On Fri, May 9, 2025 at 8:59 AM Kees Cook <k...@kernel.org> wrote: > > On Fri, May 09, 2025 at 08:13:18AM +0900, Masahiro Yamada wrote: > > 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. > > The patch was white-space damaged and wrapped, but I rebuilt it manually > and it mostly works. There still seems to be some ordering issues, as > some stuff gets rebuilt on a record build: > > # Clean the tree and pick an "everything" build > $ make O=gcc-test clean allmodconfig -s > > # Make a target normally > $ make O=gcc-test kernel/seccomp.o -s > > # Touch a gcc plugin that was in .config > $ touch scripts/gcc-plugins/stackleak_plugin.c > > # Build and a full rebuild is triggered (good) > $ make O=gcc-test kernel/seccomp.o > make[1]: Entering directory '/srv/code/gcc-test' > GEN Makefile > DESCEND objtool > HOSTCXX scripts/gcc-plugins/stackleak_plugin.so > INSTALL libsubcmd_headers > TOUCH include/generated/global-rebuild.h > CC kernel/bounds.s > CC arch/x86/kernel/asm-offsets.s > CALL ../scripts/checksyscalls.sh > CC kernel/seccomp.o > make[1]: Leaving directory '/srv/code/gcc-test' > > # Build again, but more stuff gets built > $ make O=gcc-test kernel/seccomp.o > make[1]: Entering directory '/srv/code/gcc-test' > GEN Makefile > DESCEND objtool > CC scripts/mod/empty.o > CC scripts/mod/devicetable-offsets.s > INSTALL libsubcmd_headers > MKELF scripts/mod/elfconfig.h > HOSTCC scripts/mod/modpost.o > HOSTCC scripts/mod/sumversion.o > HOSTCC scripts/mod/symsearch.o > HOSTCC scripts/mod/file2alias.o > HOSTLD scripts/mod/modpost > CALL ../scripts/checksyscalls.sh > make[1]: Leaving directory '/srv/code/gcc-test' > > # Third time finally everything is stable > $ hmake O=gcc-test kernel/seccomp.o > make[1]: Entering directory '/srv/code/gcc-test' > GEN Makefile > DESCEND objtool > CALL ../scripts/checksyscalls.sh > INSTALL libsubcmd_headers > make[1]: Leaving directory '/srv/code/gcc-test' > > > Note that scripts/mod/* gets rebuilt on the second rebuild.
Hmm. OK, my code did not work. I accept your patch set (although I am not a big fan of the added complexity...) Could you move the normalize_path macro to scripts/Kbuild? -- Best Regards Masahiro Yamada
