linux-kernel - [tip:x86/microcode] x86/microcode/AMD: Move patch family check to verify

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Message-ID: <tip-51776fb805fe4f248f264c1783c286ae60552e9a@git.kernel.org>
Date:   Mon, 19 Nov 2018 02:16:56 -0800
From:   tip-bot for Borislav Petkov <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, linux-kernel@...r.kernel.org, bp@...e.de,
        hpa@...or.com, mingo@...nel.org
Subject: [tip:x86/microcode] x86/microcode/AMD: Move patch family check to
 verify_patch()

Commit-ID:  51776fb805fe4f248f264c1783c286ae60552e9a
Gitweb:     https://git.kernel.org/tip/51776fb805fe4f248f264c1783c286ae60552e9a
Author:     Borislav Petkov <bp@...e.de>
AuthorDate: Thu, 26 Jul 2018 06:50:44 +0200
Committer:  Borislav Petkov <bp@...e.de>
CommitDate: Mon, 19 Nov 2018 10:51:05 +0100

x86/microcode/AMD: Move patch family check to verify_patch()

... where all the microcode patch verification is being concentrated.

Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: x86@...nel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-9-bp@alien8.de
---
 arch/x86/kernel/cpu/microcode/amd.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index b4450374f4b1..be46e1fda77f 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -221,7 +221,10 @@ __verify_patch_size(u8 family, u32 sh_psize, unsigned int buf_size)
 static unsigned int
 verify_patch(u8 family, const u8 *buf, unsigned int buf_size, bool early)
 {
+	struct microcode_header_amd *mc_hdr;
 	u32 sh_psize;
+	u16 proc_id;
+	u8 patch_fam;
 
 	if (!__verify_patch_section(buf, buf_size, &sh_psize, early))
 		return 0;
@@ -243,6 +246,13 @@ verify_patch(u8 family, const u8 *buf, unsigned int buf_size, bool early)
 		return 0;
 	}
 
+	mc_hdr	= (struct microcode_header_amd *)(buf + SECTION_HDR_SIZE);
+	proc_id	= mc_hdr->processor_rev_id;
+
+	patch_fam = 0xf + (proc_id >> 12);
+	if (patch_fam != family)
+		return 0;
+
 	return __verify_patch_size(family, sh_psize, buf_size);
 }
 
@@ -718,7 +728,6 @@ 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;
-	u8 patch_fam;
 	u16 proc_id;
 
 	patch_size = verify_patch(family, fw, leftover, false);
@@ -732,10 +741,6 @@ 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;
 
-	patch_fam = 0xf + (proc_id >> 12);
-	if (patch_fam != family)
-		return crnt_size;
-
 	if (mc_hdr->nb_dev_id || mc_hdr->sb_dev_id) {
 		pr_err("Patch-ID 0x%08x: chipset-specific code unsupported.\n",
 			mc_hdr->patch_id);