[GIT PULL] x86/microcode updates for v4.14

From: Ingo Molnar
Date: Mon Sep 04 2017 - 04:11:19 EST

Linus,

Please pull the latest x86-microcode-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-microcode-for-linus

# HEAD: aa78c1ccfab6018289bc2bfd0092d516d0a49ec5 x86/microcode/intel: Improve microcode patches saving flow

Update documentation, improve robustness and fix a memory leak.

Thanks,

Ingo

------------------>
Borislav Petkov (2):
x86/microcode: Document the three loading methods
x86/microcode/intel: Improve microcode patches saving flow

Shu Wang (1):
x86/microcode/AMD: Free unneeded patch before exit from update_cache()


Documentation/x86/early-microcode.txt | 70 -----------------
Documentation/x86/microcode.txt | 137 ++++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/microcode/amd.c | 5 +-
arch/x86/kernel/cpu/microcode/intel.c | 27 +++----
4 files changed, 155 insertions(+), 84 deletions(-)
delete mode 100644 Documentation/x86/early-microcode.txt
create mode 100644 Documentation/x86/microcode.txt

diff --git a/Documentation/x86/early-microcode.txt b/Documentation/x86/early-microcode.txt
deleted file mode 100644
index 07749e7f3d50..000000000000
--- a/Documentation/x86/early-microcode.txt
+++ /dev/null
@@ -1,70 +0,0 @@
-Early load microcode
-====================
-By Fenghua Yu <fenghua.yu@xxxxxxxxx>
-
-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:
-on Intel: kernel/x86/microcode/GenuineIntel.bin
-on AMD : kernel/x86/microcode/AuthenticAMD.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 -p kernel/x86/microcode
-cp ../microcode.bin kernel/x86/microcode/GenuineIntel.bin (or AuthenticAMD.bin)
-find . | cpio -o -H newc >../ucode.cpio
-cd ..
-cat ucode.cpio /boot/initrd-3.5.0.img >/boot/initrd-3.5.0.ucode.img
-
-Builtin microcode
-=================
-
-We can also load builtin microcode supplied through the regular firmware
-builtin method CONFIG_FIRMWARE_IN_KERNEL. Only 64-bit is currently
-supported.
-
-Here's an example:
-
-CONFIG_FIRMWARE_IN_KERNEL=y
-CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09 amd-ucode/microcode_amd_fam15h.bin"
-CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
-
-This basically means, you have the following tree structure locally:
-
-/lib/firmware/
-|-- amd-ucode
-...
-| |-- microcode_amd_fam15h.bin
-...
-|-- intel-ucode
-...
-| |-- 06-3a-09
-...
-
-so that the build system can find those files and integrate them into
-the final kernel image. The early loader finds them and applies them.
diff --git a/Documentation/x86/microcode.txt b/Documentation/x86/microcode.txt
new file mode 100644
index 000000000000..f57e1b45e628
--- /dev/null
+++ b/Documentation/x86/microcode.txt
@@ -0,0 +1,137 @@
+ The Linux Microcode Loader
+
+Authors: Fenghua Yu <fenghua.yu@xxxxxxxxx>
+ Borislav Petkov <bp@xxxxxxx>
+
+The kernel has a x86 microcode loading facility which is supposed to
+provide microcode loading methods in the OS. Potential use cases are
+updating the microcode on platforms beyond the OEM End-Of-Life support,
+and updating the microcode on long-running systems without rebooting.
+
+The loader supports three loading methods:
+
+1. Early load microcode
+=======================
+
+The kernel can update microcode very early during boot. Loading
+microcode early can fix CPU issues before they are observed during
+kernel boot time.
+
+The microcode is stored in an initrd file. During boot, it is read from
+it and loaded into the CPU cores.
+
+The format of the combined initrd image is microcode in (uncompressed)
+cpio format followed by the (possibly compressed) initrd image. The
+loader parses the combined initrd image during boot.
+
+The microcode files in cpio name space are:
+
+on Intel: kernel/x86/microcode/GenuineIntel.bin
+on AMD : kernel/x86/microcode/AuthenticAMD.bin
+
+During BSP (BootStrapping Processor) boot (pre-SMP), the kernel
+scans the microcode file in the initrd. If microcode matching the
+CPU is found, it will be applied in the BSP and later on in all APs
+(Application Processors).
+
+The loader also saves the matching microcode for the CPU in memory.
+Thus, the cached microcode patch is applied when CPUs resume from a
+sleep state.
+
+Here's a crude example how to prepare an initrd with microcode (this is
+normally done automatically by the distribution, when recreating the
+initrd, so you don't really have to do it yourself. It is documented
+here for future reference only).
+
+---
+ #!/bin/bash
+
+ if [ -z "$1" ]; then
+ echo "You need to supply an initrd file"
+ exit 1
+ fi
+
+ INITRD="$1"
+
+ DSTDIR=kernel/x86/microcode
+ TMPDIR=/tmp/initrd
+
+ rm -rf $TMPDIR
+
+ mkdir $TMPDIR
+ cd $TMPDIR
+ mkdir -p $DSTDIR
+
+ if [ -d /lib/firmware/amd-ucode ]; then
+ cat /lib/firmware/amd-ucode/microcode_amd*.bin > $DSTDIR/AuthenticAMD.bin
+ fi
+
+ if [ -d /lib/firmware/intel-ucode ]; then
+ cat /lib/firmware/intel-ucode/* > $DSTDIR/GenuineIntel.bin
+ fi
+
+ find . | cpio -o -H newc >../ucode.cpio
+ cd ..
+ mv $INITRD $INITRD.orig
+ cat ucode.cpio $INITRD.orig > $INITRD
+
+ rm -rf $TMPDIR
+---
+
+The system needs to have the microcode packages installed into
+/lib/firmware or you need to fixup the paths above if yours are
+somewhere else and/or you've downloaded them directly from the processor
+vendor's site.
+
+2. Late loading
+===============
+
+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.
+
+The /dev/cpu/microcode method is deprecated because it needs a special
+userspace tool for that.
+
+The easier method is simply installing the microcode packages your distro
+supplies and running:
+
+# echo 1 > /sys/devices/system/cpu/microcode/reload
+
+as root.
+
+The loading mechanism looks for microcode blobs in
+/lib/firmware/{intel-ucode,amd-ucode}. The default distro installation
+packages already put them there.
+
+3. Builtin microcode
+====================
+
+The loader supports also loading of a builtin microcode supplied through
+the regular firmware builtin method CONFIG_FIRMWARE_IN_KERNEL. Only
+64-bit is currently supported.
+
+Here's an example:
+
+CONFIG_FIRMWARE_IN_KERNEL=y
+CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09 amd-ucode/microcode_amd_fam15h.bin"
+CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
+
+This basically means, you have the following tree structure locally:
+
+/lib/firmware/
+|-- amd-ucode
+...
+| |-- microcode_amd_fam15h.bin
+...
+|-- intel-ucode
+...
+| |-- 06-3a-09
+...
+
+so that the build system can find those files and integrate them into
+the final kernel image. The early loader finds them and applies them.
+
+Needless to say, this method is not the most flexible one because it
+requires rebuilding the kernel each time updated microcode from the CPU
+vendor is available.
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 21b185793c80..c6daec4bdba5 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -400,9 +400,12 @@ static void update_cache(struct ucode_patch *new_patch)

