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-rw-r--r--arch/arm/kernel/entry-ftrace.S128
1 files changed, 72 insertions, 56 deletions
diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S
index a74289ebc803..3e7bcaca5e07 100644
--- a/arch/arm/kernel/entry-ftrace.S
+++ b/arch/arm/kernel/entry-ftrace.S
@@ -22,12 +22,9 @@
* mcount can be thought of as a function called in the middle of a subroutine
* call. As such, it needs to be transparent for both the caller and the
* callee: the original lr needs to be restored when leaving mcount, and no
- * registers should be clobbered. (In the __gnu_mcount_nc implementation, we
- * clobber the ip register. This is OK because the ARM calling convention
- * allows it to be clobbered in subroutines and doesn't use it to hold
- * parameters.)
+ * registers should be clobbered.
*
- * When using dynamic ftrace, we patch out the mcount call by a "pop {lr}"
+ * When using dynamic ftrace, we patch out the mcount call by a "add sp, #4"
* instead of the __gnu_mcount_nc call (see arch/arm/kernel/ftrace.c).
*/
@@ -38,23 +35,20 @@
.macro __mcount suffix
mcount_enter
- ldr r0, =ftrace_trace_function
- ldr r2, [r0]
- adr r0, .Lftrace_stub
+ ldr_va r2, ftrace_trace_function
+ badr r0, .Lftrace_stub
cmp r0, r2
bne 1f
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- ldr r1, =ftrace_graph_return
- ldr r2, [r1]
- cmp r0, r2
- bne ftrace_graph_caller\suffix
-
- ldr r1, =ftrace_graph_entry
- ldr r2, [r1]
- ldr r0, =ftrace_graph_entry_stub
- cmp r0, r2
- bne ftrace_graph_caller\suffix
+ ldr_va r2, ftrace_graph_return
+ cmp r0, r2
+ bne ftrace_graph_caller\suffix
+
+ ldr_va r2, ftrace_graph_entry
+ mov_l r0, ftrace_graph_entry_stub
+ cmp r0, r2
+ bne ftrace_graph_caller\suffix
#endif
mcount_exit
@@ -70,29 +64,27 @@
.macro __ftrace_regs_caller
- sub sp, sp, #8 @ space for PC and CPSR OLD_R0,
+ str lr, [sp, #-8]! @ store LR as PC and make space for CPSR/OLD_R0,
@ OLD_R0 will overwrite previous LR
- add ip, sp, #12 @ move in IP the value of SP as it was
- @ before the push {lr} of the mcount mechanism
+ ldr lr, [sp, #8] @ get previous LR
- str lr, [sp, #0] @ store LR instead of PC
+ str r0, [sp, #8] @ write r0 as OLD_R0 over previous LR
- ldr lr, [sp, #8] @ get previous LR
+ str lr, [sp, #-4]! @ store previous LR as LR
- str r0, [sp, #8] @ write r0 as OLD_R0 over previous LR
+ add lr, sp, #16 @ move in LR the value of SP as it was
+ @ before the push {lr} of the mcount mechanism
- stmdb sp!, {ip, lr}
- stmdb sp!, {r0-r11, lr}
+ push {r0-r11, ip, lr}
@ stack content at this point:
@ 0 4 48 52 56 60 64 68 72
- @ R0 | R1 | ... | LR | SP + 4 | previous LR | LR | PSR | OLD_R0 |
+ @ R0 | R1 | ... | IP | SP + 4 | previous LR | LR | PSR | OLD_R0 |
- mov r3, sp @ struct pt_regs*
+ mov r3, sp @ struct pt_regs*
- ldr r2, =function_trace_op
- ldr r2, [r2] @ pointer to the current
+ ldr_va r2, function_trace_op @ pointer to the current
@ function tracing op
ldr r1, [sp, #S_LR] @ lr of instrumented func
@@ -108,35 +100,37 @@ ftrace_regs_call:
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_regs_call
ftrace_graph_regs_call:
- mov r0, r0
+ARM( mov r0, r0 )
+THUMB( nop.w )
#endif
@ pop saved regs
- ldmia sp!, {r0-r12} @ restore r0 through r12
- ldr ip, [sp, #8] @ restore PC
- ldr lr, [sp, #4] @ restore LR
- ldr sp, [sp, #0] @ restore SP
