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Diffstat (limited to 'samples/ftrace/ftrace-direct-too.c')
-rw-r--r-- | samples/ftrace/ftrace-direct-too.c | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c new file mode 100644 index 000000000000..27efa5f6ff52 --- /dev/null +++ b/samples/ftrace/ftrace-direct-too.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/module.h> + +#include <linux/mm.h> /* for handle_mm_fault() */ +#include <linux/ftrace.h> + +void my_direct_func(struct vm_area_struct *vma, + unsigned long address, unsigned int flags) +{ + trace_printk("handle mm fault vma=%p address=%lx flags=%x\n", + vma, address, flags); +} + +extern void my_tramp(void *); + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" my_tramp:" +" pushq %rbp\n" +" movq %rsp, %rbp\n" +" pushq %rdi\n" +" pushq %rsi\n" +" pushq %rdx\n" +" call my_direct_func\n" +" popq %rdx\n" +" popq %rsi\n" +" popq %rdi\n" +" leave\n" +" ret\n" +" .popsection\n" +); + + +static int __init ftrace_direct_init(void) +{ + return register_ftrace_direct((unsigned long)handle_mm_fault, + (unsigned long)my_tramp); +} + +static void __exit ftrace_direct_exit(void) +{ + unregister_ftrace_direct((unsigned long)handle_mm_fault, + (unsigned long)my_tramp); +} + +module_init(ftrace_direct_init); +module_exit(ftrace_direct_exit); + +MODULE_AUTHOR("Steven Rostedt"); +MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()"); +MODULE_LICENSE("GPL"); |