From: Nathan Chancellor <nathan@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>, x86@kernel.org
Cc: Nick Desaulniers <ndesaulniers@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@kernel.org>,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
stable@vger.kernel.org, kernel test robot <lkp@intel.com>
Subject: Re: [PATCH] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current
Date: Wed, 13 Jul 2022 08:24:01 -0700 [thread overview]
Message-ID: <Ys7jkUxe4FXfyH/L@dev-arch.thelio-3990X> (raw)
In-Reply-To: <20220713152222.1697913-1-nathan@kernel.org>
On Wed, Jul 13, 2022 at 08:22:22AM -0700, Nathan Chancellor wrote:
> Clang warns:
>
> arch/x86/kernel/cpu/bugs.c:58:21: error: section attribute is specified on redeclared variable [-Werror,-Wsection]
> DEFINE_PER_CPU(u64, x86_spec_ctrl_current);
> ^
> arch/x86/include/asm/nospec-branch.h:283:12: note: previous declaration is here
> extern u64 x86_spec_ctrl_current;
> ^
> 1 error generated.
>
> The declaration should be using DECLARE_PER_CPU instead so all
> attributes stay in sync.
>
> Cc: stable@vger.kernel.org
> Fixes: fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
> arch/x86/include/asm/nospec-branch.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
> index bb05ed4f46bd..99a29c83adf8 100644
> --- a/arch/x86/include/asm/nospec-branch.h
> +++ b/arch/x86/include/asm/nospec-branch.h
> @@ -6,6 +6,7 @@
> #include <linux/static_key.h>
> #include <linux/objtool.h>
> #include <linux/linkage.h>
> +#include <linux/percpu.h>
Argh, forgot to amend... v2 incoming.
> #include <asm/alternative.h>
> #include <asm/cpufeatures.h>
> @@ -280,7 +281,7 @@ static inline void indirect_branch_prediction_barrier(void)
>
> /* The Intel SPEC CTRL MSR base value cache */
> extern u64 x86_spec_ctrl_base;
> -extern u64 x86_spec_ctrl_current;
> +DECLARE_PER_CPU(u64, x86_spec_ctrl_current);
> extern void write_spec_ctrl_current(u64 val, bool force);
> extern u64 spec_ctrl_current(void);
>
>
> base-commit: 72a8e05d4f66b5af7854df4490e3135168694b6b
> --
> 2.37.1
>
prev parent reply other threads:[~2022-07-13 15:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-13 15:22 [PATCH] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current Nathan Chancellor
2022-07-13 15:24 ` Nathan Chancellor [this message]
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