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Commit 094dfc54 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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ftrace/x86: Have save_mcount_regs store RIP in %rdi for first parameter 

Instead of having save_mcount_regs store the RIP in %rdx as a temp register
to place it in the proper location of the pt_regs on the stack. Use the
%rdi register as the temp register. This lets us remove the extra store
in the ftrace_caller_setup macro.

Link: http://lkml.kernel.org/r/CA+55aFwF+qCGSKdGaEgW4p6N65GZ5_XTV=1NbtWDvxnd5yYLiw@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 05df710e

arch/x86/kernel/mcount_64.S

+3 −4
Original line number Diff line number Diff line
@@ -51,8 +51,8 @@ 
	movq %r8, R8(%rsp)

	movq %r9, R9(%rsp)

	 /* Move RIP to its proper location */

	movq SS+8(%rsp), %rdx

	movq %rdx, RIP(%rsp)

	movq SS+8(%rsp), %rdi

	movq %rdi, RIP(%rsp)

	.endm



.macro restore_mcount_regs skip=0
@@ -75,8 +75,7 @@ GLOBAL(\trace_label) 
	/* Load the ftrace_ops into the 3rd parameter */

	movq function_trace_op(%rip), %rdx



	/* Load ip into the first parameter */

	movq RIP(%rsp), %rdi

	/* %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