| Message ID | 20220125075126.891825-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 880f694bd1cef484e92065ea4e736850abce5352 |
| Headers | show |
| Series | [v3] Kconfig.debug: Make DEBUG_INFO selectable from a choice | expand |
Hi Kees, On Mon, Jan 24, 2022 at 11:51:26PM -0800, Kees Cook wrote: > Currently it's not possible to enable DEBUG_INFO for an all*config build, > since it is marked as "depends on !COMPILE_TEST". This generally makes > sense because a debug build of an all*config target ends up taking much > longer and the output is much larger. Having this be "default off" makes > sense. However, there are cases where enabling DEBUG_INFO for such builds > is useful for doing treewide A/B comparisons of build options, etc. > > Make DEBUG_INFO selectable from any of the DWARF version choice options, > with DEBUG_INFO_NONE being the default for COMPILE_TEST. The mutually > exclusive relationship between DWARF5 and BTF must be inverted, but the > result remains the same. Additionally moves DEBUG_KERNEL and DEBUG_MISC > up to the top of the menu because they were enabling features _above_ > it, making it weird to navigate menuconfig. > > Suggested-by: Arnd Bergmann <arnd@arndb.de> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Masahiro Yamada <masahiroy@kernel.org> > Cc: Nick Desaulniers <ndesaulniers@google.com> > Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Reviewed-by: Arnd Bergmann <arnd@arndb.de> > Reviewed-by: Nathan Chancellor <nathan@kernel.org> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > Tested-by: Nick Desaulniers <ndesaulniers@google.com> > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > v1: https://lore.kernel.org/lkml/20211210000910.3597609-1-keescook@chromium.org > v2: https://lore.kernel.org/lkml/20220121001204.4023842-1-keescook@chromium.org > v3: - rebase to v5.17-rc1 > --- > lib/Kconfig.debug | 140 +++++++++++++++++++++++++--------------------- > 1 file changed, 75 insertions(+), 65 deletions(-) > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 14b89aa37c5c..1290e0906236 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -208,20 +208,88 @@ config DEBUG_BUGVERBOSE > > endmenu # "printk and dmesg options" > > +config DEBUG_KERNEL > + bool "Kernel debugging" > + help > + Say Y here if you are developing drivers or trying to debug and > + identify kernel problems. > + > +config DEBUG_MISC > + bool "Miscellaneous debug code" > + default DEBUG_KERNEL > + depends on DEBUG_KERNEL > + help > + Say Y here if you need to enable miscellaneous debug code that should > + be under a more specific debug option but isn't. > + > menu "Compile-time checks and compiler options" > > config DEBUG_INFO > - bool "Compile the kernel with debug info" > - depends on DEBUG_KERNEL && !COMPILE_TEST > + bool > help > - If you say Y here the resulting kernel image will include > - debugging info resulting in a larger kernel image. > + A kernel debug info option other than "None" has been selected > + in the "Debug information" choice below, indicating that debug > + information will be generated for build targets. > + > +choice > + prompt "Debug information" > + depends on DEBUG_KERNEL > + default DEBUG_INFO_NONE if COMPILE_TEST I apologize for not bringing this up sooner in review (especially with my tag) but I wanted to make sure this change is intentional. Prior to this commit, we would have to explicitly enable DEBUG_INFO after turning on DEBUG_KERNEL (i.e. DEBUG_KERNEL would not select DEBUG_INFO). Now, DEBUG_INFO automatically gets turned on with DEBUG_KERNEL because of the depends plus the default for the choice. Is this intentional? For example, with x86_64_defconfig: mainline: $ make mrproper defconfig && rg DEBUG_INFO .config 4571:# CONFIG_DEBUG_INFO is not set next-20220128: $ make mrproper defconfig && rg DEBUG_INFO .config 4573:CONFIG_DEBUG_INFO=y 4574:CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y 4575:# CONFIG_DEBUG_INFO_DWARF4 is not set 4576:# CONFIG_DEBUG_INFO_DWARF5 is not set 4577:# CONFIG_DEBUG_INFO_NONE is not set 4578:# CONFIG_DEBUG_INFO_REDUCED is not set 4579:# CONFIG_DEBUG_INFO_COMPRESSED is not set 4580:# CONFIG_DEBUG_INFO_SPLIT is not set As far as I can tell, this will have a big impact on everyone's binary and modules size that either enables DEBUG_KERNEL or EXPERT (which selects DEBUG_KERNEL), which is a lot of configs. $ for file