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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 | // SPDX-License-Identifier: GPL-2.0-only #include <linux/module.h> #include <linux/sched.h> /* for wake_up_process() */ #include <linux/ftrace.h> #ifndef CONFIG_ARM64 #include <asm/asm-offsets.h> #endif extern void my_direct_func(struct task_struct *p); void my_direct_func(struct task_struct *p) { trace_printk("waking up %s-%d\n", p->comm, p->pid); } extern void my_tramp(void *); #ifdef CONFIG_RISCV #include <asm/asm.h> asm ( " .pushsection .text, \"ax\", @progbits\n" " .type my_tramp, @function\n" " .globl my_tramp\n" " my_tramp:\n" " addi sp,sp,-3*"SZREG"\n" " "REG_S" a0,0*"SZREG"(sp)\n" " "REG_S" t0,1*"SZREG"(sp)\n" " "REG_S" ra,2*"SZREG"(sp)\n" " call my_direct_func\n" " "REG_L" a0,0*"SZREG"(sp)\n" " "REG_L" t0,1*"SZREG"(sp)\n" " "REG_L" ra,2*"SZREG"(sp)\n" " addi sp,sp,3*"SZREG"\n" " jr t0\n" " .size my_tramp, .-my_tramp\n" " .popsection\n" ); #endif /* CONFIG_RISCV */ #ifdef CONFIG_X86_64 #include <asm/ibt.h> #include <asm/nospec-branch.h> asm ( " .pushsection .text, \"ax\", @progbits\n" " .type my_tramp, @function\n" " .globl my_tramp\n" " my_tramp:" ASM_ENDBR " pushq %rbp\n" " movq %rsp, %rbp\n" CALL_DEPTH_ACCOUNT " pushq %rdi\n" " call my_direct_func\n" " popq %rdi\n" " leave\n" ASM_RET " .size my_tramp, .-my_tramp\n" " .popsection\n" ); #endif /* CONFIG_X86_64 */ #ifdef CONFIG_S390 asm ( " .pushsection .text, \"ax\", @progbits\n" " .type my_tramp, @function\n" " .globl my_tramp\n" " my_tramp:" " lgr %r1,%r15\n" " stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" " stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" " aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n" " stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n" " brasl %r14,my_direct_func\n" " aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n" " lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" " lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" " lgr %r1,%r0\n" " br %r1\n" " .size my_tramp, .-my_tramp\n" " .popsection\n" ); #endif /* CONFIG_S390 */ #ifdef CONFIG_ARM64 asm ( " .pushsection .text, \"ax\", @progbits\n" " .type my_tramp, @function\n" " .globl my_tramp\n" " my_tramp:" " hint 34\n" // bti c " sub sp, sp, #32\n" " stp x9, x30, [sp]\n" " str x0, [sp, #16]\n" " bl my_direct_func\n" " ldp x30, x9, [sp]\n" " ldr x0, [sp, #16]\n" " add sp, sp, #32\n" " ret x9\n" " .size my_tramp, .-my_tramp\n" " .popsection\n" ); #endif /* CONFIG_ARM64 */ #ifdef CONFIG_LOONGARCH asm ( " .pushsection .text, \"ax\", @progbits\n" " .type my_tramp, @function\n" " .globl my_tramp\n" " my_tramp:\n" " addi.d $sp, $sp, -32\n" " st.d $a0, $sp, 0\n" " st.d $t0, $sp, 8\n" " st.d $ra, $sp, 16\n" " bl my_direct_func\n" " ld.d $a0, $sp, 0\n" " ld.d $t0, $sp, 8\n" " ld.d $ra, $sp, 16\n" " addi.d $sp, $sp, 32\n" " jr $t0\n" " .size my_tramp, .-my_tramp\n" " .popsection\n" ); #endif /* CONFIG_LOONGARCH */ static struct ftrace_ops direct; static int __init ftrace_direct_init(void) { ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0); return register_ftrace_direct(&direct, (unsigned long) my_tramp); } static void __exit ftrace_direct_exit(void) { unregister_ftrace_direct(&direct, (unsigned long)my_tramp, true); } module_init(ftrace_direct_init); module_exit(ftrace_direct_exit); MODULE_AUTHOR("Steven Rostedt"); MODULE_DESCRIPTION("Example use case of using register_ftrace_direct()"); MODULE_LICENSE("GPL"); |