Re: [PATCH v3 0/7] MIPS: Resolve build problems on decstation_64

[Thomas Bogendoerfer]

On Sat, Sep 19, 2026 at 04:14:06PM +0100, Maciej W. Rozycki wrote:
> Hi Thomas,
> 
>  I chose to rework this patchset on behalf of WangYuli after all; I'm not 
> sure if his address cc'd works.  I've reordered the changes to put fixes 
> ahead of improvements and reworded the piece of inline documentation for 
> the KBUILD_SYM32 option since, frankly, the one we have now is hard to 
> comprehend.
> 
>  I have verified this patchset with my 5000/150.  Please apply.
> 
>  Previous iteration (v2) at 
> <https://lore.kernel.org/r/24EC7D2CA58B25F5+20250422101855.136675-1-wangyuli@xxxxxxxxxxxxx/>.
> 
>  The original cover letter follows.
> 
>   Maciej
> 
> [ Part 1 ]: MIPS: dec: Only check -msym32 when need compiler
> 
> During 'make modules_install', the need-compiler variable becomes
> null, so Makefile.compiler isn't included.
>     
> This results in call cc-option-yn returning nothing.
>     
> For more technical details on why need-compiler is null during
> 'make modules_install' and why no compiler invocation is actually
> needed at this point, please refer to commit 4fe4a6374c4d ("MIPS:
> Only fiddle with CHECKFLAGS if need-compiler") and commit
> 805b2e1d427a ("kbuild: include Makefile.compiler only when compiler
> is needed").
>     
> Commit a79a404e6c22 ("MIPS: Fix CONFIG_CPU_DADDI_WORKAROUNDS
> `modules_install' regression") tried to fix the same issue but it
> caused a compile error on clang compiler because it doesn't support
> '-msym32'. Then, commit 18ca63a2e23c ("MIPS: Probe toolchain support
> of -msym32") fixed it but reintroduced the CONFIG_CPU_DADDI_WORKAROUNDS
> `modules_install' regression.
> 
> Wrapping this entire code block with #ifdef need-compiler to avoid
> all issues is the best solution for now.
>     
> To get rid of spurious "CONFIG_CPU_DADDI_WORKAROUNDS unsupported
> without -msym32" error.
> 
> Moreover, I also identified an unnecessary check for KBUILD_SYM32
> in this Makefile section. Eliminate it for code simplification.
> 
> NOTE:
> 
> It is particularly important to note that this code fix does not
> imply that we have resolved the problem entirely.
> 
> In fact, the entire application of cc-option and its auxiliary
> commands within the kernel codebase currently carries significant
> risk.
> 
> When we execute make modules_install, the Makefile for the
> corresponding architecture under arch/subarches/Makefile is
> invariably included. Within these files, there are numerous
> usages of cc-option and its auxiliary commands, all of which will
> return empty strings. The reason other architectures can
> successfully complete compilation under these circumstances is
> purely because they do not, unlike MIPS, check the return values
> of cc-option and its auxiliary commands within their Makefiles
> and halt the compilation process when the expected results are
> not received.
> 
> A feasible approach to remediation might be to encapsulate all
> usages of cc-option and its auxiliary commands within conditional
> statements across all architecture Makefiles, preventing their
> execution entirely during make modules_install.
> 
> However, this would lead to a massive number of inelegant
> modifications, and these broader implications may require
> deliberation by Masahiro Yamada.
> 
> Regardless, this does not preclude us from addressing the
> issue on MIPS first.
> 
> Link: https://lore.kernel.org/all/41107E6D3A125047+20250211135616.1807966-1-wangyuli@xxxxxxxxxxxxx/
> Link: https://lore.kernel.org/all/F49F5EE9975F29EA+20250214094758.172055-1-wangyuli@xxxxxxxxxxxxx/
> Link: https://lore.kernel.org/all/8ABBF323414AEF93+20250217142541.48149-1-wangyuli@xxxxxxxxxxxxx/
> 
> 
> [ Part 2 ]: MIPS: decstation_64_defconfig: Compile the kernel with warnings as errors
> 
> Patch ("MIPS: dec: Only check -msym32 when need compiler") allows
> us to compile kernel image packages with decstation_64_defconfig.
> 
> However, compilation warnings remain during the build.
> 
> Address these warnings and enable CONFIG_WERROR for decstation_64_defconfig.
> 
> Link: https://lore.kernel.org/all/487CE8AA937621E2+20250218125101.663980-1-wangyuli@xxxxxxxxxxxxx/
> Link: https://lore.kernel.org/all/EA0AFB15DDCF65C1+20250227141949.1129536-1-wangyuli@xxxxxxxxxxxxx/
> Link: https://lore.kernel.org/all/303EFD6BFBDAC7C8+20250305033436.31214-1-wangyuli@xxxxxxxxxxxxx/
> 
> 
> [ Changelog: ]
> 
>  *v1->v2: Add Philippe Mathieu-Daudé's "Reviewed-by" tag in patch3.
> Link: https://lore.kernel.org/all/11740B01E659CAFF+20250407073158.493183-1-wangyuli@xxxxxxxxxxxxx/
> Link: https://lore.kernel.org/all/8dcb5c6d-be4f-4891-a999-137d53edfc05@xxxxxxxxxx/
> 
> WangYuli (6):
>   MIPS: dec: Only check -msym32 when need compiler
>   MIPS: Eliminate Redundant KBUILD_SYM32 Checks
>   MIPS: dec: Create reset.h
>   MIPS: dec: Remove dec_irq_dispatch()
>   MIPS: decstation_64_defconfig: Update configs dependencies
>   MIPS: decstation_64_defconfig: Compile the kernel with warnings as
>     errors
> 
>  arch/mips/Makefile                        |  6 ++--
>  arch/mips/configs/decstation_64_defconfig | 43 +++++++++--------------
>  arch/mips/dec/int-handler.S               |  2 +-
>  arch/mips/dec/prom/init.c                 |  3 +-
>  arch/mips/dec/reset.c                     |  2 ++
>  arch/mips/dec/setup.c                     | 15 ++------
>  arch/mips/include/asm/dec/reset.h         | 20 +++++++++++
>  7 files changed, 47 insertions(+), 44 deletions(-)
>  create mode 100644 arch/mips/include/asm/dec/reset.h

series applied to mips-next

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]