FAILED: patch "[PATCH] x86/retbleed: Fix return thunk alignment" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 9a48d604672220545d209e9996c2a1edbb5637f6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023051308-reflected-pessimism-42d1@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

9a48d6046722 ("x86/retbleed: Fix return thunk alignment")
a149180fbcf3 ("x86: Add magic AMD return-thunk")
d9e9d2300681 ("x86,objtool: Create .return_sites")
15e67227c49a ("x86: Undo return-thunk damage")
0b53c374b9ef ("x86/retpoline: Use -mfunction-return")
369ae6ffc41a ("x86/retpoline: Cleanup some #ifdefery")
a883d624aed4 ("x86/cpufeatures: Move RETPOLINE flags to word 11")
22922deae13f ("Merge tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 9a48d604672220545d209e9996c2a1edbb5637f6 Mon Sep 17 00:00:00 2001
From: "Borislav Petkov (AMD)" <[email protected]>
Date: Fri, 12 May 2023 23:12:26 +0200
Subject: [PATCH] x86/retbleed: Fix return thunk alignment

SYM_FUNC_START_LOCAL_NOALIGN() adds an endbr leading to this layout (leaving only the last 2 bytes of the address):

3bff <zen_untrain_ret>:

  3bff:       f3 0f 1e fa             endbr64
  3c03:       f6                      test   $0xcc,%bl

3c04 <__x86_return_thunk>:

  3c04:       c3                      ret
  3c05:       cc                      int3
  3c06:       0f ae e8                lfence

However, "the RET at __x86_return_thunk must be on a 64 byte boundary, for alignment within the BTB."

Use SYM_START instead.

index 27ef53fab6bd..b3b1e376dce8 100644
@@ -144,8 +144,8 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array)
  */
 	.align 64
 	.skip 63, 0xcc
-SYM_FUNC_START_NOALIGN(zen_untrain_ret);
-
+SYM_START(zen_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
+	ANNOTATE_NOENDBR
 	/*
 	 * As executed from zen_untrain_ret, this is:
 	 *

Same situation as 5.15 - see my reply there.

Thx.

Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Great, thanks for checking.

greg k-h