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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2019-02-10 15:51:00 +0900 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2019-02-20 09:39:39 +0900 |
| commit | 1e88e415ebccb9013b92b55e7512938040c53b61 (patch) | |
| tree | 2feec65be107f251a4dd6c6563939cac85b62a63 | |
| parent | 500193ec57fddf5e52d64fd7278b37a6afc9f773 (diff) | |
kbuild: Disable extra debugging info in .s output
Modern gcc adds view assignments, reset assertion checking in .loc
directives and a couple more additional debug markers, which clutters
the asm output unnecessarily:
For example:
bsp_resume:
.LFB3466:
.loc 1 1868 1 is_stmt 1 view -0
.cfi_startproc
.loc 1 1869 2 view .LVU73
# arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume)
.loc 1 1869 14 is_stmt 0 view .LVU74
movq this_cpu(%rip), %rax # this_cpu, this_cpu
movq 64(%rax), %rax # this_cpu.94_1->c_bsp_resume, _2
# arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume)
.loc 1 1869 5 view .LVU75
testq %rax, %rax # _2
je .L8 #,
.loc 1 1870 3 is_stmt 1 view .LVU76
movq $boot_cpu_data, %rdi #,
jmp __x86_indirect_thunk_rax
or
.loc 2 57 9 view .LVU478
.loc 2 57 9 view .LVU479
.loc 2 57 9 view .LVU480
.loc 2 57 9 view .LVU481
.LBB1385:
.LBB1383:
.LBB1379:
.LBB1377:
.LBB1375:
.loc 2 57 9 view .LVU482
.loc 2 57 9 view .LVU483
movl %edi, %edx # cpu, cpu
.LVL87:
.loc 2 57 9 is_stmt 0 view .LVU484
That MOV in there is drowned in debugging information and latter makes
it hard to follow the asm. And that DWARF info is not really needed for
asm output staring.
Disable the debug information generation which clutters the asm output
unnecessarily:
bsp_resume:
# arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume)
movq this_cpu(%rip), %rax # this_cpu, this_cpu
movq 64(%rax), %rax # this_cpu.94_1->c_bsp_resume, _2
# arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume)
testq %rax, %rax # _2
je .L8 #,
# arch/x86/kernel/cpu/common.c:1870: this_cpu->c_bsp_resume(&boot_cpu_data);
movq $boot_cpu_data, %rdi #,
jmp __x86_indirect_thunk_rax
.L8:
# arch/x86/kernel/cpu/common.c:1871: }
rep ret
.size bsp_resume, .-bsp_resume
[ bp: write commit message. ]
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
| -rw-r--r-- | Makefile | 13 | ||||
| -rw-r--r-- | scripts/Makefile.build | 2 |
2 files changed, 9 insertions, 6 deletions
@@ -732,25 +732,28 @@ KBUILD_CFLAGS += -fomit-frame-pointer endif endif -KBUILD_CFLAGS += $(call cc-option, -fno-var-tracking-assignments) +DEBUG_CFLAGS := $(call cc-option, -fno-var-tracking-assignments) ifdef CONFIG_DEBUG_INFO ifdef CONFIG_DEBUG_INFO_SPLIT -KBUILD_CFLAGS += $(call cc-option, -gsplit-dwarf, -g) +DEBUG_CFLAGS += $(call cc-option, -gsplit-dwarf, -g) else -KBUILD_CFLAGS += -g +DEBUG_CFLAGS += -g endif KBUILD_AFLAGS += -Wa,-gdwarf-2 endif ifdef CONFIG_DEBUG_INFO_DWARF4 -KBUILD_CFLAGS += $(call cc-option, -gdwarf-4,) +DEBUG_CFLAGS += $(call cc-option, -gdwarf-4,) endif ifdef CONFIG_DEBUG_INFO_REDUCED -KBUILD_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \ +DEBUG_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \ $(call cc-option,-fno-var-tracking) endif +KBUILD_CFLAGS += $(DEBUG_CFLAGS) +export DEBUG_CFLAGS + ifdef CONFIG_FUNCTION_TRACER ifdef CONFIG_FTRACE_MCOUNT_RECORD # gcc 5 supports generating the mcount tables directly diff --git a/scripts/Makefile.build b/scripts/Makefile.build index f8e2794107ed..0a9d849d0fab 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -104,7 +104,7 @@ modkern_cflags = \ quiet_modtag = $(if $(part-of-module),[M], ) quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ -cmd_cc_s_c = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $< + cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $< $(obj)/%.s: $(src)/%.c FORCE $(call if_changed_dep,cc_s_c) |