linux/arch/arm/mach-vexpress
Dave Martin 618d9c8f9e ARM: 6508/1: vexpress: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL
Directives such as .long and .word do not magically cause the
assembler location counter to become aligned in gas.  As a
result, using these directives in code sections can result in
misaligned data words when building a Thumb-2 kernel
(CONFIG_THUMB2_KERNEL).

This is a Bad Thing, since the ABI permits the compiler to
assume that fundamental types of word size or above are word-
aligned when accessing them from C.  If the data is not really
word-aligned, this can cause impaired performance and stray
alignment faults in some circumstances.

In general, the following rules should be applied when using
data word declaration directives inside code sections:

    * .quad and .double:
         .align 3

    * .long, .word, .single, .float:
         .align (or .align 2)

    * .short:
        No explicit alignment required, since Thumb-2
        instructions are always 2 or 4 bytes in size.
        immediately after an instruction.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-11-30 13:44:27 +00:00
..
include/mach arm: return both physical and virtual addresses from addruart 2010-10-20 00:27:33 -04:00
core.h
ct-ca9x4.c ARM: 6472/1: vexpress ct-ca9x4: only set twd_base if local timers are being used 2010-11-10 15:11:19 +00:00
headsmp.S ARM: 6508/1: vexpress: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL 2010-11-30 13:44:27 +00:00
Kconfig
localtimer.c ARM: Add Versatile Express SMP support 2010-05-02 09:35:39 +01:00
Makefile ARM: Add Versatile Express SMP support 2010-05-02 09:35:39 +01:00
Makefile.boot
platsmp.c ARM: Add Versatile Express SMP support 2010-05-02 09:35:39 +01:00
v2m.c ARM: fix section mismatch warnings in Versatile Express 2010-10-05 11:30:40 +01:00