Commit graph

67 commits

Author SHA1 Message Date
Russell King
98797a241e Merge branch 'copy_user' of git://git.marvell.com/orion into devel 2009-06-14 10:59:32 +01:00
Nicolas Pitre
c626e3f5ca [ARM] alternative copy_to_user: more precise fallback threshold
Previous size thresholds were guessed from various user space benchmarks
using a kernel with and without the alternative uaccess option.  This
is however not as precise as a kernel based test to measure the real
speed of each method.

This adds a simple test bench to show the time needed for each method.
With this, the optimal size treshold for the alternative implementation
can be determined with more confidence.  It appears that the optimal
threshold for both copy_to_user and clear_user is around 64 bytes. This
is not a surprise knowing that the memcpy and memset implementations
need at least 64 bytes to achieve maximum throughput.

One might suggest that such test be used to determine the optimal
threshold at run time instead, but results are near enough to 64 on
tested targets concerned by this alternative copy_to_user implementation,
so adding some overhead associated with a variable threshold is probably
not worth it for now.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
2009-05-30 01:10:15 -04:00
Nicolas Pitre
cb9dc92c0a [ARM] lower overhead with alternative copy_to_user for small copies
Because the alternate copy_to_user implementation has a higher setup cost
than the standard implementation, the size of the memory area to copy
is tested and the standard implementation invoked instead when that size
is too small.  Still, that test is made after the processor has preserved
a bunch of registers on the stack which have to be reloaded right away
needlessly in that case, causing a measurable performance regression
compared to plain usage of the standard implementation only.

To make the size test overhead negligible, let's factorize it out of
the alternate copy_to_user function where it is clear to the compiler
that no stack frame is needed.  Thanks to CONFIG_ARM_UNWIND allowing
for frame pointers to be disabled and tail call optimization to kick in,
the overhead in the small copy case becomes only 3 assembly instructions.

A similar trick is applied to clear_user as well.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
2009-05-29 22:38:33 -04:00
Lennert Buytenhek
39ec58f3fe [ARM] alternative copy_to_user/clear_user implementation
This implements {copy_to,clear}_user() by faulting in the userland
pages and then using the regular kernel mem{cpy,set}() to copy the
data (while holding the page table lock).  This is a win if the regular
mem{cpy,set}() implementations are faster than the user copy functions,
which is the case e.g. on Feroceon, where 8-word STMs (which memcpy()
uses under the right conditions) give significantly higher memory write
throughput than a sequence of individual 32bit stores.

Here are numbers for page sized buffers on some Feroceon cores:

 - copy_to_user on Orion5x goes from 51 MB/s to 83 MB/s
 - clear_user on Orion5x goes from 89MB/s to 314MB/s
 - copy_to_user on Kirkwood goes from 240 MB/s to 356 MB/s
 - clear_user on Kirkwood goes from 367 MB/s to 1108 MB/s
 - copy_to_user on Disco-Duo goes from 248 MB/s to 398 MB/s
 - clear_user on Disco-Duo goes from 328 MB/s to 1741 MB/s

Because the setup cost is non negligible, this is worthwhile only if
the amount of data to copy is large enough.  The operation falls back
to the standard implementation when the amount of data is below a certain
threshold. This threshold was determined empirically, however some targets
could benefit from a lower runtime determined value for optimal results
eventually.

In the copy_from_user() case, this technique does not provide any
worthwhile performance gain due to the fact that any kind of read access
allocates the cache and subsequent 32bit loads are just as fast as the
equivalent 8-word LDM.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Tested-by: Martin Michlmayr <tbm@cyrius.com>
2009-05-29 22:36:45 -04:00
Nicolas Pitre
a1f98849fd [ARM] allow for alternative __copy_to_user/__clear_user implementations
This allows for optional alternative implementations of __copy_to_user
and __clear_user, with a possible runtime fallback to the standard
version when the alternative provides no gain over that standard
version. This is done by making the standard __copy_to_user into a weak
alias for the symbol __copy_to_user_std.  Same thing for __clear_user.

Those two functions are particularly good candidates to have alternative
implementations for, since they rely on the STRT instruction which has
lower performances than STM instructions on some CPU cores such as
the ARM1176 and Marvell Feroceon.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
2009-05-29 22:34:45 -04:00
Russell King
bac4e960b5 [ARM] barriers: improve xchg, bitops and atomic SMP barriers
Mathieu Desnoyers pointed out that the ARM barriers were lacking:

- cmpxchg, xchg and atomic add return need memory barriers on
  architectures which can reorder the relative order in which memory
  read/writes can be seen between CPUs, which seems to include recent
  ARM architectures. Those barriers are currently missing on ARM.

- test_and_xxx_bit were missing SMP barriers.

