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bac4e960b5
Mathieu Desnoyers pointed out that the ARM barriers were lacking: - cmpxchg, xchg and atomic add return need memory barriers on architectures which can reorder the relative order in which memory read/writes can be seen between CPUs, which seems to include recent ARM architectures. Those barriers are currently missing on ARM. - test_and_xxx_bit were missing SMP barriers. So put these barriers in. Provide separate atomic_add/atomic_sub operations which do not require barriers. Reported-Reviewed-and-Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
130 lines
2.8 KiB
C
130 lines
2.8 KiB
C
/*
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* arch/arm/include/asm/assembler.h
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*
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* Copyright (C) 1996-2000 Russell King
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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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* This file contains arm architecture specific defines
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* for the different processors.
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*
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* Do not include any C declarations in this file - it is included by
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* assembler source.
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*/
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#ifndef __ASSEMBLY__
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#error "Only include this from assembly code"
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#endif
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#include <asm/ptrace.h>
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/*
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* Endian independent macros for shifting bytes within registers.
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*/
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#ifndef __ARMEB__
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#define pull lsr
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#define push lsl
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#define get_byte_0 lsl #0
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#define get_byte_1 lsr #8
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#define get_byte_2 lsr #16
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#define get_byte_3 lsr #24
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#define put_byte_0 lsl #0
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#define put_byte_1 lsl #8
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#define put_byte_2 lsl #16
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#define put_byte_3 lsl #24
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#else
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#define pull lsl
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#define push lsr
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#define get_byte_0 lsr #24
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#define get_byte_1 lsr #16
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#define get_byte_2 lsr #8
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#define get_byte_3 lsl #0
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#define put_byte_0 lsl #24
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#define put_byte_1 lsl #16
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#define put_byte_2 lsl #8
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#define put_byte_3 lsl #0
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#endif
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/*
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* Data preload for architectures that support it
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*/
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#if __LINUX_ARM_ARCH__ >= 5
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#define PLD(code...) code
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#else
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#define PLD(code...)
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#endif
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/*
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* This can be used to enable code to cacheline align the destination
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* pointer when bulk writing to memory. Experiments on StrongARM and
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* XScale didn't show this a worthwhile thing to do when the cache is not
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* set to write-allocate (this would need further testing on XScale when WA
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* is used).
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*
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* On Feroceon there is much to gain however, regardless of cache mode.
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*/
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#ifdef CONFIG_CPU_FEROCEON
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#define CALGN(code...) code
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#else
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#define CALGN(code...)
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#endif
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/*
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* Enable and disable interrupts
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*/
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#if __LINUX_ARM_ARCH__ >= 6
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.macro disable_irq
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cpsid i
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.endm
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.macro enable_irq
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cpsie i
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.endm
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#else
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.macro disable_irq
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msr cpsr_c, #PSR_I_BIT | SVC_MODE
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.endm
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.macro enable_irq
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msr cpsr_c, #SVC_MODE
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.endm
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#endif
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/*
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* Save the current IRQ state and disable IRQs. Note that this macro
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* assumes FIQs are enabled, and that the processor is in SVC mode.
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*/
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.macro save_and_disable_irqs, oldcpsr
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mrs \oldcpsr, cpsr
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disable_irq
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.endm
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/*
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* Restore interrupt state previously stored in a register. We don't
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* guarantee that this will preserve the flags.
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*/
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.macro restore_irqs, oldcpsr
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msr cpsr_c, \oldcpsr
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.endm
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#define USER(x...) \
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9999: x; \
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.section __ex_table,"a"; \
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.align 3; \
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.long 9999b,9001f; \
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.previous
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/*
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* SMP data memory barrier
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*/
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.macro smp_dmb
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#ifdef CONFIG_SMP
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#if __LINUX_ARM_ARCH__ >= 7
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dmb
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#elif __LINUX_ARM_ARCH__ == 6
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mcr p15, 0, r0, c7, c10, 5 @ dmb
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#endif
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#endif
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.endm
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