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71db948b9d
Add powerpc 32-bit and 64-bit samples for ftrace direct. This serves to show the sample instruction sequence to be used by ftrace direct calls to adhere to the ftrace ABI. On 64-bit powerpc, TOC setup requires some additional work. Signed-off-by: Naveen N Rao <naveen@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://patch.msgid.link/20241030070850.1361304-17-hbathini@linux.ibm.com
224 lines
5.1 KiB
C
224 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/module.h>
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#include <linux/sched.h> /* for wake_up_process() */
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#include <linux/ftrace.h>
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#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
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#include <asm/asm-offsets.h>
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#endif
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extern void my_direct_func(struct task_struct *p);
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void my_direct_func(struct task_struct *p)
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{
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trace_printk("waking up %s-%d\n", p->comm, p->pid);
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}
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extern void my_tramp(void *);
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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_tramp, @function\n"
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" .globl my_tramp\n"
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" my_tramp:\n"
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" addi sp,sp,-3*"SZREG"\n"
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" "REG_S" a0,0*"SZREG"(sp)\n"
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" "REG_S" t0,1*"SZREG"(sp)\n"
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" "REG_S" ra,2*"SZREG"(sp)\n"
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" call my_direct_func\n"
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" "REG_L" a0,0*"SZREG"(sp)\n"
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" "REG_L" t0,1*"SZREG"(sp)\n"
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" "REG_L" ra,2*"SZREG"(sp)\n"
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" addi sp,sp,3*"SZREG"\n"
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" jr t0\n"
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" .size my_tramp, .-my_tramp\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_tramp, @function\n"
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" .globl my_tramp\n"
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" my_tramp:"
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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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" pushq %rdi\n"
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" call my_direct_func\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_tramp, .-my_tramp\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_tramp, @function\n"
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" .globl my_tramp\n"
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" my_tramp:"
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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_func\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_tramp, .-my_tramp\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_tramp, @function\n"
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" .globl my_tramp\n"
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" my_tramp:"
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" hint 34\n" // bti c
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" sub sp, sp, #32\n"
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" stp x9, x30, [sp]\n"
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" str x0, [sp, #16]\n"
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" bl my_direct_func\n"
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" ldp x30, x9, [sp]\n"
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" ldr x0, [sp, #16]\n"
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" add sp, sp, #32\n"
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" ret x9\n"
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" .size my_tramp, .-my_tramp\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_tramp, @function\n"
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" .globl my_tramp\n"
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" my_tramp:\n"
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" addi.d $sp, $sp, -32\n"
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" st.d $a0, $sp, 0\n"
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" st.d $t0, $sp, 8\n"
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" st.d $ra, $sp, 16\n"
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" bl my_direct_func\n"
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" ld.d $a0, $sp, 0\n"
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" ld.d $t0, $sp, 8\n"
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" ld.d $ra, $sp, 16\n"
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" addi.d $sp, $sp, 32\n"
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" jr $t0\n"
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" .size my_tramp, .-my_tramp\n"
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" .popsection\n"
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);
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#endif /* CONFIG_LOONGARCH */
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#ifdef CONFIG_PPC
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#include <asm/ppc_asm.h>
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#ifdef CONFIG_PPC64
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#define STACK_FRAME_SIZE 48
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#else
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#define STACK_FRAME_SIZE 24
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#endif
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#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)
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#define PPC64_TOC_SAVE_AND_UPDATE \
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" std 2, 24(1)\n" \
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" bcl 20, 31, 1f\n" \
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" 1: mflr 12\n" \
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" ld 2, (99f - 1b)(12)\n"
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#define PPC64_TOC_RESTORE \
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" ld 2, 24(1)\n"
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#define PPC64_TOC \
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" 99: .quad .TOC.@tocbase\n"
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#else
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#define PPC64_TOC_SAVE_AND_UPDATE ""
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#define PPC64_TOC_RESTORE ""
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#define PPC64_TOC ""
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#endif
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#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
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#define PPC_FTRACE_RESTORE_LR \
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PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \
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" mtlr 0\n"
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#define PPC_FTRACE_RET \
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" blr\n"
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#else
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#define PPC_FTRACE_RESTORE_LR \
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PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \
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" mtctr 0\n"
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#define PPC_FTRACE_RET \
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" mtlr 0\n" \
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" bctr\n"
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#endif
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asm (
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" .pushsection .text, \"ax\", @progbits\n"
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" .type my_tramp, @function\n"
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" .globl my_tramp\n"
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" my_tramp:\n"
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PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
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PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
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" mflr 0\n"
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PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
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PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"
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PPC64_TOC_SAVE_AND_UPDATE
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PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
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" bl my_direct_func\n"
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PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
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PPC64_TOC_RESTORE
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" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n"
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PPC_FTRACE_RESTORE_LR
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" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"
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PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
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PPC_FTRACE_RET
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PPC64_TOC
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" .size my_tramp, .-my_tramp\n"
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" .popsection\n"
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);
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#endif /* CONFIG_PPC */
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static struct ftrace_ops direct;
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static int __init ftrace_direct_init(void)
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{
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ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
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return register_ftrace_direct(&direct, (unsigned long) my_tramp);
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}
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static void __exit ftrace_direct_exit(void)
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{
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unregister_ftrace_direct(&direct, (unsigned long)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 register_ftrace_direct()");
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MODULE_LICENSE("GPL");
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