130 lines
2.6 KiB
ArmAsm
130 lines
2.6 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (C) 2017 Andes Technology Corporation */
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#include <linux/init.h>
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#include <linux/linkage.h>
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#include <asm/asm.h>
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#include <asm/csr.h>
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#include <asm/unistd.h>
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#include <asm/thread_info.h>
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#include <asm/asm-offsets.h>
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#include <asm-generic/export.h>
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#include <asm/ftrace.h>
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.text
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.macro SAVE_ABI_STATE
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addi sp, sp, -16
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sd s0, 0(sp)
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sd ra, 8(sp)
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addi s0, sp, 16
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.endm
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/*
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* The call to ftrace_return_to_handler would overwrite the return
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* register if a0 was not saved.
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*/
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.macro SAVE_RET_ABI_STATE
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addi sp, sp, -32
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sd s0, 16(sp)
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sd ra, 24(sp)
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sd a0, 8(sp)
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addi s0, sp, 32
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.endm
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.macro RESTORE_ABI_STATE
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ld ra, 8(sp)
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ld s0, 0(sp)
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addi sp, sp, 16
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.endm
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.macro RESTORE_RET_ABI_STATE
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ld ra, 24(sp)
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ld s0, 16(sp)
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ld a0, 8(sp)
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addi sp, sp, 32
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.endm
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ENTRY(ftrace_stub)
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#ifdef CONFIG_DYNAMIC_FTRACE
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.global _mcount
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.set _mcount, ftrace_stub
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#endif
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ret
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ENDPROC(ftrace_stub)
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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ENTRY(return_to_handler)
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/*
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* On implementing the frame point test, the ideal way is to compare the
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* s0 (frame pointer, if enabled) on entry and the sp (stack pointer) on return.
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* However, the psABI of variable-length-argument functions does not allow this.
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*
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* So alternatively we check the *old* frame pointer position, that is, the
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* value stored in -16(s0) on entry, and the s0 on return.
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*/
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#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
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mv t6, s0
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#endif
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SAVE_RET_ABI_STATE
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#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
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mv a0, t6
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#endif
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call ftrace_return_to_handler
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mv a1, a0
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RESTORE_RET_ABI_STATE
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jalr a1
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ENDPROC(return_to_handler)
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#endif
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#ifndef CONFIG_DYNAMIC_FTRACE
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ENTRY(_mcount)
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la t4, ftrace_stub
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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la t0, ftrace_graph_return
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ld t1, 0(t0)
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bne t1, t4, do_ftrace_graph_caller
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la t3, ftrace_graph_entry
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ld t2, 0(t3)
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la t6, ftrace_graph_entry_stub
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bne t2, t6, do_ftrace_graph_caller
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#endif
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la t3, ftrace_trace_function
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ld t5, 0(t3)
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bne t5, t4, do_trace
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ret
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/*
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* A pseudo representation for the function graph tracer:
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* prepare_to_return(&ra_to_caller_of_caller, ra_to_caller)
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*/
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do_ftrace_graph_caller:
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addi a0, s0, -8
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mv a1, ra
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#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
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ld a2, -16(s0)
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#endif
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SAVE_ABI_STATE
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call prepare_ftrace_return
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RESTORE_ABI_STATE
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ret
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#endif
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/*
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* A pseudo representation for the function tracer:
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* (*ftrace_trace_function)(ra_to_caller, ra_to_caller_of_caller)
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*/
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do_trace:
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ld a1, -8(s0)
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mv a0, ra
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SAVE_ABI_STATE
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jalr t5
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RESTORE_ABI_STATE
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ret
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ENDPROC(_mcount)
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#endif
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EXPORT_SYMBOL(_mcount)
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