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"); 242