Mark, Michael,

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

Thanks

On 10/17/2025 8:14 AM, [email protected] wrote:
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Today's Topics:

    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 <[email protected]>
To: [email protected],  [email protected]
Cc: [email protected], Mark Gross <[email protected]>, Mark
        Gross <[email protected]>, Michal Camacho Romero
        <[email protected]>
Subject: [tboot-devel] [PATCH 1/1] Disable CET when calling tboot
        shutdown procedure.
Message-ID:
        <[email protected]>

From: Mark Gross <[email protected]>

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 <[email protected]>
Signed-off-by: Michal Camacho Romero <[email protected]>
---
  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();



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