| // SPDX-License-Identifier: GPL-2.0-only | |
| #include <linux/module.h> | |
| #include <linux/kthread.h> | |
| #include <linux/ftrace.h> | |
| #if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32) | |
| #include <asm/asm-offsets.h> | |
| #endif | |
| extern void my_direct_func1(unsigned long ip); | |
| extern void my_direct_func2(unsigned long ip); | |
| void my_direct_func1(unsigned long ip) | |
| { | |
| trace_printk("my direct func1 ip %lx\n", ip); | |
| } | |
| void my_direct_func2(unsigned long ip) | |
| { | |
| trace_printk("my direct func2 ip %lx\n", ip); | |
| } | |
| extern void my_tramp1(void *); | |
| extern void my_tramp2(void *); | |
| #ifdef CONFIG_RISCV | |
| #include <asm/asm.h> | |
| asm ( | |
| " .pushsection .text, \"ax\", @progbits\n" | |
| " .type my_tramp1, @function\n" | |
| " .globl my_tramp1\n" | |
| " my_tramp1:\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" | |
| " mv a0,t0\n" | |
| " call my_direct_func1\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_tramp1, .-my_tramp1\n" | |
| " .type my_tramp2, @function\n" | |
| " .globl my_tramp2\n" | |
| " my_tramp2:\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" | |
| " mv a0,t0\n" | |
| " call my_direct_func2\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_tramp2, .-my_tramp2\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_tramp1, @function\n" | |
| " .globl my_tramp1\n" | |
| " my_tramp1:" | |
| ASM_ENDBR | |
| " pushq %rbp\n" | |
| " movq %rsp, %rbp\n" | |
| CALL_DEPTH_ACCOUNT | |
| " pushq %rdi\n" | |
| " movq 8(%rbp), %rdi\n" | |
| " call my_direct_func1\n" | |
| " popq %rdi\n" | |
| " leave\n" | |
| ASM_RET | |
| " .size my_tramp1, .-my_tramp1\n" | |
| " .type my_tramp2, @function\n" | |
| " .globl my_tramp2\n" | |
| " my_tramp2:" | |
| ASM_ENDBR | |
| " pushq %rbp\n" | |
| " movq %rsp, %rbp\n" | |
| CALL_DEPTH_ACCOUNT | |
| " pushq %rdi\n" | |
| " movq 8(%rbp), %rdi\n" | |
| " call my_direct_func2\n" | |
| " popq %rdi\n" | |
| " leave\n" | |
| ASM_RET | |
| " .size my_tramp2, .-my_tramp2\n" | |
| " .popsection\n" | |
| ); | |
| #endif /* CONFIG_X86_64 */ | |
| #ifdef CONFIG_S390 | |
| asm ( | |
| " .pushsection .text, \"ax\", @progbits\n" | |
| " .type my_tramp1, @function\n" | |
| " .globl my_tramp1\n" | |
| " my_tramp1:" | |
| " 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" | |
| " lgr %r2,%r0\n" | |
| " brasl %r14,my_direct_func1\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_tramp1, .-my_tramp1\n" | |
| "\n" | |
| " .type my_tramp2, @function\n" | |
| " .globl my_tramp2\n" | |
| " my_tramp2:" | |
| " 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" | |
| " lgr %r2,%r0\n" | |
| " brasl %r14,my_direct_func2\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_tramp2, .-my_tramp2\n" | |
| " .popsection\n" | |
| ); | |
| #endif /* CONFIG_S390 */ | |
| #ifdef CONFIG_ARM64 | |
| asm ( | |
| " .pushsection .text, \"ax\", @progbits\n" | |
| " .type my_tramp1, @function\n" | |
| " .globl my_tramp1\n" | |
| " my_tramp1:" | |
| " hint 34\n" // bti c | |
| " sub sp, sp, #32\n" | |
| " stp x9, x30, [sp]\n" | |
| " str x0, [sp, #16]\n" | |
| " mov x0, x30\n" | |
| " bl my_direct_func1\n" | |
