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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2013-06-25 20:28:59 +0200 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2013-06-25 22:53:27 +0200 |
| commit | 0644414e62561f0ba1bea7c5ba6a94cc50dac3e3 (patch) | |
| tree | deb10365752b0959a3429bb1e19b6d785d354cbc /arch/x86 | |
| parent | Linux 3.10-rc7 (diff) | |
| download | linux-0644414e62561f0ba1bea7c5ba6a94cc50dac3e3.tar.xz linux-0644414e62561f0ba1bea7c5ba6a94cc50dac3e3.zip | |
mce: acpi/apei: Add comments to clarify usage of the various bitfields in the MCA subsystem
There is some confusion about the 'mce_poll_banks' and 'mce_banks_owned'
per-cpu bitmaps. Provide comments so that we all know exactly what these
are used for, and why.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/mcheck/mce.c | 5 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/mcheck/mce_intel.c | 12 |
2 files changed, 16 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 9239504b41cb..bf49cdbb010f 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -89,7 +89,10 @@ static DECLARE_WAIT_QUEUE_HEAD(mce_chrdev_wait); static DEFINE_PER_CPU(struct mce, mces_seen); static int cpu_missing; -/* MCA banks polled by the period polling timer for corrected events */ +/* + * MCA banks polled by the period polling timer for corrected events. + * With Intel CMCI, this only has MCA banks which do not support CMCI (if any). + */ DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = { [0 ... BITS_TO_LONGS(MAX_NR_BANKS)-1] = ~0UL }; diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel.c b/arch/x86/kernel/cpu/mcheck/mce_intel.c index ae1697c2afe3..d56405309dc1 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_intel.c +++ b/arch/x86/kernel/cpu/mcheck/mce_intel.c @@ -24,6 +24,18 @@ * Also supports reliable discovery of shared banks. */ +/* + * CMCI can be delivered to multiple cpus that share a machine check bank + * so we need to designate a single cpu to process errors logged in each bank + * in the interrupt handler (otherwise we would have many races and potential + * double reporting of the same error). + * Note that this can change when a cpu is offlined or brought online since + * some MCA banks are shared across cpus. When a cpu is offlined, cmci_clear() + * disables CMCI on all banks owned by the cpu and clears this bitfield. At + * this point, cmci_rediscover() kicks in and a different cpu may end up + * taking ownership of some of the shared MCA banks that were previously + * owned by the offlined cpu. + */ static DEFINE_PER_CPU(mce_banks_t, mce_banks_owned); /* |