@@ -182,6 +182,7 @@
#define MSR_AMD64_PATCH_LOADER 0xc0010020
#define MSR_AMD64_OSVW_ID_LENGTH 0xc0010140
#define MSR_AMD64_OSVW_STATUS 0xc0010141
+#define MSR_AMD64_LS_CFG 0xc0011020
#define MSR_AMD64_DC_CFG 0xc0011022
#define MSR_AMD64_BU_CFG2 0xc001102a
#define MSR_AMD64_IBSFETCHCTL 0xc0011030
@@ -508,6 +508,16 @@ static void early_init_amd(struct cpuinfo_x86 *c)
set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
}
#endif
+
+ /* F16h erratum 793, CVE-2013-6885 */
+ if (c->x86 == 0x16 && c->x86_model <= 0xf) {
+ u64 val;
+
+ rdmsrl(MSR_AMD64_LS_CFG, val);
+ if (!(val & BIT(15)))
+ wrmsrl(MSR_AMD64_LS_CFG, val | BIT(15));
+ }
+
}
static const int amd_erratum_383[];
This is a note to let you know that I have just added a patch titled x86, cpu, amd: Add workaround for family 16h, erratum 793 to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.11.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 292b6eb9cb65b699f293e6c6fc82c0fbaebe97ca Mon Sep 17 00:00:00 2001 From: Borislav Petkov <bp@suse.de> Date: Wed, 15 Jan 2014 00:07:11 +0100 Subject: x86, cpu, amd: Add workaround for family 16h, erratum 793 commit 3b56496865f9f7d9bcb2f93b44c63f274f08e3b6 upstream. This adds the workaround for erratum 793 as a precaution in case not every BIOS implements it. This addresses CVE-2013-6885. Erratum text: [Revision Guide for AMD Family 16h Models 00h-0Fh Processors, document 51810 Rev. 3.04 November 2013] 793 Specific Combination of Writes to Write Combined Memory Types and Locked Instructions May Cause Core Hang Description Under a highly specific and detailed set of internal timing conditions, a locked instruction may trigger a timing sequence whereby the write to a write combined memory type is not flushed, causing the locked instruction to stall indefinitely. Potential Effect on System Processor core hang. Suggested Workaround BIOS should set MSR C001_1020[15] = 1b. Fix Planned No fix planned [ hpa: updated description, fixed typo in MSR name ] Signed-off-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20140114230711.GS29865@pd.tnic Tested-by: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- arch/x86/include/uapi/asm/msr-index.h | 1 + arch/x86/kernel/cpu/amd.c | 10 ++++++++++ 2 files changed, 11 insertions(+) -- 1.8.3.2