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  1. 11 7月, 2016 3 次提交
    • L
      x86/quirks: Add early quirk to reset Apple AirPort card · abb2bafd
      由 Lukas Wunner 提交于 
      The EFI firmware on Macs contains a full-fledged network stack for
downloading OS X images from osrecovery.apple.com. Unfortunately
on Macs introduced 2011 and 2012, EFI brings up the Broadcom 4331
wireless card on every boot and leaves it enabled even after
ExitBootServices has been called. The card continues to assert its IRQ
line, causing spurious interrupts if the IRQ is shared. It also corrupts
memory by DMAing received packets, allowing for remote code execution
over the air. This only stops when a driver is loaded for the wireless
card, which may be never if the driver is not installed or blacklisted.

The issue seems to be constrained to the Broadcom 4331. Chris Milsted
has verified that the newer Broadcom 4360 built into the MacBookPro11,3
(2013/2014) does not exhibit this behaviour. The chances that Apple will
ever supply a firmware fix for the older machines appear to be zero.

The solution is to reset the card on boot by writing to a reset bit in
its mmio space. This must be done as an early quirk and not as a plain
vanilla PCI quirk to successfully combat memory corruption by DMAed
packets: Matthew Garrett found out in 2012 that the packets are written
to EfiBootServicesData memory (http://mjg59.dreamwidth.org/11235.html).
This type of memory is made available to the page allocator by
efi_free_boot_services(). Plain vanilla PCI quirks run much later, in
subsys initcall level. In-between a time window would be open for memory
corruption. Random crashes occurring in this time window and attributed
to DMAed packets have indeed been observed in the wild by Chris
Bainbridge.

When Matthew Garrett analyzed the memory corruption issue in 2012, he
sought to fix it with a grub quirk which transitions the card to D3hot:
http://git.savannah.gnu.org/cgit/grub.git/commit/?id=9d34bb85da56

This approach does not help users with other bootloaders and while it
may prevent DMAed packets, it does not cure the spurious interrupts
emanating from the card. Unfortunately the card's mmio space is
inaccessible in D3hot, so to reset it, we have to undo the effect of
Matthew's grub patch and transition the card back to D0.

Note that the quirk takes a few shortcuts to reduce the amount of code:
The size of BAR 0 and the location of the PM capability is identical
on all affected machines and therefore hardcoded. Only the address of
BAR 0 differs between models. Also, it is assumed that the BCMA core
currently mapped is the 802.11 core. The EFI driver seems to always take
care of this.

Michael Büsch, Bjorn Helgaas and Matt Fleming contributed feedback
towards finding the best solution to this problem.

The following should be a comprehensive list of affected models:
    iMac13,1        2012  21.5"       [Root Port 00:1c.3 = 8086:1e16]
    iMac13,2        2012  27"         [Root Port 00:1c.3 = 8086:1e16]
    Macmini5,1      2011  i5 2.3 GHz  [Root Port 00:1c.1 = 8086:1c12]
    Macmini5,2      2011  i5 2.5 GHz  [Root Port 00:1c.1 = 8086:1c12]
    Macmini5,3      2011  i7 2.0 GHz  [Root Port 00:1c.1 = 8086:1c12]
    Macmini6,1      2012  i5 2.5 GHz  [Root Port 00:1c.1 = 8086:1e12]
    Macmini6,2      2012  i7 2.3 GHz  [Root Port 00:1c.1 = 8086:1e12]
    MacBookPro8,1   2011  13"         [Root Port 00:1c.1 = 8086:1c12]
    MacBookPro8,2   2011  15"         [Root Port 00:1c.1 = 8086:1c12]
    MacBookPro8,3   2011  17"         [Root Port 00:1c.1 = 8086:1c12]
    MacBookPro9,1   2012  15"         [Root Port 00:1c.1 = 8086:1e12]
    MacBookPro9,2   2012  13"         [Root Port 00:1c.1 = 8086:1e12]
    MacBookPro10,1  2012  15"         [Root Port 00:1c.1 = 8086:1e12]
    MacBookPro10,2  2012  13"         [Root Port 00:1c.1 = 8086:1e12]

