x86/bugs: Avoid warning when overriding return thunk

[ Upstream commit 9f85fdb9fc5a1bd308a10a0a7d7e34f2712ba58b ]

The purpose of the warning is to prevent an unexpected change to the return
thunk mitigation. However, there are legitimate cases where the return
thunk is intentionally set more than once. For example, ITS and SRSO both
can set the return thunk after retbleed has set it. In both the cases
retbleed is still mitigated.

Replace the warning with an info about the active return thunk.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250611-eibrs-fix-v4-3-5ff86cac6c61@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 7c269dcb7cecee5b0920da4a4accd8ab782bb94b..6ff9fd836d874a2ff8090488ddf078983f9bebb1 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -67,10 +67,9 @@ void (*x86_return_thunk)(void) __ro_after_init = &__x86_return_thunk;
 
 static void __init set_return_thunk(void *thunk)
 {
-       if (x86_return_thunk != __x86_return_thunk)
-               pr_warn("x86/bugs: return thunk changed\n");
-
        x86_return_thunk = thunk;
+
+       pr_info("active return thunk: %ps\n", thunk);
 }
 
 /* Update SPEC_CTRL MSR and its cached copy unconditionally */