Re: [tboot-devel] tboot-devel Digest, Vol 160, Issue 1

[Tony C. <tc...@re...>]

Mark, Michael,

Has this patch been submitted upstream yet?
If so, to what branch?

Thanks

On 10/17/2025 8:14 AM, tbo...@li... wrote:
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> Today's Topics:
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>     1. [PATCH 1/1] Disable CET when calling tboot shutdown
>        procedure. (Michal Camacho Romero)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Fri, 17 Oct 2025 09:36:19 +0200
> From: Michal Camacho Romero <mic...@li...>
> To: tbo...@li...,	nin...@in...
> Cc: mat...@in..., Mark Gross <mg...@li...>, Mark
> 	Gross <mar...@in...>, Michal Camacho Romero
> 	<mic...@li...>
> Subject: [tboot-devel] [PATCH 1/1] Disable CET when calling tboot
> 	shutdown procedure.
> Message-ID:
> 	<202...@li...>
> 
> From: Mark Gross <mg...@li...>
> 
> The tboot->shutdown_entry is effectively bios code and CET needs to be
> disabled before calling it.
> 
> It resolves TBOOT shutdown failure bug, reported on the SLES (SUSE Linux
> Enterprise Server) 16.0 OS. OS power off, called by the "init 0" command,
> was failing, due to activated Intel Control-Flow Enforcement Technology (CET).
> Disabling CET has allowed to execute OS and TBOOT shutdown properly.
> 
> Closes: https://bugzilla.suse.com/show_bug.cgi?id=1247950
> Signed-off-by: Mark Gross <mar...@in...>
> Signed-off-by: Michal Camacho Romero <mic...@li...>
> ---
>   arch/x86/kernel/tboot.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 46b8f1f16676..73396c43a7ad 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -28,6 +28,7 @@
>   #include <asm/setup.h>
>   #include <asm/e820/api.h>
>   #include <asm/io.h>
> +#include <asm/cpu.h>
>   
>   #include "../realmode/rm/wakeup.h"
>   
> @@ -247,6 +248,10 @@ void tboot_shutdown(u32 shutdown_type)
>   
>   	switch_to_tboot_pt();
>   
> +	/*
> +	 * toggle off CET while we call shutdown_entry in bios
> +	 */
> +	cet_disable();
>   	shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
>   	shutdown();
>