725ca4adae
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>
40 lines
906 B
ArmAsm
40 lines
906 B
ArmAsm
/*
|
|
* linux/arch/arm/mach-realview/headsmp.S
|
|
*
|
|
* Copyright (c) 2003 ARM Limited
|
|
* All Rights Reserved
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#include <linux/linkage.h>
|
|
#include <linux/init.h>
|
|
|
|
__INIT
|
|
|
|
/*
|
|
* Realview specific entry point for secondary CPUs. This provides
|
|
* a "holding pen" into which all secondary cores are held until we're
|
|
* ready for them to initialise.
|
|
*/
|
|
ENTRY(realview_secondary_startup)
|
|
mrc p15, 0, r0, c0, c0, 5
|
|
and r0, r0, #15
|
|
adr r4, 1f
|
|
ldmia r4, {r5, r6}
|
|
sub r4, r4, r5
|
|
add r6, r6, r4
|
|
pen: ldr r7, [r6]
|
|
cmp r7, r0
|
|
bne pen
|
|
|
|
/*
|
|
* we've been released from the holding pen: secondary_stack
|
|
* should now contain the SVC stack for this core
|
|
*/
|
|
b secondary_startup
|
|
|
|
.align
|
|
1: .long .
|
|
.long pen_release
|