From f9f1ac61f4d9d74de3cf33729deb7ca267ba5ad5 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 14 May 2024 22:00:37 +0200 Subject: Adding debian version 3.20230719.1~deb11u1. Signed-off-by: Daniel Baumann --- debian/README.Debian | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 debian/README.Debian (limited to 'debian/README.Debian') diff --git a/debian/README.Debian b/debian/README.Debian new file mode 100644 index 0000000..b0116a4 --- /dev/null +++ b/debian/README.Debian @@ -0,0 +1,100 @@ +amd64-microcode for Debian +-------------------------- + +Introduction: + +AMD AMD64 processors are capable of field-upgrading their control program +(microcode). These microcode updates correct processor errata, and are +often important for safe, correct system operation. + +While most of the microcode updates fix problems that happen extremely +rarely, there are enough updates fixing issues that would cause system +lockup, memory corruption, or unpredictable system behavior, to warrant +taking it seriously. + +Microcode updates are ephemeral: they will be lost after a processor hard +reset or after the processor is powered off. They must be reapplied at +every boot and after the system wakes up from suspend to RAM or disk. + +Updating the processor microcode is the responsibility of the system +firmware (BIOS or EFI). However, not all vendors will release timely +updates for their firmware when AMD releases updated microcode, and most +users don't update their system firmware in a timely fashion (or at all) +anyway. + +The end result is that, unless some other method of distributing microcode +updates is in place, the processor in many systems will be running with +outdated microcode, increasing the chances of incorrect system operation. + +Debian can apply microcode updates to the system processors during the +operating system boot automatically. This requires the use of a suitably +configured Linux kernel 3.14 or later, and an initramfs. + + +Installing microcode updates: + +For the Debian default kernel, it is enough to install the amd64-microcode +package as well as the initramfs-tools package and the microcode update +will be applied automatically at the next reboot. + +It is also possible to use "dracut" instead of initramfs-tools, but the +support for early microcode updates must be enabled manually in +dracut.conf (set the option "early_microcode=yes"). Force an update of +the initramfs using dracut, and reboot. Note that since Linux kernel 4.4, +one must use dracut 044 or later. + +Applying the microcode updates without the use of an early initramfs is +not automatically supported anymore, due to future safety concerns. +However, the local administrator may trigger an immediate microcode update +attempt at any time, at her own risk: + + USING AN INITRAMFS+REBOOT IS SAFER. DO THIS ONLY WHEN YOU KNOW BETTER: + as root: + echo 1 > /sys/devices/system/cpu/microcode/reload + + +RECOVERY PROCEDURE: + +It is possible for a microcode update to not work well, or to not work at +all on specific system models. This is very rare when using the safe +microcode update procedure described above and an up-to-date Linux kernel, +but it has happened at least once. + +Should you experience problems because of the microcode update, you will +have to bypass the microcode update process that happens during operating +system startup (boot), and remove the amd64-microcode package until the +underlying issue is fixed. + +To bypass the microcode update during system startup, you must instruct the +boot loader (grub, lilo, etc) to pass the "dis_ucode_ldr" parameter +(without the quotes) to the kernel. + +If your system uses grub (the default bootloader in Debian): + + 1. Access the grub menu during boot (press and hold the left "Shift" + key right after starting the system up if you don't see a grub menu + during boot); + + 2. Move the highlight/cursor to the kernel/boot option you want to + use, and press the "e" key to edit it; + + 3. Locate the line that starts with "linux" using the cursor + keys. You must add the word "dis_ucode_ldr" (without the quotes) to + the end of that line; + + 4. Press "Ctrl+X" to start (boot) the system. The microcode updates + will be skipped. + +After the system is running, remove or purge the amd64-microcode package. + +If removing/purging the package doesn't do it automatically for some +reason, refresh the initramfs using the "update-initramfs -u" command (as +the root user), and possibly "update-initramfs -u -k ". + +"dracut" users, please refer to the dracut documentation on how to update +the initramfs images for every installed kernel. + +Please report any issues caused by microcode updates to the mailing-list or +to the Debian bug tracker. + + -- Henrique de Moraes Holschuh , 2016-04-05 -- cgit v1.2.3