diff mbox series

xen/nospec: Remove unreachable code

Message ID 20240410192659.1490271-1-andrew.cooper3@citrix.com (mailing list archive)
State New
Headers show
Series xen/nospec: Remove unreachable code | expand

Commit Message

Andrew Cooper April 10, 2024, 7:26 p.m. UTC 
When CONFIG_SPECULATIVE_HARDEN_LOCK is active, this reads:

  static always_inline bool lock_evaluate_nospec(bool condition)
  {
      return arch_lock_evaluate_nospec(condition);
      return condition;
  }

Insert an #else to take out the second return.

Fixes: 7ef0084418e1 ("x86/spinlock: introduce support for blocking speculation into critical regions")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: consulting@bugseng.com <consulting@bugseng.com>
CC: Roberto Bagnara <roberto.bagnara@bugseng.com>
CC: Federico Serafini <federico.serafini@bugseng.com>
CC: Nicola Vetrini <nicola.vetrini@bugseng.com>
---
 xen/include/xen/nospec.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)


base-commit: 0e7ea8ca5fc9bce9248414f6aaf2dc861abd45d9

Comments

Luca Fancellu April 10, 2024, 9:27 p.m. UTC | #1 
> On 10 Apr 2024, at 20:26, Andrew Cooper <andrew.cooper3@citrix.com> wrote:
> 
> When CONFIG_SPECULATIVE_HARDEN_LOCK is active, this reads:
> 
>  static always_inline bool lock_evaluate_nospec(bool condition)
>  {
>      return arch_lock_evaluate_nospec(condition);
>      return condition;
>  }
> 
> Insert an #else to take out the second return.
> 
> Fixes: 7ef0084418e1 ("x86/spinlock: introduce support for blocking speculation into critical regions")
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---

Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Stefano Stabellini April 10, 2024, 10:15 p.m. UTC | #2 
On Wed, 10 Apr 2024, Andrew Cooper wrote:
> When CONFIG_SPECULATIVE_HARDEN_LOCK is active, this reads:
> 
>   static always_inline bool lock_evaluate_nospec(bool condition)
>   {
>       return arch_lock_evaluate_nospec(condition);
>       return condition;
>   }
> 
> Insert an #else to take out the second return.
> 
> Fixes: 7ef0084418e1 ("x86/spinlock: introduce support for blocking speculation into critical regions")
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
diff mbox series

Patch

diff --git a/xen/include/xen/nospec.h b/xen/include/xen/nospec.h
index 9fb15aa26aa9..828dbd4e0ad8 100644
--- a/xen/include/xen/nospec.h
+++ b/xen/include/xen/nospec.h
@@ -82,8 +82,9 @@  static always_inline bool lock_evaluate_nospec(bool condition)
 {
 #ifdef CONFIG_SPECULATIVE_HARDEN_LOCK
     return arch_lock_evaluate_nospec(condition);
-#endif
+#else
     return condition;
+#endif
 }
 
 #endif /* XEN_NOSPEC_H */