lkml.org 
[lkml]   [2022]   [Mar]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] arm64: fix clang warning about TRAMP_VALIAS
From
On 2022-03-16 18:38, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> The newly introduced TRAMP_VALIAS definition causes a build warning
> with clang-14:
>
> arch/arm64/include/asm/vectors.h:66:31: error: arithmetic on a null pointer treated as a cast from integer to pointer is a GNU extension [-Werror,-Wnull-pointer-arithmetic]

Tangentially, all the other GNU extensions we depend on throughout Linux
are also GNU extensions. Do we know what's special about this one?

Robin.

> return (char *)TRAMP_VALIAS + SZ_2K * slot;
>
> Change the addition to something clang does not complain about.
>
> Fixes: bd09128d16fa ("arm64: Add percpu vectors for EL1")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> arch/arm64/include/asm/vectors.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> I see this warning on 5.17-rc8, but did not test it on linux-next,
> which may already have a fix.
>
> diff --git a/arch/arm64/include/asm/vectors.h b/arch/arm64/include/asm/vectors.h
> index f64613a96d53..bc9a2145f419 100644
> --- a/arch/arm64/include/asm/vectors.h
> +++ b/arch/arm64/include/asm/vectors.h
> @@ -56,14 +56,14 @@ enum arm64_bp_harden_el1_vectors {
> DECLARE_PER_CPU_READ_MOSTLY(const char *, this_cpu_vector);
>
> #ifndef CONFIG_UNMAP_KERNEL_AT_EL0
> -#define TRAMP_VALIAS 0
> +#define TRAMP_VALIAS 0ul
> #endif
>
> static inline const char *
> arm64_get_bp_hardening_vector(enum arm64_bp_harden_el1_vectors slot)
> {
> if (arm64_kernel_unmapped_at_el0())
> - return (char *)TRAMP_VALIAS + SZ_2K * slot;
> + return (char *)(TRAMP_VALIAS + SZ_2K * slot);
>
> WARN_ON_ONCE(slot == EL1_VECTOR_KPTI);
>

\
 
 \ /
  Last update: 2022-03-18 20:14    [W:0.058 / U:0.680 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site