From: Fenghua Yu <fenghua...@intel.com>
The problem in current microcode loading method is that we load a microcode way,
way too late; ideally we should load it before turning paging on. This may only
be practical on 32 bits since we can't get to 64-bit mode without paging on,
but we should still do it as early as at all possible.
Similarly, we should load the microcode update as early as possible during AP
bringup and when processors are brought back online after hotplug or S3/S4.
In order to do that, the microcode patch needs to be permanently present in
kernel memory. Each individual patch is fairly small, so that is OK, but the
entire blob with support for each CPU is too big. Since only CPU's with same
model can be in the same platform, we store microcode with the same model as
BSP. Later on AP's can upload microcode from the saved microcodep patches.
Note, however, that Linux users have gotten used to being able to install a
microcode patch in the field without having a reboot; we support that model too.
v2: Detect vendor before loading microcode. Move some functions from
microcode_intel_early.c to microcode_intel_lib.c. Change some early loading
microcode dependencies in Kconfig. Reword doc.
Fenghua Yu (10):
Documentation/x86: Early load microcode
x86/microcode_intel.h: Define functions and macros for early load
ucode
x86/microcode_core_early.c: Define interfaces for early load ucode
x86/microcode_intel_lib.c: Early update ucode on Intel's CPU
x86/microcode_intel_early.c: Early update ucode on Intel's CPU
x86/head_32.S: Early update ucode in 32-bit
x86/head64.c: Early update ucode in 64-bit
x86/smpboot.c: Early update ucode on AP
x86/mm/init.c: Copy ucode from initrd image to memory
x86/Kconfig: Configurations to enable/disable the feature
Documentation/x86/early-microcode.txt | 43 +++
arch/x86/Kconfig | 18 ++
arch/x86/include/asm/microcode.h | 23 ++
arch/x86/include/asm/microcode_intel.h | 106 ++++++++
arch/x86/kernel/Makefile | 3 +
arch/x86/kernel/head64.c | 6 +
arch/x86/kernel/head_32.S | 6 +
arch/x86/kernel/microcode_core.c | 7 +-
arch/x86/kernel/microcode_core_early.c | 70 +++++
arch/x86/kernel/microcode_intel.c | 185 +-------------
arch/x86/kernel/microcode_intel_early.c | 438 +++++++++++++++++++++++++++++++
arch/x86/kernel/microcode_intel_lib.c | 174 ++++++++++++
arch/x86/kernel/smpboot.c | 7 +
arch/x86/mm/init.c | 10 +
14 files changed, 915 insertions(+), 181 deletions(-)
create mode 100644 Documentation/x86/early-microcode.txt
create mode 100644 arch/x86/include/asm/microcode_intel.h
create mode 100644 arch/x86/kernel/microcode_core_early.c
create mode 100644 arch/x86/kernel/microcode_intel_early.c
create mode 100644 arch/x86/kernel/microcode_intel_lib.c
--
1.7.2
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