quoted

quoted

quoted

the GROUP until after the FIRMWARE, so this can't work, as it already
will have included all the ones below, hence why I bracketed top and
bottom with a group.

well... that is something that can be adapted easily by using a 2 pass
approach, filtering out the list based on the groups.

I agree that yours is simpler though.  If we can rely on the
order produced by the compiler and we document the expectations of
MODULE_FIRMWARE_GROUP_ONLY_ONE, then I believe we can stay with the
simpler approach.

Luis, any thoughts here?

I see the Dracut code indicates that the order says now that you should
put the preferred firmware last, and that seems to match most coding
conventions, ie, new firmwares likely get added last, so it's a nice

not all. i915 for example keeps it newest first so when attempting
multiple firmware versions it starts from the preferred version.  It
will be harder to convert since it also uses a x-macro to make sure the
MODULE_FIRMWARE() and the the platform mapping are actually using the same
firmware.

quoted

coincidence. Will this always work? I don't know. But if you like to

short answer: it depends if your compiler is gcc *and* -O2 is used
Longer debug ahead. Simple test with the expansion of MODULE_FIRMWARE
baked in:

        $ cat /tmp/a.c
        static const __attribute__((section("__modinfo_manual"), used, aligned(1))) char foo[] = "modinfo_manual_foo";
        static const __attribute__((section("__modinfo_manual"), used, aligned(1))) char bar[] = "modinfo_manual_bar";
        $ gcc -c -o /tmp/a.o /tmp/a.c
        $ objcopy -O binary --only-section=__modinfo_manual /tmp/a.o /tmp/modinfo_manual
        $ strings /tmp/modinfo_manual
        modinfo_manual_foo
        modinfo_manual_bar

However that doesn't match when building modules. In kmod:

diff --git a/testsuite/module-playground/mod-simple.c b/testsuite/module-playground/mod-simple.c
index 503e4d8..6dd5771 100644
--- a/testsuite/module-playground/mod-simple.c
+++ b/testsuite/module-playground/mod-simple.c

@@ -30,3 +30,9 @@ module_exit(test_module_exit);

  MODULE_AUTHOR("Lucas De Marchi <lucas.demarchi@intel.com>");
  MODULE_LICENSE("GPL");
+
+
+static const char __UNIQUE_ID_firmware404[] __attribute__((__used__)) __attribute__((__section__("__modinfo_cpp"))) __attribute__((__aligned__(1))) = "modinfo_cpp_foo";
+static const char __UNIQUE_ID_firmware405[] __attribute__((__used__)) __attribute__((__section__("__modinfo_cpp"))) __attribute__((__aligned__(1))) = "modinfo_cpp_bar";

        $ make ....
        $ objcopy -O binary --only-section=__modinfo_cpp testsuite/module-playground/mod-simple.ko /tmp/modinfo_cpp
        $ strings /tmp/modinfo_cpp
        modinfo_cpp_bar
        modinfo_cpp_foo

It doesn't seem to be ./scripts/Makefile.modfinal neither as it's also
inverted in testsuite/module-playground/mod-simple.o

After checking the options passed to gcc, here is the "culprit": -O2

        $ gcc -c -o /tmp/a.o /tmp/a.c && objcopy -O binary --only-section=__modinfo_manual /tmp/a.o /tmp/modinfo_manual && strings /tmp/modinfo_manual
        modinfo_manual_foo
        modinfo_manual_bar
        $ gcc -O2 -c -o /tmp/a.o /tmp/a.c && objcopy -O binary --only-section=__modinfo_manual /tmp/a.o /tmp/modinfo_manual && strings /tmp/modinfo_manual
        modinfo_manual_bar
        modinfo_manual_foo

It seems anything but -O0 inverts the section.

        $ gcc --version
        gcc (GCC) 12.2.1 20230201

It doesn't match the behavior described in its man page though. Manually
specifying all the options that -O1 turns on doesn't invert it.

        $ gcc -fauto-inc-dec -fbranch-count-reg -fcombine-stack-adjustments \
                -fcompare-elim -fcprop-registers -fdce -fdefer-pop -fdelayed-branch
                -fdse -fforward-propagate -fguess-branch-probability -fif-conversion \
                -fif-conversion2 -finline-functions-called-once -fipa-modref \
                -fipa-profile -fipa-pure-const -fipa-reference -fipa-reference-addressable \
                -fmerge-constants -fmove-loop-stores -fomit-frame-pointer -freorder-blocks \
                -fshrink-wrap -fshrink-wrap-separate -fsplit-wide-types -fssa-backprop \
                -fssa-phiopt -ftree-bit-ccp -ftree-ccp -ftree-ch -ftree-coalesce-vars \
                -ftree-copy-prop -ftree-dce -ftree-dominator-opts -ftree-dse -ftree-forwprop \
                -ftree-fre -ftree-phiprop -ftree-pta -ftree-scev-cprop -ftree-sink -ftree-slsr \
                -ftree-sra -ftree-ter -funit-at-a-time -c -o /tmp/a.o /tmp/a.c \
                && objcopy -O binary --only-section=__modinfo_manual /tmp/a.o /tmp/modinfo_manual && strings /tmp/modinfo_manual
        cc1: warning: this target machine does not have delayed branches
        modinfo_manual_foo
        modinfo_manual_bar