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 #if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
   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_RISCV
  21 #include <asm/asm.h>
  22
  23 asm (
  24 "       .pushsection    .text, \"ax\", @progbits\n"
  25 "       .type           my_tramp, @function\n"
  26 "       .globl          my_tramp\n"
  27 "   my_tramp:\n"
  28 "       addi    sp,sp,-3*"SZREG"\n"
  29 "       "REG_S" a0,0*"SZREG"(sp)\n"
  30 "       "REG_S" t0,1*"SZREG"(sp)\n"
  31 "       "REG_S" ra,2*"SZREG"(sp)\n"
  32 "       mv      a0,t0\n"
  33 "       call    my_direct_func\n"
  34 "       "REG_L" a0,0*"SZREG"(sp)\n"
  35 "       "REG_L" t0,1*"SZREG"(sp)\n"
  36 "       "REG_L" ra,2*"SZREG"(sp)\n"
  37 "       addi    sp,sp,3*"SZREG"\n"
  38 "       jr      t0\n"
  39 "       .size           my_tramp, .-my_tramp\n"
  40 "       .popsection\n"
  41 );
  42
  43 #endif /* CONFIG_RISCV */
  44
  45 #ifdef CONFIG_X86_64
  46
  47 #include <asm/ibt.h>
  48 #include <asm/nospec-branch.h>
  49
  50 asm (
  51 "       .pushsection    .text, \"ax\", @progbits\n"
  52 "       .type           my_tramp, @function\n"
  53 "       .globl          my_tramp\n"
  54 "   my_tramp:"
  55         ASM_ENDBR
  56 "       pushq %rbp\n"
  57 "       movq %rsp, %rbp\n"
  58         CALL_DEPTH_ACCOUNT
  59 "       pushq %rdi\n"
  60 "       movq 8(%rbp), %rdi\n"
  61 "       call my_direct_func\n"
  62 "       popq %rdi\n"
  63 "       leave\n"
  64         ASM_RET
  65 "       .size           my_tramp, .-my_tramp\n"
  66 "       .popsection\n"
  67 );
  68
  69 #endif /* CONFIG_X86_64 */
  70
  71 #ifdef CONFIG_S390
  72
  73 asm (
  74 "       .pushsection    .text, \"ax\", @progbits\n"
  75 "       .type           my_tramp, @function\n"
  76 "       .globl          my_tramp\n"
  77 "   my_tramp:"
  78 "       lgr             %r1,%r15\n"
  79 "       stmg            %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
  80 "       stg             %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
  81 "       aghi            %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
  82 "       stg             %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
  83 "       lgr             %r2,%r0\n"
  84 "       brasl           %r14,my_direct_func\n"
  85 "       aghi            %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
  86 "       lmg             %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
  87 "       lg              %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
  88 "       lgr             %r1,%r0\n"
  89 "       br              %r1\n"
  90 "       .size           my_tramp, .-my_tramp\n"
  91 "       .popsection\n"
  92 );
  93
  94 #endif /* CONFIG_S390 */
  95
  96 #ifdef CONFIG_ARM64
  97
  98 asm (
  99 "       .pushsection    .text, \"ax\", @progbits\n"
 100 "       .type           my_tramp, @function\n"
 101 "       .globl          my_tramp\n"
 102 "   my_tramp:"
 103 "       hint    34\n" // bti    c
 104 "       sub     sp, sp, #32\n"
 105 "       stp     x9, x30, [sp]\n"
 106 "       str     x0, [sp, #16]\n"
 107 "       mov     x0, x30\n"
 108 "       bl      my_direct_func\n"
 109 "       ldp     x30, x9, [sp]\n"
 110 "       ldr     x0, [sp, #16]\n"
 111 "       add     sp, sp, #32\n"
 112 "       ret     x9\n"
 113 "       .size           my_tramp, .-my_tramp\n"
 114 "       .popsection\n"
 115 );
 116
 117 #endif /* CONFIG_ARM64 */
 118
 119 #ifdef CONFIG_LOONGARCH
 120
 121 #include <asm/asm.h>
 122 asm (
 123 "       .pushsection    .text, \"ax\", @progbits\n"
 124 "       .type           my_tramp, @function\n"
 125 "       .globl          my_tramp\n"
 126 "   my_tramp:\n"
 127 "       addi.d  $sp, $sp, -32\n"
 128 "       st.d    $a0, $sp, 0\n"
 129 "       st.d    $t0, $sp, 8\n"
 130 "       st.d    $ra, $sp, 16\n"
 131 "       move    $a0, $t0\n"
 132 "       bl      my_direct_func\n"
 133 "       ld.d    $a0, $sp, 0\n"
 134 "       ld.d    $t0, $sp, 8\n"
 135 "       ld.d    $ra, $sp, 16\n"
 136 "       addi.d  $sp, $sp, 32\n"
 137 "       jr      $t0\n"