So put these barriers in.  Provide separate atomic_add/atomic_sub
operations which do not require barriers.

Reported-Reviewed-and-Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-28 19:39:27 +01:00
Russell King
31bccbf392 Merge branch 'clps7500' into devel
Conflicts:

	arch/arm/Kconfig
2008-11-27 12:39:43 +00:00
Russell King
635f0258e5 [ARM] clps7500: remove support
The CLPS7500 platform has not built since 2.6.22-git7 and there
seems to be no interest in fixing it.  So, remove the platform
support.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-27 12:38:11 +00:00
Russell King
59f0cb0fdd [ARM] remove memzero()
As suggested by Andrew Morton, remove memzero() - it's not supported
on other architectures so use of it is a potential build breaking bug.
Since the compiler optimizes memset(x,0,n) to __memzero() perfectly
well, we don't miss out on the underlying benefits of memzero().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-27 12:37:59 +00:00
Russell King
6a4690c22f Merge branch 'ptebits' into devel
Conflicts:

	arch/arm/Kconfig
2008-10-09 21:31:56 +01:00
Catalin Marinas
22acc4e650 [ARM] 5231/1: Do not save the frame pointer in the csum_partial_copy_* functions
Since the other assembly functions do not seem to save the frame
pointer onto the stack, this patch changes the csum_partial_copy_*
functions to behave in the same way.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01 12:06:35 +01:00
Catalin Marinas
9c23e5fefa [ARM] 5232/1: Do not post-index STRT instruction in clear_user.S
The last strnebt instruction has a post-index of 1 but the address
register is set to 0 in the next instruction, so no need for
post-indexing.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01 12:06:34 +01:00
Catalin Marinas
93ed397011 [ARM] 5227/1: Add the ENDPROC declarations to the .S files
This declaration specifies the "function" type and size for various
assembly functions, mainly needed for generating the correct branch
instructions in Thumb-2.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01 12:06:34 +01:00
Jean-Christophe DUBOIS
212496fd9a [ARM] 5226/1: remove unmatched comment end.
remove unmatched comment end.

Signed-off-by: Jean-Christophe DUBOIS <jcd@tribudubois.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-28 17:12:29 +01:00
Russell King
a09e64fbc0 [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach
This just leaves include/asm-arm/plat-* to deal with.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-07 09:55:48 +01:00
Russell King
be50972935 [ARM] Remove asm/hardware.h, use asm/arch/hardware.h instead
Remove includes of asm/hardware.h in addition to asm/arch/hardware.h.
Then, since asm/hardware.h only exists to include asm/arch/hardware.h,
update everything to directly include asm/arch/hardware.h and remove
asm/hardware.h.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-07 09:40:08 +01:00
Russell King
4baa992243 [ARM] move include/asm-arm to arch/arm/include/asm
Move platform independent header files to arch/arm/include/asm, leaving
those in asm/arch* and asm/plat* alone.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-02 21:32:35 +01:00
Nicolas Pitre
f91a8dcc25 [ARM] cache align memset and memzero
This is a natural extension following the previous patch.
Non Feroceon based targets are unchanged.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
2008-06-22 22:44:39 +02:00
Nicolas Pitre
2239aff6ab [ARM] cache align destination pointer when copying memory for some processors
The implementation for memory copy functions on ARM had a (disabled)
provision for aligning the source pointer before loading registers with
data.  Turns out that aligning the _destination_ pointer is much more
useful, as the read side is already sufficiently helped with the use of
preload.

So this changes the definition of the CALGN() macro to target the
destination pointer instead, and turns it on for Feroceon processors
where the gain is very noticeable.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
2008-06-22 22:44:38 +02:00
Nicolas Pitre
4c4925c1f4 [ARM] fix cache alignment code in memset.S
This code is currently disabled, which explains why no one was affected.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
2008-06-22 22:44:37 +02:00
Simon Arlott
6cbdc8c535 [ARM] spelling fixes
Spelling fixes in arch/arm/.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-05-20 20:10:32 +01:00
Russell King
235b185ce4 [ARM] getuser.S and putuser.S don't need thread_info.h nor asm-offsets.h
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-04-21 20:35:22 +01:00
Russell King
7ab3f8d595 [ARM] Add ability to dump exception stacks to kernel backtraces
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-04-21 20:34:34 +01:00
Jörn Engel
6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Russell King
583e7f5d36 [ARM] nommu: backtrace code must not reference a discarded section
The code in "1007:" is in the .fixup section, which in the mmuless
case is discarded.  Since this code is referenced from the .text
section, it causes an link error.  Move this code into the .text
section instead.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-06-28 17:59:57 +01:00
Russell King
9641c7cc5a [ARM] nommu: uaccess tweaks
MMUless systems have only one address space for all threads, so
both the usual access_ok() checks, and the exception handling do
not make much sense.

