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  1. May 27, 2013
  3. May 26, 2013
  5. May 25, 2013
    • Vineet Gupta's avatar
      ARC: lazy dcache flush broke gdb in non-aliasing configs · 7bb66f6e
      Vineet Gupta authored 
      

gdbserver inserting a breakpoint ends up calling copy_user_page() for a
code page. The generic version of which (non-aliasing config) didn't set
the PG_arch_1 bit hence update_mmu_cache() didn't sync dcache/icache for
corresponding dynamic loader code page - causing garbade to be executed.

So now aliasing versions of copy_user_highpage()/clear_page() are made
default. There is no significant overhead since all of special alias
handling code is compiled out for non-aliasing build

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
      7bb66f6e
    • Helge Deller's avatar
      parisc: fix irq stack on UP and SMP · d96b51ec
      Helge Deller authored 
      

The logic to detect if the irq stack was already in use with
raw_spin_trylock() is wrong, because it will generate a "trylock failure
on UP" error message with CONFIG_SMP=n and CONFIG_DEBUG_SPINLOCK=y.

arch_spin_trylock() can't be used either since in the CONFIG_SMP=n case
no atomic protection is given and we are reentrant here. A mutex didn't
worked either and brings more overhead by turning off interrupts.

So, let's use the fastest path for parisc which is the ldcw instruction.

Counting how often the irq stack was used is pretty useless, so just
drop this piece of code.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      d96b51ec
    • John David Anglin's avatar
      parisc: make interrupt and interruption stack allocation reentrant · b63a2bbc
      John David Anglin authored 
      

The get_stack_use_cr30 and get_stack_use_r30 macros allocate a stack
frame for external interrupts and interruptions requiring a stack frame.
They are currently not reentrant in that they save register context
before the stack is set or adjusted.

I have observed a number of system crashes where there was clear
evidence of stack corruption during interrupt processing, and as a
result register corruption. Some interruptions can still occur during
interruption processing, however external interrupts are disabled and
data TLB misses don't occur for absolute accesses. So, it's not entirely
clear what triggers this issue. Also, if an interruption occurs when
Q=0, it is generally not possible to recover as the shadowed registers
are not copied.

The attached patch reworks the get_stack_use_cr30 and get_stack_use_r30
macros to allocate stack before doing register saves. The new code is a
couple of instructions shorter than the old implementation. Thus, it's
an improvement even if it doesn't fully resolve the stack corruption
issue. Based on limited testing, it improves SMP system stability.

Signed-off-by: default avatarJohn David Anglin <dave.anglin@bell.net>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      b63a2bbc
    • Helge Deller's avatar
      parisc: show number of FPE and unaligned access handler calls in /proc/interrupts · d0c3be80
      Helge Deller authored 
      

Show number of floating point assistant and unaligned access fixup
handler in /proc/interrupts file.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      d0c3be80
    • Helge Deller's avatar
      parisc: use PAGE_SHIFT instead of hardcoded value 12 in pacache.S · d845b5fb
      Helge Deller authored 
      

additionally clean up some whitespaces & tabs.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      d845b5fb
    • Helge Deller's avatar
      parisc: add rp5470 entry to machine database · 949451b9
      Helge Deller authored 
      

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      949451b9
  7. May 24, 2013
  9. May 23, 2013
    • Vineet Gupta's avatar
      ARC: Use enough bits for determining page's cache color · 006dfb3c
      Vineet Gupta authored 
      

The current code uses 2 bits for determining page's dcache color, thus
sorting pages into 4 bins, whereas the aliasing dcache really has 2 bins
(8k page, 64k dcache - 4 way-set-assoc).
This can cause extraneous flushes - e.g. color 0 and 2.

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
      006dfb3c
    • Vineet Gupta's avatar
      ARC: Brown paper bag bug in macro for checking cache color · 3e87974d
      Vineet Gupta authored 
      

The VM_EXEC check in update_mmu_cache() was getting optimized away
because of a stupid error in definition of macro addr_not_cache_congruent()

The intention was to have the equivalent of following:

	if (a || (1 ? b : 0))

but we ended up with following:

	if (a || 1 ? b : 0)

And because precedence of '||' is more that that of '?', gcc was optimizing
away evaluation of <a>

Nasty Repercussions:
1. For non-aliasing configs it would mean some extraneous dcache flushes
   for non-code pages if U/K mappings were not congruent.
2. For aliasing config, some needed dcache flush for code pages might
   be missed if U/K mappings were congruent.

