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https://github.com/ARM-software/arm-trusted-firmware.git
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8cec598ba3
The current code does not always use data and instruction barriers as required by the architecture and frequently uses barriers excessively due to their inclusion in all of the write_*() helper functions. Barriers should be used explicitly in assembler or C code when modifying processor state that requires the barriers in order to enable review of correctness of the code. This patch removes the barriers from the helper functions and introduces them as necessary elsewhere in the code. PORTING NOTE: check any port of Trusted Firmware for use of system register helper functions for reliance on the previous barrier behaviour and add explicit barriers as necessary. Fixes ARM-software/tf-issues#92 Change-Id: Ie63e187404ff10e0bdcb39292dd9066cb84c53bf
57 lines
2 KiB
ArmAsm
57 lines
2 KiB
ArmAsm
/*
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* Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of ARM nor the names of its contributors may be used
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* to endorse or promote products derived from this software without specific
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* prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <arch.h>
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#include <asm_macros.S>
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.weak cpu_reset_handler
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func cpu_reset_handler
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mov x19, x30 // lr
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/* ---------------------------------------------
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* As a bare minimal enable the SMP bit.
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* ---------------------------------------------
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*/
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bl read_midr
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lsr x0, x0, #MIDR_PN_SHIFT
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and x0, x0, #MIDR_PN_MASK
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cmp x0, #MIDR_PN_A57
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b.eq smp_setup_begin
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cmp x0, #MIDR_PN_A53
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b.ne smp_setup_end
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smp_setup_begin:
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bl read_cpuectlr
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orr x0, x0, #CPUECTLR_SMP_BIT
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bl write_cpuectlr
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isb
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smp_setup_end:
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ret x19
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