Commit Graph

11 Commits

Author SHA1 Message Date
Andi Kleen 88ccbedd9c x86, mce, cmci: add CMCI support
Impact: Major new feature

Intel CMCI (Corrected Machine Check Interrupt) is a new
feature on Nehalem CPUs. It allows the CPU to trigger
interrupts on corrected events, which allows faster
reaction to them instead of with the traditional
polling timer.

Also use CMCI to discover shared banks. Machine check banks
can be shared by CPU threads or even cores. Using the CMCI enable
bit it is possible to detect the fact that another CPU already
saw a specific bank. Use this to assign shared banks only
to one CPU to avoid reporting duplicated events.

On CPU hot unplug bank sharing is re discovered. This is done
using a thread that cycles through all the CPUs.

To avoid races between the poller and CMCI we only poll
for banks that are not CMCI capable and only check CMCI
owned banks on a interrupt.

The shared banks ownership information is currently only used for
CMCI interrupts, not polled banks.

The sharing discovery code follows the algorithm recommended in the
IA32 SDM Vol3a 14.5.2.1

The CMCI interrupt handler just calls the machine check poller to
pick up the machine check event that caused the interrupt.

I decided not to implement a separate threshold event like
the AMD version has, because the threshold is always one currently
and adding another event didn't seem to add any value.

Some code inspired by Yunhong Jiang's Xen implementation,
which was in term inspired by a earlier CMCI implementation
by me.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:41:00 -08:00
Andi Kleen 03195c6b40 x86, mce, cmci: define MSR names and fields for new CMCI registers
Impact: New register definitions only

CMCI means support for raising an interrupt on a corrected machine
check event instead of having to poll for it. It's a new feature in
Intel Nehalem CPUs available on some machine check banks.

For details see the IA32 SDM Vol3a 14.5

Define the registers for it as a preparation for further patches.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:41:00 -08:00
Andi Kleen ee031c31d6 x86, mce, cmci: use polled banks bitmap in machine check poller
Define a per cpu bitmap that contains the banks polled by the machine
check poller. This is needed for the CMCI code in the next patches
to be able to disable polling on specific banks.

The bank by default contains all banks, so there is no behaviour
change. Only future code will remove some banks from the polling
set.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:26:05 -08:00
Andi Kleen b276268631 x86, mce, cmci: factor out threshold interrupt handler
Impact: cleanup; preparation for feature

The mce_amd_64 code has an own private MC threshold vector with an own
interrupt handler. Since Intel needs a similar handler
it makes sense to share the vector because both can not
be active at the same time.

I factored the common APIC handler code into a separate file which can
be used by both the Intel or AMD MC code.

This is needed for the next patch which adds an Intel specific
CMCI handler.

This patch should be a nop for AMD, it just moves some code
around.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:24:42 -08:00
Andi Kleen 41fdff322e x86, mce, cmci: export MAX_NR_BANKS
Impact: Cleanup (code movement)

Move MAX_NR_BANKS into mce.h because it's needed there
for followup patches.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:24:42 -08:00
Andi Kleen b79109c3bb x86, mce: separate correct machine check poller and fatal exception handler
Impact: cleanup, performance enhancement

The machine check poller is diverging more and more from the fatal
exception handler. Instead of adding more special cases separate the code
paths completely. The corrected poll path is actually quite simple,
and this doesn't result in much code duplication.

This makes both handlers much easier to read and results in
cleaner code flow.  The exception handler now only needs to care
about uncorrected errors, which also simplifies the handling of multiple
errors. The corrected poller also now always runs in standard interrupt
context and does not need to do anything special to handle NMI context.

Minor behaviour changes:
- MCG status is now not cleared on polling.
- Only the banks which had corrected errors get cleared on polling
- The exception handler only clears banks with errors now

v2: Forward port to new patch order. Add "uc" argument.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-02-19 14:52:20 -08:00
Andi Kleen b5f2fa4ea0 x86, mce: factor out duplicated struct mce setup into one function
Impact: cleanup

This merely factors out duplicated code to set up
the initial struct mce state into a single function.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-02-19 14:51:39 -08:00
Andi Kleen 123aa76ec0 x86, mce: don't disable machine checks during code patching
Impact: low priority bug fix

This removes part of a a patch I added myself some time ago. After some
consideration the patch was a bad idea. In particular it stopped machine check
exceptions during code patching.

To quote the comment:

        * MCEs only happen when something got corrupted and in this
        * case we must do something about the corruption.
        * Ignoring it is worse than a unlikely patching race.
        * Also machine checks tend to be broadcast and if one CPU
        * goes into machine check the others follow quickly, so we don't
        * expect a machine check to cause undue problems during to code
        * patching.

So undo the machine check related parts of
8f4e956b31 NMIs are still disabled.

This only removes code, the only additions are a new comment.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-17 15:32:38 -08:00
Jaswinder Singh Rajput 999b697b9d headers_check fix: x86, mce.h
fix the following 'make headers_check' warnings:

  usr/include/asm/mce.h:7: include of <linux/types.h> is preferred over <asm/types.h>
  usr/include/asm/mce.h:29: found __[us]{8,16,32,64} type without #include <linux/types.h>

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
2009-01-31 00:17:13 +05:30
H. Peter Anvin 1965aae3c9 x86: Fix ASM_X86__ header guards
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-22 22:55:23 -07:00
Al Viro bb8985586b x86, um: ... and asm-x86 move
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-22 22:55:20 -07:00