in $(rg -l "CONFIG_(DEBUG_KERNEL|EXPERT)" arch/*/configs); do rg DEBUG_INFO $file &>/dev/null || echo $file; done |& wc -l 170 If this change is intentional, then it probably warrants more of an explicit callout in the commit message. I only noticed this because the vmlinux for the multi_v7_defconfig kernel I build for my Raspberry Pi 3 went from 32.44 MB to 262.75 MB. Cheers, Nathan > + help > + Selecting something other than "None" results in a kernel image > + that will include debugging info resulting in a larger kernel image. > This adds debug symbols to the kernel and modules (gcc -g), and > is needed if you intend to use kernel crashdump or binary object > tools like crash, kgdb, LKCD, gdb, etc on the kernel. > - Say Y here only if you plan to debug the kernel. > > - If unsure, say N. > + Choose which version of DWARF debug info to emit. If unsure, > + select "Toolchain default". > + > +config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT > + bool "Rely on the toolchain's implicit default DWARF version" > + select DEBUG_INFO > + help > + The implicit default version of DWARF debug info produced by a > + toolchain changes over time. > + > + This can break consumers of the debug info that haven't upgraded to > + support newer revisions, and prevent testing newer versions, but > + those should be less common scenarios. > + > +config DEBUG_INFO_DWARF4 > + bool "Generate DWARF Version 4 debuginfo" > + select DEBUG_INFO > + help > + Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. > + > + If you have consumers of DWARF debug info that are not ready for > + newer revisions of DWARF, you may wish to choose this or have your > + config select this. > + > +config DEBUG_INFO_DWARF5 > + bool "Generate DWARF Version 5 debuginfo" > + select DEBUG_INFO > + depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) > + help > + Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc > + 5.0+ accepts the -gdwarf-5 flag but only had partial support for some > + draft features until 7.0), and gdb 8.0+. > + > + Changes to the structure of debug info in Version 5 allow for around > + 15-18% savings in resulting image and debug info section sizes as > + compared to DWARF Version 4. DWARF Version 5 standardizes previous > + extensions such as accelerators for symbol indexing and the format > + for fission (.dwo/.dwp) files. Users may not want to select this > + config if they rely on tooling that has not yet been updated to > + support DWARF Version 5. > + > +config DEBUG_INFO_NONE > + bool "Disable debug information" > + help > + Do not build the kernel with debugging information, which will > + result in a faster and smaller build. > + > +endchoice # "Debug information" > > if DEBUG_INFO > > @@ -267,56 +335,12 @@ config DEBUG_INFO_SPLIT > to know about the .dwo files and include them. > Incompatible with older versions of ccache. > > -choice > - prompt "DWARF version" > - help > - Which version of DWARF debug info to emit. > - > -config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT > - bool "Rely on the toolchain's implicit default DWARF version" > - help > - The implicit default version of DWARF debug info produced by a > - toolchain changes over time. > - > - This can break consumers of the debug info that haven't upgraded to > - support newer revisions, and prevent testing newer versions, but > - those should be less common scenarios. > - > - If unsure, say Y. > - > -config DEBUG_INFO_DWARF4 > - bool "Generate DWARF Version 4 debuginfo" > - help > - Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. > - > - If you have consumers of DWARF debug info that are not ready for > - newer revisions of DWARF, you may wish to choose this or have your > - config select this. > - > -config DEBUG_INFO_DWARF5 > - bool "Generate DWARF Version 5 debuginfo" > - depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) > - depends on !DEBUG_INFO_BTF > - help > - Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc > - 5.0+ accepts the -gdwarf-5 flag but only had partial support for some > - draft features until 7.0), and gdb 8.0+. > - > - Changes to the structure of debug info in Version 5 allow for around > - 15-18% savings in resulting image and debug info section sizes as > - compared to DWARF Version 4. DWARF Version 5 standardizes previous > - extensions such as accelerators for symbol indexing and the