linux-kernel - [PATCH 2/5] x86, microcode, AMD: Add a reusable buffer

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri,  9 Dec 2011 19:08:52 +0100
From:	Borislav Petkov <bp@...64.org>
To:	X86-ML <x86@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Borislav Petkov <borislav.petkov@....com>
Subject: [PATCH 2/5] x86, microcode, AMD: Add a reusable buffer

From: Borislav Petkov <borislav.petkov@....com>

Add a simple 4K page which gets allocated on driver init and freed on
driver exit instead of vmalloc'ing small buffers for each ucode patch.

Signed-off-by: Borislav Petkov <borislav.petkov@....com>
---
 arch/x86/kernel/microcode_amd.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/microcode_amd.c b/arch/x86/kernel/microcode_amd.c
index e8a68c2..9129c69 100644
--- a/arch/x86/kernel/microcode_amd.c
+++ b/arch/x86/kernel/microcode_amd.c
@@ -71,6 +71,9 @@ struct microcode_amd {
 
 static struct equiv_cpu_entry *equiv_cpu_table;
 
+/* page-sized ucode patch buffer */
+void *patch;
+
 static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
 {
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
@@ -351,9 +354,14 @@ static struct microcode_ops microcode_amd_ops = {
 
 struct microcode_ops * __init init_amd_microcode(void)
 {
+	patch = (void *)get_zeroed_page(GFP_KERNEL);
+	if (!patch)
+		return NULL;
+
 	return &microcode_amd_ops;
 }
 
 void __exit exit_amd_microcode(void)
 {
+	free_page((unsigned long)patch);
 }
-- 
1.7.8.rc0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/