Commit 71db948b authored by Naveen N Rao's avatar Naveen N Rao Committed by Michael Ellerman
Browse files

samples/ftrace: Add support for ftrace direct samples on powerpc 



Add powerpc 32-bit and 64-bit samples for ftrace direct. This serves to
show the sample instruction sequence to be used by ftrace direct calls
to adhere to the ftrace ABI.

On 64-bit powerpc, TOC setup requires some additional work.

Signed-off-by: default avatarNaveen N Rao <naveen@kernel.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/20241030070850.1361304-17-hbathini@linux.ibm.com
parent a52f6043

arch/powerpc/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -275,6 +275,8 @@ config PPC 
	select HAVE_REGS_AND_STACK_ACCESS_API

	select HAVE_RELIABLE_STACKTRACE

	select HAVE_RSEQ

	select HAVE_SAMPLE_FTRACE_DIRECT	if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS

	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS

	select HAVE_SETUP_PER_CPU_AREA		if PPC64

	select HAVE_SOFTIRQ_ON_OWN_STACK

	select HAVE_STACKPROTECTOR		if PPC32 && $(cc-option,$(m32-flag) -mstack-protector-guard=tls -mstack-protector-guard-reg=r2 -mstack-protector-guard-offset=0)

samples/ftrace/ftrace-direct-modify.c

+84 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
#include <linux/module.h>

#include <linux/kthread.h>

#include <linux/ftrace.h>

#ifndef CONFIG_ARM64

#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)

#include <asm/asm-offsets.h>

#endif
@@ -199,6 +199,89 @@ asm ( 


#endif /* CONFIG_LOONGARCH */



#ifdef CONFIG_PPC

#include <asm/ppc_asm.h>



#ifdef CONFIG_PPC64

#define STACK_FRAME_SIZE 48

#else

#define STACK_FRAME_SIZE 24

#endif



#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)

#define PPC64_TOC_SAVE_AND_UPDATE			\

"	std		2, 24(1)\n"			\

"	bcl		20, 31, 1f\n"			\

"   1:	mflr		12\n"				\

"	ld		2, (99f - 1b)(12)\n"

#define PPC64_TOC_RESTORE				\

"	ld		2, 24(1)\n"

#define PPC64_TOC					\

"   99:	.quad		.TOC.@tocbase\n"

#else

#define PPC64_TOC_SAVE_AND_UPDATE ""

#define PPC64_TOC_RESTORE ""

#define PPC64_TOC ""

#endif



#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE

#define PPC_FTRACE_RESTORE_LR				\

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\

"	mtlr		0\n"

#define PPC_FTRACE_RET					\

"	blr\n"

#else

#define PPC_FTRACE_RESTORE_LR				\

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\

"	mtctr		0\n"

#define PPC_FTRACE_RET					\

"	mtlr		0\n"				\

"	bctr\n"

#endif



asm (

"	.pushsection	.text, \"ax\", @progbits\n"

"	.type		my_tramp1, @function\n"

"	.globl		my_tramp1\n"

"   my_tramp1:\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

"	mflr		0\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"

	PPC64_TOC_SAVE_AND_UPDATE

"	bl		my_direct_func1\n"

	PPC64_TOC_RESTORE

"	addi		1, 1, "__stringify(STACK_FRAME_SIZE)"\n"

	PPC_FTRACE_RESTORE_LR

"	addi		1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_FTRACE_RET

"	.size		my_tramp1, .-my_tramp1\n"



"	.type		my_tramp2, @function\n"

"	.globl		my_tramp2\n"

"   my_tramp2:\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

"	mflr		0\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"

	PPC64_TOC_SAVE_AND_UPDATE

"	bl		my_direct_func2\n"

	PPC64_TOC_RESTORE

"	addi		1, 1, "__stringify(STACK_FRAME_SIZE)"\n"

	PPC_FTRACE_RESTORE_LR

"	addi		1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_FTRACE_RET

	PPC64_TOC

"	.size		my_tramp2, .-my_tramp2\n"

"	.popsection\n"

);



#endif /* CONFIG_PPC */



static struct ftrace_ops direct;



static unsigned long my_tramp = (unsigned long)my_tramp1;

samples/ftrace/ftrace-direct-multi-modify.c

+100 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
#include <linux/module.h>

#include <linux/kthread.h>

#include <linux/ftrace.h>

#ifndef CONFIG_ARM64

#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)

#include <asm/asm-offsets.h>

#endif
@@ -225,6 +225,105 @@ asm ( 


#endif /* CONFIG_LOONGARCH */



#ifdef CONFIG_PPC

#include <asm/ppc_asm.h>



#ifdef CONFIG_PPC64

#define STACK_FRAME_SIZE 48

#else

#define STACK_FRAME_SIZE 24

#endif



#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)