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
      3e87974d
    • Vineet Gupta's avatar
      ARC: copy_(to|from)_user() to honor usermode-access permissions · a950549c
      Vineet Gupta authored 
      

This manifested as grep failing psuedo-randomly:

-------------->8---------------------
[ARCLinux]$ ip address show lo | grep inet
[ARCLinux]$ ip address show lo | grep inet
[ARCLinux]$ ip address show lo | grep inet
[ARCLinux]$
[ARCLinux]$ ip address show lo | grep inet
    inet 127.0.0.1/8 scope host lo
-------------->8---------------------

ARC700 MMU provides fully orthogonal permission bits per page:
Ur, Uw, Ux, Kr, Kw, Kx

The user mode page permission templates used to have all Kernel mode
access bits enabled.
This caused a tricky race condition observed with uClibc buffered file
read and UNIX pipes.

1. Read access to an anon mapped page in libc .bss: write-protected
   zero_page mapped: TLB Entry installed with Ur + K[rwx]

2. grep calls libc:getc() -> buffered read layer calls read(2) with the
   internal read buffer in same .bss page.
   The read() call is on STDIN which has been redirected to a pipe.
   read(2) => sys_read() => pipe_read() => copy_to_user()

3. Since page has Kernel-write permission (despite being user-mode
   write-protected), copy_to_user() suceeds w/o taking a MMU TLB-Miss
   Exception (page-fault for ARC). core-MM is unaware that kernel
   erroneously wrote to the reserved read-only zero-page (BUG #1)

4. Control returns to userspace which now does a write to same .bss page
   Since Linux MM is not aware that page has been modified by kernel, it
   simply reassigns a new writable zero-init page to mapping, loosing the
   prior write by kernel - effectively zero'ing out the libc read buffer
   under the hood - hence grep doesn't see right data (BUG #2)

The fix is to make all kernel-mode access permissions mirror the
user-mode ones. Note that the kernel still has full access to pages,
when accessed directly (w/o MMU) - this fix ensures that kernel-mode
access in copy_to_from() path uses the same faulting access model as for
pure user accesses to keep MM fully aware of page state.

The issue is peudo-random because it only shows up if the TLB entry
installed in #1 is present at the time of #3. If it is evicted out, due
to TLB pressure or some-such, then copy_to_user() does take a TLB Miss
Exception, with a routine write-to-anon COW processing installing a
fresh page for kernel writes and also usable as it is in userspace.

Further the issue was dormant for so long as it depends on where the
libc internal read buffer (in .bss) is mapped at runtime.
If it happens to reside in file-backed data mapping of libc (in the
page-aligned slack space trailing the file backed data), loader zero
padding the slack space, does the early cow page replacement, setting
things up at the very beginning itself.

With gcc 4.8 based builds, the libc buffer got pushed out to a real
anon mapping which triggers the issue.

Reported-by: default avatarAnton Kolesov <akolesov@synopsys.com>
Cc: <stable@vger.kernel.org> # 3.9
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
      a950549c
    • Vineet Gupta's avatar
      ARC: [mm] Prevent stray dcache lines after__sync_icache_dcach() · f538881c
      Vineet Gupta authored 
      

Flush and INVALIDATE the dcache page.

This helper is only used for writeback of CODE pages to memory. So
there's no value in keeping the dcache lines around. Infact it is risky
as a writeback on natural eviction under pressure can cause un-needed
writeback with weird issues on aliasing dcache configurations.

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
      f538881c
    • Will Deacon's avatar
      ARM: 7729/1: vfp: ensure VFP_arch is non-zero when VFP is not supported · f27d6e17
      Will Deacon authored 
      Commit d3f79584

 ("ARM: cleanup undefined instruction entry code")
improved the register scheduling when handling undefined instructions.
A side effect of this is that r5 is now used as a temporary, whilst the
VFP probing code relies on r5 containing a non-zero value when VFP is
not supported.

This patch fixes the VFP detection code so that we don't rely on the
contents of r5. Without this patch, Linux dies loudly on CPUs without
VFP support.

Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      f27d6e17
    • Steven Capper's avatar
      ARM: 7727/1: remove the .vm_mm value from gate_vma · 4ca46c5e
      Steven Capper authored 
      If one reads /proc/$PID/smaps, the mmap_sem belonging to the
address space of the task being examined is locked for reading.
All the pages of the vmas belonging to the task's address space
are then walked with this lock held.

