1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/module.h> 3 4 #include <linux/mm.h> /* for handle_mm_fault() */ 5 #include <linux/ftrace.h> 6 #include <linux/sched/stat.h> 7 #include <asm/asm-offsets.h> 8 9 extern void my_direct_func(unsigned long ip); 10 11 void my_direct_func(unsigned long ip) 12 { 13 trace_printk("ip %lx\n", ip); 14 } 15 16 extern void my_tramp(void *); 17 18 #ifdef CONFIG_X86_64 19 20 asm ( 21 " .pushsection .text, \"ax\", @progbits\n" 22 " .type my_tramp, @function\n" 23 " .globl my_tramp\n" 24 " my_tramp:" 25 " pushq %rbp\n" 26 " movq %rsp, %rbp\n" 27 " pushq %rdi\n" 28 " movq 8(%rbp), %rdi\n" 29 " call my_direct_func\n" 30 " popq %rdi\n" 31 " leave\n" 32 " ret\n" 33 " .size my_tramp, .-my_tramp\n" 34 " .popsection\n" 35 ); 36 37 #endif /* CONFIG_X86_64 */ 38 39 #ifdef CONFIG_S390 40 41 asm ( 42 " .pushsection .text, \"ax\", @progbits\n" 43 " .type my_tramp, @function\n" 44 " .globl my_tramp\n" 45 " my_tramp:" 46 " lgr %r1,%r15\n" 47 " stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" 48 " stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" 49 " aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n" 50 " stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n" 51 " lgr %r2,%r0\n" 52 " brasl %r14,my_direct_func\n" 53 " aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n" 54 " lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" 55 " lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" 56 " lgr %r1,%r0\n" 57 " br %r1\n" 58 " .size my_tramp, .-my_tramp\n" 59 " .popsection\n" 60 ); 61 62 #endif /* CONFIG_S390 */ 63 64 static struct ftrace_ops direct; 65 66 static int __init ftrace_direct_multi_init(void) 67 { 68 ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0); 69 ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0); 70 71 return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp); 72 } 73 74 static void __exit ftrace_direct_multi_exit(void) 75 { 76 unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp); 77 } 78 79 module_init(ftrace_direct_multi_init); 80 module_exit(ftrace_direct_multi_exit); 81 82 MODULE_AUTHOR("Jiri Olsa"); 83 MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()"); 84 MODULE_LICENSE("GPL"); 85