For posterity, spurious interrupts caused by the Broadcom 4331 wireless
card resulted in splats like this (stacktrace omitted):

    irq 17: nobody cared (try booting with the "irqpoll" option)
    handlers:
    [<ffffffff81374370>] pcie_isr
    [<ffffffffc0704550>] sdhci_irq [sdhci] threaded [<ffffffffc07013c0>] sdhci_thread_irq [sdhci]
    [<ffffffffc0a0b960>] azx_interrupt [snd_hda_codec]
    Disabling IRQ #17

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=79301
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=111781
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=728916
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=895951#c16
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1009819
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1098621
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1149632#c5
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1279130
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1332732
Tested-by: Konstantin Simanov <k.simanov@stlk.ru>        # [MacBookPro8,1]
Tested-by: Lukas Wunner <lukas@wunner.de>                # [MacBookPro9,1]
Tested-by: Bryan Paradis <bryan.paradis@gmail.com>       # [MacBookPro9,2]
Tested-by: Andrew Worsley <amworsley@gmail.com>          # [MacBookPro10,1]
Tested-by: Chris Bainbridge <chris.bainbridge@gmail.com> # [MacBookPro10,2]
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Acked-by: NRafał Miłecki <zajec5@gmail.com>
Acked-by: NMatt Fleming <matt@codeblueprint.co.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris Milsted <cmilsted@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Michael Buesch <m@bues.ch>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: b43-dev@lists.infradead.org
Cc: linux-pci@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: stable@vger.kernel.org
Cc: stable@vger.kernel.org # 123456789abc: x86/quirks: Apply nvidia_bugs quirk only on root bus
Cc: stable@vger.kernel.org # 123456789abc: x86/quirks: Reintroduce scanning of secondary buses
Link: http://lkml.kernel.org/r/48d0972ac82a53d460e5fce77a07b2560db95203.1465690253.git.lukas@wunner.de
[ Did minor readability edits. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      abb2bafd
    • L
      x86/quirks: Reintroduce scanning of secondary buses · 850c3210
      由 Lukas Wunner 提交于 
      We used to scan secondary buses until the following commit that
was applied in 2009:

  8659c406 ("x86: only scan the root bus in early PCI quirks")

which commit constrained early quirks to the root bus only. Its
motivation was to prevent application of the nvidia_bugs quirk
on secondary buses.

We're about to add a quirk to reset the Broadcom 4331 wireless card on
2011/2012 Macs, which is located on a secondary bus behind a PCIe root
port. To facilitate that, reintroduce scanning of secondary buses.

The commit message of 8659c406 notes that scanning only the root bus
"saves quite some unnecessary scanning work". The algorithm used prior
to 8659c406 was particularly time consuming because it scanned
buses 0 to 31 brute force. To avoid lengthening boot time, employ a
recursive strategy which only scans buses that are actually reachable
from the root bus.

Yinghai Lu pointed out that the secondary bus number read from a
bridge's config space may be invalid, in particular a value of 0 would
cause an infinite loop. The PCI core goes beyond that and recurses to a
child bus only if its bus number is greater than the parent bus number
(see pci_scan_bridge()). Since the root bus is numbered 0, this implies
that secondary buses may not be 0. Do the same on early scanning.

If this algorithm is found to significantly impact boot time or cause
infinite loops on broken hardware, it would be possible to limit its
recursion depth: The Broadcom 4331 quirk applies at depth 1, all others
at depth 0, so the bus need not be scanned deeper than that for now. An
alternative approach would be to revert to scanning only the root bus,
and apply the Broadcom 4331 quirk to the root ports 8086:1c12, 8086:1e12
and 8086:1e16. Apple always positioned the card behind either of these
three ports. The quirk would then check presence of the card in slot 0
below the root port and do its deed.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
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: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-pci@vger.kernel.org
Link: http://lkml.kernel.org/r/f0daa70dac1a9b2483abdb31887173eb6ab77bdf.1465690253.git.lukas@wunner.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      850c3210
    • L
      x86/quirks: Apply nvidia_bugs quirk only on root bus · 447d29d1
      由 Lukas Wunner 提交于 
      Since the following commit:

  8659c406 ("x86: only scan the root bus in early PCI quirks")

... early quirks are only applied to devices on the root bus.

The motivation was to prevent application of the nvidia_bugs quirk on
secondary buses.

