linux-toradex.git/arch/sparc/include, branch v3.7.6

sparc: huge_ptep_set_* functions need to call set_huge_pte_at()

2013-01-11T17:18:50+00:00

[ Upstream commit 6cb9c3697585c47977c42c5cc1b9fc49247ac530 ]

Modifying the huge pte's requires that all the underlying pte's be
modified.

Version 2: added missing flush_tlb_page()

Signed-off-by: Dave Kleikamp 
Cc: "David S. Miller" 
Cc: sparclinux@vger.kernel.org
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

of/address: sparc: Declare of_iomap as an extern function for sparc again

2012-11-23T22:01:15+00:00

This bug-fix makes sure that of_iomap is defined extern for sparc so that the
sparc-specific implementation of_iomap is once again used when including
include/linux/of_address.h in a sparc context. OF_GPIO that is now available for
sparc relies on this.

The bug was inadvertently introduced in a850a75, "of/address: add empty static
inlines for !CONFIG_OF", that added a static dummy inline for of_iomap when
!CONFIG_OF_ADDRESS. However, CONFIG_OF_ADDRESS is never defined for sparc, but
there is a sparc-specific implementation /arch/sparc/kernel/of_device_common.c.

This fix takes the same approach as 0bce04b that solved the equivalent problem
for of_address_to_resource.

Signed-off-by: Andreas Larsson 
Acked-by: David Miller 
Signed-off-by: Grant Likely

sparc: Support atomic64_dec_if_positive properly.

2012-11-10T03:37:59+00:00

Sparc32 already supported it, as a consequence of using the
generic atomic64 implementation.  And the sparc64 implementation
is rather trivial.

This allows us to set ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE for all
of sparc, and avoid the annoying warning from lib/atomic64_test.c

Signed-off-by: David S. Miller

of/address: sparc: Declare of_address_to_resource() as an extern function for sparc again

2012-11-10T00:30:50+00:00

This bug-fix makes sure that of_address_to_resource is defined extern for sparc
so that the sparc-specific implementation of of_address_to_resource() is once
again used when including include/linux/of_address.h in a sparc context. A
number of drivers in mainline relies on this function working for sparc.

The bug was introduced in a850a7554442f08d3e910c6eeb4ee216868dda1e, "of/address:
add empty static inlines for !CONFIG_OF". Contrary to that commit title, the
static inlines are added for !CONFIG_OF_ADDRESS, and CONFIG_OF_ADDRESS is never
defined for sparc. This is good behavior for the other functions in
include/linux/of_address.h, as the extern functions defined in
drivers/of/address.c only gets linked when OF_ADDRESS is configured. However,
for of_address_to_resource there exists a sparc-specific implementation in
arch/sparc/arch/sparc/kernel/of_device_common.c

Solution suggested by: Sam Ravnborg 

Signed-off-by: Andreas Larsson 
Acked-by: Rob Herring 
Signed-off-by: David S. Miller

sparc: Wire up sys_kcmp.

2012-10-28T20:15:09+00:00

Signed-off-by: David S. Miller

sparc64: Improvde documentation and readability of atomic backoff code.

2012-10-28T20:04:47+00:00

Document what's going on in asm/backoff.h with a large and descriptive
comment.  Refer to it above the cpu_relax() definition in
asm/processor_64.h

Rename the pause patching section to have "3insn" in it's name like
the other patching sections do.

Based upon feedback from Sam Ravnborg.

Signed-off-by: David S. Miller

sparc64: Use pause instruction when available.

2012-10-28T06:00:41+00:00

In atomic backoff and cpu_relax(), use the pause instruction
found on SPARC-T4 and later.

It makes the cpu strand unselectable for the given number of
cycles, unless an intervening disrupting trap occurs.

Signed-off-by: David S. Miller

sparc64: Fix cpu strand yielding.

2012-10-28T01:35:27+00:00

For atomic backoff, we just loop over an exponentially backed off
counter.  This is extremely ineffective as it doesn't actually yield
the cpu strand so that other competing strands can use the cpu core.

In cpus previous to SPARC-T4 we have to do this in a slightly hackish
way, by doing an operation with no side effects that also happens to
mark the strand as unavailable.

The mechanism we choose for this is three reads of the %ccr
(condition-code) register into %g0 (the zero register).

SPARC-T4 has an explicit "pause" instruction, and we'll make use of
that in a subsequent commit.

Yield strands also in cpu_relax().  We really should have done this a
very long time ago.

