[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>
#include <asm/asm-offsets.h>

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_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_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 */

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
b06457c8 SRV	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>
1254cfbc	6	#include <asm/asm-offsets.h>
b06457c8	7
0daf5cb2 JO	8	extern void my_direct_func(struct task_struct *p);
0daf5cb2 JO	9
b06457c8 SRV	10	void my_direct_func(struct task_struct *p)
b06457c8 SRV	11	{
760f8bc7	12	trace_printk("waking up %s-%d\n", p->comm, p->pid);
b06457c8 SRV	13	}
	14
	15	extern void my_tramp(void *);
	16
1254cfbc HC	17	#ifdef CONFIG_X86_64
1254cfbc HC	18
0aec21cf	19	#include <asm/ibt.h>
01678fbc	20	#include <asm/nospec-branch.h>
0aec21cf	21
b06457c8 SRV	22	asm (
b06457c8 SRV	23	" .pushsection .text, \"ax\", @progbits\n"
9d907f1a	24	" .type my_tramp, @function\n"
983df5f2	25	" .globl my_tramp\n"
b06457c8	26	" my_tramp:"
0aec21cf	27	ASM_ENDBR
b06457c8 SRV	28	" pushq %rbp\n"
b06457c8 SRV	29	" movq %rsp, %rbp\n"
ee3e2469	30	CALL_DEPTH_ACCOUNT
b06457c8 SRV	31	" pushq %rdi\n"
	32	" call my_direct_func\n"
	33	" popq %rdi\n"
	34	" leave\n"
b17c2baa	35	ASM_RET
9d907f1a	36	" .size my_tramp, .-my_tramp\n"
b06457c8 SRV	37	" .popsection\n"
	38	);
	39
1254cfbc HC	40	#endif /* CONFIG_X86_64 */
	41
	42	#ifdef CONFIG_S390
	43
	44	asm (
	45	" .pushsection .text, \"ax\", @progbits\n"
	46	" .type my_tramp, @function\n"
	47	" .globl my_tramp\n"
	48	" my_tramp:"
	49	" lgr %r1,%r15\n"
	50	" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
	51	" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
	52	" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
	53	" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
	54	" brasl %r14,my_direct_func\n"
	55	" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
	56	" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
	57	" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
	58	" lgr %r1,%r0\n"
	59	" br %r1\n"
	60	" .size my_tramp, .-my_tramp\n"
	61	" .popsection\n"
	62	);
	63
	64	#endif /* CONFIG_S390 */
b06457c8	65
22f367a6 YT	66	#ifdef CONFIG_LOONGARCH
	67
	68	asm (
	69	" .pushsection .text, \"ax\", @progbits\n"
	70	" .type my_tramp, @function\n"
	71	" .globl my_tramp\n"
	72	" my_tramp:\n"
	73	" addi.d $sp, $sp, -32\n"
	74	" st.d $a0, $sp, 0\n"
	75	" st.d $t0, $sp, 8\n"
	76	" st.d $ra, $sp, 16\n"
	77	" bl my_direct_func\n"
	78	" ld.d $a0, $sp, 0\n"
	79	" ld.d $t0, $sp, 8\n"
	80	" ld.d $ra, $sp, 16\n"
	81	" addi.d $sp, $sp, 32\n"
	82	" jr $t0\n"
	83	" .size my_tramp, .-my_tramp\n"
	84	" .popsection\n"
	85	);
	86
	87	#endif /* CONFIG_LOONGARCH */
	88
23edf483 FR	89	static struct ftrace_ops direct;
23edf483 FR	90
b06457c8 SRV	91	static int __init ftrace_direct_init(void)
b06457c8 SRV	92	{
23edf483 FR	93	ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
23edf483 FR	94
da8bdfbd	95	return register_ftrace_direct(&direct, (unsigned long) my_tramp);
b06457c8 SRV	96	}
	97
	98	static void __exit ftrace_direct_exit(void)
	99	{
da8bdfbd	100	unregister_ftrace_direct(&direct, (unsigned long)my_tramp, true);
b06457c8 SRV	101	}
	102
	103	module_init(ftrace_direct_init);
	104	module_exit(ftrace_direct_exit);
	105
	106	MODULE_AUTHOR("Steven Rostedt");
da8bdfbd	107	MODULE_DESCRIPTION("Example use case of using register_ftrace_direct()");
b06457c8	108	MODULE_LICENSE("GPL");