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159 lines
4.1 KiB
159 lines
4.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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#include <linux/module.h> |
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#include <linux/kthread.h> |
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#include <linux/ftrace.h> |
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#include <asm/asm-offsets.h> |
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extern void my_direct_func1(unsigned long ip); |
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extern void my_direct_func2(unsigned long ip); |
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void my_direct_func1(unsigned long ip) |
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{ |
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trace_printk("my direct func1 ip %lx\n", ip); |
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} |
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void my_direct_func2(unsigned long ip) |
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{ |
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trace_printk("my direct func2 ip %lx\n", ip); |
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} |
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extern void my_tramp1(void *); |
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extern void my_tramp2(void *); |
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#ifdef CONFIG_X86_64 |
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#include <asm/ibt.h> |
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asm ( |
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" .pushsection .text, \"ax\", @progbits\n" |
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" .type my_tramp1, @function\n" |
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" .globl my_tramp1\n" |
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" my_tramp1:" |
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ASM_ENDBR |
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" pushq %rbp\n" |
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" movq %rsp, %rbp\n" |
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" pushq %rdi\n" |
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" movq 8(%rbp), %rdi\n" |
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" call my_direct_func1\n" |
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" popq %rdi\n" |
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" leave\n" |
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ASM_RET |
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" .size my_tramp1, .-my_tramp1\n" |
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" .type my_tramp2, @function\n" |
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" .globl my_tramp2\n" |
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" my_tramp2:" |
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ASM_ENDBR |
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" pushq %rbp\n" |
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" movq %rsp, %rbp\n" |
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" pushq %rdi\n" |
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" movq 8(%rbp), %rdi\n" |
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" call my_direct_func2\n" |
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" popq %rdi\n" |
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" leave\n" |
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ASM_RET |
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" .size my_tramp2, .-my_tramp2\n" |
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" .popsection\n" |
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); |
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#endif /* CONFIG_X86_64 */ |
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#ifdef CONFIG_S390 |
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asm ( |
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" .pushsection .text, \"ax\", @progbits\n" |
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" .type my_tramp1, @function\n" |
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" .globl my_tramp1\n" |
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" my_tramp1:" |
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" lgr %r1,%r15\n" |
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" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" |
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" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" |
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" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n" |
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" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n" |
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" lgr %r2,%r0\n" |
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" brasl %r14,my_direct_func1\n" |
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" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n" |
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" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" |
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" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" |
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" lgr %r1,%r0\n" |
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" br %r1\n" |
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" .size my_tramp1, .-my_tramp1\n" |
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"\n" |
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" .type my_tramp2, @function\n" |
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" .globl my_tramp2\n" |
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" my_tramp2:" |
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" lgr %r1,%r15\n" |
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" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" |
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" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" |
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" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n" |
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" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n" |
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" lgr %r2,%r0\n" |
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" brasl %r14,my_direct_func2\n" |
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" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n" |
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" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" |
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" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" |
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" lgr %r1,%r0\n" |
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" br %r1\n" |
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" .size my_tramp2, .-my_tramp2\n" |
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" .popsection\n" |
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); |
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#endif /* CONFIG_S390 */ |
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static unsigned long my_tramp = (unsigned long)my_tramp1; |
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static unsigned long tramps[2] = { |
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(unsigned long)my_tramp1, |
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(unsigned long)my_tramp2, |
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}; |
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static struct ftrace_ops direct; |
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static int simple_thread(void *arg) |
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{ |
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static int t; |
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int ret = 0; |
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while (!kthread_should_stop()) { |
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set_current_state(TASK_INTERRUPTIBLE); |
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schedule_timeout(2 * HZ); |
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if (ret) |
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continue; |
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t ^= 1; |
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ret = modify_ftrace_direct_multi(&direct, tramps[t]); |
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if (!ret) |
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my_tramp = tramps[t]; |
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WARN_ON_ONCE(ret); |
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} |
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return 0; |
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} |
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static struct task_struct *simple_tsk; |
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static int __init ftrace_direct_multi_init(void) |
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{ |
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int ret; |
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ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0); |
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ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0); |
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ret = register_ftrace_direct_multi(&direct, my_tramp); |
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if (!ret) |
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simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn"); |
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return ret; |
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} |
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static void __exit ftrace_direct_multi_exit(void) |
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{ |
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kthread_stop(simple_tsk); |
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unregister_ftrace_direct_multi(&direct, my_tramp); |
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} |
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module_init(ftrace_direct_multi_init); |
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module_exit(ftrace_direct_multi_exit); |
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MODULE_AUTHOR("Jiri Olsa"); |
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MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct_multi()"); |
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MODULE_LICENSE("GPL");
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