#define PPC64_TOC_SAVE_AND_UPDATE			\

"	std		2, 24(1)\n"			\

"	bcl		20, 31, 1f\n"			\

"   1:	mflr		12\n"				\

"	ld		2, (99f - 1b)(12)\n"

#define PPC64_TOC_RESTORE				\

"	ld		2, 24(1)\n"

#define PPC64_TOC					\

"   99:	.quad		.TOC.@tocbase\n"

#else

#define PPC64_TOC_SAVE_AND_UPDATE ""

#define PPC64_TOC_RESTORE ""

#define PPC64_TOC ""

#endif



#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE

#define PPC_FTRACE_RESTORE_LR				\

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\

"	mtlr		0\n"

#define PPC_FTRACE_RET					\

"	blr\n"

#define PPC_FTRACE_RECOVER_IP				\

"	lwz		8, 4(3)\n"			\

"	li		9, 6\n"				\

"	slw		8, 8, 9\n"			\

"	sraw		8, 8, 9\n"			\

"	add		3, 3, 8\n"			\

"	addi		3, 3, 4\n"

#else

#define PPC_FTRACE_RESTORE_LR				\

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\

"	mtctr		0\n"

#define PPC_FTRACE_RET					\

"	mtlr		0\n"				\

"	bctr\n"

#define PPC_FTRACE_RECOVER_IP ""

#endif



asm (

"	.pushsection	.text, \"ax\", @progbits\n"

"	.type		my_tramp1, @function\n"

"	.globl		my_tramp1\n"

"   my_tramp1:\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

"	mflr		0\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"

	PPC64_TOC_SAVE_AND_UPDATE

	PPC_STL"	3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

"	mr		3, 0\n"

	PPC_FTRACE_RECOVER_IP

"	bl		my_direct_func1\n"

	PPC_LL"		3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

	PPC64_TOC_RESTORE

"	addi		1, 1, "__stringify(STACK_FRAME_SIZE)"\n"

	PPC_FTRACE_RESTORE_LR

"	addi		1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_FTRACE_RET

"	.size		my_tramp1, .-my_tramp1\n"



"	.type		my_tramp2, @function\n"

"	.globl		my_tramp2\n"

"   my_tramp2:\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

"	mflr		0\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"

	PPC64_TOC_SAVE_AND_UPDATE

	PPC_STL"	3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

"	mr		3, 0\n"

	PPC_FTRACE_RECOVER_IP

"	bl		my_direct_func2\n"

	PPC_LL"		3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

	PPC64_TOC_RESTORE

"	addi		1, 1, "__stringify(STACK_FRAME_SIZE)"\n"

	PPC_FTRACE_RESTORE_LR

"	addi		1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_FTRACE_RET

	PPC64_TOC

	"	.size		my_tramp2, .-my_tramp2\n"

"	.popsection\n"

);



#endif /* CONFIG_PPC */



static unsigned long my_tramp = (unsigned long)my_tramp1;

static unsigned long tramps[2] = {

	(unsigned long)my_tramp1,

samples/ftrace/ftrace-direct-multi.c

+78 −1
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 
#include <linux/mm.h> /* for handle_mm_fault() */

#include <linux/ftrace.h>

#include <linux/sched/stat.h>

#ifndef CONFIG_ARM64

#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)

#include <asm/asm-offsets.h>

#endif
@@ -141,6 +141,83 @@ asm ( 


#endif /* CONFIG_LOONGARCH */



#ifdef CONFIG_PPC

#include <asm/ppc_asm.h>



#ifdef CONFIG_PPC64

#define STACK_FRAME_SIZE 48

#else

#define STACK_FRAME_SIZE 24

#endif



#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)

#define PPC64_TOC_SAVE_AND_UPDATE			\

"	std		2, 24(1)\n"			\

"	bcl		20, 31, 1f\n"			\

"   1:	mflr		12\n"				\

"	ld		2, (99f - 1b)(12)\n"

#define PPC64_TOC_RESTORE				\

"	ld		2, 24(1)\n"

#define PPC64_TOC					\

"   99:	.quad		.TOC.@tocbase\n"

#else

#define PPC64_TOC_SAVE_AND_UPDATE ""

#define PPC64_TOC_RESTORE ""

#define PPC64_TOC ""

#endif



#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE

#define PPC_FTRACE_RESTORE_LR				\

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\

"	mtlr		0\n"

#define PPC_FTRACE_RET					\

"	blr\n"

#define PPC_FTRACE_RECOVER_IP				\

"	lwz		8, 4(3)\n"			\

"	li		9, 6\n"				\

"	slw		8, 8, 9\n"			\

"	sraw		8, 8, 9\n"			\

"	add		3, 3, 8\n"			\

"	addi		3, 3, 4\n"

