From 2d0486424791b0d012d060854ce3bd1c6217a82c Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 16 Sep 2016 11:14:36 -0700 Subject: [PATCH] ARC: dw2 unwind: don't force dwarf 2 In .debug_frame based unwinding regime, we used to force -gdwarf-2 since kernel unwinder only claimed to handle dwarf 2. This changed since commit 6d0d506012c93d ("ARC: dw2 unwind: Don't bail for CIE.version != 1") which added some support beyond dwarf 2, atleast to handle CIE != 1 The ill-effect of -gdwarf-2 is that it forces generation of .debug_* sections, which bloats loadable modules .ko files. For the curious, this doesn't affect vmlinx binary since linker script discards .debug_* but same discard is not yet implemented for modules. So it seems we can drop the -gdwarf-2 toggle, which should not be needed anyways given that we now use .eh_frame based unwinding. I've verified using GNU 2016.09-engo10 that the actual unwind info is not different with or w/o this toggle - but the debug_* sections are gone for good. before ----- arc-linux-readelf -S q_proc.ko-unwinding-1-eh_frame-switch | grep debug [15] .debug_info PROGBITS 00000000 000300 00d08d 00 0 0 1 [16] .rela.debug_info RELA 00000000 0162a0 008844 0c I 29 15 4 [17] .debug_abbrev PROGBITS 00000000 00d38d 0005f8 00 0 0 1 [18] .debug_loc PROGBITS 00000000 00d985 000070 00 0 0 1 [19] .rela.debug_loc RELA 00000000 01eae4 0000c0 0c I 29 18 4 [20] .debug_aranges PROGBITS 00000000 00d9f5 000040 00 0 0 1 [21] .rela.debug_arang RELA 00000000 01eba4 000030 0c I 29 20 4 [22] .debug_ranges PROGBITS 00000000 00da35 000018 00 0 0 1 [23] .rela.debug_range RELA 00000000 01ebd4 000030 0c I 29 22 4 [24] .debug_line PROGBITS 00000000 00da4d 000b5b 00 0 0 1 [25] .rela.debug_line RELA 00000000 01ec04 0000cc 0c I 29 24 4 [26] .debug_str PROGBITS 00000000 00e5a8 007831 01 MS 0 0 1 after ---- Signed-off-by: Vineet Gupta --- arch/arc/Makefile | 6 ------ 1 file changed, 6 deletions(-) diff --git a/arch/arc/Makefile b/arch/arc/Makefile index fc6ff8f09f23..a2a6a4614241 100644 --- a/arch/arc/Makefile +++ b/arch/arc/Makefile @@ -47,7 +47,6 @@ endif upto_gcc44 := $(call cc-ifversion, -le, 0404, y) atleast_gcc44 := $(call cc-ifversion, -ge, 0404, y) -atleast_gcc48 := $(call cc-ifversion, -ge, 0408, y) cflags-$(atleast_gcc44) += -fsection-anchors @@ -68,11 +67,6 @@ 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 -endif - ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE # Generic build system uses -O2, we want -O3 # Note: No need to add to cflags-y as that happens anyways