344 lines
7.6 KiB
ArmAsm
344 lines
7.6 KiB
ArmAsm
/*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <asm/assembler.h>
|
|
#include <asm/ftrace.h>
|
|
#include <asm/unwind.h>
|
|
|
|
#include "entry-header.S"
|
|
|
|
/*
|
|
* When compiling with -pg, gcc inserts a call to the mcount routine at the
|
|
* start of every function. In mcount, apart from the function's address (in
|
|
* lr), we need to get hold of the function's caller's address.
|
|
*
|
|
* Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
|
|
*
|
|
* bl mcount
|
|
*
|
|
* These versions have the limitation that in order for the mcount routine to
|
|
* be able to determine the function's caller's address, an APCS-style frame
|
|
* pointer (which is set up with something like the code below) is required.
|
|
*
|
|
* mov ip, sp
|
|
* push {fp, ip, lr, pc}
|
|
* sub fp, ip, #4
|
|
*
|
|
* With EABI, these frame pointers are not available unless -mapcs-frame is
|
|
* specified, and if building as Thumb-2, not even then.
|
|
*
|
|
* Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
|
|
* with call sites like:
|
|
*
|
|
* push {lr}
|
|
* bl __gnu_mcount_nc
|
|
*
|
|
* With these compilers, frame pointers are not necessary.
|
|
*
|
|
* 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.)
|
|
*
|
|
* When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
|
|
* for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
|
|
* arch/arm/kernel/ftrace.c).
|
|
*/
|
|
|
|
#ifndef CONFIG_OLD_MCOUNT
|
|
#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
|
|
#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
|
|
#endif
|
|
#endif
|
|
|
|
.macro mcount_adjust_addr rd, rn
|
|
bic \rd, \rn, #1 @ clear the Thumb bit if present
|
|
sub \rd, \rd, #MCOUNT_INSN_SIZE
|
|
.endm
|
|
|
|
.macro __mcount suffix
|
|
mcount_enter
|
|
ldr r0, =ftrace_trace_function
|
|
ldr r2, [r0]
|
|
adr 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
|
|
#endif
|
|
|
|
mcount_exit
|
|
|
|
1: mcount_get_lr r1 @ lr of instrumented func
|
|
mcount_adjust_addr r0, lr @ instrumented function
|
|
badr lr, 2f
|
|
mov pc, r2
|
|
2: mcount_exit
|
|
.endm
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
|
|
.macro __ftrace_regs_caller
|
|
|
|
sub sp, sp, #8 @ space for PC and 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
|
|
|
|
str lr, [sp, #0] @ store LR instead of PC
|
|
|
|
ldr lr, [sp, #8] @ get previous LR
|
|
|
|
str r0, [sp, #8] @ write r0 as OLD_R0 over previous LR
|
|
|
|
stmdb sp!, {ip, lr}
|
|
stmdb sp!, {r0-r11, 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 |
|
|
|
|
mov r3, sp @ struct pt_regs*
|
|
|
|
ldr r2, =function_trace_op
|
|
ldr r2, [r2] @ pointer to the current
|
|
@ function tracing op
|
|
|
|
ldr r1, [sp, #S_LR] @ lr of instrumented func
|
|
|
|
ldr lr, [sp, #S_PC] @ get LR
|
|
|
|
mcount_adjust_addr r0, lr @ instrumented function
|
|
|
|
.globl ftrace_regs_call
|
|
ftrace_regs_call:
|
|
bl ftrace_stub
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
.globl ftrace_graph_regs_call
|
|
ftrace_graph_regs_call:
|
|
mov r0, r0
|
|
#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
|
|
.endm
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
.macro __ftrace_graph_regs_caller
|
|
|
|
sub r0, fp, #4 @ lr of instrumented routine (parent)
|
|
|
|
@ called from __ftrace_regs_caller
|
|
ldr r1, [sp, #S_PC] @ instrumented routine (func)
|
|
