When doing
echo 1 > /sys/devices/system/cpu/microcode/reload
in order to reload microcode, I get:
microcode: Total microcode saved: 1
BUG: using smp_processor_id() in preemptible [00000000] code: bash/2606
caller is debug_smp_processor_id+0x17/0x20
CPU: 1 PID: 2606 Comm: bash Not tainted 3.19.0-rc7+ #9
Hardware name: LENOVO 2320CTO/2320CTO, BIOS G2ET86WW (2.06 ) 11/13/2012
ffffffff81a4266d ffff8802131db808 ffffffff81666588 0000000000000007
0000000000000001 ffff8802131db838 ffffffff812e6eef ffff8802131db868
00000000000306a9 0000000000000010 0000000000000015 ffff8802131db848
Call Trace:
dump_stack
check_preemption_disabled
debug_smp_processor_id
show_saved_mc
? save_microcode.constprop.8
save_mc_for_early
? print_context_stack
? dump_trace
? __bfs
? mark_held_locks
? get_page_from_freelist
? trace_hardirqs_on_caller
? trace_hardirqs_on
? __alloc_pages_nodemask
? __get_vm_area_node
? map_vm_area
? __vmalloc_node_range
? generic_load_microcode
generic_load_microcode
? microcode_fini_cpu
request_microcode_fw
reload_store
dev_attr_store
sysfs_kf_write
kernfs_fop_write
vfs_write
? sysret_check
SyS_write
system_call_fastpath
microcode: CPU1: sig=0x306a9, pf=0x10, rev=0x15
microcode: mc_saved[0]: sig=0x306a9, pf=0x12, rev=0x1b, toal size=0x3000, date = 2014-05-29
because we're using smp_processor_id() in preemtible context. And we
don't really need to use it there because the microcode container we're
dumping is global and CPU-specific info is irrelevant.
While at it, make pr_* stuff use "microcode: " prefix for easier
grepping and document how to enable the DEBUG build.
Signed-off-by: Borislav Petkov <bp@suse.de>
... arguments list so that it comes more natural for those functions to
have the signature, processor flags and revision together, before the
rest of the args.
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
* remove state variable and out label
* get rid of completely unused mc_size
* shorten variable names
* get rid of local variables
* don't do assignments in local var declarations for less cluttered code
* finally rename it to the shorter and perfectly fine load_microcode_early()
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
... to the header. Split the family acquiring function into a
main one, doing CPUID and a helper which computes the extended
family and is used in multiple places. Get rid of the locally-grown
get_x86_{family,model}().
While at it, rename local variables to something more descriptive and
vertically align assignments for better readability.
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <bp@suse.de>
Shorten local variable names for better readability and flatten loop
indentation levels.
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
... of microcode patches instead of handing in a pointer which is used
for I/O in an otherwise void function.
Signed-off-by: Borislav Petkov <bp@suse.de>
Don't compute start and end from start and size in order to compute size
again down the path in scan_microcode(). So pass size directly instead
and simplify a bunch. Shorten variable names and remove useless ones.
Signed-off-by: Borislav Petkov <bp@suse.de>
... and only then deref it. Also, shorten some variable names and rename
others so as to diminish the ubiquitous presence of the "mc_" prefix
everywhere and make it a bit more readable.
Use kcalloc so that we don't kfree() uninitialized memory on the unwind
path, as suggested by Quentin.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
We should check the return value of the routines fishing out the proper
microcode and not try to apply if we haven't found a suitable blob.
Signed-off-by: Borislav Petkov <bp@suse.de>
Pull microcode fixes from Borislav Petkov:
- Two fixes hardening microcode data handling. (Quentin Casasnovas)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commits 65cef1311d ("x86, microcode: Add a disable chicken bit") and
a18a0f6850 ("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 <boris.ostrovsky@oracle.com>
Link: http://lkml.kernel.org/r/1422411669-25147-1-git-send-email-boris.ostrovsky@oracle.com
Reported-by: James Digwall <james@dingwall.me.uk>
Cc: stable@vger.kernel.org # 3.18
Signed-off-by: Borislav Petkov <bp@suse.de>
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 <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20141208110820.GB20057@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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 <bp@suse.de>
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 <boris.ostrovsky@oracle.com>
Link: http://lkml.kernel.org/r/1417469264-31470-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Borislav Petkov <bp@suse.de>
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 <bp@suse.de>
Link: http://lkml.kernel.org/r/1417428741-4501-1-git-send-email-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