- mov pc, ip @ return
+ pop {r0-r11, ip, lr} @ restore r0 through r12
+ ldr lr, [sp], #4 @ restore LR
+ ldr pc, [sp], #12
.endm
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.macro __ftrace_graph_regs_caller
- sub r0, fp, #4 @ lr of instrumented routine (parent)
+#ifdef CONFIG_UNWINDER_FRAME_POINTER
+ sub r0, fp, #4 @ lr of instrumented routine (parent)
+#else
+ add r0, sp, #S_LR
+#endif
@ called from __ftrace_regs_caller
- ldr r1, [sp, #S_PC] @ instrumented routine (func)
+ ldr r1, [sp, #S_PC] @ instrumented routine (func)
mcount_adjust_addr r1, r1
- mov r2, fp @ frame pointer
+ mov r2, fpreg @ frame pointer
+ add r3, sp, #PT_REGS_SIZE
bl prepare_ftrace_return
@ pop registers saved in ftrace_regs_caller
- ldmia sp!, {r0-r12} @ restore r0 through r12
- ldr ip, [sp, #8] @ restore PC
- ldr lr, [sp, #4] @ restore LR
- ldr sp, [sp, #0] @ restore SP
- mov pc, ip @ return
+ pop {r0-r11, ip, lr} @ restore r0 through r12
+ ldr lr, [sp], #4 @ restore LR
+ ldr pc, [sp], #12
.endm
#endif
@@ -149,8 +143,7 @@ ftrace_graph_regs_call:
mcount_adjust_addr r0, lr @ instrumented function
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- ldr r2, =function_trace_op
- ldr r2, [r2] @ pointer to the current
+ ldr_va r2, function_trace_op @ pointer to the current
@ function tracing op
mov r3, #0 @ regs is NULL
#endif
@@ -162,14 +155,19 @@ ftrace_call\suffix:
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_call\suffix
ftrace_graph_call\suffix:
- mov r0, r0
+ARM( mov r0, r0 )
+THUMB( nop.w )
#endif
mcount_exit
.endm
.macro __ftrace_graph_caller
+#ifdef CONFIG_UNWINDER_FRAME_POINTER
sub r0, fp, #4 @ &lr of instrumented routine (&parent)
+#else
+ add r0, sp, #20
+#endif
#ifdef CONFIG_DYNAMIC_FTRACE
@ called from __ftrace_caller, saved in mcount_enter
ldr r1, [sp, #16] @ instrumented routine (func)
@@ -178,7 +176,8 @@ ftrace_graph_call\suffix:
@ called from __mcount, untouched in lr
mcount_adjust_addr r1, lr @ instrumented routine (func)
#endif
- mov r2, fp @ frame pointer
+ mov r2, fpreg @ frame pointer
+ add r3, sp, #24
bl prepare_ftrace_return
mcount_exit
.endm
@@ -202,16 +201,17 @@ ftrace_graph_call\suffix:
.endm
.macro mcount_exit
- ldmia sp!, {r0-r3, ip, lr}
- ret ip
+ ldmia sp!, {r0-r3}
+ ldr lr, [sp, #4]
+ ldr pc, [sp], #8
.endm
ENTRY(__gnu_mcount_nc)
UNWIND(.fnstart)
#ifdef CONFIG_DYNAMIC_FTRACE
- mov ip, lr
- ldmia sp!, {lr}
- ret ip
+ push {lr}
+ ldr lr, [sp, #4]
+ ldr pc, [sp], #8
#else
__mcount
#endif
@@ -256,17 +256,33 @@ ENDPROC(ftrace_graph_regs_caller)
.purgem mcount_exit
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- .globl return_to_handler
-return_to_handler:
+ENTRY(return_to_handler)
stmdb sp!, {r0-r3}
- mov r0, fp @ frame pointer
+ add r0, sp, #16 @ sp at exit of instrumented routine
bl ftrace_return_to_handler
mov lr, r0 @ r0 has real ret addr
ldmia sp!, {r0-r3}
ret lr
+ENDPROC(return_to_handler)
#endif
ENTRY(ftrace_stub)
.Lftrace_stub:
ret lr
ENDPROC(ftrace_stub)
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+ __INIT
+
+ .macro init_tramp, dst:req
+ENTRY(\dst\()_from_init)
+ ldr pc, =\dst
+ENDPROC(\dst\()_from_init)
+ .endm
+
+ init_tramp ftrace_caller
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+ init_tramp ftrace_regs_caller
+#endif
+#endif
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