Randy Dunlap <rdunlap@xxxxxxxxxxxxx> writes: > Hi, > > On 10/4/23 09:58, Stephen Brennan wrote: >> The option CONFIG_IKCONFIG allows the gzip compressed kernel >> configuration to be included into vmlinux or a module. In these cases, >> debuggers can access the config data and use it to adjust their behavior >> according to the configuration. However, distributions rarely enable >> this, likely because it uses a fair bit of kernel memory which cannot be >> swapped out. > > x86_64 allmodconfig is 91 KB gzipped... oh well. Yeah, and info like BTF is much larger, yet this is the config setting that gets trimmed out by distros :( (This is not a criticism of BTF, just an observation) Unfortunately I don't control it and am just trying to work around it :) > Reviewed-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Thanks! Stephen >> This means that in practice, the kernel configuration is rarely >> available to debuggers. >> >> So, introduce an alternative, CONFIG_DEBUG_INFO_IKCONFIG. This strategy, >> which is only available if IKCONFIG is not already built-in, adds a >> section ".debug_linux_ikconfig", to the vmlinux ELF. It will be stripped >> out of the final images, but will remain in the debuginfo files. So >> debuggers which rely on vmlinux debuginfo can have access to the kernel >> configuration, without incurring a cost to the kernel at runtime. >> >> Signed-off-by: Stephen Brennan <stephen.s.brennan@xxxxxxxxxx> >> --- >> include/asm-generic/vmlinux.lds.h | 3 ++- >> kernel/Makefile | 1 + >> kernel/configs-debug.S | 18 ++++++++++++++++++ >> lib/Kconfig.debug | 14 ++++++++++++++ >> 4 files changed, 35 insertions(+), 1 deletion(-) >> create mode 100644 kernel/configs-debug.S > > > -- > ~Randy
