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Commit f1ab00af authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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ftrace/x86: Get rid of ftrace_caller_setup 

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: default avatarThomas Gleixner <tglx@linutronix.de>
Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 0687c36e

arch/x86/kernel/mcount_64.S

+42 −29
Original line number Diff line number Diff line
@@ -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