2fd7c761a2
If -pg of gcc is enabled with CONFIG_FUNCTION_TRACER=y. a calling to _mcount will be inserted into each kernel function. so, there is a possibility to trace the kernel functions in _mcount. This patch add the specific _mcount support for static function tracing. by default, ftrace_trace_function is initialized as ftrace_stub(an empty function), so, the default _mcount will introduce very little overhead. after enabling ftrace in user-space, it will jump to a real tracing function and do static function tracing for us. Commit message from Wu Zhangjin <wuzhangjin@gmail.com> Signed-off-by: Michal Simek <monstr@monstr.eu>
105 lines
2.2 KiB
ArmAsm
105 lines
2.2 KiB
ArmAsm
/*
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* Low-level ftrace handling
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*
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* Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2009 PetaLogix
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*
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* This file is subject to the terms and conditions of the GNU General
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* Public License. See the file COPYING in the main directory of this
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* archive for more details.
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*/
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#include <linux/linkage.h>
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#define NOALIGN_ENTRY(name) .globl name; name:
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/* FIXME MS: I think that I don't need to save all regs */
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#define SAVE_REGS \
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addik r1, r1, -120; \
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swi r2, r1, 4; \
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swi r3, r1, 8; \
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swi r4, r1, 12; \
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swi r5, r1, 116; \
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swi r6, r1, 16; \
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swi r7, r1, 20; \
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swi r8, r1, 24; \
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swi r9, r1, 28; \
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swi r10, r1, 32; \
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swi r11, r1, 36; \
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swi r12, r1, 40; \
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swi r13, r1, 44; \
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swi r14, r1, 48; \
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swi r16, r1, 52; \
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swi r17, r1, 56; \
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swi r18, r1, 60; \
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swi r19, r1, 64; \
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swi r20, r1, 68; \
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swi r21, r1, 72; \
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swi r22, r1, 76; \
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swi r23, r1, 80; \
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swi r24, r1, 84; \
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swi r25, r1, 88; \
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swi r26, r1, 92; \
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swi r27, r1, 96; \
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swi r28, r1, 100; \
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swi r29, r1, 104; \
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swi r30, r1, 108; \
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swi r31, r1, 112;
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#define RESTORE_REGS \
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lwi r2, r1, 4; \
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lwi r3, r1, 8; \
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lwi r4, r1, 12; \
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lwi r5, r1, 116; \
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lwi r6, r1, 16; \
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lwi r7, r1, 20; \
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lwi r8, r1, 24; \
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lwi r9, r1, 28; \
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lwi r10, r1, 32; \
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lwi r11, r1, 36; \
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lwi r12, r1, 40; \
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lwi r13, r1, 44; \
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lwi r14, r1, 48; \
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lwi r16, r1, 52; \
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lwi r17, r1, 56; \
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lwi r18, r1, 60; \
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lwi r19, r1, 64; \
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lwi r20, r1, 68; \
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lwi r21, r1, 72; \
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lwi r22, r1, 76; \
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lwi r23, r1, 80; \
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lwi r24, r1, 84; \
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lwi r25, r1, 88; \
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lwi r26, r1, 92; \
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lwi r27, r1, 96; \
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lwi r28, r1, 100; \
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lwi r29, r1, 104; \
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lwi r30, r1, 108; \
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lwi r31, r1, 112; \
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addik r1, r1, 120;
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ENTRY(ftrace_stub)
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rtsd r15, 8;
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nop;
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ENTRY(_mcount)
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SAVE_REGS
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swi r15, r1, 0;
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/* MS: test function trace if is taken or not */
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lwi r20, r0, ftrace_trace_function;
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addik r6, r0, ftrace_stub;
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cmpu r5, r20, r6; /* ftrace_trace_function != ftrace_stub */
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beqid r5, end; /* MS: not taken -> jump over */
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nop;
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/* static normal trace */
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lwi r6, r1, 120; /* MS: load parent addr */
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addik r5, r15, 0; /* MS: load current function addr */
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/* MS: here is dependency on previous code */
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brald r15, r20; /* MS: jump to ftrace handler */
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nop;
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end:
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lwi r15, r1, 0;
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RESTORE_REGS
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rtsd r15, 8; /* MS: jump back */
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nop;
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