format > - for fission (.dwo/.dwp) files. Users may not want to select this > - config if they rely on tooling that has not yet been updated to > - support DWARF Version 5. > - > -endchoice # "DWARF version" > - > config DEBUG_INFO_BTF > bool "Generate BTF typeinfo" > depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED > depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST > depends on BPF_SYSCALL > + depends on !DEBUG_INFO_DWARF5 > help > Generate deduplicated BTF type information from DWARF debug info. > Turning this on expects presence of pahole tool, which will convert > @@ -585,20 +609,6 @@ source "lib/Kconfig.kcsan" > > endmenu > > -config DEBUG_KERNEL > - bool "Kernel debugging" > - help > - Say Y here if you are developing drivers or trying to debug and > - identify kernel problems. > - > -config DEBUG_MISC > - bool "Miscellaneous debug code" > - default DEBUG_KERNEL > - depends on DEBUG_KERNEL > - help > - Say Y here if you need to enable miscellaneous debug code that should > - be under a more specific debug option but isn't. > - > menu "Networking Debugging" > > source "net/Kconfig.debug" > -- > 2.30.2 > >
On Fri, Jan 28, 2022 at 01:58:19PM -0700, Nathan Chancellor wrote: > Hi Kees, > > On Mon, Jan 24, 2022 at 11:51:26PM -0800, Kees Cook wrote: > > Currently it's not possible to enable DEBUG_INFO for an all*config build, > > since it is marked as "depends on !COMPILE_TEST". This generally makes > > sense because a debug build of an all*config target ends up taking much > > longer and the output is much larger. Having this be "default off" makes > > sense. However, there are cases where enabling DEBUG_INFO for such builds > > is useful for doing treewide A/B comparisons of build options, etc. > > > > Make DEBUG_INFO selectable from any of the DWARF version choice options, > > with DEBUG_INFO_NONE being the default for COMPILE_TEST. The mutually > > exclusive relationship between DWARF5 and BTF must be inverted, but the > > result remains the same. Additionally moves DEBUG_KERNEL and DEBUG_MISC > > up to the top of the menu because they were enabling features _above_ > > it, making it weird to navigate menuconfig. > > > > Suggested-by: Arnd Bergmann <arnd@arndb.de> > > Cc: Andrew Morton <akpm@linux-foundation.org> > > Cc: Masahiro Yamada <masahiroy@kernel.org> > > Cc: Nick Desaulniers <ndesaulniers@google.com> > > Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > > Reviewed-by: Arnd Bergmann <arnd@arndb.de> > > Reviewed-by: Nathan Chancellor <nathan@kernel.org> > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > Tested-by: Nick Desaulniers <ndesaulniers@google.com> > > Signed-off-by: Kees Cook <keescook@chromium.org> > > --- > > v1: https://lore.kernel.org/lkml/20211210000910.3597609-1-keescook@chromium.org > > v2: https://lore.kernel.org/lkml/20220121001204.4023842-1-keescook@chromium.org > > v3: - rebase to v5.17-rc1 > > --- > > lib/Kconfig.debug | 140 +++++++++++++++++++++++++--------------------- > > 1 file changed, 75 insertions(+), 65 deletions(-) > > > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index 14b89aa37c5c..1290e0906236 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -208,20 +208,88 @@ config DEBUG_BUGVERBOSE > > > > endmenu # "printk and dmesg options" > > > > +config DEBUG_KERNEL > > + bool "Kernel debugging" > > + help > > + Say Y here if you are developing drivers or trying to debug and > > + identify kernel problems. > > + > > +config DEBUG_MISC > > + bool "Miscellaneous debug code" > > + default DEBUG_KERNEL > > + depends on DEBUG_KERNEL > > + help > > + Say Y here if you need to enable miscellaneous debug code that should > > + be under a more specific debug option but isn't. > > + > > menu "Compile-time checks and compiler options" > > > > config DEBUG_INFO > > - bool "Compile the kernel with debug info" > > - depends on DEBUG_KERNEL && !COMPILE_TEST > > + bool > > help > > - If you say Y here the resulting kernel image will include > > - debugging info resulting in a larger kernel image. > > + A kernel debug info option other than "None" has been selected > > + in the "Debug information" choice below, indicating that debug > > + information will be generated for build targets. > > + > > +choice > > + prompt "Debug information" > > + depends on DEBUG_KERNEL > > + default DEBUG_INFO_NONE if COMPILE_TEST > > I apologize for not bringing this