[linux-2.6-block.git] / samples / ftrace / ftrace-direct.c

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>

#include <linux/sched.h> /* for wake_up_process() */
#include <linux/ftrace.h>
#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
#include <asm/asm-offsets.h>
#endif

extern void my_direct_func(struct task_struct *p);

void my_direct_func(struct task_struct *p)
{
	trace_printk("waking up %s-%d\n", p->comm, p->pid);
}

extern void my_tramp(void *);

#ifdef CONFIG_RISCV
#include <asm/asm.h>

asm (
"       .pushsection    .text, \"ax\", @progbits\n"
"       .type           my_tramp, @function\n"
"       .globl          my_tramp\n"
"   my_tramp:\n"
"       addi	sp,sp,-3*"SZREG"\n"
"       "REG_S"	a0,0*"SZREG"(sp)\n"
"       "REG_S"	t0,1*"SZREG"(sp)\n"
"       "REG_S"	ra,2*"SZREG"(sp)\n"
"       call	my_direct_func\n"
"       "REG_L"	a0,0*"SZREG"(sp)\n"
"       "REG_L"	t0,1*"SZREG"(sp)\n"
"       "REG_L"	ra,2*"SZREG"(sp)\n"
"       addi	sp,sp,3*"SZREG"\n"
"       jr	t0\n"
"       .size           my_tramp, .-my_tramp\n"
"       .popsection\n"
);

#endif /* CONFIG_RISCV */

#ifdef CONFIG_X86_64

#include <asm/ibt.h>
#include <asm/nospec-branch.h>

asm (
"	.pushsection    .text, \"ax\", @progbits\n"
"	.type		my_tramp, @function\n"
"	.globl		my_tramp\n"
"   my_tramp:"
	ASM_ENDBR
"	pushq %rbp\n"
"	movq %rsp, %rbp\n"
	CALL_DEPTH_ACCOUNT
"	pushq %rdi\n"
"	call my_direct_func\n"
"	popq %rdi\n"
"	leave\n"
	ASM_RET
"	.size		my_tramp, .-my_tramp\n"
"	.popsection\n"
);

#endif /* CONFIG_X86_64 */

#ifdef CONFIG_S390

asm (
"	.pushsection	.text, \"ax\", @progbits\n"
"	.type		my_tramp, @function\n"
"	.globl		my_tramp\n"
"   my_tramp:"
"	lgr		%r1,%r15\n"
"	stmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
"	stg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
"	aghi		%r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
"	stg		%r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
"	brasl		%r14,my_direct_func\n"
"	aghi		%r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
"	lmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
"	lg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
"	lgr		%r1,%r0\n"
"	br		%r1\n"
"	.size		my_tramp, .-my_tramp\n"
"	.popsection\n"
);

#endif /* CONFIG_S390 */

#ifdef CONFIG_ARM64

asm (
"	.pushsection	.text, \"ax\", @progbits\n"
"	.type		my_tramp, @function\n"
"	.globl		my_tramp\n"
"   my_tramp:"
"	hint	34\n" // bti	c
"	sub	sp, sp, #32\n"
"	stp	x9, x30, [sp]\n"
"	str	x0, [sp, #16]\n"
"	bl	my_direct_func\n"
"	ldp	x30, x9, [sp]\n"
"	ldr	x0, [sp, #16]\n"
"	add	sp, sp, #32\n"
"	ret	x9\n"
"	.size		my_tramp, .-my_tramp\n"
"	.popsection\n"
);

#endif /* CONFIG_ARM64 */

#ifdef CONFIG_LOONGARCH

asm (
"	.pushsection	.text, \"ax\", @progbits\n"
"	.type		my_tramp, @function\n"
"	.globl		my_tramp\n"
"   my_tramp:\n"
"	addi.d	$sp, $sp, -32\n"
"	st.d	$a0, $sp, 0\n"
"	st.d	$t0, $sp, 8\n"
"	st.d	$ra, $sp, 16\n"
"	bl	my_direct_func\n"
"	ld.d	$a0, $sp, 0\n"
"	ld.d	$t0, $sp, 8\n"
"	ld.d	$ra, $sp, 16\n"
"	addi.d	$sp, $sp, 32\n"
"	jr	$t0\n"
"	.size		my_tramp, .-my_tramp\n"
"	.popsection\n"
);