Signed-off-by: David S. Miller

sparc64: Make montmul/montsqr/mpmul usable in 32-bit threads.

2012-10-26T22:18:37+00:00

The Montgomery Multiply, Montgomery Square, and Multiple-Precision
Multiply instructions work by loading a combination of the floating
point and multiple register windows worth of integer registers
with the inputs.

These values are 64-bit.  But for 32-bit userland processes we only
save the low 32-bits of each integer register during a register spill.
This is because the register window save area is in the user stack and
has a fixed layout.

Therefore, the only way to use these instruction in 32-bit mode is to
perform the following sequence:

1) Load the top-32bits of a choosen integer register with a sentinel,
   say "-1".  This will be in the outer-most register window.

   The idea is that we're trying to see if the outer-most register
   window gets spilled, and thus the 64-bit values were truncated.

2) Load all the inputs for the montmul/montsqr/mpmul instruction,
   down to the inner-most register window.

3) Execute the opcode.

4) Traverse back up to the outer-most register window.

5) Check the sentinel, if it's still "-1" store the results.
   Otherwise retry the entire sequence.

This retry is extremely troublesome.  If you're just unlucky and an
interrupt or other trap happens, it'll push that outer-most window to
the stack and clear the sentinel when we restore it.

We could retry forever and never make forward progress if interrupts
arrive at a fast enough rate (consider perf events as one example).
So we have do limited retries and fallback to software which is
extremely non-deterministic.

Luckily it's very straightforward to provide a mechanism to let
32-bit applications use a 64-bit stack.  Stacks in 64-bit mode are
biased by 2047 bytes, which means that the lowest bit is set in the
actual %sp register value.

So if we see bit zero set in a 32-bit application's stack we treat
it like a 64-bit stack.

Runtime detection of such a facility is tricky, and cumbersome at
best.  For example, just trying to use a biased stack and seeing if it
works is hard to recover from (the signal handler will need to use an
alt stack, plus something along the lines of longjmp).  Therefore, we
add a system call to report a bitmask of arch specific features like
this in a cheap and less hairy way.

With help from Andy Polyakov.

Signed-off-by: David S. Miller

Merge tag 'uapi-fixes-20121017' of git://git.infradead.org/users/dhowells/linux-headers

2012-10-17T20:40:22+00:00

Pull misc UAPI fixes from David Howells:
 "They do a number of things:

  (1) Import a patch from Catalin Marinas to extend the generic-y in
      Kbuild facility to uapi directories.

  (2) Make arch/tile's ucontext.h file use (1) and remove the header-y
      line from the kernel internal side of things.

  (3) Remove some now-empty conditional bits from include/linux/Kbuild.
      The contents got moved to the UAPI side of things along with new
      conditionals.

  (4) Deal with now-empty files:

     (a) Empty Kbuild files under include/ get removed.

     (b) Empty Kbuild files under arch/ get comments to hold them as
         they are likely to end up with generic-y or genhdr-y lines.
         Deleting them appears to work if we want to go that route.

     (c) Put a comment into uapi/asm-generic/kvm_para.h to prevent the
         patch program from deleting that, and made the arches with
         empty kvm_para.h uapi files use that instead of having their
         own files.

     (d) Put comments into four other empty uapi/ headers to prevent the
         patch program from deleting them.

  A question: Is this the right way to deal with the now-empty Kbuild
  files?

  The ones under include/ are unlikely to be used - even for generated
  files, I think - so getting rid of them is probably okay.  Once all
  the bits are in, we can probably remove all the Kbuild files under
  include/ that aren't also under include/uapi/.

  The ones under arch/ are more of an issue because of the potential for
  generic-y and genhdr-y."

* tag 'uapi-fixes-20121017' of git://git.infradead.org/users/dhowells/linux-headers:
  UAPI: Make arch/sparc/include/uapi/asm/sigcontext.h non-empty
  UAPI: Make arch/sh/include/uapi/asm/hw_breakpoint.h non-empty
  UAPI: Make arch/mn10300/include/uapi/asm/setup.h non-empty
  UAPI: Put a comment into uapi/asm-generic/kvm_para.h and use it from arches
  UAPI: The tile arch uses the generic ucontext.h file
  UAPI: Place comments in empty arch Kbuilds to make them non-empty
  UAPI: Remove empty non-UAPI Kbuild files
  UAPI: Remove empty conditionals from include/linux/Kbuild
  UAPI: Make uapi/linux/irqnr.h non-empty
  uapi: Allow automatic generation of uapi/asm/ header files