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  1. May 29, 2014
  3. May 27, 2014
  5. May 23, 2014
  7. May 22, 2014
  9. May 20, 2014
  11. May 16, 2014
  13. May 15, 2014
    • John David Anglin's avatar
      parisc: Improve LWS-CAS performance · c776cd89
      John David Anglin authored 
      

The attached change significantly improves the performance of the LWS-CAS code
in syscall.S.
This allows a number of packages to build (e.g., zeromq3, gtest and libxs)
that previously failed because slow LWS-CAS performance under contention. In
particular, interrupts taken while the lock was taken degraded performance
significantly.

The change does the following:

1) Disables interrupts around the CAS operation, and
2) Changes the loads and stores to use the ordered completer, "o", on
PA 2.0. "o" and "ma" with a zero offset are equivalent. The latter is
accepted on both PA 1.X and 2.0.

The use of ordered loads and stores probably makes no difference on all
existing hardware, but it seemed pedantically correct. In particular, the CAS
operation must complete before LDCW lock is released. As written before, a
processor could reorder the operations.

I don't believe the period interrupts are disabled is long enough to
significantly increase interrupt latency. For example, the TLB insert code is
longer. Worst case is a memory fault in the CAS operation.

Signed-off-by: default avatarJohn David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # 3.13+
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      c776cd89
    • Helge Deller's avatar
      parisc: ratelimit userspace segfault printing · fef47e2a
      Helge Deller authored 
      

Ratelimit printing of userspace segfaults and make it runtime
configurable via the /proc/sys/debug/exception-trace variable. This
should resolve syslog from growing way too fast and thus prevents
possible system service attacks.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # 3.13+
      fef47e2a
  15. May 14, 2014
    • Linus Torvalds's avatar
      x86-64, modify_ldt: Make support for 16-bit segments a runtime option · fa81511b
      Linus Torvalds authored 
      

Checkin:

b3b42ac2 x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels

disabled 16-bit segments on 64-bit kernels due to an information
leak.  However, it does seem that people are genuinely using Wine to
run old 16-bit Windows programs on Linux.

A proper fix for this ("espfix64") is coming in the upcoming merge
window, but as a temporary fix, create a sysctl to allow the
administrator to re-enable support for 16-bit segments.

It adds a "/proc/sys/abi/ldt16" sysctl that defaults to zero (off). If
you hit this issue and care about your old Windows program more than
you care about a kernel stack address information leak, you can do

   echo 1 > /proc/sys/abi/ldt16

as root (add it to your startup scripts), and you should be ok.

The sysctl table is only added if you have COMPAT support enabled on
x86-64, but I assume anybody who runs old windows binaries very much
does that ;)

Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/CA%2B55aFw9BPoD10U1LfHbOMpHWZkvJTkMcfCs9s3urPr1YyWBxw@mail.gmail.com
Cc: <stable@vger.kernel.org>
      fa81511b
    • James Hogan's avatar
      metag: Remove _STK_LIM_MAX override · c70458f5
      James Hogan authored 
      

Meta overrode _STK_LIM_MAX (the default RLIMIT_STACK hard limit) to
256MB, apparently in an attempt to prevent setup_arg_pages's
STACK_GROWSUP code from choosing the maximum stack size of 1GB, which is
far too large for Meta's limited virtual address space and hits a BUG_ON
(stack_top is usually 0x3ffff000).

However the commit "metag: Reduce maximum stack size to 256MB" reduces
the absolute stack size limit to a safe value for metag. This allows the
default _STK_LIM_MAX override to be removed, bringing the default
behaviour in line with all other architectures. Parisc in particular
recently removed their override of _STK_LIMT_MAX in commit e0d8898d
(parisc: remove _STK_LIM_MAX override) since it subtly affects stack
allocation semantics in userland. Meta's uapi/asm/resource.h can now be
removed and switch to using generic-y.

Suggested-by: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org
Cc: John David Anglin <dave.anglin@bell.net>
      c70458f5
    • Helge Deller's avatar
      parisc,metag: Do not hardcode maximum userspace stack size · 042d27ac
      Helge Deller authored 
      

This patch affects only architectures where the stack grows upwards
(currently parisc and metag only). On those do not hardcode the maximum
initial stack size to 1GB for 32-bit processes, but make it configurable
via a config option.

The main problem with the hardcoded stack size is, that we have two
memory regions which grow upwards: stack and heap. To keep most of the
memory available for heap in a flexmap memory layout, it makes no sense
to hard allocate up to 1GB of the memory for stack which can't be used
as heap then.

This patch makes the stack size for 32-bit processes configurable and
uses 80MB as default value which has been in use during the last few
years on parisc and which hasn't showed any problems yet.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: linux-parisc@vger.kernel.org
Cc: linux-metag@vger.kernel.org
Cc: John David Anglin <dave.anglin@bell.net>
      042d27ac
    • James Hogan's avatar
      metag: Reduce maximum stack size to 256MB · d71f290b
      James Hogan authored 
      

Specify the maximum stack size for arches where the stack grows upward
(parisc and metag) in asm/processor.h rather than hard coding in
fs/exec.c so that metag can specify a smaller value of 256MB rather than
1GB.

