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Re: [XEN PATCH] xen/lib: remove the overwrtitten string functions from x86 build


  • To: Federico Serafini <federico.serafini@xxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
  • From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
  • Date: Thu, 2 Nov 2023 10:29:59 +0000
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  • Cc: consulting@xxxxxxxxxxx, George Dunlap <george.dunlap@xxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxx>, Julien Grall <julien@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>
  • Delivery-date: Thu, 02 Nov 2023 10:30:12 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 02/11/2023 10:21 am, Federico Serafini wrote:
> Remove the generic implementation of memcpy(), memmove() and
> memset() from the x86 build since a version written in asm is present.
> This addesses violations of MISRA C:2012 Rule 8.6 ("An identifier with
> external linkage shall have exactly one external definition").
>
> Signed-off-by: Federico Serafini <federico.serafini@xxxxxxxxxxx>

As I said on one of the previous calls, this is an error in analysis,
not a bug in Xen.

The behaviour when linking a library is well defined by the toolchain. 
Disassemble the final hypervisor and observe that there really is only
one implementation, and it's always the arch-optimised version when both
exist.

~Andrew



 


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