ARC: dw2 unwind: switch to .eh_frame based unwinding (6716dbbd) · Commits · 戴 / test

arch/arc/Makefile

+2 −0

Original line number	Diff line number	Diff line
		@@ -66,6 +66,8 @@ endif

		endif

		cflags-$(CONFIG_ARC_DW2_UNWIND) += -fasynchronous-unwind-tables

		# By default gcc 4.8 generates dwarf4 which kernel unwinder can't grok
		ifeq ($(atleast_gcc48),y)
		cflags-$(CONFIG_ARC_DW2_UNWIND) += -gdwarf-2

+0 −12

Original line number	Diff line number	Diff line
		@@ -61,18 +61,6 @@ ENTRY(ret_from_fork)
		b ret_from_exception
		END(ret_from_fork)

		#ifdef CONFIG_ARC_DW2_UNWIND
		; Workaround for bug 94179 (STAR ):
		; Despite -fasynchronous-unwind-tables, linker is not making dwarf2 unwinder
		; section (.debug_frame) as loadable. So we force it here.
		; This also fixes STAR 9000487933 where the prev-workaround (objcopy --setflag)
		; would not work after a clean build due to kernel build system dependencies.
		.section .debug_frame, "wa",@progbits

		; Reset to .text as this file is included in entry-<isa>.S
		.section .text, "ax",@progbits
		#endif

		;################### Non TLB Exception Handling #############################

		; ---------------------------------------------

+4 −9

Original line number	Diff line number	Diff line
		@@ -22,13 +22,9 @@ static inline void arc_write_me(unsigned short *addr, unsigned long value)
		*(addr + 1) = (value & 0xffff);
		}

		/* ARC specific section quirks - before relocation loop in generic loader
		*
		* For dwarf unwinding out of modules, this needs to
		* 1. Ensure the .debug_frame is allocatable (ARC Linker bug: despite
		* -fasynchronous-unwind-tables it doesn't).
		* 2. Since we are iterating thru sec hdr tbl anyways, make a note of
		* the exact section index, for later use.
		/*
		* This gets called before relocation loop in generic loader
		* Make a note of the section index of unwinding section
		*/
		int module_frob_arch_sections(Elf_Ehdr hdr, Elf_Shdr sechdrs,
		char secstr, struct module mod)
		@@ -40,8 +36,7 @@ int module_frob_arch_sections(Elf_Ehdr hdr, Elf_Shdr sechdrs,
		mod->arch.unw_info = NULL;

		for (i = 1; i < hdr->e_shnum; i++) {
		if (strcmp(secstr+sechdrs[i].sh_name, ".debug_frame") == 0) {
		sechdrs[i].sh_flags \|= SHF_ALLOC;
		if (strcmp(secstr+sechdrs[i].sh_name, ".eh_frame") == 0) {
		mod->arch.unw_sec_idx = i;
		break;
		}

+2 −3

Original line number	Diff line number	Diff line
		@@ -111,7 +111,7 @@ UNW_REGISTER_INFO};
		#define DW_EH_PE_indirect 0x80
		#define DW_EH_PE_omit 0xff

		#define CIE_ID 0xffffffffUL
		#define CIE_ID 0

		typedef unsigned long uleb128_t;
		typedef signed long sleb128_t;
		@@ -510,8 +510,7 @@ static const u32 __cie_for_fde(const u32 fde)
		{
		const u32 *cie;

		/* cie = fde + 1 - fde[1] / sizeof(fde); /
		cie = (u32 *) fde[1];
		cie = fde + 1 - fde[1] / sizeof(*fde);

		return cie;
		}

+5 −10

Original line number	Diff line number	Diff line
		@@ -84,7 +84,7 @@ SECTIONS

		/*
		* .exit.text is discard at runtime, not link time, to deal with
		* references from .debug_frame
		* references from unwinding sections
		* It will be init freed, being inside [__init_start : __init_end]
		*/
		.exit.text : { EXIT_TEXT }
		@@ -120,18 +120,13 @@ SECTIONS

		#ifdef CONFIG_ARC_DW2_UNWIND
		. = ALIGN(PAGE_SIZE);
		.debug_frame : {
		.eh_frame : {
		__start_unwind = .;
		*(.debug_frame)
		*(.eh_frame)
		__end_unwind = .;
		}
		/*
		* gcc 4.8 generates this for -fasynchonous-unwind-tables,
		* while we still use the .debug_frame based unwinder
		*/
		/DISCARD/ : { *(.eh_frame) }
		#else
		/DISCARD/ : { *(.debug_frame) }
		/DISCARD/ : { *(.eh_frame) }
		#endif

		NOTES
		@@ -148,7 +143,7 @@ SECTIONS
		}

		#ifndef CONFIG_DEBUG_INFO
		/* open-coded because we need .debug_frame seperately for unwinding */
		/DISCARD/ : { *(.debug_frame) }
		/DISCARD/ : { *(.debug_aranges) }
		/DISCARD/ : { *(.debug_pubnames) }
		/DISCARD/ : { *(.debug_info) }