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  1. 07 Sep, 2016 4 commits
    • Jason S. McMullan's avatar
      PCI: Support PCIe devices with short cfg_size · e64ccb6b
      Jason S. McMullan authored 
      commit c20aecf6 upstream.

If a device quirk modifies the pci_dev->cfg_size to be less than
PCI_CFG_SPACE_EXP_SIZE (4096), but greater than PCI_CFG_SPACE_SIZE (256),
the PCI sysfs interface truncates the readable size to PCI_CFG_SPACE_SIZE.

Allow sysfs access to config space up to cfg_size, even if the device
doesn't support the entire 4096-byte PCIe config space.

Note that pci_read_config() and pci_write_config() limit access to
dev->cfg_size even though pcie_config_attr contains 4096 (the maximum
size).
Signed-off-by: default avatarJason S. McMullan <jason.mcmullan@netronome.com>
[simon: edited changelog]
Signed-off-by: default avatarSimon Horman <simon.horman@netronome.com>
[bhelgaas: more changelog edits]
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e64ccb6b
    • Helge Deller's avatar
      parisc: Fix order of EREFUSED define in errno.h · b021a054
      Helge Deller authored 
      commit 3eb53b20 upstream.

When building gccgo in userspace, errno.h gets parsed and the go include file
sysinfo.go is generated.

Since EREFUSED is defined to the same value as ECONNREFUSED, and ECONNREFUSED
is defined later on in errno.h, this leads to go complaining that EREFUSED
isn't defined yet.

Fix this trivial problem by moving the define of EREFUSED down after
ECONNREFUSED in errno.h (and clean up the indenting while touching this line).
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b021a054
    • James Hogan's avatar
      arm64: Define AT_VECTOR_SIZE_ARCH for ARCH_DLINFO · 7b01567a
      James Hogan authored 
      commit 3146bc64 upstream.

AT_VECTOR_SIZE_ARCH should be defined with the maximum number of
NEW_AUX_ENT entries that ARCH_DLINFO can contain, but it wasn't defined
for arm64 at all even though ARCH_DLINFO will contain one NEW_AUX_ENT
for the VDSO address.

This shouldn't be a problem as AT_VECTOR_SIZE_BASE includes space for
AT_BASE_PLATFORM which arm64 doesn't use, but lets define it now and add
the comment above ARCH_DLINFO as found in several other architectures to
remind future modifiers of ARCH_DLINFO to keep AT_VECTOR_SIZE_ARCH up to
date.

Fixes: f668cd16 ("arm64: ELF definitions")
Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7b01567a
    • Sebastian Andrzej Siewior's avatar
      x86/mm: Disable preemption during CR3 read+write · a5ec4bf8
      Sebastian Andrzej Siewior authored 
      commit 5cf0791d upstream.

There's a subtle preemption race on UP kernels:

Usually current->mm (and therefore mm->pgd) stays the same during the
lifetime of a task so it does not matter if a task gets preempted during
the read and write of the CR3.

But then, there is this scenario on x86-UP:

TaskA is in do_exit() and exit_mm() sets current->mm = NULL followed by:

 -> mmput()
 -> exit_mmap()
 -> tlb_finish_mmu()
 -> tlb_flush_mmu()
 -> tlb_flush_mmu_tlbonly()
 -> tlb_flush()
 -> flush_tlb_mm_range()
 -> __flush_tlb_up()
 -> __flush_tlb()
 ->  __native_flush_tlb()

At this point current->mm is NULL but current->active_mm still points to
the "old" mm.

Let's preempt taskA _after_ native_read_cr3() by taskB. TaskB has its
own mm so CR3 has changed.

Now preempt back to taskA. TaskA has no ->mm set so it borrows taskB's
mm and so CR3 remains unchanged. Once taskA gets active it continues
where it was interrupted and that means it writes its old CR3 value
back. Everything is fine because userland won't need its memory
anymore.

Now the fun part:

Let's preempt taskA one more time and get back to taskB. This
time switch_mm() won't do a thing because oldmm (->active_mm)
is the same as mm (as per context_switch()). So we remain
with a bad CR3 / PGD and return to userland.

The next thing that happens is handle_mm_fault() with an address for
the execution of its code in userland. handle_mm_fault() realizes that
it has a PTE with proper rights so it returns doing nothing. But the
CPU looks at the wrong PGD and insists that something is wrong and
faults again. And again. And one more time…

This pagefault circle continues until the scheduler gets tired of it and
puts another task on the CPU. It gets little difficult if the task is a
RT task with a high priority. The system will either freeze or it gets
fixed by the software watchdog thread which usually runs at RT-max prio.
But waiting for the watchdog will increase the latency of the RT task
which is no good.

Fix this by disabling preemption across the critical code section.
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.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: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1470404259-26290-1-git-send-email-bigeasy@linutronix.de
[ Prettified the changelog. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a5ec4bf8
  3. 20 Aug, 2016 36 commits
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