The file Documentation/x86/early-microcode.txt was renamed to
Documentation/x86/microcode.txt in 0e3258753f, but it was still
referenced by its old name in a three places:
* Documentation/x86/00-INDEX
* arch/x86/Kconfig
* arch/x86/kernel/cpu/microcode/amd.c
This commit updates these references accordingly.
Fixes: 0e3258753f ("x86/microcode: Document the three loading methods")
Signed-off-by: Jaak Ristioja <jaak@ristioja.ee>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
verify_and_add_patch() allocates memory for a microcode patch and hands
it down to be added to the cache of patches. However, if the cache
already has the latest patch, the newly allocated one needs to be freed
before returning. Do that.
This issue has been found by kmemleak:
unreferenced object 0xffff88010e780b40 (size 32):
comm "bash", pid 860, jiffies 4294690939 (age 29.297s)
backtrace:
kmemleak_alloc
kmem_cache_alloc_trace
load_microcode_amd.isra.0
request_microcode_amd
reload_store
dev_attr_store
sysfs_kf_write
kernfs_fop_write
__vfs_write
vfs_write
SyS_write
do_syscall_64
return_from_SYSCALL_64
0xffffffffffffffff
(gdb) list *0xffffffff81050d60
0xffffffff81050d60 is in load_microcode_amd
(arch/x86/kernel/cpu/microcode/amd.c:616).
which is this:
patch = kzalloc(sizeof(*patch), GFP_KERNEL);
--> if (!patch) {
pr_err("Patch allocation failure.\n");
return -EINVAL;
}
Signed-off-by: Shu Wang <shuwang@redhat.com>
[ Rewrite commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: chuhu@redhat.com
Cc: liwang@redhat.com
Link: http://lkml.kernel.org/r/20170724101228.17326-2-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The helper function __load_ucode_amd() and pointer intel_ucode_patch do
not need to be in global scope, so make them static.
Fixes those sparse warnings:
"symbol '__load_ucode_amd' was not declared. Should it be static?"
"symbol 'intel_ucode_patch' was not declared. Should it be static?"
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170622095736.11937-1-colin.king@canonical.com
With CONFIG_DEBUG_PREEMPT enabled, I get:
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is debug_smp_processor_id
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc2+ #2
Call Trace:
dump_stack
check_preemption_disabled
debug_smp_processor_id
save_microcode_in_initrd_amd
? microcode_init
save_microcode_in_initrd
...
because, well, it says it above, we're using smp_processor_id() in
preemptible code.
But passing the CPU number is not really needed. It is only used to
determine whether we're on the BSP, and, if so, to save the microcode
patch for early loading.
[ We don't absolutely need to do it on the BSP but we do that
customarily there. ]
Instead, convert that function parameter to a boolean which denotes
whether the patch should be saved or not, thereby avoiding the use of
smp_processor_id() in preemptible code.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170528200414.31305-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The equivalence ID was needed outside of the container scanning logic
but now, after this has been cleaned up, not anymore. Now, cont_desc.mc
is used to denote whether the container we're looking at has the proper
microcode patch for this CPU or not.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-17-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The idea was to not scan the microcode blob on each AP (Application
Processor) during boot and thus save us some milliseconds. However, on
architectures where the microcode engine is shared between threads, this
doesn't work. Here's why:
The microcode on CPU0, i.e., the first thread, gets updated. The second
thread, i.e., CPU1, i.e., the first AP walks into load_ucode_amd_ap(),
sees that there's no container cached and goes and scans for the proper
blob.
It finds it and as a last step of apply_microcode_early_amd(), it tries
to apply the patch but that core has already the updated microcode
revision which it has received through CPU0's update. So it returns
false and we do desc->size = -1 to prevent other APs from scanning.
However, the next AP, CPU2, has a different microcode engine which
hasn't been updated yet. The desc->size == -1 test prevents it from
scanning the blob anew and we fail to update it.
The fix is much more straight-forward than it looks: the BSP
(BootStrapping Processor), i.e., CPU0, caches the microcode patch
in amd_ucode_patch. We use that on the AP and try to apply it.
In the 99.9999% of cases where we have homogeneous cores - *not*
mixed-steppings - the application will be successful and we're good to
go.
In the remaining small set of systems, we will simply rescan the blob
and find (or not, if none present) the proper patch and apply it then.
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-16-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
It was pretty clumsy before and the whole work of parsing the microcode
containers was spread around the functions wrongly.
Clean it up so that there's a main scan_containers() function which
iterates over the microcode blob and picks apart the containers glued
together. For each container, it calls a parse_container() helper which
concentrates on one container only: sanity-checking, parsing, counting
microcode patches in there, etc.
It makes much more sense now and it is actually very readable. Oh, and
we luvz a diffstat removing more crap than adding.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-8-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Make it into a container descriptor which is being passed around and
stores important info like the matching container and the patch for the
current CPU. Make it static too.
Later patches will use this and thus get rid of a double container
parsing.
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-7-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
No need to have it marked "inline" - let gcc decide. Also, shorten the
argument name and simplify while-test.
While at it, make it into a proper for-loop and simplify it even more,
as tglx suggests.
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-5-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
