| // SPDX-License-Identifier: GPL-2.0-only |
| #include <linux/module.h> |
| #include <linux/kthread.h> |
| #include <linux/ftrace.h> |
| #ifndef CONFIG_ARM64 |
| #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 $t0, $sp, 8\n" |
| " ld.d $ra, $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 $t0, $sp, 8\n" |
| " ld.d $ra, $sp, 16\n" |
| " addi.d $sp, $sp, 32\n" |
| " jr $t0\n" |
| " .size my_tramp2, .-my_tramp2\n" |
| " .popsection\n" |
| ); |
| |
| #endif /* CONFIG_LOONGARCH */ |
| |
| 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) |
| simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn"); |
| return ret; |
| } |
| |
| 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"); |