list_for_each_entry(p, &microcode_cache, plist) {
if (p->equiv_cpu == new_patch->equiv_cpu) {
- if (p->patch_id >= new_patch->patch_id)
+ if (p->patch_id >= new_patch->patch_id) {
/* we already have the latest patch */
+ kfree(new_patch->data);
+ kfree(new_patch);
return;
+ }

list_replace(&p->plist, &new_patch->plist);
kfree(p->data);
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 59edbe9d4ccb..8f7a9bbad514 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -146,18 +146,18 @@ static bool microcode_matches(struct microcode_header_intel *mc_header,
return false;
}

-static struct ucode_patch *__alloc_microcode_buf(void *data, unsigned int size)
+static struct ucode_patch *memdup_patch(void *data, unsigned int size)
{
struct ucode_patch *p;

p = kzalloc(sizeof(struct ucode_patch), GFP_KERNEL);
if (!p)
- return ERR_PTR(-ENOMEM);
+ return NULL;

p->data = kmemdup(data, size, GFP_KERNEL);
if (!p->data) {
kfree(p);
- return ERR_PTR(-ENOMEM);
+ return NULL;
}

return p;
@@ -183,8 +183,8 @@ static void save_microcode_patch(void *data, unsigned int size)
if (mc_hdr->rev <= mc_saved_hdr->rev)
continue;

- p = __alloc_microcode_buf(data, size);
- if (IS_ERR(p))
+ p = memdup_patch(data, size);
+ if (!p)
pr_err("Error allocating buffer %p\n", data);
else
list_replace(&iter->plist, &p->plist);
@@ -196,24 +196,25 @@ static void save_microcode_patch(void *data, unsigned int size)
* newly found.
*/
if (!prev_found) {
- p = __alloc_microcode_buf(data, size);
- if (IS_ERR(p))
+ p = memdup_patch(data, size);
+ if (!p)
pr_err("Error allocating buffer for %p\n", data);
else
list_add_tail(&p->plist, &microcode_cache);
}

+ if (!p)
+ return;
+
/*
* Save for early loading. On 32-bit, that needs to be a physical
* address as the APs are running from physical addresses, before
* paging has been enabled.
*/
- if (p) {
- if (IS_ENABLED(CONFIG_X86_32))
- intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
- else
- intel_ucode_patch = p->data;
- }
+ if (IS_ENABLED(CONFIG_X86_32))
+ intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
+ else
+ intel_ucode_patch = p->data;
}

static int microcode_sanity_check(void *mc, int print_err)