#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_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"
"	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_init(void)
{
	ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);

	return register_ftrace_direct(&direct, (unsigned long) my_tramp);
}

static void __exit ftrace_direct_exit(void)
{
	unregister_ftrace_direct(&direct, (unsigned long)my_tramp, true);
}

module_init(ftrace_direct_init);
module_exit(ftrace_direct_exit);

MODULE_AUTHOR("Steven Rostedt");
MODULE_DESCRIPTION("Example use case of using register_ftrace_direct()");
MODULE_LICENSE("GPL");
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0-only
	2	#include <linux/module.h>
	3
	4	#include <linux/sched.h> /* for wake_up_process() */
	5	#include <linux/ftrace.h>
	6	#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
	7	#include <asm/asm-offsets.h>
	8	#endif
	9
	10	extern void my_direct_func(struct task_struct *p);
	11
	12	void my_direct_func(struct task_struct *p)
	13	{
	14	trace_printk("waking up %s-%d\n", p->comm, p->pid);
	15	}
	16
	17	extern void my_tramp(void *);
	18
	19	#ifdef CONFIG_RISCV
	20	#include <asm/asm.h>
	21
	22	asm (
	23	" .pushsection .text, \"ax\", @progbits\n"
	24	" .type my_tramp, @function\n"
	25	" .globl my_tramp\n"
	26	" my_tramp:\n"
	27	" addi sp,sp,-3*"SZREG"\n"
	28	" "REG_S" a0,0*"SZREG"(sp)\n"
	29	" "REG_S" t0,1*"SZREG"(sp)\n"
	30	" "REG_S" ra,2*"SZREG"(sp)\n"
	31	" call my_direct_func\n"
	32	" "REG_L" a0,0*"SZREG"(sp)\n"
	33	" "REG_L" t0,1*"SZREG"(sp)\n"
	34	" "REG_L" ra,2*"SZREG"(sp)\n"
	35	" addi sp,sp,3*"SZREG"\n"
	36	" jr t0\n"
	37	" .size my_tramp, .-my_tramp\n"
	38	" .popsection\n"
	39	);
	40
	41	#endif /* CONFIG_RISCV */
	42
	43	#ifdef CONFIG_X86_64
	44
	45	#include <asm/ibt.h>
	46	#include <asm/nospec-branch.h>
	47
	48	asm (
	49	" .pushsection .text, \"ax\", @progbits\n"
	50	" .type my_tramp, @function\n"
	51	" .globl my_tramp\n"
	52	" my_tramp:"
	53	ASM_ENDBR
	54	" pushq %rbp\n"
	55	" movq %rsp, %rbp\n"
	56	CALL_DEPTH_ACCOUNT
	57	" pushq %rdi\n"
	58	" call my_direct_func\n"
	59	" popq %rdi\n"
	60	" leave\n"
	61	ASM_RET
	62	" .size my_tramp, .-my_tramp\n"
	63	" .popsection\n"
	64	);
	65
	66	#endif /* CONFIG_X86_64 */
	67
	68	#ifdef CONFIG_S390
	69
	70	asm (
	71	" .pushsection .text, \"ax\", @progbits\n"
	72	" .type my_tramp, @function\n"
	73	" .globl my_tramp\n"
	74	" my_tramp:"
	75	" lgr %r1,%r15\n"
	76	" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
	77	" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
	78	" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
	79	" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
	80	" brasl %r14,my_direct_func\n"
	81	" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
	82	" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
	83	" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
	84	" lgr %r1,%r0\n"
	85	" br %r1\n"
	86	" .size my_tramp, .-my_tramp\n"
	87	" .popsection\n"
	88	);
	89
	90	#endif /* CONFIG_S390 */
	91
	92	#ifdef CONFIG_ARM64
	93
	94	asm (
	95	" .pushsection .text, \"ax\", @progbits\n"
	96	" .type my_tramp, @function\n"
	97	" .globl my_tramp\n"
	98	" my_tramp:"
	99	" hint 34\n" // bti c
	100	" sub sp, sp, #32\n"
	101	" stp x9, x30, [sp]\n"
	102	" str x0, [sp, #16]\n"
	103	" bl my_direct_func\n"
	104	" ldp x30, x9, [sp]\n"
	105	" ldr x0, [sp, #16]\n"
