6.6-stable review patch. If anyone has any objections, please let me know.
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From: Borislav Petkov (AMD) bp@alien8.de
commit fcf8239ad6a5de54fa7ce18e464c6b5951b982cb upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/cpu/microcode/amd.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -161,8 +161,28 @@ static int cmp_id(const void *key, const 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; @@ -744,8 +764,6 @@ static struct ucode_patch *cache_find_pa 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;