76c2f13c55
Linus pointed out that there were locations that did the hard coded update of the parent and rip parameters. One of them was the static tracer which could also use the ftrace_caller_setup to do that work. In fact, because it did not use it, it is prone to bugs, and since the static tracer is hardly ever used (who wants function tracing code always being called?) it doesn't get tested very often. I only run a few "does it still work" tests on it. But I do not run stress tests on that code. Although, since it is never turned off, just having it on should be stressful enough. (especially for the performance folks) There's no reason that the static tracer can't also use ftrace_caller_setup. Have it do so. Link: http://lkml.kernel.org/r/CA+55aFwF+qCGSKdGaEgW4p6N65GZ5_XTV=1NbtWDvxnd5yYLiw@mail.gmail.com Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1411262304010.3961@nanos Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
258 lines
4.7 KiB
ArmAsm
258 lines
4.7 KiB
ArmAsm
/*
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* linux/arch/x86_64/mcount_64.S
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*
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* Copyright (C) 2014 Steven Rostedt, Red Hat Inc
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*/
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#include <linux/linkage.h>
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#include <asm/ptrace.h>
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#include <asm/ftrace.h>
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.code64
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.section .entry.text, "ax"
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#ifdef CONFIG_FUNCTION_TRACER
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#ifdef CC_USING_FENTRY
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# define function_hook __fentry__
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#else
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# define function_hook mcount
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#endif
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/* skip is set if stack has been adjusted */
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.macro ftrace_caller_setup trace_label skip=0
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MCOUNT_SAVE_FRAME \skip
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/* Save this location */
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GLOBAL(\trace_label)
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/* Load the ftrace_ops into the 3rd parameter */
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movq function_trace_op(%rip), %rdx
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/* Load ip into the first parameter */
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movq RIP(%rsp), %rdi
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subq $MCOUNT_INSN_SIZE, %rdi
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/* Load the parent_ip into the second parameter */
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#ifdef CC_USING_FENTRY
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movq SS+16(%rsp), %rsi
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#else
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movq 8(%rbp), %rsi
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#endif
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.endm
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#ifdef CONFIG_DYNAMIC_FTRACE
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ENTRY(function_hook)
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retq
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END(function_hook)
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#ifdef CONFIG_FRAME_POINTER
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/*
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* Stack traces will stop at the ftrace trampoline if the frame pointer
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* is not set up properly. If fentry is used, we need to save a frame
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* pointer for the parent as well as the function traced, because the
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* fentry is called before the stack frame is set up, where as mcount
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* is called afterward.
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*/
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.macro create_frame parent rip
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#ifdef CC_USING_FENTRY
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pushq \parent
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pushq %rbp
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movq %rsp, %rbp
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#endif
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pushq \rip
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pushq %rbp
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movq %rsp, %rbp
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.endm
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.macro restore_frame
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#ifdef CC_USING_FENTRY
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addq $16, %rsp
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#endif
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popq %rbp
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addq $8, %rsp
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.endm
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#else
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.macro create_frame parent rip
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.endm
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.macro restore_frame
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.endm
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#endif /* CONFIG_FRAME_POINTER */
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ENTRY(ftrace_caller)
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ftrace_caller_setup ftrace_caller_op_ptr
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/* regs go into 4th parameter (but make it NULL) */
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movq $0, %rcx
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create_frame %rsi, %rdi
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GLOBAL(ftrace_call)
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call ftrace_stub
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restore_frame
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MCOUNT_RESTORE_FRAME
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/*
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* The copied trampoline must call ftrace_return as it
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* still may need to call the function graph tracer.