	106	" add sp, sp, #32\n"
	107	" ret x9\n"
	108	" .size my_tramp, .-my_tramp\n"
	109	" .popsection\n"
	110	);
	111
	112	#endif /* CONFIG_ARM64 */
	113
	114	#ifdef CONFIG_LOONGARCH
	115
	116	asm (
	117	" .pushsection .text, \"ax\", @progbits\n"
	118	" .type my_tramp, @function\n"
	119	" .globl my_tramp\n"
	120	" my_tramp:\n"
	121	" addi.d $sp, $sp, -32\n"
	122	" st.d $a0, $sp, 0\n"
	123	" st.d $t0, $sp, 8\n"
	124	" st.d $ra, $sp, 16\n"
	125	" bl my_direct_func\n"
	126	" ld.d $a0, $sp, 0\n"
	127	" ld.d $t0, $sp, 8\n"
	128	" ld.d $ra, $sp, 16\n"
	129	" addi.d $sp, $sp, 32\n"
	130	" jr $t0\n"
	131	" .size my_tramp, .-my_tramp\n"
	132	" .popsection\n"
	133	);
	134
	135	#endif /* CONFIG_LOONGARCH */
	136
	137	#ifdef CONFIG_PPC
	138	#include <asm/ppc_asm.h>
	139
	140	#ifdef CONFIG_PPC64
	141	#define STACK_FRAME_SIZE 48
	142	#else
	143	#define STACK_FRAME_SIZE 24
	144	#endif
	145
	146	#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)
	147	#define PPC64_TOC_SAVE_AND_UPDATE \
	148	" std 2, 24(1)\n" \
	149	" bcl 20, 31, 1f\n" \
	150	" 1: mflr 12\n" \
	151	" ld 2, (99f - 1b)(12)\n"
	152	#define PPC64_TOC_RESTORE \
	153	" ld 2, 24(1)\n"
	154	#define PPC64_TOC \
	155	" 99: .quad .TOC.@tocbase\n"
	156	#else
	157	#define PPC64_TOC_SAVE_AND_UPDATE ""
	158	#define PPC64_TOC_RESTORE ""
	159	#define PPC64_TOC ""
	160	#endif
	161
	162	#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
	163	#define PPC_FTRACE_RESTORE_LR \
	164	PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \
	165	" mtlr 0\n"
	166	#define PPC_FTRACE_RET \
	167	" blr\n"
	168	#else
	169	#define PPC_FTRACE_RESTORE_LR \
	170	PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \
	171	" mtctr 0\n"
	172	#define PPC_FTRACE_RET \
	173	" mtlr 0\n" \
	174	" bctr\n"
	175	#endif
	176
	177	asm (
	178	" .pushsection .text, \"ax\", @progbits\n"
	179	" .type my_tramp, @function\n"
	180	" .globl my_tramp\n"
	181	" my_tramp:\n"
	182	PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
	183	PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
	184	" mflr 0\n"
	185	PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
	186	PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"
	187	PPC64_TOC_SAVE_AND_UPDATE
	188	PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
	189	" bl my_direct_func\n"
	190	PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
	191	PPC64_TOC_RESTORE
	192	" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n"
	193	PPC_FTRACE_RESTORE_LR
	194	" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"
	195	PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
	196	PPC_FTRACE_RET
	197	PPC64_TOC
	198	" .size my_tramp, .-my_tramp\n"
	199	" .popsection\n"
	200	);
	201
	202	#endif /* CONFIG_PPC */
	203
	204	static struct ftrace_ops direct;
	205
	206	static int __init ftrace_direct_init(void)
	207	{
	208	ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
	209
	210	return register_ftrace_direct(&direct, (unsigned long) my_tramp);
	211	}
	212
	213	static void __exit ftrace_direct_exit(void)
	214	{
	215	unregister_ftrace_direct(&direct, (unsigned long)my_tramp, true);
	216	}
	217
	218	module_init(ftrace_direct_init);
	219	module_exit(ftrace_direct_exit);
	220
	221	MODULE_AUTHOR("Steven Rostedt");
	222	MODULE_DESCRIPTION("Example use case of using register_ftrace_direct()");
	223	MODULE_LICENSE("GPL");