05f226391d
Dynamic function tracing was not working on MIPS. When doing dynamic tracing, the tracer attempts to match up the passed in address with the one the compiler creates in the mcount tables. The MIPS code was passing in the return address from the tracing function call, but the compiler tables were the address of the function call. So they wouldn't match. Just subtracting 8 from the return address will give the address of the function call. Easy enough. Signed-off-by: Corey Minyard <cminyard@mvista.com> [david.daney@cavium.com: Adjusted code comment and patch Subject.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Patchwork: https://patchwork.linux-mips.org/patch/5592/
203 lines
3.9 KiB
ArmAsm
203 lines
3.9 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/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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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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lw t1, function_trace_stop
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bnez t1, ftrace_stub
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nop
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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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.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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lw t1, function_trace_stop
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bnez t1, ftrace_stub
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nop
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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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bne t1, t2, static_trace
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nop
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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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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b ftrace_stub
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nop
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static_trace:
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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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.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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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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