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ftrace/x86: Get rid of ftrace_caller_setup

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Move all the work from ftrace_caller_setup into save_mcount_regs. This
simplifies the code and makes it easier to understand.

Link: http://lkml.kernel.org/r/CA+55aFxUTUbdxpjVMW8X9c=o8sui7OB_MYPfcbJuDyfUWtNrNg@mail.gmail.com
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1411262304010.3961@nanos

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2014-11-24 21:38:40 -05:00 committed by Steven Rostedt
parent 0687c36e45
commit f1ab00af81
1 changed files with 42 additions and 29 deletions
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71
arch/x86/kernel/mcount_64.S
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@ -54,7 +54,15 @@
* be saved in the locations that pt_regs has them in.
*/
/* @added: the amount of stack added before calling this */
/*
* @added: the amount of stack added before calling this
*
* After this is called, the following registers contain:
*
* %rdi - holds the address that called the trampoline
* %rsi - holds the parent function (traced function's return address)
* %rdx - holds the original %rbp
*/
.macro save_mcount_regs added=0
/* Always save the original rbp */
@ -101,9 +109,24 @@
movq MCOUNT_REG_SIZE-8(%rsp), %rdx
movq %rdx, RBP(%rsp)
/* Copy the parent address into %rsi (second parameter) */
#ifdef CC_USING_FENTRY
movq MCOUNT_REG_SIZE+8+\added(%rsp), %rsi
#else
/* %rdx contains original %rbp */
movq 8(%rdx), %rsi
#endif
/* Move RIP to its proper location */
movq MCOUNT_REG_SIZE+\added(%rsp), %rdi
movq %rdi, RIP(%rsp)
/*
* Now %rdi (the first parameter) has the return address of
* where ftrace_call returns. But the callbacks expect the
* the address of the call itself.
*/
subq $MCOUNT_INSN_SIZE, %rdi
.endm
.macro restore_mcount_regs
@ -122,28 +145,6 @@
.endm
/* skip is set if stack has been adjusted */
.macro ftrace_caller_setup trace_label added=0
save_mcount_regs \added
/* Save this location */
GLOBAL(\trace_label)
/* Load the ftrace_ops into the 3rd parameter */
movq function_trace_op(%rip), %rdx
/* %rdi already has %rip from the save_mcount_regs macro */
subq $MCOUNT_INSN_SIZE, %rdi
/* Load the parent_ip into the second parameter */
#ifdef CC_USING_FENTRY
movq MCOUNT_REG_SIZE+8+\added(%rsp), %rsi
#else
/* Need to grab the original %rbp */
movq RBP(%rsp), %rsi
/* Now parent address is 8 above original %rbp */
movq 8(%rsi), %rsi
#endif
.endm
#ifdef CONFIG_DYNAMIC_FTRACE
ENTRY(function_hook)
@ -151,7 +152,13 @@ ENTRY(function_hook)
END(function_hook)
ENTRY(ftrace_caller)
ftrace_caller_setup ftrace_caller_op_ptr
/* save_mcount_regs fills in first two parameters */
save_mcount_regs
GLOBAL(ftrace_caller_op_ptr)
/* Load the ftrace_ops into the 3rd parameter */
movq function_trace_op(%rip), %rdx
/* regs go into 4th parameter (but make it NULL) */
movq $0, %rcx
@ -182,7 +189,12 @@ ENTRY(ftrace_regs_caller)
pushfq
/* added 8 bytes to save flags */
ftrace_caller_setup ftrace_regs_caller_op_ptr 8
save_mcount_regs 8
/* save_mcount_regs fills in first two parameters */
GLOBAL(ftrace_regs_caller_op_ptr)
/* Load the ftrace_ops into the 3rd parameter */
movq function_trace_op(%rip), %rdx
/* Save the rest of pt_regs */
movq %r15, R15(%rsp)
@ -263,7 +275,8 @@ GLOBAL(ftrace_stub)
retq
trace:
ftrace_caller_setup ftrace_caller_op_ptr
/* save_mcount_regs fills in first two parameters */
save_mcount_regs
call *ftrace_trace_function
@ -276,16 +289,16 @@ END(function_hook)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
ENTRY(ftrace_graph_caller)
/* Saves rbp into %rdx */
save_mcount_regs
#ifdef CC_USING_FENTRY
leaq MCOUNT_REG_SIZE+8(%rsp), %rdi
movq $0, %rdx /* No framepointers needed */
#else
/* Need to grab the original %rbp */
movq RBP(%rsp), %rdx
/* Now parent address is 8 above original %rbp */
/* Save address of the return address of traced function */
leaq 8(%rdx), %rdi
/* ftrace does sanity checks against frame pointers */
movq (%rdx), %rdx
#endif
movq RIP(%rsp), %rsi