[PATCH 1/3] Rename ARM assembler push/pull macros
The ARM assembler library functions use a macro called push that
along with a macro called pull is used to shift bytes around in a
word in an endian-independent way. However, the modern unified
ARM assembler syntax also defines the instruction push to push
data onto the stack, which has specific encodings in the Thumb2
instruction set. For prevent possible conflicts going forward, and
to allow the use of the more transparent push instruction along
with the modern unified assembler syntax, this patch renames all
occurrences of the push macro to pushbits, as well as renaming
the macro argument, when also called push, to pushshift.

For consistency, the macro called pull with its argument name
pull are also renamed to pullbits and pullshift, respectively.
ARM: 7668/1: fix memset-related crashes caused by recent GCC (4.7.2) optimizations

Recent GCC versions (e.g. GCC-4.7.2) perform optimizations based on
assumptions about the implementation of memset and similar functions.
The current ARM optimized memset code does not return the value of
its first argument, as is usually expected from standard implementations.

For instance in the following function:

void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
{
	memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
	waiter->magic = waiter;
	INIT_LIST_HEAD(&waiter->list);
}

compiled as:

800554d0 <debug_mutex_lock_common>:
800554d0:       e92d4008        push    {r3, lr}
800554d4:       e1a00001        mov     r0, r1
800554d8:       e3a02010        mov     r2, #16 ; 0x10
800554dc:       e3a01011        mov     r1, #17 ; 0x11
800554e0:       eb04426e        bl      80165ea0 <memset>
800554e4:       e1a03000        mov     r3, r0
800554e8:       e583000c        str     r0, [r3, #12]
800554ec:       e5830000        str     r0, [r3]
800554f0:       e5830004        str     r0, [r3, #4]
800554f4:       e8bd8008        pop     {r3, pc}

GCC assumes memset returns the value of pointer 'waiter' in register r0; causing
register/memory corruptions.

This patch fixes the return value of the assembly version of memset.
It adds a 'mov' instruction and merges an additional load+store into
existing load/store instructions.
For ease of review, here is a breakdown of the patch into 4 simple steps:

Step 1
======
Perform the following substitutions:
ip -> r8, then
r0 -> ip,
and insert 'mov ip, r0' as the first statement of the function.
At this point, we have a memset() implementation returning the proper result,
but corrupting r8 on some paths (the ones that were using ip).

Step 2
======
Make sure r8 is saved and restored when (! CALGN(1)+0) == 1:

save r8:
-       str     lr, [sp, #-4]!
+       stmfd   sp!, {r8, lr}

and restore r8 on both exit paths:
-       ldmeqfd sp!, {pc}               @ Now <64 bytes to go.
+       ldmeqfd sp!, {r8, pc}           @ Now <64 bytes to go.
(...)
        tst     r2, #16
        stmneia ip!, {r1, r3, r8, lr}
-       ldr     lr, [sp], #4
+       ldmfd   sp!, {r8, lr}

Step 3
======
Make sure r8 is saved and restored when (! CALGN(1)+0) == 0:

save r8:
-       stmfd   sp!, {r4-r7, lr}
+       stmfd   sp!, {r4-r8, lr}

and restore r8 on both exit paths:
        bgt     3b
-       ldmeqfd sp!, {r4-r7, pc}
+       ldmeqfd sp!, {r4-r8, pc}
(...)
        tst     r2, #16
        stmneia ip!, {r4-r7}
-       ldmfd   sp!, {r4-r7, lr}
+       ldmfd   sp!, {r4-r8, lr}

Step 4
======
Rewrite register list "r4-r7, r8" as "r4-r8".

Signed-off-by: Ivan Djelic <ivan.djelic@parrot.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7670/1: fix the memset fix

Commit 455bd4c430b0 ("ARM: 7668/1: fix memset-related crashes caused by
recent GCC (4.7.2) optimizations") attempted to fix a compliance issue
with the memset return value.  However the memset itself became broken
by that patch for misaligned pointers.

This fixes the above by branching over the entry code from the
misaligned fixup code to avoid reloading the original pointer.

Also, because the function entry alignment is wrong in the Thumb mode
compilation, that fixup code is moved to the end.

While at it, the entry instructions are slightly reworked to help dual
issue pipelines.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Alexander Holler <holler@ahsoftware.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[PATCH 3/3] Optimize ARM memset and memzero functions

The ARM memset and memzero functions are optimized with lower overhead
for small requests, generation of more 16-bit Thumb2 instructions when
compiled in Thumb2 mode, and configurable destination alignment before
the main block-copying loop.

The new compile-time constant MEMSET_WRITE_ALIGN_BYTES is introduced
in assembler.h, to augment the CALGN macro that previously regulated
32-byte write alignment but was only used on the Feroceon platform.
MEMSET_WRITE_ALIGN_BYTES can have values of 0 (no write alignment),
8, or 32. Apart from Feroceon, memset write alignment of 32 bytes
appears to benefit the armv6 platform, while the armv7 platform
seems benefit from alignment to 8 bytes for memset/memzero.

The CALGN macro is renamed to MEMSET_CALGN for memset and memzero; the
original CALGN macro is reserved for the memcpy family of functions
(memcpy, copy_from_user, copy_to_user) currently implemented in
copy_template.S, and the associated compile time constant
WRITE_ALIGN_BYTES defines the write alignment for memcpy-related
functions that will be utilized in subsequent contributions. Because
the current CALGN implementation in copy_template.S only implements
32-byte write alignment and is broken on Thumb2, it is only enabled
when WRITE_ALIGN_BYTES is equal to 32 and Thumb2 mode is not enabled.

Finally, memset and memzero now include a directive to enable unified
ARM assembler syntax.

Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>
[PATCH 2/3] Optimize copy_page for modern ARM platforms

The existing implementation of copy_page for ARM appears to be
optimized for older platforms. Benchmark testing in a sandbox
environment shows suboptimal performance on modern platforms
like armv6 and armv7, with speed-ups ranging from 10% (Cortex A8)
to 80% (armv6 used in Raspberry Pi) being achievable.

This commit optimizes copy_page and introduces the new compile-time
constant PREFETCH_DISTANCE, defined in cache.h, which when
multiplied by L1_CACHE_BYTES is equal to the offset used for
prefetches performed with the PLD instruction. For platforms where
L1_CACHE_BYTES is 32 (armv5 and armv6), copy_page processes 32 bytes
at a time while doing one prefetch per iteration, while for armv7
(with L1_CACHE_BYTES equal to 64), 64 bytes are processed at at time
with one prefetch per iteration. When no preload instruction is
available (platforms earlier than armv5), no preload instructions
are generated and 32 bytes are processed at at time.

To facilitate specifying instructions for architectures with no
preload instruction, the NO_PLD macro is added to assembler.h,
augmenting the PLD macro.

Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>
omap2plus-cpufreq.c: Add several options: Screen_on_min_freq, gpu_clock, use of max OC freq when the requested target freq is higher than the usual stock freq...