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  1. 01 11月, 2015 2 次提交
  3. 28 9月, 2015 1 次提交
    • A
      x86/mce: Don't clear shared banks on Intel when offlining CPUs · 6e06780a
      由 Ashok Raj 提交于 
      It is not safe to clear global MCi_CTL banks during CPU offline
or suspend/resume operations. These MSRs are either
thread-scoped (meaning private to a thread), or core-scoped
(private to threads in that core only), or with a socket scope:
visible and controllable from all threads in the socket.

When we offline a single CPU, clearing those MCi_CTL bits will
stop signaling for all the shared, i.e., socket-wide resources,
such as LLC, iMC, etc.

In addition, it might be possible to compromise the integrity of
an Intel Secure Guard eXtentions (SGX) system if the attacker
has control of the host system and is able to inject errors
which would be otherwise ignored when MCi_CTL bits are cleared.

Hence on SGX enabled systems, if MCi_CTL is cleared, SGX gets
disabled.
Tested-by: NSerge Ayoun <serge.ayoun@intel.com>
Signed-off-by: NAshok Raj <ashok.raj@intel.com>
[ Cleanup text. ]
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NTony Luck <tony.luck@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
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: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1441391390-16985-1-git-send-email-ashok.raj@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      6e06780a
  5. 13 8月, 2015 8 次提交
  7. 23 7月, 2015 1 次提交
  9. 07 7月, 2015 1 次提交
    • A
      x86/entry: Remove exception_enter() from most trap handlers · 8c84014f
      由 Andy Lutomirski 提交于 
      On 64-bit kernels, we don't need it any more: we handle context
tracking directly on entry from user mode and exit to user mode.

On 32-bit kernels, we don't support context tracking at all, so
these callbacks had no effect.

Note: this doesn't change do_page_fault().  Before we do that,
we need to make sure that there is no code that can page fault
from kernel mode with CONTEXT_USER.  The 32-bit fast system call
stack argument code is the only offender I'm aware of right now.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/ae22f4dfebd799c916574089964592be218151f9.1435952415.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      8c84014f
  11. 06 7月, 2015 2 次提交
  13. 07 6月, 2015 2 次提交
  15. 28 5月, 2015 2 次提交
  17. 27 5月, 2015 1 次提交
  19. 18 5月, 2015 1 次提交
    • B
      x86/mce: Fix MCE severity messages · 17fea54b
      由 Borislav Petkov 提交于 
      Derek noticed that a critical MCE gets reported with the wrong
error type description:

  [Hardware Error]: CPU 34: Machine Check Exception: 5 Bank 9: f200003f000100b0
  [Hardware Error]: RIP !INEXACT! 10:<ffffffff812e14c1> {intel_idle+0xb1/0x170}
  [Hardware Error]: TSC 49587b8e321cb
  [Hardware Error]: PROCESSOR 0:306e4 TIME 1431561296 SOCKET 1 APIC 29
  [Hardware Error]: Some CPUs didn't answer in synchronization
  [Hardware Error]: Machine check: Invalid
				   ^^^^^^^

The last line with 'Invalid' should have printed the high level
MCE error type description we get from mce_severity, i.e.
something like:

  [Hardware Error]: Machine check: Action required: data load error in a user process

this happens due to the fact that mce_no_way_out() iterates over
all MCA banks and possibly overwrites the @msg argument which is
used in the panic printing later.

Change behavior to take the message of only and the (last)
critical MCE it detects.
Reported-by: NDerek <denc716@gmail.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
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>
Link: http://lkml.kernel.org/r/1431936437-25286-3-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      17fea54b
  21. 07 5月, 2015 1 次提交
    • A
      x86/mce: Add support for deferred errors on AMD · 7559e13f
      由 Aravind Gopalakrishnan 提交于 
      Deferred errors indicate error conditions that were not corrected, but
those errors have not been consumed yet. They require no action from
S/W (or action is optional). These errors provide info about a latent
uncorrectable MCE that can occur when a poisoned data is consumed by the
processor.

Newer AMD processors can generate deferred errors and can be configured
to generate APIC interrupts on such events.

SUCCOR stands for S/W UnCorrectable error COntainment and Recovery.
It indicates support for data poisoning in HW and deferred error
interrupts.

Add new bitfield to mce_vendor_flags for this. We use this to verify
presence of deferred error interrupts before we enable them in mce_amd.c

While at it, clarify comments in mce_vendor_flags to provide an
indication of usages of the bitfields.
Signed-off-by: NAravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1430913538-1415-4-git-send-email-Aravind.Gopalakrishnan@amd.com
[ beef up commit message, do CPUID(8000_0007) only once. ]
Signed-off-by: NBorislav Petkov <bp@suse.de>
      7559e13f
  23. 24 3月, 2015 2 次提交
  25. 23 3月, 2015 2 次提交
  27. 19 2月, 2015 2 次提交
  29. 10 2月, 2015 1 次提交
    • T
      x86/mce: Fix regression. All error records should report via /dev/mcelog · a2413d8b
      由 Tony Luck 提交于 
      I'm getting complaints from validation teams that have updated their
Linux kernels from ancient versions to current. They don't see the
error logs they expect. I tell the to unload any EDAC drivers[1], and
things start working again.  The problem is that we short-circuit
the logging process if any function on the decoder chain claims to
have dealt with the problem:

	ret = atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);
	if (ret == NOTIFY_STOP)
		return;

The logic we used when we added this code was that we did not want
to confuse users with double reports of the same error.

