Re: [PATCH 4/4] vdso: avoid including asm/page.h

Christophe Leroy
2024-02-26T18:54:00Z

Le 26/02/2024 à 17:14, Arnd Bergmann a écrit :
> From: Arnd Bergmann <arnd@arndb.de>
>
> The recent change to the vdso_data_store broke building compat VDSO
> on at least arm64 because it includes headers outside of the include/vdso/
> namespace:

I understand that powerpc64 also has an issue, see
https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20231221120410.2226678-1-mpe@ellerman.id.au/

>
> In file included from arch/arm64/include/asm/lse.h:5,
> from arch/arm64/include/asm/cmpxchg.h:14,
> from arch/arm64/include/asm/atomic.h:16,
> from include/linux/atomic.h:7,
> from include/asm-generic/bitops/atomic.h:5,
> from arch/arm64/include/asm/bitops.h:25,
> from include/linux/bitops.h:68,
> from arch/arm64/include/asm/memory.h:209,
> from arch/arm64/include/asm/page.h:46,
> from include/vdso/datapage.h:22,
> from lib/vdso/gettimeofday.c:5,
> from <command-line>:
> arch/arm64/include/asm/atomic_ll_sc.h:298:9: error: unknown type name 'u128'
> 298 | u128 full;
>
> Use an open-coded page size calculation based on the new CONFIG_PAGE_SHIFT
> Kconfig symbol instead.
>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Fixes: a0d2fcd62ac2 ("vdso/ARM: Make union vdso_data_store available for all architectures")
> Link: https://lore.kernel.org/lkml/CA+G9fYtrXXm_KO9fNPz3XaRxHV7UD_yQp-TEuPQrNRHU+_0W_Q@mail.gmail.com/
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> include/vdso/datapage.h | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
> index 7ba44379a095..2c39a67d7e23 100644
> --- a/include/vdso/datapage.h
> +++ b/include/vdso/datapage.h
> @@ -19,8 +19,6 @@
> #include <vdso/time32.h>
> #include <vdso/time64.h>
>
> -#include <asm/page.h>
> -
> #ifdef CONFIG_ARCH_HAS_VDSO_DATA
> #include <asm/vdso/data.h>
> #else
> @@ -128,7 +126,7 @@ extern struct vdso_data _timens_data[CS_BASES] __attribute__((visibility("hidden
> */
> union vdso_data_store {
> struct vdso_data data[CS_BASES];
> - u8 page[PAGE_SIZE];
> + u8 page[1ul << CONFIG_PAGE_SHIFT];

Usually 1UL is used (capital letter)

Maybe better to (re)define PAGE_SIZE instead, something like:

#define PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)

> };
>
> /*