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c9d0f5a18b
commitbb85d206beupstream. Ensure that in the ftrace direct call logic, the CPU register state (with ra = parent return address) is restored to the correct state after the execution of the custom trampoline function and before returning to the traced function. Additionally, guarantee the correctness of the jump logic for jr t0 (traced function address). Cc: stable@vger.kernel.org Fixes:9cdc3b6a29("LoongArch: ftrace: Add direct call support") Reported-by: Youling Tang <tangyouling@kylinos.cn> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
257 lines
5.4 KiB
C
257 lines
5.4 KiB
C
// 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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#ifndef CONFIG_ARM64
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#include <asm/asm-offsets.h>
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#endif
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extern void my_direct_func1(void);
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extern void my_direct_func2(void);
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void my_direct_func1(void)
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{
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trace_printk("my direct func1\n");
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}
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void my_direct_func2(void)
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{
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trace_printk("my direct func2\n");
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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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static unsigned long my_ip = (unsigned long)schedule;
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#ifdef CONFIG_RISCV
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#include <asm/asm.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:\n"
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" addi sp,sp,-2*"SZREG"\n"
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" "REG_S" t0,0*"SZREG"(sp)\n"
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" "REG_S" ra,1*"SZREG"(sp)\n"
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" call my_direct_func1\n"
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" "REG_L" t0,0*"SZREG"(sp)\n"
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" "REG_L" ra,1*"SZREG"(sp)\n"
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" addi sp,sp,2*"SZREG"\n"
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" jr t0\n"
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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:\n"
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" addi sp,sp,-2*"SZREG"\n"
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" "REG_S" t0,0*"SZREG"(sp)\n"
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" "REG_S" ra,1*"SZREG"(sp)\n"
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" call my_direct_func2\n"
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" "REG_L" t0,0*"SZREG"(sp)\n"
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" "REG_L" ra,1*"SZREG"(sp)\n"
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" addi sp,sp,2*"SZREG"\n"
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" jr t0\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_RISCV */
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#ifdef CONFIG_X86_64
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#include <asm/ibt.h>
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#include <asm/nospec-branch.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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CALL_DEPTH_ACCOUNT
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" call my_direct_func1\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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CALL_DEPTH_ACCOUNT
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" call my_direct_func2\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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" 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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" .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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" 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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#ifdef CONFIG_ARM64
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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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" hint 34\n" // bti c
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" sub sp, sp, #16\n"
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" stp x9, x30, [sp]\n"
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" bl my_direct_func1\n"
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" ldp x30, x9, [sp]\n"
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" add sp, sp, #16\n"
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" ret x9\n"
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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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" hint 34\n" // bti c
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" sub sp, sp, #16\n"
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" stp x9, x30, [sp]\n"
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" bl my_direct_func2\n"
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" ldp x30, x9, [sp]\n"
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" add sp, sp, #16\n"
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" ret x9\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_ARM64 */
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#ifdef CONFIG_LOONGARCH
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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:\n"
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" addi.d $sp, $sp, -16\n"
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" st.d $t0, $sp, 0\n"
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" st.d $ra, $sp, 8\n"
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" bl my_direct_func1\n"
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" ld.d $ra, $sp, 0\n"
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" ld.d $t0, $sp, 8\n"
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" addi.d $sp, $sp, 16\n"
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" jr $t0\n"
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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:\n"
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" addi.d $sp, $sp, -16\n"
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" st.d $t0, $sp, 0\n"
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" st.d $ra, $sp, 8\n"
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" bl my_direct_func2\n"
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" ld.d $ra, $sp, 0\n"
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" ld.d $t0, $sp, 8\n"
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" addi.d $sp, $sp, 16\n"
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" jr $t0\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_LOONGARCH */
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static struct ftrace_ops direct;
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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 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(&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_init(void)
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{
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int ret;
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ftrace_set_filter_ip(&direct, (unsigned long) my_ip, 0, 0);
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ret = register_ftrace_direct(&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_exit(void)
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{
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kthread_stop(simple_tsk);
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unregister_ftrace_direct(&direct, my_tramp, true);
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}
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module_init(ftrace_direct_init);
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module_exit(ftrace_direct_exit);
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MODULE_AUTHOR("Steven Rostedt");
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MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()");
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MODULE_LICENSE("GPL");
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