Commit Graph

15 Commits

Author SHA1 Message Date
David S. Miller
517ffce4e1 sparc64: Make montmul/montsqr/mpmul usable in 32-bit threads.
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 <davem@davemloft.net>
2012-10-26 15:18:37 -07:00
David S. Miller
456d3d4246 sparc64: Fix several bugs in quad floating point emulation.
UltraSPARC-T2 and later do not use the fp_exception_other trap and do
not set the floating point trap type field in the %fsr at all when you
try to execute an unimplemented FPU operation.

Instead, it uses the illegal_instruction trap and it leaves the
floating point trap type field clear.

So we should not validate the %fsr trap type field when do_mathemu()
is invoked from the illegal instruction handler.

Also, the floating point trap type field is 3 bits, not 4 bits.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-25 00:31:56 -07:00
David Howells
d550bbd40c Disintegrate asm/system.h for Sparc
Disintegrate asm/system.h for Sparc.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: sparclinux@vger.kernel.org
2012-03-28 18:30:03 +01:00
Peter Zijlstra
a8b0ca17b8 perf: Remove the nmi parameter from the swevent and overflow interface
The nmi parameter indicated if we could do wakeups from the current
context, if not, we would set some state and self-IPI and let the
resulting interrupt do the wakeup.

For the various event classes:

  - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from
    the PMI-tail (ARM etc.)
  - tracepoint: nmi=0; since tracepoint could be from NMI context.
  - software: nmi=[0,1]; some, like the schedule thing cannot
    perform wakeups, and hence need 0.

As one can see, there is very little nmi=1 usage, and the down-side of
not using it is that on some platforms some software events can have a
jiffy delay in wakeup (when arch_irq_work_raise isn't implemented).

The up-side however is that we can remove the nmi parameter and save a
bunch of conditionals in fast paths.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Cree <mcree@orcon.net.nz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-01 11:06:35 +02:00
Lucas De Marchi
25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Linus Torvalds
13da9e200f Revert "endian: #define __BYTE_ORDER"
This reverts commit b3b77c8cae, which was
also totally broken (see commit 0d2daf5cc8 that reverted the crc32
version of it).  As reported by Stephen Rothwell, it causes problems on
big-endian machines:

> In file included from fs/jfs/jfs_types.h:33,
>                  from fs/jfs/jfs_incore.h:26,
>                  from fs/jfs/file.c:22:
> fs/jfs/endian24.h:36:101: warning: "__LITTLE_ENDIAN" is not defined

The kernel has never had that crazy "__BYTE_ORDER == __LITTLE_ENDIAN"
model.  It's not how we do things, and it isn't how we _should_ do
things.  So don't go there.

Requested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-26 08:30:15 -07:00
Joakim Tjernlund
b3b77c8cae endian: #define __BYTE_ORDER
Linux does not define __BYTE_ORDER in its endian header files which makes
some header files bend backwards to get at the current endian.  Lets
#define __BYTE_ORDER in big_endian.h/litte_endian.h to make it easier for
header files that are used in user space too.

In userspace the convention is that

  1. _both_ __LITTLE_ENDIAN and __BIG_ENDIAN are defined,
  2. you have to test for e.g. __BYTE_ORDER == __BIG_ENDIAN.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:07:02 -07:00
David S. Miller
121dd5f277 sparc: Add alignment and emulation fault perf events.
This mirrors commit 196f02bf90
(powerpc: perf_event: Add alignment-faults and emulation-faults software events)

Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-11 01:07:53 -08:00
Sam Ravnborg
5115f39c20 sparc64: unify math-emu
Move relavent files to sparc/math-emu and
adjust path/include accordingly.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-04 09:16:56 -08:00
Sam Ravnborg
774434bf33 sparc: prepare math-emu for unification
Add _32 to filenames to make them 32 bit unique

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-04 09:16:56 -08:00
Sam Ravnborg
d59b3706a9 sparc: cleanup math-emu
- Drop unused assignment from Makefile
- Replace EXTRA_CFLAGS with ccflags-y
- Delete unused file

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-04 09:16:55 -08:00
Adrian Bunk
88278ca27a sparc: remove CVS keywords
This patch removes the CVS keywords that weren't updated for a long time
from comments.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-20 00:33:44 -07:00
Sam Ravnborg
b46da0567d kbuild: use relative path to -I
Using a relative path has the advantage that when the kernel source
tree is moved the relevant .o files will not be rebuild just because
the path to the kernel src has changed.
This also got rid of a user of TOPDIR - which has been deprecated for a long time now.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2006-04-04 16:56:10 +02:00
David S. Miller
22f01da398 [SPARC]: Fix compile failures in math-emu.
Kill debugging default switch cases in do_one_mathemu().
That case is handled properly already and gcc hates
the empty statement that results when the debug code is
disabled.

Pointed out by kaffe.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-30 16:46:24 -08:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00