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 f2721801d8d4238594a0f9bdba40d17e8086d568..d19972d5d729556bf3e399b79fefa34c3c28e113 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -115,10 +115,9 @@ 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 */