84 lines
1.9 KiB
C
84 lines
1.9 KiB
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 */
|
||
|
|
|
||
|
|
static int __init ftrace_direct_init(void)
|
||
|
|
{
|
||
|
|
return register_ftrace_direct((unsigned long)wake_up_process,
|
||
|
|
(unsigned long)my_tramp);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __exit ftrace_direct_exit(void)
|
||
|
|
{
|
||
|
|
unregister_ftrace_direct((unsigned long)wake_up_process,
|
||
|
|
(unsigned long)my_tramp);
|
||
|
|
}
|
||
|
|
|
||
|
|
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");
|