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linux
ARC: dw2 unwind: add infrastructure for adding cfi pseudo ops to asm
1. detect whether binutils supports the cfi pseudo ops
2. define conditional macros to generate the ops
3. define new ENTRY_CFI/END_CFI to annotate hand asm code.
- Needed because we don't want to emit dwarf info in general ENTRY/END
used by lowest level trap/exception/interrutp handlers as unwinder
gets confused trying to unwind out of them. We want unwinder to
instead stop when it hits onfo those routines
- These provide minimal start/end cfi ops assuming routine doesn't
touch stack memory/regs
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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arch/arc/Makefile
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arch/arc/Makefile
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endif
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-
cflags-$(CONFIG_ARC_DW2_UNWIND) += -fasynchronous-unwind-tables
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cfi := $(call as-instr,.cfi_startproc\n.cfi_endproc,-DARC_DW2_UNWIND_AS_CFI)
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cflags-$(CONFIG_ARC_DW2_UNWIND) += -fasynchronous-unwind-tables $(cfi)
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ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
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# Generic build system uses -O2, we want -O3
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arch/arc/include/asm/dwarf.h
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arch/arc/include/asm/dwarf.h
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/*
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* Copyright (C) 2016-17 Synopsys, Inc. (www.synopsys.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef _ASM_ARC_DWARF_H
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#define _ASM_ARC_DWARF_H
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#ifdef __ASSEMBLY__
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#ifdef ARC_DW2_UNWIND_AS_CFI
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#define CFI_STARTPROC .cfi_startproc
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#define CFI_ENDPROC .cfi_endproc
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#define CFI_DEF_CFA .cfi_def_cfa
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#define CFI_REGISTER .cfi_register
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#define CFI_REL_OFFSET .cfi_rel_offset
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#define CFI_UNDEFINED .cfi_undefined
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#else
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#define CFI_IGNORE #
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#define CFI_STARTPROC CFI_IGNORE
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#define CFI_ENDPROC CFI_IGNORE
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#define CFI_DEF_CFA CFI_IGNORE
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#define CFI_REGISTER CFI_IGNORE
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#define CFI_REL_OFFSET CFI_IGNORE
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#define CFI_UNDEFINED CFI_IGNORE
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#endif /* !ARC_DW2_UNWIND_AS_CFI */
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_ARC_DWARF_H */
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arch/arc/include/asm/linkage.h
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arch/arc/include/asm/linkage.h
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#ifndef __ASM_LINKAGE_H
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#define __ASM_LINKAGE_H
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#include <asm/dwarf.h>
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#ifdef __ASSEMBLY__
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#define ASM_NL ` /* use '`' to mark new line in macro */
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.section .text, "ax",@progbits
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#endif
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.endm
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#define ENTRY_CFI(name) \
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.globl name ASM_NL \
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ALIGN ASM_NL \
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name: ASM_NL \
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CFI_STARTPROC ASM_NL
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#define END_CFI(name) \
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CFI_ENDPROC ASM_NL \
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.size name, .-name
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#else /* !__ASSEMBLY__ */
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