Hence, discard the fixup and exception tables at link time, use
memcpy/memset for the user copy/clearing functions, and define
the permission check macros to be constants.

Some of this patch was derived from the equivalent patch by
Hyok S. Choi.

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-06-28 17:59:46 +01:00
Russell King
02fcb97436 [ARM] Remove the __arch_* layer from uaccess.h
Back in the days when we had armo (26-bit) and armv (32-bit) combined,
we had an additional layer to the uaccess macros to ensure correct
typing.  Since we no longer have 26-bit in this tree, we no longer
need this layer, so eliminate it.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-06-28 17:53:27 +01:00
Russell King
405040a78b [ARM] Remove save_lr/restore_pc macros
As for RETINSTR/LOADREGS macros, these were for compatibility
with 26-bit ARMs.  No longer required, so remove them.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-06-25 11:37:09 +01:00
Russell King
1b93a71755 [ARM] Remove LOADREGS macro
As for RETINSTR, LOADREGS is a left-over from the 26-bit days.
Remove it.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-06-25 11:23:45 +01:00
Russell King
7999d8d7a6 [ARM] Remove RETINSTR macro
RETINSTR is a left-over from the days when we had 26-bit and
32-bit CPU support integrated into the same tree.  Since this
is no longer the case, we can now remove RETINSTR.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-06-25 11:17:23 +01:00
Nicolas Pitre
1d6760a3ac [ARM] 3524/1: ARM EABI: more 64-bit aligned stack fixes
Patch from Nicolas Pitre

Assembly code that calls C code must ensure the C code sees a 64-bit
aligned stack pointer.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-05-16 11:39:31 +01:00
Linus Torvalds
ca9ba4471c Merge master.kernel.org:/home/rmk/linux-2.6-arm
* master.kernel.org:/home/rmk/linux-2.6-arm:
  [ARM] 3388/1: ixp23xx: add core ixp23xx support
  [ARM] 3417/1: add support for logicpd pxa270 card engine
  [ARM] 3387/1: ixp23xx: add defconfig
  [ARM] 3377/2: add support for intel xsc3 core
  [ARM] Move ice-dcc code into misc.c
  [ARM] Fix decompressor serial IO to give CRLF not LFCR
  [ARM] proc-v6: mark page table walks outer-cacheable, shared.  Enable NX.
  [ARM] nommu: trivial patch for arch/arm/lib/Makefile
  [ARM] 3416/1: Update LART site URL
  [ARM] 3415/1: Akita: Add missing EXPORT_SYMBOL
  [ARM] 3414/1: ep93xx: reset ethernet controller before uncompressing
2006-03-28 13:53:03 -08:00
Alexey Dobriyan
7f927fcc2f [PATCH] Typo fixes
Fix a lot of typos.  Eyeballed by jmc@ in OpenBSD.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 09:16:08 -08:00
Hyok S. Choi
4682adcfb0 [ARM] nommu: trivial patch for arch/arm/lib/Makefile
ifeq ($CONFIG_PREEMPT,y) -> ifeq ($(CONFIG_PREEMPT),y)

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-03-27 15:46:06 +01:00
Malcolm Parsons
3ee357f0f3 [ARM] 3399/1: Fix link problem when CONFIG_PRINTK is disabled
Patch from Malcolm Parsons

Printking a backtrace requires printk, so disable backtrace code
when printk is disabled.

Without this patch, a kernel with CONFIG_PRINTK disabled does not link:

arch/arm/lib/lib.a(backtrace.o): In function `c_backtrace':
arch/arm/lib/backtrace.S:(.text+0x108): undefined reference to `printk'
arch/arm/lib/backtrace.S:(.text+0x11c): undefined reference to `printk'
arch/arm/lib/lib.a(backtrace.o):(.fixup+0x8): undefined reference to `printk'

Signed-off-by: Malcolm Parsons <malcolm.parsons@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-03-25 21:58:03 +00:00
Peter Teichmann
6d4518d76f [ARM] 3346/1: Fix udelay() for HZ values different from 100
Patch from Peter Teichmann

Currently, if the kernels HZ value is greater than 100, delays with the udelay function are too short. This can cause trouble for instance with the zd1201 usb wlan driver.

This patch suggests a solution that keeps the overhead small and maintains (hopefully) sufficient resolution.

