg
+ ldr \reg, [fp, #-4]
+.endm
+
+.macro mcount_exit
+ ldr lr, [fp, #-4]
+ ldmia sp!, {r0-r3, pc}
+.endm
+
ENTRY(mcount)
+#ifdef CONFIG_DYNAMIC_FTRACE
stmdb sp!, {lr}
ldr lr, [fp, #-4]
ldmia sp!, {pc}
+#else
+ __mcount _old
+#endif
ENDPROC(mcount)

+#ifdef CONFIG_DYNAMIC_FTRACE
ENTRY(ftrace_caller_old)
- stmdb sp!, {r0-r3, lr}
- ldr r1, [fp, #-4]
- mov r0, lr
- sub r0, r0, #MCOUNT_INSN_SIZE
-
- .globl ftrace_call_old
-ftrace_call_old:
- bl ftrace_stub
- ldr lr, [fp, #-4] @ restore lr
- ldmia sp!, {r0-r3, pc}
+ __ftrace_caller _old
ENDPROC(ftrace_caller_old)
#endif

-#else
+.purgem mcount_enter
+.purgem mcount_get_lr
+.purgem mcount_exit
+#endif

-ENTRY(__gnu_mcount_nc)
+/*
+ * __gnu_mcount_nc
+ */
+
+.macro mcount_enter
stmdb sp!, {r0-r3, lr}
- ldr r0, =ftrace_trace_function
- ldr r2, [r0]
- adr r0, .Lftrace_stub
- cmp r0, r2
- bne gnu_trace
+.endm
+
+.macro mcount_get_lr reg
+ ldr \reg, [sp, #20]
+.endm
+
+.macro mcount_exit
ldmia sp!, {r0-r3, ip, lr}
mov pc, ip
+.endm

-gnu_trace:
- ldr r1, [sp, #20] @ lr of instrumented routine
- mov r0, lr
- sub r0, r0, #MCOUNT_INSN_SIZE
- adr lr, BSYM(1f)
- mov pc, r2
-1:
- ldmia sp!, {r0-r3, ip, lr}
+ENTRY(__gnu_mcount_nc)
+#ifdef CONFIG_DYNAMIC_FTRACE
+ mov ip, lr
+ ldmia sp!, {lr}
mov pc, ip
+#else
+ __mcount
+#endif
ENDPROC(__gnu_mcount_nc)

-#ifdef CONFIG_OLD_MCOUNT
-/*
- * This is under an ifdef in order to force link-time errors for people trying
- * to build with !FRAME_POINTER with a GCC which doesn't use the new-style
- * mcount.
- */
-ENTRY(mcount)
- stmdb sp!, {r0-r3, lr}
- ldr r0, =ftrace_trace_function
- ldr r2, [r0]
- adr r0, ftrace_stub
- cmp r0, r2
- bne trace
- ldr lr, [fp, #-4] @ restore lr
- ldmia sp!, {r0-r3, pc}
-
-trace:
- ldr r1, [fp, #-4] @ lr of instrumented routine
- mov r0, lr
- sub r0, r0, #MCOUNT_INSN_SIZE
- mov lr, pc
- mov pc, r2
- ldr lr, [fp, #-4] @ restore lr
- ldmia sp!, {r0-r3, pc}
-ENDPROC(mcount)
+#ifdef CONFIG_DYNAMIC_FTRACE
+ENTRY(ftrace_caller)
+ __ftrace_caller
+ENDPROC(ftrace_caller)
#endif

-#endif /* CONFIG_DYNAMIC_FTRACE */
+.purgem mcount_enter
+.purgem mcount_get_lr
+.purgem mcount_exit

ENTRY(ftrace_stub)
.Lftrace_stub:
--
1.7.2.3


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