samples/ftrace/ftrace-direct-multi.c

   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 "       hint    34\n" // bti    c
  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");