Commit 6cdce951 authored by Borislav Petkov's avatar Borislav Petkov
Browse files

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: default avatarBorislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-8-bp@alien8.de
parent 2b8d34b1

arch/x86/kernel/cpu/microcode/amd.c

+3 −24
Original line number Diff line number Diff line
@@ -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) {

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