Signed-off-by: Peter Teichmann
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-03-21 22:06:07 +00:00
Russell King
f78f104368 [ARM] Remove unnecessary asm/hardware.h includes
asm/hardware.h is not required for the majority of processor support
files, ioremap support, mm initialisation, acorn IO support, nor
the debug code (which picks up its machine specific includes via
debug-macros.S)

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-03-21 22:05:50 +00:00
Russell King
3c8fdae78c [ARM] Fix muldi3.S
When shifting the low-parts of signed numbers, a logical shift
should be used to avoid sign-extending a bit which isn't a sign
bit.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-03-08 17:25:33 +00:00
Nicolas Pitre
ba95e4e4a0 [ARM] 3104/1: ARM EABI: new helper function names
Patch from Nicolas Pitre

The ARM EABI defines new names for GCC helper functions.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-14 16:18:29 +00:00
Nicolas Pitre
499b2ea11f [ARM] 3103/1: ARM EABI: stack pointer must be 64-bit aligned (part 2)
Patch from Nicolas Pitre

We must make sure that assembly code that modifies the stack pointer
before calling a C function does it so it remains 64-bit aligned.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-14 16:18:09 +00:00
Catalin Marinas
90303b1023 [ARM] 3256/1: Make the function-returning ldm's use sp as the base register
Patch from Catalin Marinas

If the low interrupt latency mode is enabled for the CPU (from ARMv6
onwards), the ldm/stm instructions are no longer atomic. An ldm instruction
restoring the sp and pc registers can be interrupted immediately after sp
was updated but before the pc. If this happens, the CPU restores the base
register to the value before the ldm instruction but if the base register
is not sp, the interrupt routine will corrupt the stack and the restarted
ldm instruction will load garbage.

Note that future ARM cores might always run in the low interrupt latency
mode.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-12 16:53:51 +00:00
Russell King
d2c5b69099 [ARM] Fix get_user when passed a const pointer
Unfortunately, later gcc versions error out when our get_user is passed
a const pointer, since we write to a temporary variable declared as
typeof(*(p)) which propagates the const-ness.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-18 14:22:03 +00:00
Nicolas Pitre
8adbb3718d [ARM] 3152/1: make various assembly local labels actually local (the rest)
Patch from Nicolas Pitre

For assembly labels to actually be local they must start with ".L" and
not only "." otherwise they still remain visible in the final link and
clutter kallsyms needlessly, and possibly make for unclear symbolic
backtrace. This patch simply inserts a"L" where appropriate. The code
itself is unchanged.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-11 21:51:49 +00:00
Nicolas Pitre
a9c4814d8d [ARM] 3151/1: make various assembly local labels actually local (io-*.S)
Patch from Nicolas Pitre

For assembly labels to actually be local they must start with ".L" and
not only "." otherwise they still remain visible in the final link and
clutter kallsyms needlessly, and possibly make for unclear symbolic
backtrace. This patch simply inserts a"L" where appropriate. The code
itself is unchanged.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-11 21:51:48 +00:00
Nicolas Pitre
7ba11a9c15 [ARM] 3150/1: make various assembly local labels actually local (uaccess.S)
Patch from Nicolas Pitre

For assembly labels to actually be local they must start with ".L" and
not only "." otherwise they still remain visible in the final link and
clutter kallsyms needlessly, and possibly make for unclear symbolic
backtrace. This patch simply inserts a"L" where appropriate. The code
itself is unchanged.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-11 21:51:47 +00:00
Russell King
af36bef0c5 [ARM] Fix csumpartial corner case
Ji-In Park discovered a bug in csumpartial which caused wrong
checksums with misaligned buffers.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-10 11:40:53 +00:00
Russell King
59d1ff3bfb [ARM] Clean up save_and_disable_irqs macro and allow use of ARMv6 CPSID
save_and_disable_irqs does not need to use mov + msr (which was
introduced to work around a documentation bug which was propagated
into binutils.)  Use msr with an immediate constant, and if we're
building for ARMv6 or later, use the new CPSID instruction.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-09 15:04:22 +00:00
Nicolas Pitre
73f0f7c79b [ARM] 3094/1: remove PLD stuff from old uaccess code
Patch from Nicolas Pitre

ARM processors that have pld instructions are not using those copy_user
implementation anymore.  Let's remove the useless PLD lines which were
half wrong anyway.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-04 17:15:43 +00:00
Russell King
4a5f79e7e6 [ARM SMP] Add configuration option for ARMv6K processors
The 'K' extension adds several new instructions to the ARMv6 ISA
which are primerily useful for SMP.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-03 15:48:21 +00:00
Nicolas Pitre
fadab0943d [ARM] 2948/1: new preemption safe copy_{to|from}_user implementation
Patch from Nicolas Pitre

This patch provides a preemption safe implementation of copy_to_user
and copy_from_user based on the copy template also used for memcpy.
It is enabled unconditionally when CONFIG_PREEMPT=y.  Otherwise if the
configured architecture is not ARMv3 then it is enabled as well as it
gives better performances at least on StrongARM and XScale cores.  If
ARMv3 is not too affected or if it doesn't matter too much then
uaccess.S could be removed altogether.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-11-01 19:52:24 +00:00