| " ldp x30, x9, [sp]\n" | |
| " ldr x0, [sp, #16]\n" | |
| " add sp, sp, #32\n" | |
| " ret x9\n" | |
| " .size my_tramp1, .-my_tramp1\n" | |
| " .type my_tramp2, @function\n" | |
| " .globl my_tramp2\n" | |
| " my_tramp2:" | |
| " hint 34\n" // bti c | |
| " sub sp, sp, #32\n" | |
| " stp x9, x30, [sp]\n" | |
| " str x0, [sp, #16]\n" | |
| " mov x0, x30\n" | |
| " bl my_direct_func2\n" | |
| " ldp x30, x9, [sp]\n" | |
| " ldr x0, [sp, #16]\n" | |
| " add sp, sp, #32\n" | |
| " ret x9\n" | |
| " .size my_tramp2, .-my_tramp2\n" | |
| " .popsection\n" | |
| ); | |
| #endif /* CONFIG_ARM64 */ | |
| #ifdef CONFIG_LOONGARCH | |
| #include <asm/asm.h> | |
| asm ( | |
| " .pushsection .text, \"ax\", @progbits\n" | |
| " .type my_tramp1, @function\n" | |
| " .globl my_tramp1\n" | |
| " my_tramp1:\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" | |
| " move $a0, $t0\n" | |
| " bl my_direct_func1\n" | |
| " ld.d $a0, $sp, 0\n" | |
| " ld.d $ra, $sp, 8\n" | |
| " ld.d $t0, $sp, 16\n" | |
| " addi.d $sp, $sp, 32\n" | |
| " jr $t0\n" | |
| " .size my_tramp1, .-my_tramp1\n" | |
| " .type my_tramp2, @function\n" | |
| " .globl my_tramp2\n" | |
| " my_tramp2:\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" | |
| " move $a0, $t0\n" | |
| " bl my_direct_func2\n" | |
| " ld.d $a0, $sp, 0\n" | |
| " ld.d $ra, $sp, 8\n" | |
| " ld.d $t0, $sp, 16\n" | |
| " addi.d $sp, $sp, 32\n" | |
| " jr $t0\n" | |
| " .size my_tramp2, .-my_tramp2\n" | |
| " .popsection\n" | |
| ); | |
| #endif /* CONFIG_LOONGARCH */ | |
| #ifdef CONFIG_PPC | |
| #include <asm/ppc_asm.h> | |
| #ifdef CONFIG_PPC64 | |
| #define STACK_FRAME_SIZE 48 | |
| #else | |
| #define STACK_FRAME_SIZE 24 | |
| #endif | |
| #if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL) | |
| #define PPC64_TOC_SAVE_AND_UPDATE \ | |
| " std 2, 24(1)\n" \ | |
| " bcl 20, 31, 1f\n" \ | |
| " 1: mflr 12\n" \ | |
| " ld 2, (99f - 1b)(12)\n" | |
| #define PPC64_TOC_RESTORE \ | |
| " ld 2, 24(1)\n" | |
| #define PPC64_TOC \ | |
| " 99: .quad .TOC.@tocbase\n" | |
| #else | |
| #define PPC64_TOC_SAVE_AND_UPDATE "" | |
| #define PPC64_TOC_RESTORE "" | |
| #define PPC64_TOC "" | |
| #endif | |
| #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE | |
| #define PPC_FTRACE_RESTORE_LR \ | |
| PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ | |
| " mtlr 0\n" | |
| #define PPC_FTRACE_RET \ | |
| " blr\n" | |
| #define PPC_FTRACE_RECOVER_IP \ | |
| " lwz 8, 4(3)\n" \ | |
| " li 9, 6\n" \ | |
| " slw 8, 8, 9\n" \ | |
| " sraw 8, 8, 9\n" \ | |
| " add 3, 3, 8\n" \ | |
| " addi 3, 3, 4\n" | |
| #else | |
| #define PPC_FTRACE_RESTORE_LR \ | |
| PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \ | |
| " mtctr 0\n" | |
| #define PPC_FTRACE_RET \ | |
| " mtlr 0\n" \ | |
| " bctr\n" | |
| #define PPC_FTRACE_RECOVER_IP "" | |
| #endif | |
| asm ( | |
| " .pushsection .text, \"ax\", @progbits\n" | |
| " .type my_tramp1, @function\n" | |
| " .globl my_tramp1\n" | |
| " my_tramp1:\n" | |
| PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" | |
| PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" | |
| " mflr 0\n" | |
| PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" | |
| PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n" | |
| PPC64_TOC_SAVE_AND_UPDATE | |
| PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" | |
| " mr 3, 0\n" | |
| PPC_FTRACE_RECOVER_IP | |
| " bl my_direct_func1\n" | |
| PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" | |
| PPC64_TOC_RESTORE | |
| " addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n" | |
| PPC_FTRACE_RESTORE_LR | |
| " addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n" | |
| PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" | |
| PPC_FTRACE_RET | |
| " .size my_tramp1, .-my_tramp1\n" | |
| " .type my_tramp2, @function\n" | |
| " .globl my_tramp2\n" | |
| " my_tramp2:\n" | |
| PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" | |
| PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" | |
| " mflr 0\n" | |
| PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" | |
| PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n" | |
| PPC64_TOC_SAVE_AND_UPDATE | |
| PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" | |
| " mr 3, 0\n" | |
| PPC_FTRACE_RECOVER_IP | |
| " bl my_direct_func2\n" | |
| PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n" | |
| PPC64_TOC_RESTORE | |
| " addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n" | |
| PPC_FTRACE_RESTORE_LR | |
| " addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n" | |
| PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" | |
| PPC_FTRACE_RET | |
| PPC64_TOC | |
| " .size my_tramp2, .-my_tramp2\n" | |
| " .popsection\n" | |
| ); | |
| #endif /* CONFIG_PPC */ | |
| static unsigned long my_tramp = (unsigned long)my_tramp1; | |
| static unsigned long tramps[2] = { | |
| (unsigned long)my_tramp1, | |
| (unsigned long)my_tramp2, | |
| }; | |
| static struct ftrace_ops direct; | |
| static int simple_thread(void *arg) | |
| { | |
| static int t; | |
| int ret = 0; | |
| while (!kthread_should_stop()) { | |
| set_current_state(TASK_INTERRUPTIBLE); | |
| schedule_timeout(2 * HZ); | |
| if (ret) | |
| continue; | |
| t ^= 1; | |
| ret = modify_ftrace_direct(&direct, tramps[t]); | |
| if (!ret) | |
| my_tramp = tramps[t]; | |
| WARN_ON_ONCE(ret); | |
| } | |
| return 0; | |
| } | |
| static struct task_struct *simple_tsk; | |
| static int __init ftrace_direct_multi_init(void) | |
| { | |
| int ret; | |
| ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0); | |
| ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0); | |
| ret = register_ftrace_direct(&direct, my_tramp); | |
| if (ret) | |
| return ret; | |
| simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn"); | |
| if (IS_ERR(simple_tsk)) { | |
| unregister_ftrace_direct(&direct, my_tramp, true); | |
| return PTR_ERR(simple_tsk); | |
| } | |
| return 0; | |
| } | |
| static void __exit ftrace_direct_multi_exit(void) | |
| { | |
| kthread_stop(simple_tsk); | |
| unregister_ftrace_direct(&direct, my_tramp, true); | |
| } | |
| module_init(ftrace_direct_multi_init); | |
| module_exit(ftrace_direct_multi_exit); | |
| MODULE_AUTHOR("Jiri Olsa"); | |
| MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()"); | |
| MODULE_LICENSE("GPL"); |