linux-stable.git/arch/x86/kernel/cpu/microcode, branch linux-3.19.y

x86, microcode: Return error from driver init code when loader is disabled

2015-01-28T08:23:40+00:00

Commits 65cef1311d5d ("x86, microcode: Add a disable chicken bit") and
a18a0f6850d4 ("x86, microcode: Don't initialize microcode code on
paravirt") allow microcode driver skip initialization when microcode
loading is not permitted.

However, they don't prevent the driver from being loaded since the
init code returns 0. If at some point later the driver gets unloaded
this will result in an oops while trying to deregister the (never
registered) device.

To avoid this, make init code return an error on paravirt or when
microcode loading is disabled. The driver will then never be loaded.

Signed-off-by: Boris Ostrovsky 
Link: http://lkml.kernel.org/r/1422411669-25147-1-git-send-email-boris.ostrovsky@oracle.com
Reported-by: James Digwall 
Cc: stable@vger.kernel.org # 3.18
Signed-off-by: Borislav Petkov

x86/microcode/intel: Fish out the stashed microcode for the BSP

2014-12-10T10:36:28+00:00

I'm such a moron! The simple solution of saving the BSP patch
for use on resume was too simple (and wrong!), hint:
sizeof(struct microcode_intel).

What needs to be done instead is to fish out the microcode patch
we have stashed previously and apply that on the BSP in case the
late loader hasn't been utilized.

So do that instead.

Signed-off-by: Borislav Petkov 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/20141208110820.GB20057@pd.tnic
Signed-off-by: Ingo Molnar

x86, microcode: Reload microcode on resume

2014-12-06T12:03:03+00:00

Normally, we do reapply microcode on resume. However, in the cases where
that microcode comes from the early loader and the late loader hasn't
been utilized yet, there's no easy way for us to go and apply the patch
applied during boot by the early loader.

Thus, reuse the patch stashed by the early loader for the BSP.

Signed-off-by: Borislav Petkov

x86, microcode: Don't initialize microcode code on paravirt

2014-12-06T11:59:03+00:00

Paravirtual guests are not expected to load microcode into processors
and therefore it is not necessary to initialize microcode loading
logic.

In fact, under certain circumstances initializing this logic may cause
the guest to crash. Specifically, 32-bit kernels use __pa_nodebug()
macro which does not work in Xen (the code path that leads to this macro
happens during resume when we call mc_bp_resume()->load_ucode_ap()
->check_loader_disabled_ap())

Signed-off-by: Boris Ostrovsky 
Link: http://lkml.kernel.org/r/1417469264-31470-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Borislav Petkov

x86, microcode, intel: Drop unused parameter

2014-12-06T11:58:56+00:00

apply_microcode_early() doesn't use mc_saved_data, kill it.

Signed-off-by: Borislav Petkov

x86, microcode, AMD: Do not use smp_processor_id() in preemtible context

2014-12-01T10:51:05+00:00

Hand down the cpu number instead, otherwise lockdep screams when doing

echo 1 > /sys/devices/system/cpu/microcode/reload.

BUG: using smp_processor_id() in preemptible [00000000] code: amd64-microcode/2470
caller is debug_smp_processor_id+0x12/0x20
CPU: 1 PID: 2470 Comm: amd64-microcode Not tainted 3.18.0-rc6+ #26
...

Signed-off-by: Borislav Petkov 
Link: http://lkml.kernel.org/r/1417428741-4501-1-git-send-email-bp@alien8.de
Signed-off-by: Thomas Gleixner

x86, microcode: Update BSPs microcode on resume

2014-11-18T17:32:24+00:00

In the situation when we apply early microcode but do *not* apply late
microcode, we fail to update the BSP's microcode on resume because we
haven't initialized the uci->mc microcode pointer. So, in order to
alleviate that, we go and dig out the stashed microcode patch during
early boot. It is basically the same thing that is done on the APs early
during boot so do that too here.