This fixes a BUG on metag if the RLIMIT_STACK hard limit is increased
beyond a safe value by root. E.g. when starting a process after running
"ulimit -H -s unlimited" it will then attempt to use a stack size of the
maximum 1GB which is far too big for metag's limited user virtual
address space (stack_top is usually 0x3ffff000):

BUG: failure at fs/exec.c:589/shift_arg_pages()!

Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: linux-parisc@vger.kernel.org
Cc: linux-metag@vger.kernel.org
Cc: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # only needed for >= v3.9 (arch/metag)
      d71f290b
    • Mikulas Patocka's avatar
      metag: fix memory barriers · 2425ce84
      Mikulas Patocka authored 
      

Volatile access doesn't really imply the compiler barrier. Volatile access
is only ordered with respect to other volatile accesses, it isn't ordered
with respect to general memory accesses. Gcc may reorder memory accesses
around volatile access, as we can see in this simple example (if we
compile it with optimization, both increments of *b will be collapsed to
just one):

void fn(volatile int *a, long *b)
{
	(*b)++;
	*a = 10;
	(*b)++;
}

Consequently, we need the compiler barrier after a write to the volatile
variable, to make sure that the compiler doesn't reorder the volatile
write with something else.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
      2425ce84
    • Steven J. Hill's avatar
      MIPS: mm: Fix broken microMIPS kernel regression. · 7bb39409
      Steven J. Hill authored 
      

Commit f4ae17aa [MIPS: mm: Use scratch for
PGD when !CONFIG_MIPS_PGD_C0_CONTEXT] broke microMIPS kernel builds. This
patch refactors that code similar to what was done for the 'clear_page'
and 'copy_page' functions.

Signed-off-by: default avatarSteven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6744/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      7bb39409
    • Stephen Warren's avatar
      ARM: tegra: tegra_defconfig updates · 9956dcc5
      Stephen Warren authored 
      

AT24C EEPROM:

This is used for the board ID EEPROM on Jetson TK1, as well as likely
a whole slew of other NVIDIA reference boards; we simply haven't added
enabled the EEPROM in the DT files until now.

MTD_SPI_NOR:

This defconfig contains the CONFIG_M25P80 symbol, which is now
dependent on the MTD_SPI_NOR symbol. Add CONFIG_MTD_SPI_NOR to satisfy
the new dependency.

FRAMEBUFFER_CONSOLE_ROTATION:

Needed for devices like Tegra Note 7 and NVIDIA SHIELD to get the boot
console in the expected orientation.

CAN*, RTC_DRV_DS1307:

Toradex Colibri Evaluation Board uses the DS1307 RTC and the MCP251x CAN
controller. The NVIDIA Tegra 3 based Colibri T30 module can be used on
this carrier board.

Furthermore the NVIDIA Tegra 3 based Apalis T30 module too contains two
MCP251x CAN controllers.

INPUT_JOYDEV:

NVIDIA SHIELD embeds a USB joystick device.

Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Signed-off-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: default avatarStefan Agner <stefan@agner.ch>
Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
      9956dcc5
  17. May 13, 2014
  19. May 12, 2014
    • Ralf Baechle's avatar
      MIPS: inst.h: Rename BITFIELD_FIELD to __BITFIELD_FIELD. · 8471ac1b
      Ralf Baechle authored 
      

<uapi/asm/inst.h> is exported to userland so the macro name BITFIELD_FIELD
pollutes the namespace.  Prefix the name with __ fixes this.

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      8471ac1b
    • Ralf Baechle's avatar
      MIPS: Remove file missed when removing rm9k support a while ago. · cdbb03b0
      Ralf Baechle authored 
      

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      cdbb03b0
    • Aaro Koskinen's avatar
      MIPS/loongson2_cpufreq: Fix CPU clock rate setting · 8e8acb32
      Aaro Koskinen authored 
      

Loongson2 has been using (incorrectly) kHz for cpu_clk rate. This has
been unnoticed, as loongson2_cpufreq was the only place where the rate
was set/get. After commit 652ed95d
(cpufreq: introduce cpufreq_generic_get() routine) things however broke,
and now loops_per_jiffy adjustments are incorrect (1000 times too long).
The patch fixes this by changing cpu_clk rate to Hz.

Signed-off-by: default avatarAaro Koskinen <aaro.koskinen@iki.fi>
Cc: stable@vger.kernel.org
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: cpufreq@vger.kernel.org
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Patchwork: https://patchwork.linux-mips.org/patch/6678/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      8e8acb32
    • Paul Bolle's avatar
      MIPS: Loongson: No need to select GENERIC_HARDIRQS_NO__DO_IRQ · 3deff253
      Paul Bolle authored 
      

Commit 0e476d91 ("MIPS: Loongson: Add Loongson-3 Kconfig options")
added "select GENERIC_HARDIRQS_NO__DO_IRQ". But the Kconfig symbol
GENERIC_HARDIRQS_NO__DO_IRQ was already removed in v2.6.38, so that
select is a nop. Drop it.

