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 #ifndef CONFIG_ARM64 8 #include <asm/asm-offsets.h> 9 #endif 10 11 extern void my_direct_func(unsigned long ip); 12 13 void my_direct_func(unsigned long ip) 14 { 15 trace_printk("ip %lx\n", ip); 16 } 17 18 extern void my_tramp(void *); 19 20 #ifdef CONFIG_X86_64 21 22 #include <asm/ibt.h> 23 #include <asm/nospec-branch.h> 24 25 asm ( 26 " .pushsection .text, \"ax\", @progbits\n" 27 " .type my_tramp, @function\n" 28 " .globl my_tramp\n" 29 " my_tramp:" 30 ASM_ENDBR 31 " pushq %rbp\n" 32 " movq %rsp, %rbp\n" 33 CALL_DEPTH_ACCOUNT 34 " pushq %rdi\n" 35 " movq 8(%rbp), %rdi\n" 36 " call my_direct_func\n" 37 " popq %rdi\n" 38 " leave\n" 39 ASM_RET 40 " .size my_tramp, .-my_tramp\n" 41 " .popsection\n" 42 ); 43 44 #endif /* CONFIG_X86_64 */ 45 46 #ifdef CONFIG_S390 47 48 asm ( 49 " .pushsection .text, \"ax\", @progbits\n" 50 " .type my_tramp, @function\n" 51 " .globl my_tramp\n" 52 " my_tramp:" 53 " lgr %r1,%r15\n" 54 " stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" 55 " stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" 56 " aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n" 57 " stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n" 58 " lgr %r2,%r0\n" 59 " brasl %r14,my_direct_func\n" 60 " aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n" 61 " lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" 62 " lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" 63 " lgr %r1,%r0\n" 64 " br %r1\n" 65 " .size my_tramp, .-my_tramp\n" 66 " .popsection\n" 67 ); 68 69 #endif /* CONFIG_S390 */ 70 71 #ifdef CONFIG_ARM64 72 73 asm ( 74 " .pushsection .text, \"ax\", @progbits\n" 75 " .type my_tramp, @function\n" 76 " .globl my_tramp\n" 77 " my_tramp:" 78 " bti c\n" 79 " sub sp, sp, #32\n" 80 " stp x9, x30, [sp]\n" 81 " str x0, [sp, #16]\n" 82 " mov x0, x30\n" 83 " bl my_direct_func\n" 84 " ldp x30, x9, [sp]\n" 85 " ldr x0, [sp, #16]\n" 86 " add sp, sp, #32\n" 87 " ret x9\n" 88 " .size my_tramp, .-my_tramp\n" 89 " .popsection\n" 90 ); 91 92 #endif /* CONFIG_ARM64 */ 93 94 #ifdef CONFIG_LOONGARCH 95 96 #include <asm/asm.h> 97 asm ( 98 " .pushsection .text, \"ax\", @progbits\n" 99 " .type my_tramp, @function\n" 100 " .globl my_tramp\n" 101 " my_tramp:\n" 102 " addi.d $sp, $sp, -32\n" 103 " st.d $a0, $sp, 0\n" 104 " st.d $t0, $sp, 8\n" 105 " st.d $ra, $sp, 16\n" 106 " move $a0, $t0\n" 107 " bl my_direct_func\n" 108 " ld.d $a0, $sp, 0\n" 109 " ld.d $t0, $sp, 8\n" 110 " ld.d $ra, $sp, 16\n" 111 " addi.d $sp, $sp, 32\n" 112 " jr $t0\n" 113 " .size my_tramp, .-my_tramp\n" 114 " .popsection\n" 115 ); 116 117 #endif /* CONFIG_LOONGARCH */ 118 119 static struct ftrace_ops direct; 120 121 static int __init ftrace_direct_multi_init(void) 122 { 123 ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0); 124 ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0); 125 126 return register_ftrace_direct(&direct, (unsigned long) my_tramp); 127 } 128 129 static void __exit ftrace_direct_multi_exit(void) 130 { 131 unregister_ftrace_direct(&direct, (unsigned long) my_tramp, true); 132 } 133 134 module_init(ftrace_direct_multi_init); 135 module_exit(ftrace_direct_multi_exit); 136 137 MODULE_AUTHOR("Jiri Olsa"); 138 MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()"); 139 MODULE_LICENSE("GPL"); 140