Tested-by: alex.schnaidt@gmail.com
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=88001
Cc: Henrique de Moraes Holschuh 
Cc: Fenghua Yu 
Cc:  # v3.9
Signed-off-by: Borislav Petkov 
Link: http://lkml.kernel.org/r/20141118094657.GA6635@pd.tnic
Signed-off-by: Thomas Gleixner

x86, microcode, AMD: Fix ucode patch stashing on 32-bit

2014-11-10T12:50:55+00:00

Save the patch while we're running on the BSP instead of later, before
the initrd has been jettisoned. More importantly, on 32-bit we need to
access the physical address instead of the virtual.

This way we actually do find it on the APs instead of having to go
through the initrd each time.

Tested-by: Richard Hendershot 
Fixes: 5335ba5cf475 ("x86, microcode, AMD: Fix early ucode loading")
Cc:  # v3.13+
Signed-off-by: Borislav Petkov

x86, microcode: Fix accessing dis_ucode_ldr on 32-bit

2014-11-05T16:28:06+00:00

We should be accessing it through a pointer, like on the BSP.

Tested-by: Richard Hendershot 
Fixes: 65cef1311d5d ("x86, microcode: Add a disable chicken bit")
Cc:  # v3.15+
Signed-off-by: Borislav Petkov

x86, microcode, AMD: Fix early ucode loading on 32-bit

2014-11-01T19:24:21+00:00

Konrad triggered the following splat below in a 32-bit guest on an AMD
box. As it turns out, in save_microcode_in_initrd_amd() we're using the
*physical* address of the container *after* we have enabled paging and
thus we #PF in load_microcode_amd() when trying to access the microcode
container in the ramdisk range.

Because the ramdisk is exactly there:

[    0.000000] RAMDISK: [mem 0x35e04000-0x36ef9fff]

and we fault at 0x35e04304.

And since this guest doesn't relocate the ramdisk, we don't do the
computation which will give us the correct virtual address and we end up
with the PA.

So, we should actually be using virtual addresses on 32-bit too by the
time we're freeing the initrd. Do that then!

Unpacking initramfs...
BUG: unable to handle kernel paging request at 35d4e304
IP: [] load_microcode_amd+0x25/0x4a0
*pde = 00000000
Oops: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.17.1-302.fc21.i686 #1
Hardware name: Xen HVM domU, BIOS 4.4.1 10/01/2014
task: f5098000 ti: f50d0000 task.ti: f50d0000
EIP: 0060:[] EFLAGS: 00010246 CPU: 0
EIP is at load_microcode_amd+0x25/0x4a0
EAX: 00000000 EBX: f6e9ec4c ECX: 00001ec4 EDX: 00000000
ESI: f5d4e000 EDI: 35d4e2fc EBP: f50d1ed0 ESP: f50d1e94
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
CR0: 8005003b CR2: 35d4e304 CR3: 00e33000 CR4: 000406d0
Stack:
 00000000 00000000 f50d1ebc f50d1ec4 f5d4e000 c0d7735a f50d1ed0 15a3d17f
 f50d1ec4 00600f20 00001ec4 bfb83203 f6e9ec4c f5d4e000 c0d7735a f50d1ed8
 c0d80861 f50d1ee0 c0d80429 f50d1ef0 c0d889a9 f5d4e000 c0000000 f50d1f04
Call Trace:
? unpack_to_rootfs
? unpack_to_rootfs
save_microcode_in_initrd_amd
save_microcode_in_initrd
free_initrd_mem
populate_rootfs
? unpack_to_rootfs
do_one_initcall
? unpack_to_rootfs
? repair_env_string
? proc_mkdir
kernel_init_freeable
kernel_init
ret_from_kernel_thread
? rest_init

Reported-and-tested-by: Konrad Rzeszutek Wilk 
References: https://bugzilla.redhat.com/show_bug.cgi?id=1158204
Fixes: 75a1ba5b2c52 ("x86, microcode, AMD: Unify valid container checks")
Signed-off-by: Borislav Petkov 
Cc:  # v3.14+
Link: http://lkml.kernel.org/r/20141101100100.GA4462@pd.tnic
Signed-off-by: Thomas Gleixner