Re: [PATCH 06/12] arch: Declare screen_info in <asm/screen_info.h>

On 2023/6/29 19:45, Thomas Zimmermann wrote:
> The variable screen_info does not exist on all architectures. Declare
> it in <asm-generic/screen_info.h>. All architectures that do declare it
> will provide it via <asm/screen_info.h>.
> 
> Add the Kconfig token ARCH_HAS_SCREEN_INFO to guard against access on
> architectures that don't provide screen_info.
> 
> Signed-off-by: Thomas Zimmermann <[email protected]>
> Cc: Richard Henderson <[email protected]>
> Cc: Ivan Kokshaysky <[email protected]>
> Cc: Matt Turner <[email protected]>
> Cc: Russell King <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Guo Ren <[email protected]>
> Cc: Brian Cain <[email protected]>
> Cc: Huacai Chen <[email protected]>
> Cc: WANG Xuerui <[email protected]>
> Cc: Thomas Bogendoerfer <[email protected]>
> Cc: Dinh Nguyen <[email protected]>
> Cc: Michael Ellerman <[email protected]>
> Cc: Nicholas Piggin <[email protected]>
> Cc: Christophe Leroy <[email protected]>
> Cc: Paul Walmsley <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> Cc: Albert Ou <[email protected]>
> Cc: Yoshinori Sato <[email protected]>
> Cc: Rich Felker <[email protected]>
> Cc: John Paul Adrian Glaubitz <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: [email protected]
> Cc: "H. Peter Anvin" <[email protected]>
> Cc: Chris Zankel <[email protected]>
> Cc: Max Filippov <[email protected]>
> Cc: Helge Deller <[email protected]>
> Cc: Arnd Bergmann <[email protected]>
> Cc: Kees Cook <[email protected]>
> Cc: "Paul E. McKenney" <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Frederic Weisbecker <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Ard Biesheuvel <[email protected]>
> Cc: Sami Tolvanen <[email protected]>
> Cc: Juerg Haefliger <[email protected]>
> Cc: Geert Uytterhoeven <[email protected]>
> Cc: Anshuman Khandual <[email protected]>
> Cc: Niklas Schnelle <[email protected]>
> Cc: "Russell King (Oracle)" <[email protected]>
> Cc: Linus Walleij <[email protected]>
> Cc: Sebastian Reichel <[email protected]>
> Cc: "Mike Rapoport (IBM)" <[email protected]>
> Cc: "Kirill A. Shutemov" <[email protected]>
> Cc: Zi Yan <[email protected]>
> ---
>   arch/Kconfig                      |  6 ++++++
>   arch/alpha/Kconfig                |  1 +
>   arch/arm/Kconfig                  |  1 +
>   arch/arm64/Kconfig                |  1 +
>   arch/csky/Kconfig                 |  1 +
>   arch/hexagon/Kconfig              |  1 +
>   arch/ia64/Kconfig                 |  1 +
>   arch/loongarch/Kconfig            |  1 +
>   arch/mips/Kconfig                 |  1 +
>   arch/nios2/Kconfig                |  1 +
>   arch/powerpc/Kconfig              |  1 +
>   arch/riscv/Kconfig                |  1 +
>   arch/sh/Kconfig                   |  1 +
>   arch/sparc/Kconfig                |  1 +
>   arch/x86/Kconfig                  |  1 +
>   arch/xtensa/Kconfig               |  1 +
>   drivers/video/Kconfig             |  3 +++
>   include/asm-generic/Kbuild        |  1 +
>   include/asm-generic/screen_info.h | 12 ++++++++++++
>   include/linux/screen_info.h       |  2 +-
>   20 files changed, 38 insertions(+), 1 deletion(-)
>   create mode 100644 include/asm-generic/screen_info.h
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 205fd23e0cada..2f58293fd7bcb 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -1466,6 +1466,12 @@ config ARCH_HAS_NONLEAF_PMD_YOUNG
>   	  address translations. Page table walkers that clear the accessed bit
>   	  may use this capability to reduce their search space.
>   
> +config ARCH_HAS_SCREEN_INFO
> +	bool
> +	help
> +	  Selected by architectures that provide a global instance of
> +	  screen_info.
> +
>   source "kernel/gcov/Kconfig"
>   
>   source "scripts/gcc-plugins/Kconfig"
> [snip]
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index d38b066fc931b..6aab2fb7753da 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -13,6 +13,7 @@ config LOONGARCH
>   	select ARCH_HAS_FORTIFY_SOURCE
>   	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
>   	select ARCH_HAS_PTE_SPECIAL
> +	select ARCH_HAS_SCREEN_INFO
>   	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
>   	select ARCH_INLINE_READ_LOCK if !PREEMPTION
>   	select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
> [snip]

Acked-by: WANG Xuerui <[email protected]> # loongarch

Thanks!

-- 
WANG "xen0n" Xuerui

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