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Commit 7dc48bf9 authored by Mark Rutland's avatar Mark Rutland Committed by Will Deacon
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arm64: ftrace: always pass instrumented pc in x0 



The core ftrace hooks take the instrumented PC in x0, but for some
reason arm64's prepare_ftrace_return() takes this in x1.

For consistency, let's flip the argument order and always pass the
instrumented PC in x0.

There should be no functional change as a result of this patch.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Torsten Duwe <duwe@suse.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 49e258e0

arch/arm64/kernel/entry-ftrace.S

+3 −3
Original line number Diff line number Diff line
@@ -176,10 +176,10 @@ ENDPROC(ftrace_stub) 
 * and run return_to_handler() later on its exit.

 */

ENTRY(ftrace_graph_caller)

	mcount_get_lr_addr	  x0	//     pointer to function's saved lr

	mcount_get_pc		  x1	//     function's pc

	mcount_get_pc		  x0	//     function's pc

	mcount_get_lr_addr	  x1	//     pointer to function's saved lr

	mcount_get_parent_fp	  x2	//     parent's fp

	bl	prepare_ftrace_return	// prepare_ftrace_return(&lr, pc, fp)

	bl	prepare_ftrace_return	// prepare_ftrace_return(pc, &lr, fp)



	mcount_exit

ENDPROC(ftrace_graph_caller)

arch/arm64/kernel/ftrace.c

+1 −1
Original line number Diff line number Diff line
@@ -211,7 +211,7 @@ int __init ftrace_dyn_arch_init(void) 
 *

 * Note that @frame_pointer is used only for sanity check later.

 */

void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,

void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,

			   unsigned long frame_pointer)

{

	unsigned long return_hooker = (unsigned long)&return_to_handler;