But it turns out users are not confused - they are upset that they
don't see a log where their tools used to find a log.

I could also get into a long description of how the consumer of this
log does more than just decode model specific details of the error.
It keeps counts, tracks thresholds, takes actions and runs scripts
that can alert administrators to problems.

[1] We've recently compounded the problem because the acpi_extlog
driver also registers for this notifier and also returns NOTIFY_STOP.
Signed-off-by: NTony Luck <tony.luck@intel.com>
      a2413d8b
  31. 04 2月, 2015 1 次提交
  33. 07 1月, 2015 1 次提交
  35. 03 1月, 2015 1 次提交
    • A
      x86, traps: Track entry into and exit from IST context · 95927475
      由 Andy Lutomirski 提交于 
      We currently pretend that IST context is like standard exception
context, but this is incorrect.  IST entries from userspace are like
standard exceptions except that they use per-cpu stacks, so they are
atomic.  IST entries from kernel space are like NMIs from RCU's
perspective -- they are not quiescent states even if they
interrupted the kernel during a quiescent state.

Add and use ist_enter and ist_exit to track IST context.  Even
though x86_32 has no IST stacks, we track these interrupts the same
way.

This fixes two issues:

 - Scheduling from an IST interrupt handler will now warn.  It would
   previously appear to work as long as we got lucky and nothing
   overwrote the stack frame.  (I don't know of any bugs in this
   that would trigger the warning, but it's good to be on the safe
   side.)

 - RCU handling in IST context was dangerous.  As far as I know,
   only machine checks were likely to trigger this, but it's good to
   be on the safe side.

Note that the machine check handlers appears to have been missing
any context tracking at all before this patch.

Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
      95927475
  37. 23 12月, 2014 2 次提交
  39. 08 12月, 2014 1 次提交
  41. 20 11月, 2014 2 次提交
    • C
      x86, mce: Support memory error recovery for both UCNA and Deferred error in machine_check_poll · fa92c586
      由 Chen Yucong 提交于 
      Uncorrected no action required (UCNA) - is a uncorrected recoverable
machine check error that is not signaled via a machine check exception
and, instead, is reported to system software as a corrected machine
check error. UCNA errors indicate that some data in the system is
corrupted, but the data has not been consumed and the processor state
is valid and you may continue execution on this processor. UCNA errors
require no action from system software to continue execution. Note that
UCNA errors are supported by the processor only when IA32_MCG_CAP[24]
(MCG_SER_P) is set.
                                               -- Intel SDM Volume 3B

Deferred errors are errors that cannot be corrected by hardware, but
do not cause an immediate interruption in program flow, loss of data
integrity, or corruption of processor state. These errors indicate
that data has been corrupted but not consumed. Hardware writes information
to the status and address registers in the corresponding bank that
identifies the source of the error if deferred errors are enabled for
logging. Deferred errors are not reported via machine check exceptions;
they can be seen by polling the MCi_STATUS registers.
                                                -- AMD64 APM Volume 2

Above two items, both UCNA and Deferred errors belong to detected
errors, but they can't be corrected by hardware, and this is very
similar to Software Recoverable Action Optional (SRAO) errors.
Therefore, we can take some actions that have been used for handling
SRAO errors to handle UCNA and Deferred errors.
Acked-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NChen Yucong <slaoub@gmail.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>
      fa92c586
    • C
      x86, mce, severity: Extend the the mce_severity mechanism to handle UCNA/DEFERRED error · e3480271
      由 Chen Yucong 提交于 
      Until now, the mce_severity mechanism can only identify the severity
of UCNA error as MCE_KEEP_SEVERITY. Meanwhile, it is not able to filter
out DEFERRED error for AMD platform.

This patch extends the mce_severity mechanism for handling
UCNA/DEFERRED error. In order to do this, the patch introduces a new
severity level - MCE_UCNA/DEFERRED_SEVERITY.

In addition, mce_severity is specific to machine check exception,
and it will check MCIP/EIPV/RIPV bits. In order to use mce_severity
mechanism in non-exception context, the patch also introduces a new
argument (is_excp) for mce_severity. `is_excp' is used to explicitly
specify the calling context of mce_severity.
Reviewed-by: NAravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Signed-off-by: NChen Yucong <slaoub@gmail.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>
      e3480271
  43. 27 8月, 2014 1 次提交
    • C
      x86: Replace __get_cpu_var uses · 89cbc767
      由 Christoph Lameter 提交于 
      __get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Acked-by: NH. Peter Anvin <hpa@linux.intel.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      89cbc767
  45. 09 8月, 2014 1 次提交
  47. 22 7月, 2014 1 次提交