Signed-off-by: default avatarPaul Bolle <pebolle@tiscali.nl>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/6677/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      3deff253
    • Maciej W. Rozycki's avatar
      MIPS: csum_partial.S CPU_DADDI_WORKAROUNDS bug fix · 44ba138f
      Maciej W. Rozycki authored 
      

This change reverts most of commit
60724ca5 [MIPS: IP checksums: Remove
unncessary .set pseudos] that introduced warnings with the
CPU_DADDI_WORKAROUNDS option set:

arch/mips/lib/csum_partial.S: Assembler messages:
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
[...]
arch/mips/lib/csum_partial.S:577: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:577: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:577: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3"
[and so on, and so on...]

The warnings are benign and good code is produced regardless because no
macros that'd use the assembler's temporary register are involved, however
the `.set noat' directives removed by the commit referred are crucial to
guarantee this is still going to be the case after any changes in the
future.  Therefore they need to be brought back to place which this
change does.

Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6686/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      44ba138f
    • Maciej W. Rozycki's avatar
      MIPS: __strncpy_from_user_asm CPU_DADDI_WORKAROUNDS bug fix · 465ca5d6
      Maciej W. Rozycki authored 
      

This corrects assembler warnings and broken code generated in
__strncpy_from_user_asm:

arch/mips/lib/strncpy_user.S: Assembler messages:
arch/mips/lib/strncpy_user.S:52: Warning: Macro instruction expanded into
multiple instructions in a branch delay slot

with the CPU_DADDI_WORKAROUNDS option set.  The function schedules delay
slots manually where there is really no need to as GAS is happy to do it
all itself, so undo it all and remove `.set noreorder'.

Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6685/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      465ca5d6
    • Maciej W. Rozycki's avatar
      MIPS: __delay CPU_DADDI_WORKAROUNDS bug fix · 2db4bc34
      Maciej W. Rozycki authored 
      

With CPU_DADDI_WORKAROUNDS enabled __delay assembles with a macro in a
branch delay slot:

{standard input}: Assembler messages:
{standard input}:18: Warning: Macro instruction expanded into multiple
instructions in a branch delay slot

and broken code results:

0000000000000000 <__delay>:
   0:	1480ffff 	bnez	a0,0 <__delay>
   4:	24010001 	li	at,1
   8:	0081202f 	dsubu	a0,a0,at
   c:	03e00008 	jr	ra
  10:	00000000 	nop
  14:	00000000 	nop

Consequently the function loops indefinitely, showing up prominently as a
hang in the delay loop calibration at bootstrap.

This change corrects the problem by forcing the immediate 1 into a
register while keeping code produced identical where CPU_DADDI_WORKAROUNDS
is disabled.

Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6669/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      2db4bc34
    • Maciej W. Rozycki's avatar
      MIPS: DEC/SNI: O32 wrapper stack switching fixes · 824122a3
      Maciej W. Rozycki authored 
      

Commit 231a35d3 [[MIPS] RM: Collected
changes] broke DECstation support by introducing an incompatible copy of
arch/mips/dec/prom/call_o32.S in arch/mips/fw/lib/, built unconditionally.
The copy happens to land earlier of the two among the modules used in the
link and is therefore chosen for the DECstation rather than the intended
original.  As a result random kernel data is corrupted because a pointer
to the "%s" formatted output template is used as a temporary stack pointer
rather than being passed down to prom_printf.  This also explains why
prom_printf still works, up to a point -- the next argument is the actual
string to output so it works just fine as the output template until enough
kernel data has been corrupted to cause a crash.

This change adjusts the modified wrapper in arch/mips/fw/lib/call_o32.S to
let callers request no stack switching by passing a null temporary stack
pointer in $a1, reworks the DECstation callers to work with the updated
interface and removes the old copy from arch/mips/dec/prom/call_o32.S.  A
few minor readability adjustments are included as well, most importantly
O32_SZREG is now used throughout where applicable rather than hardcoded
multiplies of 4 and $fp is used to access the argument save area as a more
usual register to operate the stack with rather than $s0.

Finally an update is made to the temporary stack space used by the SNI
platform to guarantee 8-byte alignment as per o32 requirements.

Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6668/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      824122a3
    • Maciej W. Rozycki's avatar
      MIPS: DEC: Bus error handler <asm/cpu-type.h> fixes · af37530b
      Maciej W. Rozycki authored 
      

Commit 69f24d17 [MIPS: Optimize
current_cpu_type() for better code.] missed an update for two DECstation
bus error support files that now do not build, this is a fix.

Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6667/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      af37530b