[PATCH RFC next 00/18] sync scripts/Makefile.extrawarn with 6.1, enable WERROR for host tools

[Quentin Schulz]

Hi Tom,

On 5/4/26 8:04 PM, Tom Rini wrote:
> On Mon, May 04, 2026 at 03:20:27PM +0200, Quentin Schulz wrote:
[...]
>> The first two patches are for fixing pytest calling make directly on a
>> "dirty" build directory as generated by buildman using the clang-20
>> toolchain, but pytest does not set HOSTCC and CC to clang-20, resulting
>> in clang flags being used with gcc).
>>
>> One can simply reproduce it (after backporting up to patch
>> "scripts/Makefile.extrawarn: sync with 6.1") by doing so in the
>> container:
>>
>> make HOSTCC=clang-20 CC=clang-20 O=build/sandbox sandbox_defconfig
>> make HOSTCC=clang-20 CC=clang-20 O=build/sandbox -j`nproc
>> make O=build/sandbox u-boot-initial-env
>>
>> It'll print:
>> gcc: error: unrecognized command-line option '-mno-global-merge'
>> gcc: error: unrecognized command-line option '-Wformat-invalid-specifier'
>> gcc: error: unrecognized command-line option '-Qunused-arguments'
>>
>> This is essentially what's run within test_env_initial_env_file in
>> test/py/tests/test_env.py.
>>
>> While I'm not unhappy with the patches to pytest, it feels to me we may
>> be missing something else for the u-boot-initial-env make target to
>> update the kconfig symbol based on the toolchain being used when called.
> 
> Is there some other target in the Makefile that should catch this kind
> of change? It's not just that build target that needs to be remade, it's
> everything, yes?
> 

For the reproducer, one actually needs to do

diff --git a/Makefile b/Makefile
index bd33437fdfd..9079131f81e 100644
--- a/Makefile
+++ b/Makefile
@@ -1007,15 +1007,15 @@ KBUILD_CFLAGS += $(call 
cc-option,-Wno-format-nonliteral)
  KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)

  ifdef CONFIG_CC_IS_CLANG
-KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
-KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
-KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
+KBUILD_CPPFLAGS += -Qunused-arguments
+KBUILD_CFLAGS += -Wno-format-invalid-specifier
+KBUILD_CFLAGS += -Wno-gnu
  # Quiet clang warning: comparison of unsigned expression < 0 is always 
false
-KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare)
+KBUILD_CFLAGS += -Wno-tautological-compare
  # CLANG uses a _MergedGlobals as optimization, but this breaks 
modpost, as the
  # source of a reference will be _MergedGlobals and not on of the 
whitelisted names.
  # See modpost pattern 2
-KBUILD_CFLAGS += $(call cc-option, -mno-global-merge,)
+KBUILD_CFLAGS += -mno-global-merge
  else

  # These warnings generated too much noise in a regular build.

Which is what's being done since kernel commit a1494304346a ("kbuild: 
add all Clang-specific flags unconditionally"). I actually had this in 
an earlier version of this patch series and forgot I removed it.

This seems to apply to envtools and tools-only as well, though make 
prompts me for the desired state of symbols that are now reachable, e.g. 
ARM64_CRC32. And if I rerun the same command, then it works. It seems 
like the config from the previous run is used? I don't know if it's 
related but those two commands call make directly ($(Q)$(MAKE) 
$(build)=<path>). Do you have something in mind maybe? Or some more 
commands to run?

Cheers,
Quentin