Re: git: a9e77eb7016d - main - arm64: Correctly align the SVE signal context

Hi.

Can this be related to this issue?

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=292195
"arm64: panic on coredump with sve instructions"

Regards,
Ronald.

 
Van: Andrew Turner <andrew@FreeBSD.org>
Datum: dinsdag, 6 januari 2026 12:04
Aan: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Onderwerp: git: a9e77eb7016d - main - arm64: Correctly align the SVE signal context
> 
> The branch main has been updated by andrew:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=a9e77eb7016df70723c208fc09fbd01ec23a732d
> 
> commit a9e77eb7016df70723c208fc09fbd01ec23a732d
> Author:     Andrew Turner <andrew@FreeBSD.org>
> AuthorDate: 2026-01-06 10:35:55 +0000
> Commit:     Andrew Turner <andrew@FreeBSD.org>
> CommitDate: 2026-01-06 10:36:37 +0000
> 
>     arm64: Correctly align the SVE signal context
>     
>     The SVE signal context needs to be correctly aligned. Fix this by
>     creating a new macro to calculate the needed size to provide this
>     alignment, and use it when setting and checking the saved SVE signal
>     context.
>     
>     Reported by:    cperciva
>     Reviewed by:    cperciva, markj
>     Sponsored by:   Arm Ltd
>     Differential Revision:  https://reviews.freebsd.org/D54396
> ---
>  sys/arm64/arm64/exec_machdep.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/sys/arm64/arm64/exec_machdep.c b/sys/arm64/arm64/exec_machdep.c
> index 7c50dc93fdb4..207e10ede96c 100644
> --- a/sys/arm64/arm64/exec_machdep.c
> +++ b/sys/arm64/arm64/exec_machdep.c
> @@ -60,6 +60,10 @@
>  #include <machine/vfp.h>
>  #endif
>  
> +#define    CTX_SIZE_SVE(buf_size)                  \
> +    roundup2(sizeof(struct sve_context) + (buf_size),      \
> +      _Alignof(struct sve_context))
> +
>  _Static_assert(sizeof(mcontext_t) == 880, "mcontext_t size incorrect");
>  _Static_assert(sizeof(ucontext_t) == 960, "ucontext_t size incorrect");
>  _Static_assert(sizeof(siginfo_t) == 80, "siginfo_t size incorrect");
> @@ -585,8 +589,7 @@ set_mcontext(struct thread *td, mcontext_t *mcp)
>  
>                 buf_size = sve_buf_size(td);
>                 /* Check the size is valid */
> -               if (ctx.ctx_size !=
> -                   (sizeof(sve_ctx) + buf_size))
> +               if (ctx.ctx_size != CTX_SIZE_SVE(buf_size))
>                     return (EINVAL);
>  
>                 memset(pcb->pcb_svesaved, 0,
> @@ -729,7 +732,7 @@ sendsig_ctx_sve(struct thread *td, vm_offset_t *addrp)
>  {
>     struct sve_context ctx;
>     struct pcb *pcb;
> -   size_t buf_size;
> +   size_t buf_size, ctx_size;
>     vm_offset_t ctx_addr;
>  
>     pcb = td->td_pcb;
> @@ -740,14 +743,15 @@ sendsig_ctx_sve(struct thread *td, vm_offset_t *addrp)
>     MPASS(pcb->pcb_svesaved != NULL);
>  
>     buf_size = sve_buf_size(td);
> +   ctx_size = CTX_SIZE_SVE(buf_size);
>  
>     /* Address for the full context */
> -   *addrp -= sizeof(ctx) + buf_size;
> +   *addrp -= ctx_size;
>     ctx_addr = *addrp;
>  
>     memset(&ctx, 0, sizeof(ctx));
>     ctx.sve_ctx.ctx_id = ARM64_CTX_SVE;
> -   ctx.sve_ctx.ctx_size = sizeof(ctx) + buf_size;
> +   ctx.sve_ctx.ctx_size = ctx_size;
>     ctx.sve_vector_len = pcb->pcb_sve_len;
>     ctx.sve_flags = 0;
>  
>  
> 
> 
>