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 #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 #include <asm/ibt.h>
  21 #include <asm/nospec-branch.h>
  22
  23 asm (
  24 "       .pushsection    .text, \"ax\", @progbits\n"
  25 "       .type           my_tramp, @function\n"
  26 "       .globl          my_tramp\n"
  27 "   my_tramp:"
  28         ASM_ENDBR
  29 "       pushq %rbp\n"
  30 "       movq %rsp, %rbp\n"
  31         CALL_DEPTH_ACCOUNT
  32 "       pushq %rdi\n"
  33 "       movq 8(%rbp), %rdi\n"
  34 "       call my_direct_func\n"
  35 "       popq %rdi\n"
  36 "       leave\n"
  37         ASM_RET
  38 "       .size           my_tramp, .-my_tramp\n"
  39 "       .popsection\n"
  40 );
  41
  42 #endif /* CONFIG_X86_64 */
  43
  44 #ifdef CONFIG_S390
  45
  46 asm (
  47 "       .pushsection    .text, \"ax\", @progbits\n"
  48 "       .type           my_tramp, @function\n"
  49 "       .globl          my_tramp\n"
  50 "   my_tramp:"
  51 "       lgr             %r1,%r15\n"
  52 "       stmg            %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
  53 "       stg             %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
  54 "       aghi            %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
  55 "       stg             %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
  56 "       lgr             %r2,%r0\n"
  57 "       brasl           %r14,my_direct_func\n"
  58 "       aghi            %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
  59 "       lmg             %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
  60 "       lg              %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
  61 "       lgr             %r1,%r0\n"
  62 "       br              %r1\n"
  63 "       .size           my_tramp, .-my_tramp\n"
  64 "       .popsection\n"
  65 );
  66
  67 #endif /* CONFIG_S390 */
  68
  69 #ifdef CONFIG_LOONGARCH
  70
  71 #include <asm/asm.h>
  72 asm (
  73 "       .pushsection    .text, \"ax\", @progbits\n"
  74 "       .type           my_tramp, @function\n"
  75 "       .globl          my_tramp\n"
  76 "   my_tramp:\n"
  77 "       addi.d  $sp, $sp, -32\n"
  78 "       st.d    $a0, $sp, 0\n"
  79 "       st.d    $t0, $sp, 8\n"
  80 "       st.d    $ra, $sp, 16\n"
  81 "       move    $a0, $t0\n"
  82 "       bl      my_direct_func\n"
  83 "       ld.d    $a0, $sp, 0\n"
  84 "       ld.d    $t0, $sp, 8\n"
  85 "       ld.d    $ra, $sp, 16\n"
  86 "       addi.d  $sp, $sp, 32\n"
  87 "       jr      $t0\n"
  88 "       .size           my_tramp, .-my_tramp\n"
  89 "       .popsection\n"
  90 );
  91
  92 #endif /* CONFIG_LOONGARCH */
  93
  94 static struct ftrace_ops direct;
  95
  96 static int __init ftrace_direct_multi_init(void)
  97 {
  98         ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
  99         ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
 100
 101         return register_ftrace_direct(&direct, (unsigned long) my_tramp);
 102 }
 103
 104 static void __exit ftrace_direct_multi_exit(void)
 105 {
 106         unregister_ftrace_direct(&direct, (unsigned long) my_tramp, true);
 107 }
 108
 109 module_init(ftrace_direct_multi_init);
 110 module_exit(ftrace_direct_multi_exit);
 111
 112 MODULE_AUTHOR("Jiri Olsa");
 113 MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()");
 114 MODULE_LICENSE("GPL");