x86/microcode/AMD: Simplify patch family detection

Instead of traversing the equivalence table, compute the family a patch
is for, from the processor revision ID in the microcode header.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-8-bp@alien8.de

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 8f012a7f88c447d0bc05c32b90adff6b20fe759b..b4450374f4b19e39dff7f8d9051f570251759170 100644 (file)
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -540,20 +540,6 @@ static u16 __find_equiv_id(unsigned int cpu)
        return find_equiv_id(equiv_cpu_table, uci->cpu_sig.sig);
 }
 
-static u32 find_cpu_family_by_equiv_cpu(u16 equiv_cpu)
-{
-       int i = 0;
-
-       BUG_ON(!equiv_cpu_table);
-
-       while (equiv_cpu_table[i].equiv_cpu != 0) {
-               if (equiv_cpu == equiv_cpu_table[i].equiv_cpu)
-                       return equiv_cpu_table[i].installed_cpu;
-               i++;
-       }
-       return 0;
-}
-
 /*
  * a small, trivial cache of per-family ucode patches
  */
@@ -732,7 +718,7 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
        struct microcode_header_amd *mc_hdr;
        unsigned int patch_size, crnt_size;
        struct ucode_patch *patch;
-       u32 proc_fam;
+       u8 patch_fam;
        u16 proc_id;
 
        patch_size = verify_patch(family, fw, leftover, false);
@@ -746,15 +732,8 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
        mc_hdr      = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
        proc_id     = mc_hdr->processor_rev_id;
 
-       proc_fam = find_cpu_family_by_equiv_cpu(proc_id);
-       if (!proc_fam) {
-               pr_err("No patch family for equiv ID: 0x%04x\n", proc_id);
-               return crnt_size;
-       }
-
-       /* check if patch is for the current family */
-       proc_fam = ((proc_fam >> 8) & 0xf) + ((proc_fam >> 20) & 0xff);
-       if (proc_fam != family)
+       patch_fam = 0xf + (proc_id >> 12);
+       if (patch_fam != family)
                return crnt_size;
 
        if (mc_hdr->nb_dev_id || mc_hdr->sb_dev_id) {