We're about to reintroduce scanning of secondary buses for a quirk to
reset the Broadcom 4331 wireless card on 2011/2012 Macs. To prevent
regressions, open code the requirement to apply nvidia_bugs only on the
root bus.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
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: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/4d5477c1d76b2f0387a780f2142bbcdd9fee869b.1465690253.git.lukas@wunner.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      447d29d1
  3. 08 7月, 2016 2 次提交
  5. 01 7月, 2016 1 次提交
  7. 27 6月, 2016 2 次提交
  9. 25 6月, 2016 2 次提交
    • M
      x86: get rid of superfluous __GFP_REPEAT · a3a9a59d
      由 Michal Hocko 提交于 
      __GFP_REPEAT has a rather weak semantic but since it has been introduced
around 2.6.12 it has been ignored for low order allocations.

PGALLOC_GFP uses __GFP_REPEAT but none of the allocation which uses this
flag is for more than order-0.  This means that this flag has never been
actually useful here because it has always been used only for
PAGE_ALLOC_COSTLY requests.

Link: http://lkml.kernel.org/r/1464599699-30131-3-git-send-email-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a3a9a59d
    • L
      x86: fix up a few misc stack pointer vs thread_info confusions · aca9c293
      由 Linus Torvalds 提交于 
      As the actual pointer value is the same for the thread stack allocation
and the thread_info, code that confused the two worked fine, but will
break when the thread info is moved away from the stack allocation.  It
also looks very confusing.

For example, the kprobe code wanted to know the current top of stack.
To do that, it used this:

	(unsigned long)current_thread_info() + THREAD_SIZE

which did indeed give the correct value.  But it's not only a fairly
nonsensical expression, it's also rather complex, especially since we
actually have this:

	static inline unsigned long current_top_of_stack(void)

which not only gives us the value we are interested in, but happens to
be how "current_thread_info()" is currently defined as:

	(struct thread_info *)(current_top_of_stack() - THREAD_SIZE);

so using current_thread_info() to figure out the top of the stack really
is a very round-about thing to do.

The other cases are just simpler confusion about task_thread_info() vs
task_stack_page(), which currently return the same pointer - but if you
want the stack page, you really should be using the latter one.

And there was one entirely unused assignment of the current stack to a
thread_info pointer.

All cleaned up to make more sense today, and make it easier to move the
thread_info away from the stack in the future.

No semantic changes.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      aca9c293
  11. 24 6月, 2016 1 次提交
  13. 14 6月, 2016 2 次提交
    • M
      kprobes/x86: Clear TF bit in fault on single-stepping · dcfc4724
      由 Masami Hiramatsu 提交于 
      Fix kprobe_fault_handler() to clear the TF (trap flag) bit of
the flags register in the case of a fault fixup on single-stepping.

If we put a kprobe on the instruction which caused a
page fault (e.g. actual mov instructions in copy_user_*),
that fault happens on the single-stepping buffer. In this
case, kprobes resets running instance so that the CPU can
retry execution on the original ip address.

However, current code forgets to reset the TF bit. Since this
fault happens with TF bit set for enabling single-stepping,
when it retries, it causes a debug exception and kprobes
can not handle it because it already reset itself.

On the most of x86-64 platform, it can be easily reproduced
by using kprobe tracer. E.g.

  # cd /sys/kernel/debug/tracing
  # echo p copy_user_enhanced_fast_string+5 > kprobe_events
  # echo 1 > events/kprobes/enable

And you'll see a kernel panic on do_debug(), since the debug
trap is not handled by kprobes.

To fix this problem, we just need to clear the TF bit when
resetting running kprobe.
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: NAnanth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
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: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: systemtap@sourceware.org
Cc: stable@vger.kernel.org # All the way back to ancient kernels
Link: http://lkml.kernel.org/r/20160611140648.25885.37482.stgit@devbox
[ Updated the comments. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      dcfc4724
    • T
      x86/mce: Do not use bank 1 for APEI generated error logs · b2de4360
      由 Tony Luck 提交于 
      BIOS can report a memory error to Linux using ACPI/APEI mechanism. When
it does this, we create a fictitious machine check error record and
feed it into the standard mce_log() function. The error record needs a
machine check bank number, and for some reason we chose "1" for this.

But "1" is a valid bank number, and this causes confusion and heartburn
among h/w folks who are concerned that a memory error signature was
somehow logged in bank 1.

