ARM: 7301/1: Rename the T() macro to TUSER() to avoid namespace conflicts

This macro is used to generate unprivileged accesses (LDRT/STRT) to user
space.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[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.

Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>
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>
defconfig: enable RCU boost