mcount_adjust_addr r1, r1
|
|
|
|
mov r2, fp @ frame pointer
|
|
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
|
|
|
|
.endm
|
|
#endif
|
|
#endif
|
|
|
|
.macro __ftrace_caller suffix
|
|
mcount_enter
|
|
|
|
mcount_get_lr r1 @ lr of instrumented func
|
|
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
|
|
@ function tracing op
|
|
mov r3, #0 @ regs is NULL
|
|
#endif
|
|
|
|
.globl ftrace_call\suffix
|
|
ftrace_call\suffix:
|
|
bl ftrace_stub
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
.globl ftrace_graph_call\suffix
|
|
ftrace_graph_call\suffix:
|
|
mov r0, r0
|
|
#endif
|
|
|
|
mcount_exit
|
|
.endm
|
|
|
|
.macro __ftrace_graph_caller
|
|
sub r0, fp, #4 @ &lr of instrumented routine (&parent)
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
@ called from __ftrace_caller, saved in mcount_enter
|
|
ldr r1, [sp, #16] @ instrumented routine (func)
|
|
mcount_adjust_addr r1, r1
|
|
#else
|
|
@ called from __mcount, untouched in lr
|
|
mcount_adjust_addr r1, lr @ instrumented routine (func)
|
|
#endif
|
|
mov r2, fp @ frame pointer
|
|
bl prepare_ftrace_return
|
|
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)
|
|
__ftrace_caller _old
|
|
ENDPROC(ftrace_caller_old)
|
|
#endif
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
ENTRY(ftrace_graph_caller_old)
|
|
__ftrace_graph_caller
|
|
ENDPROC(ftrace_graph_caller_old)
|
|
#endif
|
|
|
|
.purgem mcount_enter
|
|
.purgem mcount_get_lr
|
|
.purgem mcount_exit
|
|
#endif
|
|
|
|
/*
|
|
* __gnu_mcount_nc
|
|
*/
|
|
|
|
.macro mcount_enter
|
|
/*
|
|
* This pad compensates for the push {lr} at the call site. Note that we are
|
|
* unable to unwind through a function which does not otherwise save its lr.
|
|
*/
|
|
UNWIND(.pad #4)
|
|
stmdb sp!, {r0-r3, lr}
|
|
UNWIND(.save {r0-r3, lr})
|
|
.endm
|
|
|
|
.macro mcount_get_lr reg
|
|
ldr \reg, [sp, #20]
|
|
.endm
|
|
|
|
.macro mcount_exit
|
|
ldmia sp!, {r0-r3, ip, lr}
|
|
ret ip
|
|
.endm
|
|
|
|
ENTRY(__gnu_mcount_nc)
|
|
UNWIND(.fnstart)
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
mov ip, lr
|
|
ldmia sp!, {lr}
|
|
ret ip
|
|
#else
|
|
__mcount
|
|
#endif
|
|
UNWIND(.fnend)
|
|
ENDPROC(__gnu_mcount_nc)
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
ENTRY(ftrace_caller)
|
|
UNWIND(.fnstart)
|
|
__ftrace_caller
|
|
UNWIND(.fnend)
|
|
ENDPROC(ftrace_caller)
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
ENTRY(ftrace_regs_caller)
|
|
UNWIND(.fnstart)
|
|
__ftrace_regs_caller
|
|
UNWIND(.fnend)
|
|
ENDPROC(ftrace_regs_caller)
|
|
#endif
|
|
|
|
#endif
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
ENTRY(ftrace_graph_caller)
|
|
UNWIND(.fnstart)
|
|
__ftrace_graph_caller
|
|
UNWIND(.fnend)
|
|
ENDPROC(ftrace_graph_caller)
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
ENTRY(ftrace_graph_regs_caller)
|
|
UNWIND(.fnstart)
|
|
__ftrace_graph_regs_caller
|
|
UNWIND(.fnend)
|
|
ENDPROC(ftrace_graph_regs_caller)
|
|
#endif
|
|
#endif
|
|
|
|
.purgem mcount_enter
|
|
.purgem mcount_get_lr
|
|
.purgem mcount_exit
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
.globl return_to_handler
|
|
return_to_handler:
|
|
stmdb sp!, {r0-r3}
|
|
mov r0, fp @ frame pointer
|
|
bl ftrace_return_to_handler
|
|
mov lr, r0 @ r0 has real ret addr
|
|
ldmia sp!, {r0-r3}
|
|
ret lr
|
|
#endif
|
|
|
|
ENTRY(ftrace_stub)
|
|
.Lftrace_stub:
|
|
ret lr
|
|
ENDPROC(ftrace_stub)
|