Change to use "-1" (field is a "u8" so will typically print as 255).
This should make it clearer that this error did not originate in a
machine check bank.
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Aristeu Rozanski <arozansk@redhat.com>
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: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
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/b7fffb2b326bc1dd150ffceb9919a803f9496e0e.1464805958.git.tony.luck@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      b2de4360
  15. 10 6月, 2016 2 次提交
  17. 08 6月, 2016 1 次提交
  19. 24 5月, 2016 1 次提交
  21. 21 5月, 2016 3 次提交
    • P
      printk/nmi: generic solution for safe printk in NMI · 42a0bb3f
      由 Petr Mladek 提交于 
      printk() takes some locks and could not be used a safe way in NMI
context.

The chance of a deadlock is real especially when printing stacks from
all CPUs.  This particular problem has been addressed on x86 by the
commit a9edc880 ("x86/nmi: Perform a safe NMI stack trace on all
CPUs").

The patchset brings two big advantages.  First, it makes the NMI
backtraces safe on all architectures for free.  Second, it makes all NMI
messages almost safe on all architectures (the temporary buffer is
limited.  We still should keep the number of messages in NMI context at
minimum).

Note that there already are several messages printed in NMI context:
WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
handlers.  These are not easy to avoid.

This patch reuses most of the code and makes it generic.  It is useful
for all messages and architectures that support NMI.

The alternative printk_func is set when entering and is reseted when
leaving NMI context.  It queues IRQ work to copy the messages into the
main ring buffer in a safe context.

__printk_nmi_flush() copies all available messages and reset the buffer.
Then we could use a simple cmpxchg operations to get synchronized with
writers.  There is also used a spinlock to get synchronized with other
flushers.

We do not longer use seq_buf because it depends on external lock.  It
would be hard to make all supported operations safe for a lockless use.
It would be confusing and error prone to make only some operations safe.

The code is put into separate printk/nmi.c as suggested by Steven
Rostedt.  It needs a per-CPU buffer and is compiled only on
architectures that call nmi_enter().  This is achieved by the new
HAVE_NMI Kconfig flag.

The are MN10300 and Xtensa architectures.  We need to clean up NMI
handling there first.  Let's do it separately.

The patch is heavily based on the draft from Peter Zijlstra, see

  https://lkml.org/lkml/2015/6/10/327

[arnd@arndb.de: printk-nmi: use %zu format string for size_t]
[akpm@linux-foundation.org: min_t->min - all types are size_t here]
Signed-off-by: NPetr Mladek <pmladek@suse.com>
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>	[arm part]
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      42a0bb3f
    • J
      exit_thread: accept a task parameter to be exited · e6464694
      由 Jiri Slaby 提交于 
      We need to call exit_thread from copy_process in a fail path.  So make it
accept task_struct as a parameter.

[v2]
* s390: exit_thread_runtime_instr doesn't make sense to be called for
  non-current tasks.
* arm: fix the comment in vfp_thread_copy
* change 'me' to 'tsk' for task_struct
* now we can change only archs that actually have exit_thread

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e6464694
    • S
      ftrace/x86: Set ftrace_stub to weak to prevent gcc from using short jumps to it · 8329e818
      由 Steven Rostedt 提交于 
      Matt Fleming reported seeing crashes when enabling and disabling
function profiling which uses function graph tracer. Later Namhyung Kim
hit a similar issue and he found that the issue was due to the jmp to
ftrace_stub in ftrace_graph_call was only two bytes, and when it was
changed to jump to the tracing code, it overwrote the ftrace_stub that
was after it.

Masami Hiramatsu bisected this down to a binutils change:

8dcea93252a9ea7dff57e85220a719e2a5e8ab41 is the first bad commit
commit 8dcea93252a9ea7dff57e85220a719e2a5e8ab41
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri May 15 03:17:31 2015 -0700

    Add -mshared option to x86 ELF assembler

    This patch adds -mshared option to x86 ELF assembler.  By default,
    assembler will optimize out non-PLT relocations against defined non-weak
    global branch targets with default visibility.  The -mshared option tells
    the assembler to generate code which may go into a shared library
    where all non-weak global branch targets with default visibility can
    be preempted.  The resulting code is slightly bigger.  This option
    only affects the handling of branch instructions.

Declaring ftrace_stub as a weak call prevents gas from using two byte
jumps to it, which would be converted to a jump to the function graph
code.

