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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 | // SPDX-License-Identifier: GPL-2.0-only #include <linux/module.h> #include <linux/mm.h> /* for handle_mm_fault() */ #include <linux/ftrace.h> #ifndef CONFIG_ARM64 #include <asm/asm-offsets.h> #endif extern void my_direct_func(struct vm_area_struct *vma, unsigned long address, unsigned int flags, struct pt_regs *regs); void my_direct_func(struct vm_area_struct *vma, unsigned long address, unsigned int flags, struct pt_regs *regs) { trace_printk("handle mm fault vma=%p address=%lx flags=%x regs=%p\n", vma, address, flags, regs); } extern void my_tramp(void *); #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" " pushq %rsi\n" " pushq %rdx\n" " pushq %rcx\n" " call my_direct_func\n" " popq %rcx\n" " popq %rdx\n" " popq %rsi\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, #48\n" " stp x9, x30, [sp]\n" " stp x0, x1, [sp, #16]\n" " stp x2, x3, [sp, #32]\n" " bl my_direct_func\n" " ldp x30, x9, [sp]\n" " ldp x0, x1, [sp, #16]\n" " ldp x2, x3, [sp, #32]\n" " add sp, sp, #48\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, -48\n" " st.d $a0, $sp, 0\n" " st.d $a1, $sp, 8\n" " st.d $a2, $sp, 16\n" " st.d $t0, $sp, 24\n" " st.d $ra, $sp, 32\n" " bl my_direct_func\n" " ld.d $a0, $sp, 0\n" " ld.d $a1, $sp, 8\n" " ld.d $a2, $sp, 16\n" " ld.d $t0, $sp, 24\n" " ld.d $ra, $sp, 32\n" " addi.d $sp, $sp, 48\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) handle_mm_fault, 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("Another example use case of using register_ftrace_direct()"); MODULE_LICENSE("GPL"); |