diff options
| author |   Borislav Petkov (AMD) <bp@alien8.de> | 2025-08-20 11:58:57 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2025-08-27 10:24:10 +0200 |
| commit | fcf8239ad6a5de54fa7ce18e464c6b5951b982cb (patch) | |
| tree | fe648b78f5f88f97b71bf9fb4e6cd2154aa4827f | |
| parent | x86/cpu/intel: Fix the constant_tsc model check for Pentium 4 (diff) | |
| download | wireguard-linux-fcf8239ad6a5de54fa7ce18e464c6b5951b982cb.tar.xz wireguard-linux-fcf8239ad6a5de54fa7ce18e464c6b5951b982cb.zip | |
x86/microcode/AMD: Handle the case of no BIOS microcode
Machines can be shipped without any microcode in the BIOS. Which means,
the microcode patch revision is 0.
Handle that gracefully.
Fixes: 94838d230a6c ("x86/microcode/AMD: Use the family,model,stepping encoded in the patch ID")
Reported-by: Vítek Vávra <vit.vavra.kh@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
| -rw-r--r-- | arch/x86/kernel/cpu/microcode/amd.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 097e39327942..514f63340880 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -171,8 +171,28 @@ static int cmp_id(const void *key, const void *elem) return 1; } +static u32 cpuid_to_ucode_rev(unsigned int val) +{ + union zen_patch_rev p = {}; + union cpuid_1_eax c; + + c.full = val; + + p.stepping = c.stepping; + p.model = c.model; + p.ext_model = c.ext_model; + p.ext_fam = c.ext_fam; + + return p.ucode_rev; +} + static bool need_sha_check(u32 cur_rev) { + 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); + } + switch (cur_rev >> 8) { case 0x80012: return cur_rev <= 0x800126f; break; case 0x80082: return cur_rev <= 0x800820f; break; @@ -749,8 +769,6 @@ static struct ucode_patch *cache_find_patch(struct ucode_cpu_info *uci, u16 equi n.equiv_cpu = equiv_cpu; n.patch_id = uci->cpu_sig.rev; - WARN_ON_ONCE(!n.patch_id); - list_for_each_entry(p, µcode_cache, plist) if (patch_cpus_equivalent(p, &n, false)) return p; |