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*/
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GLOBAL(ftrace_caller_end)
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GLOBAL(ftrace_return)
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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GLOBAL(ftrace_graph_call)
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jmp ftrace_stub
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#endif
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GLOBAL(ftrace_stub)
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retq
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END(ftrace_caller)
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ENTRY(ftrace_regs_caller)
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/* Save the current flags before compare (in SS location)*/
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pushfq
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/* skip=8 to skip flags saved in SS */
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ftrace_caller_setup ftrace_regs_caller_op_ptr 8
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/* Save the rest of pt_regs */
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movq %r15, R15(%rsp)
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movq %r14, R14(%rsp)
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movq %r13, R13(%rsp)
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movq %r12, R12(%rsp)
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movq %r11, R11(%rsp)
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movq %r10, R10(%rsp)
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movq %rbp, RBP(%rsp)
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movq %rbx, RBX(%rsp)
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/* Copy saved flags */
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movq SS(%rsp), %rcx
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movq %rcx, EFLAGS(%rsp)
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/* Kernel segments */
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movq $__KERNEL_DS, %rcx
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movq %rcx, SS(%rsp)
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movq $__KERNEL_CS, %rcx
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movq %rcx, CS(%rsp)
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/* Stack - skipping return address */
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leaq SS+16(%rsp), %rcx
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movq %rcx, RSP(%rsp)
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/* regs go into 4th parameter */
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leaq (%rsp), %rcx
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create_frame %rsi, %rdi
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GLOBAL(ftrace_regs_call)
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call ftrace_stub
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restore_frame
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/* Copy flags back to SS, to restore them */
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movq EFLAGS(%rsp), %rax
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movq %rax, SS(%rsp)
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/* Handlers can change the RIP */
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movq RIP(%rsp), %rax
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movq %rax, SS+8(%rsp)
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/* restore the rest of pt_regs */
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movq R15(%rsp), %r15
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movq R14(%rsp), %r14
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movq R13(%rsp), %r13
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movq R12(%rsp), %r12
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movq R10(%rsp), %r10
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movq RBP(%rsp), %rbp
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movq RBX(%rsp), %rbx
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/* skip=8 to skip flags saved in SS */
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MCOUNT_RESTORE_FRAME 8
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/* Restore flags */
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popfq
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/*
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* As this jmp to ftrace_return can be a short jump
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* it must not be copied into the trampoline.
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* The trampoline will add the code to jump
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* to the return.
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*/
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GLOBAL(ftrace_regs_caller_end)
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jmp ftrace_return
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popfq
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jmp ftrace_stub
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END(ftrace_regs_caller)
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#else /* ! CONFIG_DYNAMIC_FTRACE */
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ENTRY(function_hook)
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cmpq $ftrace_stub, ftrace_trace_function
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jnz trace
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fgraph_trace:
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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cmpq $ftrace_stub, ftrace_graph_return
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jnz ftrace_graph_caller
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cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
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jnz ftrace_graph_caller
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#endif
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GLOBAL(ftrace_stub)
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retq
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trace:
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ftrace_caller_setup ftrace_caller_op_ptr
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call *ftrace_trace_function
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MCOUNT_RESTORE_FRAME
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jmp fgraph_trace
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END(function_hook)
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#endif /* CONFIG_DYNAMIC_FTRACE */
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#endif /* CONFIG_FUNCTION_TRACER */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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ENTRY(ftrace_graph_caller)
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MCOUNT_SAVE_FRAME
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#ifdef CC_USING_FENTRY
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leaq SS+16(%rsp), %rdi
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movq $0, %rdx /* No framepointers needed */
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#else
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leaq 8(%rbp), %rdi
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movq (%rbp), %rdx
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#endif
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movq RIP(%rsp), %rsi
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subq $MCOUNT_INSN_SIZE, %rsi
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call prepare_ftrace_return
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MCOUNT_RESTORE_FRAME
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retq
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END(ftrace_graph_caller)
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GLOBAL(return_to_handler)
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subq $24, %rsp
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/* Save the return values */
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movq %rax, (%rsp)
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movq %rdx, 8(%rsp)
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movq %rbp, %rdi
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call ftrace_return_to_handler
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movq %rax, %rdi
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movq 8(%rsp), %rdx
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movq (%rsp), %rax
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addq $24, %rsp
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jmp *%rdi
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#endif
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