up sooner in review (especially with > my tag) but I wanted to make sure this change is intentional. > > Prior to this commit, we would have to explicitly enable DEBUG_INFO > after turning on DEBUG_KERNEL (i.e. DEBUG_KERNEL would not select > DEBUG_INFO). > > Now, DEBUG_INFO automatically gets turned on with DEBUG_KERNEL because > of the depends plus the default for the choice. Is this intentional? Oh, er, no. I think this was an oversight when I tried to adapt this to Masahiro's suggestions. I will go fix this up. > For example, with x86_64_defconfig: > > mainline: > > $ make mrproper defconfig && rg DEBUG_INFO .config > 4571:# CONFIG_DEBUG_INFO is not set > > next-20220128: > > $ make mrproper defconfig && rg DEBUG_INFO .config > 4573:CONFIG_DEBUG_INFO=y > 4574:CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y > 4575:# CONFIG_DEBUG_INFO_DWARF4 is not set > 4576:# CONFIG_DEBUG_INFO_DWARF5 is not set > 4577:# CONFIG_DEBUG_INFO_NONE is not set > 4578:# CONFIG_DEBUG_INFO_REDUCED is not set > 4579:# CONFIG_DEBUG_INFO_COMPRESSED is not set > 4580:# CONFIG_DEBUG_INFO_SPLIT is not set > > As far as I can tell, this will have a big impact on everyone's binary > and modules size that either enables DEBUG_KERNEL or EXPERT (which > selects DEBUG_KERNEL), which is a lot of configs. Yes, agreed, it's a huge size difference! :) -Kees > > $ for file in $(rg -l "CONFIG_(DEBUG_KERNEL|EXPERT)" arch/*/configs); do rg DEBUG_INFO $file &>/dev/null || echo $file; done |& wc -l > 170 > > If this change is intentional, then it probably warrants more of an > explicit callout in the commit message. I only noticed this because the > vmlinux for the multi_v7_defconfig kernel I build for my Raspberry Pi 3 > went from 32.44 MB to 262.75 MB. > > Cheers, > Nathan > > > + help > > + Selecting something other than "None" results in a kernel image > > + that will include debugging info resulting in a larger kernel image. > > This adds debug symbols to the kernel and modules (gcc -g), and > > is needed if you intend to use kernel crashdump or binary object > > tools like crash, kgdb, LKCD, gdb, etc on the kernel. > > - Say Y here only if you plan to debug the kernel. > > > > - If unsure, say N. > > + Choose which version of DWARF debug info to emit. If unsure, > > + select "Toolchain default". > > + > > +config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT > > + bool "Rely on the toolchain's implicit default DWARF version" > > + select DEBUG_INFO > > + help > > + The implicit default version of DWARF debug info produced by a > > + toolchain changes over time. > > + > > + This can break consumers of the debug info that haven't upgraded to > > + support newer revisions, and prevent testing newer versions, but > > + those should be less common scenarios. > > + > > +config DEBUG_INFO_DWARF4 > > + bool "Generate DWARF Version 4 debuginfo" > > + select DEBUG_INFO > > + help > > + Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. > > + > > + If you have consumers of DWARF debug info that are not ready for > > + newer revisions of DWARF, you may wish to choose this or have your > > + config select this. > > + > > +config DEBUG_INFO_DWARF5 > > + bool "Generate DWARF Version 5 debuginfo" > > + select DEBUG_INFO > > + depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) > > + help > > + Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc > > + 5.0+ accepts the -gdwarf-5 flag but only had partial support for some > > + draft features until 7.0), and gdb 8.0+. > > + > > + Changes to the structure of debug info in Version 5 allow for around > > + 15-18% savings in resulting image and debug info section sizes as > > + compared to DWARF Version 4. DWARF Version 5 standardizes previous > > + extensions such as accelerators for symbol indexing and the format > > + for fission (.dwo/.dwp) files. Users may not want to select this > > + config if they rely on tooling that has not yet been updated to > > + support DWARF Version 5. > > + > > +config DEBUG_INFO_NONE > > + bool "Disable debug information" > > + help > > + Do not build the kernel with debugging information, which will > > + result in a faster and smaller build. > > + > > +endchoice # "Debug information" > > > > if DEBUG_INFO > > > > @@ -267,56 +335,12 @@ config DEBUG_INFO_SPLIT > > to know about the .dwo files and include them. > > Incompatible with older versions of