From: "Fenghua Yu" <fenghua.yu@intel.com>
To: "H Peter Anvin" <hpa@zytor.com>, "Ingo Molnar" <mingo@elte.hu>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Asit K Mallick" <asit.k.mallick@intel.com>,
"Tigran Aivazian" <tigran@aivazian.fsnet.co.uk>,
"Andreas Herrmann" <andreas.herrmann3@amd.com>,
"Borislav Petkov" <borislav.petkov@amd.com>,
"Yinghai Lu" <yinghai@kernel.org>,
"linux-kernel" <linux-kernel@vger.kernel.org>,
"x86" <x86@kernel.org>
Cc: "Fenghua Yu" <fenghua.yu@intel.com>
Subject: [PATCH v3 01/10] Documentation/x86: Early load microcode
Date: Sun, 16 Dec 2012 02:43:20 -0800 [thread overview]
Message-ID: <1355654609-16800-2-git-send-email-fenghua.yu@intel.com> (raw)
In-Reply-To: <1355654609-16800-1-git-send-email-fenghua.yu@intel.com>
From: Fenghua Yu <fenghua.yu@intel.com>
Documenation for early loading microcode methodology.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
Documentation/x86/early-microcode.txt | 43 +++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
create mode 100644 Documentation/x86/early-microcode.txt
diff --git a/Documentation/x86/early-microcode.txt b/Documentation/x86/early-microcode.txt
new file mode 100644
index 0000000..4aaf0df
--- /dev/null
+++ b/Documentation/x86/early-microcode.txt
@@ -0,0 +1,43 @@
+Early load microcode
+====================
+By Fenghua Yu <fenghua.yu@intel.com>
+
+Kernel can update microcode in early phase of boot time. Loading microcode early
+can fix CPU issues before they are observed during kernel boot time.
+
+Microcode is stored in an initrd file. The microcode is read from the initrd
+file and loaded to CPUs during boot time.
+
+The format of the combined initrd image is microcode in cpio format followed by
+the initrd image (maybe compressed). Kernel parses the combined initrd image
+during boot time. The microcode file in cpio name space is:
+kernel/x86/microcode/GenuineIntel.bin
+
+During BSP boot (before SMP starts), if the kernel finds the microcode file in
+the initrd file, it parses the microcode and saves matching microcode in memory.
+If matching microcode is found, it will be uploaded in BSP and later on in all
+APs.
+
+The cached microcode patch is applied when CPUs resume from a sleep state.
+
+There are two legacy user space interfaces to load microcode, either through
+/dev/cpu/microcode or through /sys/devices/system/cpu/microcode/reload file
+in sysfs.
+
+In addition to these two legacy methods, the early loading method described
+here is the third method with which microcode can be uploaded to a system's
+CPUs.
+
+The following example script shows how to generate a new combined initrd file in
+/boot/initrd-3.5.0.ucode.img with original microcode microcode.bin and
+original initrd image /boot/initrd-3.5.0.img.
+
+mkdir initrd
+cd initrd
+mkdir kernel
+mkdir kernel/x86
+mkdir kernel/x86/microcode
+cp ../microcode.bin kernel/x86/microcode/GenuineIntel.bin
+find .|cpio -oc >../ucode.cpio
+cd ..
+cat ucode.cpio /boot/initrd-3.5.0.img >/boot/initrd-3.5.0.ucode.img
--
1.8.0.1
next prev parent reply other threads:[~2012-12-16 17:45 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-16 10:43 [PATCH v3 00/10] x86/microcode: Early load microcode Fenghua Yu
2012-12-16 10:43 ` Fenghua Yu [this message]
2012-12-16 10:43 ` [PATCH v3 02/10] x86/microcode_intel.h: Define functions and macros for early loading ucode Fenghua Yu
2012-12-16 10:43 ` [PATCH v3 03/10] x86/common.c: Make have_cpuid_p() a global function Fenghua Yu
2012-12-16 10:43 ` [PATCH v3 04/10] x86/microcode_core_early.c: Define interfaces for early loading ucode Fenghua Yu
2012-12-16 17:57 ` Borislav Petkov
2012-12-16 18:09 ` Yu, Fenghua
2012-12-16 18:17 ` Borislav Petkov
2012-12-16 10:43 ` [PATCH v3 05/10] x86/microcode_intel_lib.c: Early update ucode on Intel's CPU Fenghua Yu
2012-12-16 10:43 ` [PATCH v3 06/10] x86/microcode_intel_early.c: " Fenghua Yu
2012-12-16 10:43 ` [PATCH v3 07/10] x86/head_32.S: Early update ucode in 32-bit Fenghua Yu
2012-12-16 10:43 ` [PATCH v3 08/10] x86/head64.c: Early update ucode in 64-bit Fenghua Yu
2012-12-16 17:59 ` Yinghai Lu
2012-12-16 18:38 ` Yu, Fenghua
2012-12-16 21:43 ` H. Peter Anvin
2012-12-16 23:35 ` Yinghai Lu
2012-12-16 23:59 ` Yu, Fenghua
2012-12-17 0:42 ` Yinghai Lu
2012-12-17 2:02 ` Yinghai Lu
2012-12-17 7:14 ` Yu, Fenghua
2012-12-17 23:30 ` Yu, Fenghua
2012-12-17 23:34 ` Yinghai Lu
2012-12-18 0:32 ` Yu, Fenghua
2012-12-18 0:36 ` Yinghai Lu
2012-12-18 22:55 ` Yu, Fenghua
2012-12-18 22:57 ` Yinghai Lu
2012-12-16 10:43 ` [PATCH v3 09/10] x86/mm/init.c: Copy ucode from initrd image to memory Fenghua Yu
2012-12-16 10:43 ` [PATCH v3 10/10] x86/Kconfig: Configurations to enable/disable the feature Fenghua Yu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1355654609-16800-2-git-send-email-fenghua.yu@intel.com \
--to=fenghua.yu@intel.com \
--cc=andreas.herrmann3@amd.com \
--cc=asit.k.mallick@intel.com \
--cc=borislav.petkov@amd.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=tglx@linutronix.de \
--cc=tigran@aivazian.fsnet.co.uk \
--cc=x86@kernel.org \
--cc=yinghai@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).