618d9c8f9e
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
915 B
ArmAsm
40 lines
915 B
ArmAsm
/*
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* linux/arch/arm/mach-vexpress/headsmp.S
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*
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* Copyright (c) 2003 ARM Limited
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/linkage.h>
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#include <linux/init.h>
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__INIT
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/*
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* Versatile Express specific entry point for secondary CPUs. This
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* provides a "holding pen" into which all secondary cores are held
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* until we're ready for them to initialise.
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*/
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ENTRY(vexpress_secondary_startup)
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mrc p15, 0, r0, c0, c0, 5
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and r0, r0, #15
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adr r4, 1f
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ldmia r4, {r5, r6}
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sub r4, r4, r5
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add r6, r6, r4
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pen: ldr r7, [r6]
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cmp r7, r0
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bne pen
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/*
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* we've been released from the holding pen: secondary_stack
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* should now contain the SVC stack for this core
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*/
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b secondary_startup
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.align
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1: .long .
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.long pen_release
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