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6fb8656646
ftrace_graph_caller was never run after calling ftrace_trace_function, breaking the function graph tracer. Fix this, bringing it in line with the x86 implementation. While we're at it, also streamline the control flow of _mcount a bit to reduce the number of branches. This issue was reported before: https://www.linux-mips.org/archives/linux-mips/2014-11/msg00295.html Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net> Tested-by: Matt Redfearn <matt.redfearn@mips.com> Patchwork: https://patchwork.linux-mips.org/patch/18929/ Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: stable@vger.kernel.org # v3.17+
220 lines
4.4 KiB
ArmAsm
220 lines
4.4 KiB
ArmAsm
/*
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* MIPS specific _mcount support
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive for
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* more details.
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*
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* Copyright (C) 2009 Lemote Inc. & DSLab, Lanzhou University, China
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* Copyright (C) 2010 DSLab, Lanzhou University, China
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* Author: Wu Zhangjin <wuzhangjin@gmail.com>
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*/
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#include <asm/export.h>
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#include <asm/regdef.h>
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#include <asm/stackframe.h>
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#include <asm/ftrace.h>
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.text
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.set noreorder
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.set noat
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.macro MCOUNT_SAVE_REGS
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PTR_SUBU sp, PT_SIZE
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PTR_S ra, PT_R31(sp)
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PTR_S AT, PT_R1(sp)
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PTR_S a0, PT_R4(sp)
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PTR_S a1, PT_R5(sp)
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PTR_S a2, PT_R6(sp)
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PTR_S a3, PT_R7(sp)
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#ifdef CONFIG_64BIT
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PTR_S a4, PT_R8(sp)
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PTR_S a5, PT_R9(sp)
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PTR_S a6, PT_R10(sp)
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PTR_S a7, PT_R11(sp)
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#endif
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.endm
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.macro MCOUNT_RESTORE_REGS
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PTR_L ra, PT_R31(sp)
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PTR_L AT, PT_R1(sp)
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PTR_L a0, PT_R4(sp)
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PTR_L a1, PT_R5(sp)
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PTR_L a2, PT_R6(sp)
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PTR_L a3, PT_R7(sp)
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#ifdef CONFIG_64BIT
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PTR_L a4, PT_R8(sp)
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PTR_L a5, PT_R9(sp)
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PTR_L a6, PT_R10(sp)
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PTR_L a7, PT_R11(sp)
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#endif
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PTR_ADDIU sp, PT_SIZE
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.endm
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.macro RETURN_BACK
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jr ra
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move ra, AT
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.endm
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/*
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* The -mmcount-ra-address option of gcc 4.5 uses register $12 to pass
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* the location of the parent's return address.
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*/
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#define MCOUNT_RA_ADDRESS_REG $12
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#ifdef CONFIG_DYNAMIC_FTRACE
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NESTED(ftrace_caller, PT_SIZE, ra)
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.globl _mcount
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_mcount:
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EXPORT_SYMBOL(_mcount)
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b ftrace_stub
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#ifdef CONFIG_32BIT
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addiu sp,sp,8
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#else
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nop
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#endif
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/* When tracing is activated, it calls ftrace_caller+8 (aka here) */
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MCOUNT_SAVE_REGS
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#ifdef KBUILD_MCOUNT_RA_ADDRESS
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PTR_S MCOUNT_RA_ADDRESS_REG, PT_R12(sp)
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#endif
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PTR_SUBU a0, ra, 8 /* arg1: self address */
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PTR_LA t1, _stext
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sltu t2, a0, t1 /* t2 = (a0 < _stext) */
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PTR_LA t1, _etext
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sltu t3, t1, a0 /* t3 = (a0 > _etext) */
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or t1, t2, t3
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beqz t1, ftrace_call
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nop
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#if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
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PTR_SUBU a0, a0, 16 /* arg1: adjust to module's recorded callsite */
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#else
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PTR_SUBU a0, a0, 12
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#endif
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.globl ftrace_call
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ftrace_call:
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nop /* a placeholder for the call to a real tracing function */
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move a1, AT /* arg2: parent's return address */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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.globl ftrace_graph_call
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ftrace_graph_call:
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nop
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nop
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#endif
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MCOUNT_RESTORE_REGS
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.globl ftrace_stub
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ftrace_stub:
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RETURN_BACK
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END(ftrace_caller)
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#else /* ! CONFIG_DYNAMIC_FTRACE */
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NESTED(_mcount, PT_SIZE, ra)
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EXPORT_SYMBOL(_mcount)
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PTR_LA t1, ftrace_stub
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PTR_L t2, ftrace_trace_function /* Prepare t2 for (1) */
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beq t1, t2, fgraph_trace
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nop
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MCOUNT_SAVE_REGS
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move a0, ra /* arg1: self return address */
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jalr t2 /* (1) call *ftrace_trace_function */
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move a1, AT /* arg2: parent's return address */
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MCOUNT_RESTORE_REGS
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fgraph_trace:
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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PTR_LA t1, ftrace_stub
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PTR_L t3, ftrace_graph_return
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bne t1, t3, ftrace_graph_caller
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nop
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PTR_LA t1, ftrace_graph_entry_stub
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PTR_L t3, ftrace_graph_entry
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bne t1, t3, ftrace_graph_caller
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nop
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#endif
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#ifdef CONFIG_32BIT
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addiu sp, sp, 8
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#endif
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.globl ftrace_stub
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ftrace_stub:
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RETURN_BACK
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END(_mcount)
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#endif /* ! CONFIG_DYNAMIC_FTRACE */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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NESTED(ftrace_graph_caller, PT_SIZE, ra)
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#ifndef CONFIG_DYNAMIC_FTRACE
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MCOUNT_SAVE_REGS
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#endif
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/* arg1: Get the location of the parent's return address */
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#ifdef KBUILD_MCOUNT_RA_ADDRESS
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#ifdef CONFIG_DYNAMIC_FTRACE
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PTR_L a0, PT_R12(sp)
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#else
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move a0, MCOUNT_RA_ADDRESS_REG
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#endif
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bnez a0, 1f /* non-leaf func: stored in MCOUNT_RA_ADDRESS_REG */
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nop
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#endif
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PTR_LA a0, PT_R1(sp) /* leaf func: the location in current stack */
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1:
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/* arg2: Get self return address */
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#ifdef CONFIG_DYNAMIC_FTRACE
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PTR_L a1, PT_R31(sp)
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#else
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move a1, ra
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#endif
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/* arg3: Get frame pointer of current stack */
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#ifdef CONFIG_64BIT
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PTR_LA a2, PT_SIZE(sp)
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#else
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PTR_LA a2, (PT_SIZE+8)(sp)
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#endif
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jal prepare_ftrace_return
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nop
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MCOUNT_RESTORE_REGS
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#ifndef CONFIG_DYNAMIC_FTRACE
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#ifdef CONFIG_32BIT
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addiu sp, sp, 8
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#endif
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#endif
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RETURN_BACK
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END(ftrace_graph_caller)
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.align 2
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.globl return_to_handler
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return_to_handler:
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PTR_SUBU sp, PT_SIZE
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PTR_S v0, PT_R2(sp)
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jal ftrace_return_to_handler
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PTR_S v1, PT_R3(sp)
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/* restore the real parent address: v0 -> ra */
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move ra, v0
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PTR_L v0, PT_R2(sp)
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PTR_L v1, PT_R3(sp)
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jr ra
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PTR_ADDIU sp, PT_SIZE
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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.set at
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.set reorder
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