[PATCH 3.18 13/27] x86/microcode/intel: Disable late loading on model 79

Greg Kroah-Hartman
2017-11-06T11:29:16Z

From: Borislav Petkov <bp@suse.de>

commit 723f2828a98c8ca19842042f418fb30dd8cfc0f7 upstream.

Blacklist Broadwell X model 79 for late loading due to an erratum.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Tony Luck <tony.luck@intel.com>
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/20171018111225.25635-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kernel/cpu/microcode/intel.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -267,6 +267,18 @@ static int get_ucode_fw(void *to, const
return 0;
}

+static bool is_blacklisted(unsigned int cpu)
+{
+ struct cpuinfo_x86 *c = &cpu_data(cpu);
+
+ if (c->x86 == 6 && c->x86_model == 79) {
+ pr_err_once("late loading on model 79 is disabled.\n");
+ return true;
+ }
+
+ return false;
+}
+
static enum ucode_state request_microcode_fw(int cpu, struct device *device,
bool refresh_fw)
{
@@ -275,6 +287,9 @@ static enum ucode_state request_microcod
const struct firmware *firmware;
enum ucode_state ret;

+ if (is_blacklisted(cpu))
+ return UCODE_NFOUND;
+
sprintf(name, "intel-ucode/%02x-%02x-%02x",
c->x86, c->x86_model, c->x86_mask);

@@ -299,6 +314,9 @@ static int get_ucode_user(void *to, cons
static enum ucode_state
request_microcode_user(int cpu, const void __user *buf, size_t size)
{
+ if (is_blacklisted(cpu))
+ return UCODE_NFOUND;
+
return generic_load_microcode(cpu, (void *)buf, size, &get_ucode_user);
}