ccache. > > > > -choice > > - prompt "DWARF version" > > - help > > - Which version of DWARF debug info to emit. > > - > > -config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT > > - bool "Rely on the toolchain's implicit default DWARF version" > > - help > > - The implicit default version of DWARF debug info produced by a > > - toolchain changes over time. > > - > > - This can break consumers of the debug info that haven't upgraded to > > - support newer revisions, and prevent testing newer versions, but > > - those should be less common scenarios. > > - > > - If unsure, say Y. > > - > > -config DEBUG_INFO_DWARF4 > > - bool "Generate DWARF Version 4 debuginfo" > > - help > > - Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. > > - > > - If you have consumers of DWARF debug info that are not ready for > > - newer revisions of DWARF, you may wish to choose this or have your > > - config select this. > > - > > -config DEBUG_INFO_DWARF5 > > - bool "Generate DWARF Version 5 debuginfo" > > - depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) > > - depends on !DEBUG_INFO_BTF > > - help > > - Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc > > - 5.0+ accepts the -gdwarf-5 flag but only had partial support for some > > - draft features until 7.0), and gdb 8.0+. > > - > > - Changes to the structure of debug info in Version 5 allow for around > > - 15-18% savings in resulting image and debug info section sizes as > > - compared to DWARF Version 4. DWARF Version 5 standardizes previous > > - extensions such as accelerators for symbol indexing and the format > > - for fission (.dwo/.dwp) files. Users may not want to select this > > - config if they rely on tooling that has not yet been updated to > > - support DWARF Version 5. > > - > > -endchoice # "DWARF version" > > - > > config DEBUG_INFO_BTF > > bool "Generate BTF typeinfo" > > depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED > > depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST > > depends on BPF_SYSCALL > > + depends on !DEBUG_INFO_DWARF5 > > help > > Generate deduplicated BTF type information from DWARF debug info. > > Turning this on expects presence of pahole tool, which will convert > > @@ -585,20 +609,6 @@ source "lib/Kconfig.kcsan" > > > > endmenu > > > > -config DEBUG_KERNEL > > - bool "Kernel debugging" > > - help > > - Say Y here if you are developing drivers or trying to debug and > > - identify kernel problems. > > - > > -config DEBUG_MISC > > - bool "Miscellaneous debug code" > > - default DEBUG_KERNEL > > - depends on DEBUG_KERNEL > > - help > > - Say Y here if you need to enable miscellaneous debug code that should > > - be under a more specific debug option but isn't. > > - > > menu "Networking Debugging" > > > > source "net/Kconfig.debug" > > -- > > 2.30.2 > > > >
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 14b89aa37c5c..1290e0906236 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -208,20 +208,88 @@ config DEBUG_BUGVERBOSE endmenu # "printk and dmesg options" +config DEBUG_KERNEL + bool "Kernel debugging" + help + Say Y here if you are developing drivers or trying to debug and + identify kernel problems. + +config DEBUG_MISC + bool "Miscellaneous debug code" + default DEBUG_KERNEL + depends on DEBUG_KERNEL + help + Say Y here if you need to enable miscellaneous debug code that should + be under a more specific debug option but isn't. + menu "Compile-time checks and compiler options" config DEBUG_INFO - bool "Compile the kernel with debug info" - depends on DEBUG_KERNEL && !COMPILE_TEST + bool help - If you say Y here the resulting kernel image will include - debugging info resulting in a larger kernel image. + A kernel debug info option other than "None" has been selected + in the "Debug information" choice below, indicating that debug + information will be generated for build targets. + +choice + prompt "Debug information" + depends on DEBUG_KERNEL + default DEBUG_INFO_NONE if COMPILE_TEST + help + Selecting something other than "None" results in a kernel image + that will include debugging info resulting in a larger kernel image. This adds debug symbols to the kernel and modules (gcc -g), and is needed if you intend to use kernel crashdump or binary object tools like crash, kgdb, LKCD, gdb, etc on the kernel. - Say Y here only if you plan to debug the kernel. - If unsure, say N. + Choose