#else

#define PPC_FTRACE_RESTORE_LR				\

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\

"	mtctr		0\n"

#define PPC_FTRACE_RET					\

"	mtlr		0\n"				\

"	bctr\n"

#define PPC_FTRACE_RECOVER_IP ""

#endif



asm (

"	.pushsection	.text, \"ax\", @progbits\n"

"	.type		my_tramp, @function\n"

"	.globl		my_tramp\n"

"   my_tramp:\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

"	mflr		0\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"

	PPC64_TOC_SAVE_AND_UPDATE

	PPC_STL"	3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

"	mr		3, 0\n"

	PPC_FTRACE_RECOVER_IP

"	bl		my_direct_func\n"

	PPC_LL"		3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

	PPC64_TOC_RESTORE

"	addi		1, 1, "__stringify(STACK_FRAME_SIZE)"\n"

	PPC_FTRACE_RESTORE_LR

"	addi		1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_FTRACE_RET

	PPC64_TOC

"	.size		my_tramp, .-my_tramp\n"

"	.popsection\n"

);



#endif /* CONFIG_PPC */



static struct ftrace_ops direct;



static int __init ftrace_direct_multi_init(void)

samples/ftrace/ftrace-direct-too.c

+82 −1
Original line number Diff line number Diff line
@@ -3,7 +3,7 @@ 


#include <linux/mm.h> /* for handle_mm_fault() */

#include <linux/ftrace.h>

#ifndef CONFIG_ARM64

#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)

#include <asm/asm-offsets.h>

#endif
@@ -153,6 +153,87 @@ asm ( 


#endif /* CONFIG_LOONGARCH */



#ifdef CONFIG_PPC

#include <asm/ppc_asm.h>



#ifdef CONFIG_PPC64

#define STACK_FRAME_SIZE 64

#define STACK_FRAME_ARG1 32

#define STACK_FRAME_ARG2 40

#define STACK_FRAME_ARG3 48

#define STACK_FRAME_ARG4 56

#else

#define STACK_FRAME_SIZE 32

#define STACK_FRAME_ARG1 16

#define STACK_FRAME_ARG2 20

#define STACK_FRAME_ARG3 24

#define STACK_FRAME_ARG4 28

#endif



#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)

#define PPC64_TOC_SAVE_AND_UPDATE			\

"	std		2, 24(1)\n"			\

"	bcl		20, 31, 1f\n"			\

"   1:	mflr		12\n"				\

"	ld		2, (99f - 1b)(12)\n"

#define PPC64_TOC_RESTORE				\

"	ld		2, 24(1)\n"

#define PPC64_TOC					\

"   99:	.quad		.TOC.@tocbase\n"

#else

#define PPC64_TOC_SAVE_AND_UPDATE ""

#define PPC64_TOC_RESTORE ""

#define PPC64_TOC ""

#endif



#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE

#define PPC_FTRACE_RESTORE_LR				\

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\

"	mtlr		0\n"

#define PPC_FTRACE_RET					\

"	blr\n"

#else

#define PPC_FTRACE_RESTORE_LR				\

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\

"	mtctr		0\n"

#define PPC_FTRACE_RET					\

"	mtlr		0\n"				\

"	bctr\n"

#endif



asm (

"	.pushsection	.text, \"ax\", @progbits\n"

"	.type		my_tramp, @function\n"

"	.globl		my_tramp\n"

"   my_tramp:\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"

"	mflr		0\n"

	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_STLU"	1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"

	PPC64_TOC_SAVE_AND_UPDATE

	PPC_STL"	3, "__stringify(STACK_FRAME_ARG1)"(1)\n"

	PPC_STL"	4, "__stringify(STACK_FRAME_ARG2)"(1)\n"

	PPC_STL"	5, "__stringify(STACK_FRAME_ARG3)"(1)\n"

	PPC_STL"	6, "__stringify(STACK_FRAME_ARG4)"(1)\n"

"	bl		my_direct_func\n"

	PPC_LL"		6, "__stringify(STACK_FRAME_ARG4)"(1)\n"

	PPC_LL"		5, "__stringify(STACK_FRAME_ARG3)"(1)\n"

	PPC_LL"		4, "__stringify(STACK_FRAME_ARG2)"(1)\n"

	PPC_LL"		3, "__stringify(STACK_FRAME_ARG1)"(1)\n"

	PPC64_TOC_RESTORE

"	addi		1, 1, "__stringify(STACK_FRAME_SIZE)"\n"

	PPC_FTRACE_RESTORE_LR

"	addi		1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"

	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"

	PPC_FTRACE_RET

	PPC64_TOC

"	.size		my_tramp, .-my_tramp\n"

"	.popsection\n"

);



#endif /* CONFIG_PPC */



static struct ftrace_ops direct;



static int __init ftrace_direct_init(void)