This is a note to let you know that I've just added the patch titled
Revert "x86/alternative: Make custom return thunk unconditional"
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-x86-alternative-make-custom-return-thunk-unconditional.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 04530345532fbc0e74ecdedbd537bf3f0329339c Mon Sep 17 00:00:00 2001
From: "Borislav Petkov (AMD)" <bp@xxxxxxxxx>
Date: Sat, 24 Feb 2024 12:01:34 +0100
Subject: Revert "x86/alternative: Make custom return thunk unconditional"
From: "Borislav Petkov (AMD)" <bp@xxxxxxxxx>
This reverts commit 53ebbe1c8c02aa7b7f072dd2f96bca4faa1daa59.
Revert the backport of upstream commit:
095b8303f383 ("x86/alternative: Make custom return thunk unconditional")
in order to backport the full version now that
770ae1b70952 ("x86/returnthunk: Allow different return thunks")
has been backported.
Revert it here so that the build breakage is kept at minimum.
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/nospec-branch.h | 4 ----
arch/x86/kernel/cpu/bugs.c | 2 --
2 files changed, 6 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -205,11 +205,7 @@
typedef u8 retpoline_thunk_t[RETPOLINE_THUNK_SIZE];
extern retpoline_thunk_t __x86_indirect_thunk_array[];
-#ifdef CONFIG_RETHUNK
extern void __x86_return_thunk(void);
-#else
-static inline void __x86_return_thunk(void) {}
-#endif
extern void retbleed_return_thunk(void);
extern void srso_return_thunk(void);
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -62,8 +62,6 @@ EXPORT_SYMBOL_GPL(x86_pred_cmd);
static DEFINE_MUTEX(spec_ctrl_mutex);
-void (*x86_return_thunk)(void) __ro_after_init = &__x86_return_thunk;
-
/* Update SPEC_CTRL MSR and its cached copy unconditionally */
static void update_spec_ctrl(u64 val)
{
Patches currently in stable-queue which might be from bp@xxxxxxxxx are
queue-6.1/revert-x86-alternative-make-custom-return-thunk-unconditional.patch
queue-6.1/x86-alternative-make-custom-return-thunk-unconditional.patch
queue-6.1/x86-returnthunk-allow-different-return-thunks.patch