which version of DWARF debug info to emit. If unsure, + select "Toolchain default". + +config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT + bool "Rely on the toolchain's implicit default DWARF version" + select DEBUG_INFO + help + The implicit default version of DWARF debug info produced by a + toolchain changes over time. + + This can break consumers of the debug info that haven't upgraded to + support newer revisions, and prevent testing newer versions, but + those should be less common scenarios. + +config DEBUG_INFO_DWARF4 + bool "Generate DWARF Version 4 debuginfo" + select DEBUG_INFO + help + Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. + + If you have consumers of DWARF debug info that are not ready for + newer revisions of DWARF, you may wish to choose this or have your + config select this. + +config DEBUG_INFO_DWARF5 + bool "Generate DWARF Version 5 debuginfo" + select DEBUG_INFO + depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) + help + Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc + 5.0+ accepts the -gdwarf-5 flag but only had partial support for some + draft features until 7.0), and gdb 8.0+. + + Changes to the structure of debug info in Version 5 allow for around + 15-18% savings in resulting image and debug info section sizes as + compared to DWARF Version 4. DWARF Version 5 standardizes previous + extensions such as accelerators for symbol indexing and the format + for fission (.dwo/.dwp) files. Users may not want to select this + config if they rely on tooling that has not yet been updated to + support DWARF Version 5. + +config DEBUG_INFO_NONE + bool "Disable debug information" + help + Do not build the kernel with debugging information, which will + result in a faster and smaller build. + +endchoice # "Debug information" if DEBUG_INFO @@ -267,56 +335,12 @@ config DEBUG_INFO_SPLIT to know about the .dwo files and include them. Incompatible with older versions of ccache. -choice - prompt "DWARF version" - help - Which version of DWARF debug info to emit. - -config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT - bool "Rely on the toolchain's implicit default DWARF version" - help - The implicit default version of DWARF debug info produced by a - toolchain changes over time. - - This can break consumers of the debug info that haven't upgraded to - support newer revisions, and prevent testing newer versions, but - those should be less common scenarios. - - If unsure, say Y. - -config DEBUG_INFO_DWARF4 - bool "Generate DWARF Version 4 debuginfo" - help - Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. - - If you have consumers of DWARF debug info that are not ready for - newer revisions of DWARF, you may wish to choose this or have your - config select this. - -config DEBUG_INFO_DWARF5 - bool "Generate DWARF Version 5 debuginfo" - depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) - depends on !DEBUG_INFO_BTF - help - Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc - 5.0+ accepts the -gdwarf-5 flag but only had partial support for some - draft features until 7.0), and gdb 8.0+. - - Changes to the structure of debug info in Version 5 allow for around - 15-18% savings in resulting image and debug info section sizes as - compared to DWARF Version 4. DWARF Version 5 standardizes previous - extensions such as accelerators for symbol indexing and the format - for fission (.dwo/.dwp) files. Users may not want to select this - config if they rely on tooling that has not yet been updated to - support DWARF Version 5. - -endchoice # "DWARF version" - config DEBUG_INFO_BTF bool "Generate BTF typeinfo" depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST depends on BPF_SYSCALL + depends on !DEBUG_INFO_DWARF5 help Generate deduplicated BTF type information from DWARF debug info. Turning this on expects presence of pahole tool, which will convert @@ -585,20 +609,6 @@ source "lib/Kconfig.kcsan" endmenu -config DEBUG_KERNEL - bool "Kernel debugging" - help - Say Y here if you are developing drivers or trying to debug and - identify kernel problems. - -config DEBUG_MISC - bool "Miscellaneous debug code" - default DEBUG_KERNEL - depends on DEBUG_KERNEL - help - Say Y here if you need to enable miscellaneous debug code that should - be under a more specific debug option but isn't. - menu "Networking Debugging" source "net/Kconfig.debug"