The following commit has been merged into the x86/microcode branch of tip:
Commit-ID: 098bcea71b8d257d80b0037b97b66070806600a5
Gitweb: https://git.kernel.org/tip/098bcea71b8d257d80b0037b97b66070806600a5
Author: Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate: Fri, 29 May 2026 17:27:24 -07:00
Committer: Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Thu, 04 Jun 2026 08:55:58 -07:00
x86/microcode/AMD: Move the no-revision fixup to get_patch_level()
On machines which don't have microcode applied yet, the revision is 0.
However, this doesn't work with the Zen family/model/stepping patch
arithmetic. So move the fixup to the patch level getter function and
this way make sure the patch level is always proper and thus the
arithmetic always works.
And now that it can be called on any family, make this Zen-only.
Assisted-by: claude/claude-opus-4-6
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20260530024213.86137-1-bp@kernel.org
---
arch/x86/kernel/cpu/microcode/amd.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index e533881..b90af74 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -233,11 +233,6 @@ static bool need_sha_check(u32 cur_rev)
{
u32 cutoff;
- if (!cur_rev) {
- cur_rev = cpuid_to_ucode_rev(bsp_cpuid_1_eax);
- pr_info_once("No current revision, generating the lowest one: 0x%x\n", cur_rev);
- }
-
cutoff = get_cutoff_revision(cur_rev);
if (cutoff)
return cur_rev <= cutoff;
@@ -338,6 +333,13 @@ static u32 get_patch_level(void)
}
native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
+ if (!rev) {
+ if (x86_family(bsp_cpuid_1_eax) < 0x17)
+ return rev;
+
+ rev = cpuid_to_ucode_rev(bsp_cpuid_1_eax);
+ pr_info_once("No current revision, generating the lowest one: 0x%x\n", rev);
+ }
return rev;
}