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ARM: 6318/1: ftrace: fix and update dynamic ftrace

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This adds mcount recording and updates dynamic ftrace for ARM to work
with the new ftrace dyamic tracing implementation.  It also adds support
for the mcount format used by newer ARM compilers.

With dynamic tracing, mcount() is implemented as a nop.  Callsites are
patched on startup with nops, and dynamically patched to call to the
ftrace_caller() routine as needed.

Acked-by: Steven Rostedt <rostedt@goodmis.org> [recordmcount.pl change]
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Rabin Vincent
2010-08-10 19:43:28 +01:00
committed by Russell King
parent f9810a8253
commit 3b6c223b1b
4 changed files with 155 additions and 58 deletions
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37
arch/arm/kernel/entry-common.S
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@@ -127,6 +127,10 @@ ENDPROC(ret_from_fork)
* 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
@@ -136,30 +140,45 @@ ENDPROC(ret_from_fork)
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
ENTRY(mcount)
ENTRY(__gnu_mcount_nc)
mov ip, lr
ldmia sp!, {lr}
mov pc, ip
ENDPROC(__gnu_mcount_nc)
ENTRY(ftrace_caller)
stmdb sp!, {r0-r3, lr}
mov r0, lr
sub r0, r0, #MCOUNT_INSN_SIZE
ldr r1, [sp, #20]
.globl mcount_call
mcount_call:
.global ftrace_call
ftrace_call:
bl ftrace_stub
ldr lr, [fp, #-4] @ restore lr
ldmia sp!, {r0-r3, pc}
ldmia sp!, {r0-r3, ip, lr}
mov pc, ip
ENDPROC(ftrace_caller)
#ifdef CONFIG_OLD_MCOUNT
ENTRY(mcount)
stmdb sp!, {lr}
ldr lr, [fp, #-4]
ldmia sp!, {pc}
ENDPROC(mcount)
ENTRY(ftrace_caller)
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
ftrace_call:
.globl ftrace_call_old
ftrace_call_old:
bl ftrace_stub
ldr lr, [fp, #-4] @ restore lr
ldmia sp!, {r0-r3, pc}
ENDPROC(ftrace_caller)
ENDPROC(ftrace_caller_old)
#endif
#else