If a gate_vma is present in the architecture, it too is examined
by the fs/proc/task_mmu.c code. As gate_vma doesn't belong to the
address space of the task though, its pages are not walked.

A recent cleanup (commit f6604efe

) of the gate_vma initialisation
code set the vm_mm value to &init_mm. Unfortunately a non-NULL
vm_mm value in the gate_vma will cause the task_mmu code to attempt
to walk the pages of the gate_vma (with no mmap-sem lock held). If
one enables Transparent Huge Page support and vm debugging, this
will then cause OOPses as pmd_trans_huge_lock is called without
mmap_sem being locked.

This patch removes the .vm_mm value from gate_vma, restoring the
original behaviour of the task_mmu code.

Signed-off-by: default avatarSteve Capper <steve.capper@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      4ca46c5e
    • Ard Biesheuvel's avatar
      ARM: 7723/1: crypto: sha1-armv4-large.S: fix SP handling · 934fc24d
      Ard Biesheuvel authored 
      Make the SHA1 asm code ABI conformant by making sure all stack
accesses occur above the stack pointer.

Origin:
http://git.openssl.org/gitweb/?p=openssl.git;a=commit;h=1a9d60d2



Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      934fc24d
    • Jiang Liu's avatar
      avr32: fix building warnings caused by redefinitions of HZ · 0c9b5a31
      Jiang Liu authored 
      

As suggested by David Howells <dhowells@redhat.com>, use
asm-generic/param.h and uapi/asm-generic/param.h for AVR32.

It also fixes building warnings caused by redefinitions of HZ:
In file included from /ws/linux/kernel/linux.git/include/uapi/linux/param.h:4,
                 from include/linux/timex.h:63,
                 from include/linux/jiffies.h:8,
                 from include/linux/ktime.h:25,
                 from include/linux/timer.h:5,
                 from include/linux/workqueue.h:8,
                 from include/linux/srcu.h:34,
                 from include/linux/notifier.h:15,
                 from include/linux/memory_hotplug.h:6,
                 from include/linux/mmzone.h:777,
                 from include/linux/gfp.h:4,
                 from arch/avr32/mm/init.c:10:
/ws/linux/kernel/linux.git/arch/avr32/include/asm/param.h:6:1: warning: "HZ" redefined
In file included from /ws/linux/kernel/linux.git/arch/avr32/include/asm/param.h:4,
                 from /ws/linux/kernel/linux.git/include/uapi/linux/param.h:4,
                 from include/linux/timex.h:63,
                 from include/linux/jiffies.h:8,
                 from include/linux/ktime.h:25,
                 from include/linux/timer.h:5,
                 from include/linux/workqueue.h:8,
                 from include/linux/srcu.h:34,
                 from include/linux/notifier.h:15,
                 from include/linux/memory_hotplug.h:6,
                 from include/linux/mmzone.h:777,
                 from include/linux/gfp.h:4,
                 from arch/avr32/mm/init.c:10:
/ws/linux/kernel/linux.git/arch/avr32/include/uapi/asm/param.h:6:1: warning: this is the location of the previous definition

Signed-off-by: default avatarJiang Liu <jiang.liu@huawei.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarHans-Christian Egtvedt <egtvedt@samfundet.no>
      0c9b5a31
  11. May 22, 2013
    • Aron Xu's avatar
      MIPS: N64: Wire getdents64(2) · dec33aba
      Aron Xu authored 
      

As a relatively new ABI, N64 only had getdents syscall while other modern
architectures have getdents64.

This was noticed when Python 3.3 shifted to the latter one for aarch64.

[ralf@linux-mips.org: The history of getdents64 is a little complicated.
Commit 1a1d77dd589de5a567fa95e36aa6999c704ceca4 [Merge with 2.4.0-test7.]
added N64 getdents(2) to arch/mips64/kernel/scall_64.S as syscall 5213,
then dropped again in 578720675c44e54e8aa7c68f6dce59ed37ce3d3b [Overhaul
of the 64-bit syscall interface.  Now heritage free.] for 2.5.18 in 2002.]

Signed-off-by: default avatarAron Xu <aron@debian.org>
Acked-by: default avatarDavid Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5285/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      dec33aba