 138 "       .size           my_tramp, .-my_tramp\n"
 139 "       .popsection\n"
 140 );
 141
 142 #endif /* CONFIG_LOONGARCH */
 143
 144 #ifdef CONFIG_PPC
 145 #include <asm/ppc_asm.h>
 146
 147 #ifdef CONFIG_PPC64
 148 #define STACK_FRAME_SIZE 48
 149 #else
 150 #define STACK_FRAME_SIZE 24
 151 #endif
 152
 153 #if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)
 154 #define PPC64_TOC_SAVE_AND_UPDATE                       \
 155 "       std             2, 24(1)\n"                     \
 156 "       bcl             20, 31, 1f\n"                   \
 157 "   1:  mflr            12\n"                           \
 158 "       ld              2, (99f - 1b)(12)\n"
 159 #define PPC64_TOC_RESTORE                               \
 160 "       ld              2, 24(1)\n"
 161 #define PPC64_TOC                                       \
 162 "   99: .quad           .TOC.@tocbase\n"
 163 #else
 164 #define PPC64_TOC_SAVE_AND_UPDATE ""
 165 #define PPC64_TOC_RESTORE ""
 166 #define PPC64_TOC ""
 167 #endif
 168
 169 #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
 170 #define PPC_FTRACE_RESTORE_LR                           \
 171         PPC_LL"         0, "__stringify(PPC_LR_STKOFF)"(1)\n"   \
 172 "       mtlr            0\n"
 173 #define PPC_FTRACE_RET                                  \
 174 "       blr\n"
 175 #define PPC_FTRACE_RECOVER_IP                           \
 176 "       lwz             8, 4(3)\n"                      \
 177 "       li              9, 6\n"                         \
 178 "       slw             8, 8, 9\n"                      \
 179 "       sraw            8, 8, 9\n"                      \
 180 "       add             3, 3, 8\n"                      \
 181 "       addi            3, 3, 4\n"
 182 #else
 183 #define PPC_FTRACE_RESTORE_LR                           \
 184         PPC_LL"         0, "__stringify(PPC_LR_STKOFF)"(1)\n"   \
 185 "       mtctr           0\n"
 186 #define PPC_FTRACE_RET                                  \
 187 "       mtlr            0\n"                            \
 188 "       bctr\n"
 189 #define PPC_FTRACE_RECOVER_IP ""
 190 #endif
 191
 192 asm (
 193 "       .pushsection    .text, \"ax\", @progbits\n"
 194 "       .type           my_tramp, @function\n"
 195 "       .globl          my_tramp\n"
 196 "   my_tramp:\n"
 197         PPC_STL"        0, "__stringify(PPC_LR_STKOFF)"(1)\n"
 198         PPC_STLU"       1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
 199 "       mflr            0\n"
 200         PPC_STL"        0, "__stringify(PPC_LR_STKOFF)"(1)\n"
 201         PPC_STLU"       1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"
 202         PPC64_TOC_SAVE_AND_UPDATE
 203         PPC_STL"        3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
 204 "       mr              3, 0\n"
 205         PPC_FTRACE_RECOVER_IP
 206 "       bl              my_direct_func\n"
 207         PPC_LL"         3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
 208         PPC64_TOC_RESTORE
 209 "       addi            1, 1, "__stringify(STACK_FRAME_SIZE)"\n"
 210         PPC_FTRACE_RESTORE_LR
 211 "       addi            1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"
 212         PPC_LL"         0, "__stringify(PPC_LR_STKOFF)"(1)\n"
 213         PPC_FTRACE_RET
 214         PPC64_TOC
 215 "       .size           my_tramp, .-my_tramp\n"
 216 "       .popsection\n"
 217 );
 218
 219 #endif /* CONFIG_PPC */
 220
 221 static struct ftrace_ops direct;
 222
 223 static int __init ftrace_direct_multi_init(void)
 224 {
 225         ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
 226         ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
 227
 228         return register_ftrace_direct(&direct, (unsigned long) my_tramp);
 229 }
 230
 231 static void __exit ftrace_direct_multi_exit(void)
 232 {
 233         unregister_ftrace_direct(&direct, (unsigned long) my_tramp, true);
 234 }
 235
 236 module_init(ftrace_direct_multi_init);
 237 module_exit(ftrace_direct_multi_exit);
 238
 239 MODULE_AUTHOR("Jiri Olsa");
 240 MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()");
 241 MODULE_LICENSE("GPL");