Link: http://lkml.kernel.org/r/20160516230035.1dbae571@gandalf.local.homeReported-by: NMatt Fleming <matt@codeblueprint.co.uk>
Reported-by: NNamhyung Kim <namhyung@kernel.org>
Tested-by: NMatt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      8329e818
  23. 20 5月, 2016 2 次提交
    • A
      x86/fsgsbase/64: Use TASK_SIZE_MAX for FSBASE/GSBASE upper limits · d696ca01
      由 Andy Lutomirski 提交于 
      The GSBASE upper limit exists to prevent user code from confusing
the paranoid idtentry path.  The FSBASE upper limit is just for
consistency.  There's no need to enforce a smaller limit for 32-bit
tasks.

Just use TASK_SIZE_MAX.  This simplifies the logic and will save a
few bytes of code.
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: 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>
Link: http://lkml.kernel.org/r/5357f2fe0f103eabf005773b70722451eab09a89.1462897104.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      d696ca01
    • D
      x86/mm/mpx: Work around MPX erratum SKD046 · 0f6ff2bc
      由 Dave Hansen 提交于 
      This erratum essentially causes the CPU to forget which privilege
level it is operating on (kernel vs. user) for the purposes of MPX.

This erratum can only be triggered when a system is not using
Supervisor Mode Execution Prevention (SMEP).  Our workaround for
the erratum is to ensure that MPX can only be used in cases where
SMEP is present in the processor and is enabled.

This erratum only affects Core processors.  Atom is unaffected.
But, there is no architectural way to determine Atom vs. Core.
So, we just apply this workaround to all processors.  It's
possible that it will mistakenly disable MPX on some Atom
processsors or future unaffected Core processors.  There are
currently no processors that have MPX and not SMEP.  It would
take something akin to a hypervisor masking SMEP out on an Atom
processor for this to present itself on current hardware.

More details can be found at:

  http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/desktop-6th-gen-core-family-spec-update.pdf

"
  SKD046 Branch Instructions May Initialize MPX Bound Registers Incorrectly

  Problem:

  Depending on the current Intel MPX (Memory Protection
  Extensions) configuration, execution of certain branch
  instructions (near CALL, near RET, near JMP, and Jcc
  instructions) without a BND prefix (F2H) initialize the MPX bound
  registers. Due to this erratum, such a branch instruction that is
  executed both with CPL = 3 and with CPL < 3 may not use the
  correct MPX configuration register (BNDCFGU or BNDCFGS,
  respectively) for determining whether to initialize the bound
  registers; it may thus initialize the bound registers when it
  should not, or fail to initialize them when it should.

  Implication:

  A branch instruction that has executed both in user mode and in
  supervisor mode (from the same linear address) may cause a #BR
  (bound range fault) when it should not have or may not cause a
  #BR when it should have.  Workaround An operating system can
  avoid this erratum by setting CR4.SMEP[bit 20] to enable
  supervisor-mode execution prevention (SMEP). When SMEP is
  enabled, no code can be executed both with CPL = 3 and with CPL < 3.
"
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.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/20160512220400.3B35F1BC@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      0f6ff2bc
  25. 16 5月, 2016 1 次提交
    • D
      x86/cpufeature, x86/mm/pkeys: Fix broken compile-time disabling of pkeys · e8df1a95
      由 Dave Hansen 提交于 
      When I added support for the Memory Protection Keys processor
feature, I had to reindent the REQUIRED/DISABLED_MASK macros, and
also consult the later cpufeature words.

I'm not quite sure how I bungled it, but I consulted the wrong
word at the end.  This only affected required or disabled cpu
features in cpufeature words 14, 15 and 16.  So, only Protection
Keys itself was screwed over here.

The result was that if you disabled pkeys in your .config, you
might still see some code show up that should have been compiled
out.  There should be no functional problems, though.

In verifying this patch I also realized that the DISABLE_PKU/OSPKE
macros were defined backwards and that the cpu_has() check in
setup_pku() was not doing the compile-time disabled checks.

So also fix the macro for DISABLE_PKU/OSPKE and add a compile-time
check for pkeys being enabled in setup_pku().
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: dfb4a70f ("x86/cpufeature, x86/mm/pkeys: Add protection keys related CPUID definitions")
Link: http://lkml.kernel.org/r/20160513221328.C200930B@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      e8df1a95
  27. 13 5月, 2016 1 次提交
  29. 12 5月, 2016 6 次提交
  31. 10 5月, 2016 1 次提交
  33. 07 5月, 2016 1 次提交
  35. 06 5月, 2016 1 次提交
  37. 05 5月, 2016 3 次提交
  39. 04 5月, 2016 4 次提交