On Fri, May 9, 2025 at 1:56 AM Kees Cook <k...@kernel.org> wrote: > > On Fri, May 09, 2025 at 01:44:09AM +0900, Masahiro Yamada wrote: > > On Sun, May 4, 2025 at 2:37 AM Kees Cook <k...@kernel.org> wrote: > > > > > > On Sat, May 03, 2025 at 06:39:28PM +0900, Masahiro Yamada wrote: > > > > On Sat, May 3, 2025 at 7:54 AM Kees Cook <k...@kernel.org> wrote: > > > > > > > > > > v2: > > > > > - switch from -include to -I with a -D gated include > > > > > compiler-version.h > > > > > v1: > > > > > https://lore.kernel.org/lkml/20250501193839.work.525-k...@kernel.org/ > > > > > > > > > > > > What do you think of my patch as a prerequisite? > > > > https://lore.kernel.org/linux-kbuild/20250503084145.1994176-1-masahi...@kernel.org/T/#u > > > > Perhaps, can you implement this series more simply? > > > > > > > > My idea is to touch a single include/generated/global-rebuild.h > > > > rather than multiple files such as gcc-plugins-deps.h, integer-wrap.h, > > > > etc. > > > > > > > > When the file is touched, the entire kernel source tree will be rebuilt. > > > > This may rebuild more than needed (e.g. vdso) but I do not think > > > > it is a big deal. > > > > > > This is roughly where I started when trying to implement this, but I > > > didn't like the ergonomics of needing to scatter "touch" calls all over, > > > which was especially difficult for targets that shared a build rule but > > > may not all need to trigger a global rebuild. But what ultimately pushed > > > me away from it was when I needed to notice if a non-built source file > > > changed (the Clang .scl file), and I saw that I need to be dependency > > > driven rather than target driven. (Though perhaps there is a way to > > > address this with your global-rebuild.h?) > > > > > > As far as doing a full rebuild, if it had been available last week, I > > > probably would have used it, but now given the work that Nicolas, you, > > > and I have put into this, we have a viable way (I think) to make this > > > more specific. It does end up being a waste of time/resources to rebuild > > > stuff that doesn't need to be (efi-stub, vdso, boot code, etc), and that > > > does add up when I'm iterating on something that keeps triggering a full > > > rebuild. We already have to do the argument filtering for targets that > > > don't want randstruct, etc, so why not capitalize on that and make the > > > rebuild avoid those files too? > > > > > > efi-stub, vdso are very small. > > > > Unless this turns out to be painful, I prefer > > a simpler implementation. > > > > You will see how .scl file is handled. > > > > See the below code: > > > > > > diff --git a/Kbuild b/Kbuild > > index f327ca86990c..85747239314c 100644 > > --- a/Kbuild > > +++ b/Kbuild > > @@ -67,10 +67,20 @@ targets += $(atomic-checks) > > $(atomic-checks): $(obj)/.checked-%: include/linux/atomic/% FORCE > > $(call if_changed,check_sha1) > > > > +rebuild-$(CONFIG_GCC_PLUGINS) += $(addprefix > > scripts/gcc-plugins/, $(GCC_PLUGIN)) > > +rebuild-$(CONFIG_RANDSTRUCT) += > > include/generated/randstruct_hash.h > > These are in $(objtree)
Yes. > > +rebuild-$(CONFIG_UBSAN_INTEGER_WRAP) += scripts/integer-wrap-ignore.scl > > This is in $(srctree) Yes. > > + > > +quiet_cmd_touch = TOUCH $@ > > + cmd_touch = touch $@ > > + > > +include/generated/global-rebuild.h: $(rebuild-y) > > + $(call cmd,touch) > > Is this rule going to find the right versions of the dependencies? I think so, but please test it. > > --- a/Makefile > > +++ b/Makefile > > @@ -558,7 +558,8 @@ USERINCLUDE := \ > > -I$(srctree)/include/uapi \ > > -I$(objtree)/include/generated/uapi \ > > -include $(srctree)/include/linux/compiler-version.h \ > > - -include $(srctree)/include/linux/kconfig.h > > + -include $(srctree)/include/linux/kconfig.h \ > > + -include $(objtree)/include/generated/global-rebuild.h > > Instead of adding a new file, why not just touch compiler-version.h? Because the compiler-version.h is in $(srctree), which might be in the read-only file system. > But whatever the case, sure, I can live with this. :) > > -Kees > > -- > Kees Cook -- Best Regards Masahiro Yamada
