Commit dc97d8b7 authored by Xie XiuQi's avatar Xie XiuQi Committed by Luis Henriques

x86/mce: Reenable CMCI banks when swiching back to interrupt mode

commit 1b484655 upstream.

Zhang Liguang reported the following issue:

1) System detects a CMCI storm on the current CPU.

2) Kernel disables the CMCI interrupt on banks owned by the
   current CPU and switches to poll mode

3) After the CMCI storm subsides, kernel switches back to
   interrupt mode

4) We expect the system to reenable the CMCI interrupt on banks
   owned by the current CPU

   mce_intel_adjust_timer
   |-> cmci_reenable
       |-> cmci_discover     # owned banks are ignored here

  static void cmci_discover(int banks)
	...
	for (i = 0; i < banks; i++) {
		...
		if (test_bit(i, owned))	# ownd banks is ignore here
			continue;

So convert cmci_storm_disable_banks() to
cmci_toggle_interrupt_mode() which controls whether to enable or
disable CMCI interrupts with its argument.

NB: We cannot clear the owned bit because the banks won't be
polled, otherwise. See:

  27f6c573 ("x86, CMCI: Add proper detection of end of CMCI storms")

for more info.
Reported-by: default avatarZhang Liguang <zhangliguang@huawei.com>
Signed-off-by: default avatarXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: huawei.libin@huawei.com
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: rui.xiang@huawei.com
Link: http://lkml.kernel.org/r/1439396985-12812-10-git-send-email-bp@alien8.deSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
[ luis: backported to 3.16:
  - use __get_cpu_var() instead of this_cpu_ptr()
  - adjusted context ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 325bc3cb
......@@ -97,6 +97,27 @@ void mce_intel_hcpu_update(unsigned long cpu)
per_cpu(cmci_storm_state, cpu) = CMCI_STORM_NONE;
}
static void cmci_toggle_interrupt_mode(bool on)
{
unsigned long flags, *owned;
int bank;
u64 val;
raw_spin_lock_irqsave(&cmci_discover_lock, flags);
owned = __get_cpu_var(mce_banks_owned);
for_each_set_bit(bank, owned, MAX_NR_BANKS) {
rdmsrl(MSR_IA32_MCx_CTL2(bank), val);
if (on)
val |= MCI_CTL2_CMCI_EN;
else
val &= ~MCI_CTL2_CMCI_EN;
wrmsrl(MSR_IA32_MCx_CTL2(bank), val);
}
raw_spin_unlock_irqrestore(&cmci_discover_lock, flags);
}
unsigned long mce_intel_adjust_timer(unsigned long interval)
{
int r;
......@@ -125,7 +146,7 @@ unsigned long mce_intel_adjust_timer(unsigned long interval)
*/
if (!atomic_read(&cmci_storm_on_cpus)) {
__this_cpu_write(cmci_storm_state, CMCI_STORM_NONE);
cmci_reenable();
cmci_toggle_interrupt_mode(true);
cmci_recheck();
}
return CMCI_POLL_INTERVAL;
......@@ -138,22 +159,6 @@ unsigned long mce_intel_adjust_timer(unsigned long interval)
}
}
static void cmci_storm_disable_banks(void)
{
unsigned long flags, *owned;
int bank;
u64 val;
raw_spin_lock_irqsave(&cmci_discover_lock, flags);
owned = __get_cpu_var(mce_banks_owned);
for_each_set_bit(bank, owned, MAX_NR_BANKS) {
rdmsrl(MSR_IA32_MCx_CTL2(bank), val);
val &= ~MCI_CTL2_CMCI_EN;
wrmsrl(MSR_IA32_MCx_CTL2(bank), val);
}
raw_spin_unlock_irqrestore(&cmci_discover_lock, flags);
}
static bool cmci_storm_detect(void)
{
unsigned int cnt = __this_cpu_read(cmci_storm_cnt);
......@@ -175,7 +180,7 @@ static bool cmci_storm_detect(void)
if (cnt <= CMCI_STORM_THRESHOLD)
return false;
cmci_storm_disable_banks();
cmci_toggle_interrupt_mode(false);
__this_cpu_write(cmci_storm_state, CMCI_STORM_ACTIVE);
r = atomic_add_return(1, &cmci_storm_on_cpus);
mce_timer_kick(CMCI_POLL_INTERVAL);
......
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