linux/arch/arm/mach-realview
Dave Martin 725ca4adae ARM: 6507/1: RealView: 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
Kconfig ARM: 6201/1: RealView: Do not use outer_sync() on ARM11MPCore boards with L220 2010-07-02 10:10:09 +01:00
Makefile ARM: Realview/Versatile/Integrator: separate out common clock code 2010-05-02 09:35:33 +01:00
Makefile.boot RealView: Allow PHYS_OFFSET at 0x70000000 2008-12-01 14:54:55 +00:00
core.c ARM: 6307/1: mmci: allow the card detect GPIO value not to be inverted 2010-08-26 19:54:27 +01:00
core.h RealView: Add default memory configuration 2009-11-05 10:10:36 +00:00
headsmp.S ARM: 6507/1: RealView: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL 2010-11-30 13:44:27 +00:00
hotplug.c ARM: rename mach_cpu_disable() to platform_cpu_disable() 2010-05-15 15:03:51 +01:00
localtimer.c [ARM] smp: allow re-use of realview localtimer TWD support 2009-05-17 19:16:41 +01:00
platsmp.c RealView: Remove duplicated #define REALVIEW_SYS_FLAGS* statements 2009-11-05 10:10:36 +00:00
realview_eb.c arm: remove machine_desc.io_pg_offst and .phys_io 2010-10-20 00:27:46 -04:00
realview_pb11mp.c arm: remove machine_desc.io_pg_offst and .phys_io 2010-10-20 00:27:46 -04:00
realview_pb1176.c arm: remove machine_desc.io_pg_offst and .phys_io 2010-10-20 00:27:46 -04:00
realview_pba8.c arm: remove machine_desc.io_pg_offst and .phys_io 2010-10-20 00:27:46 -04:00
realview_pbx.c arm: remove machine_desc.io_pg_offst and .phys_io 2010-10-20 00:27:46 -04:00