Re: git: 1ba29614c4ce - main - amd64: revert back struct trapframe to the pre-FRED definition

Am Tage des Herren Sat, 21 Mar 2026 22:37:48 +0000
Konstantin Belousov <kib@FreeBSD.org> schrieb:

> The branch main has been updated by kib:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=1ba29614c4ce5e261ade0bd7def94079b7b9647a
> 
> commit 1ba29614c4ce5e261ade0bd7def94079b7b9647a
> Author:     Konstantin Belousov <kib@FreeBSD.org>
> AuthorDate: 2026-03-21 22:26:48 +0000
> Commit:     Konstantin Belousov <kib@FreeBSD.org>
> CommitDate: 2026-03-21 22:37:27 +0000
> 
>     amd64: revert back struct trapframe to the pre-FRED definition
>     
>     Trying to use the grown struct trapframe for IDT case broke in cases
>     where code supposed that hardware consumed sizeof(struct trapframe) of
>     the stack space when delivering interrupt or exception.  In particular,
>     this was broken for #NM/#DB/#MC.  Naive attempt of using IDT-trapframe
>     size for stack consumption caused later problems with larger C type.
>     
>     Instead of pretending that IDT event delivery pushed two never-accessed
>     doubleword to the stack, keep it honest and provide separate type for
>     the FRED interrupt frame, i.e. struct trapframe_fred.
>     
>     Convert between trapframe_fred and trapframe can be done by trivial pointer
>     arithmetic.
>     
>     Sponsored by:   The FreeBSD Foundation
>     MFC after:      1 week
> ---
>  sys/x86/include/frame.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/sys/x86/include/frame.h b/sys/x86/include/frame.h
> index a6444d55cfaf..b8e090ff95d0 100644
> --- a/sys/x86/include/frame.h
> +++ b/sys/x86/include/frame.h
> @@ -152,6 +152,10 @@ struct trapframe {
>  	uint16_t	tf_ss;
>  	uint16_t	tf_fred_evinfo1;
>  	uint32_t	tf_fred_evinfo2;
> +};
> +
> +struct trapframe_fred {
> +	struct trapframe tf_idt;
>  	/* two long words added by FRED */
>  	uint64_t	tf_fred_evdata;
>  	uint64_t	tf_fred_zero1;
> 

... this fixes in my case mentioned freezing/rebooting issues.
Thank you very much.

Kind regards
oh

-- 

A FreeBSD user