mirror of
https://github.com/ARM-software/arm-trusted-firmware.git
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308d359b26
Introduce zeromem_dczva function on AArch64 that can handle unaligned addresses and make use of DC ZVA instruction to zero a whole block at a time. This zeroing takes place directly in the cache to speed it up without doing external memory access. Remove the zeromem16 function on AArch64 and replace it with an alias to zeromem. This zeromem16 function is now deprecated. Remove the 16-bytes alignment constraint on __BSS_START__ in firmware-design.md as it is now not mandatory anymore (it used to comply with zeromem16 requirements). Change the 16-bytes alignment constraints in SP min's linker script to a 8-bytes alignment constraint as the AArch32 zeromem implementation is now more efficient on 8-bytes aligned addresses. Introduce zero_normalmem and zeromem helpers in platform agnostic header that are implemented this way: * AArch32: * zero_normalmem: zero using usual data access * zeromem: alias for zero_normalmem * AArch64: * zero_normalmem: zero normal memory using DC ZVA instruction (needs MMU enabled) * zeromem: zero using usual data access Usage guidelines: in most cases, zero_normalmem should be preferred. There are 2 scenarios where zeromem (or memset) must be used instead: * Code that must run with MMU disabled (which means all memory is considered device memory for data accesses). * Code that fills device memory with null bytes. Optionally, the following rule can be applied if performance is important: * Code zeroing small areas (few bytes) that are not secrets should use memset to take advantage of compiler optimizations. Note: Code zeroing security-related critical information should use zero_normalmem/zeromem instead of memset to avoid removal by compilers' optimizations in some cases or misbehaving versions of GCC. Fixes ARM-software/tf-issues#408 Change-Id: Iafd9663fc1070413c3e1904e54091cf60effaa82 Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
114 lines
4.1 KiB
C
114 lines
4.1 KiB
C
/*
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* Copyright (c) 2016-2017, 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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#ifndef __UTILS_H__
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#define __UTILS_H__
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/* Compute the number of elements in the given array */
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#define ARRAY_SIZE(a) \
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(sizeof(a) / sizeof((a)[0]))
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#define IS_POWER_OF_TWO(x) \
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(((x) & ((x) - 1)) == 0)
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#define SIZE_FROM_LOG2_WORDS(n) (4 << (n))
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#define BIT(nr) (1UL << (nr))
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/*
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* The round_up() macro rounds up a value to the given boundary in a
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* type-agnostic yet type-safe manner. The boundary must be a power of two.
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* In other words, it computes the smallest multiple of boundary which is
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* greater than or equal to value.
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*
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* round_down() is similar but rounds the value down instead.
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*/
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#define round_boundary(value, boundary) \
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((__typeof__(value))((boundary) - 1))
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#define round_up(value, boundary) \
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((((value) - 1) | round_boundary(value, boundary)) + 1)
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#define round_down(value, boundary) \
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((value) & ~round_boundary(value, boundary))
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/*
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* Evaluates to 1 if (ptr + inc) overflows, 0 otherwise.
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* Both arguments must be unsigned pointer values (i.e. uintptr_t).
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*/
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#define check_uptr_overflow(ptr, inc) \
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(((ptr) > UINTPTR_MAX - (inc)) ? 1 : 0)
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/*
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* For those constants to be shared between C and other sources, apply a 'ull'
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* suffix to the argument only in C, to avoid undefined or unintended behaviour.
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*
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* The GNU assembler and linker do not support the 'ull' suffix (it causes the
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* build process to fail) therefore the suffix is omitted when used in linker
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* scripts and assembler files.
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*/
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#if defined(__LINKER__) || defined(__ASSEMBLY__)
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# define ULL(_x) (_x)
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#else
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# define ULL(_x) (_x##ull)
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#endif
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/*
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* C code should be put in this part of the header to avoid breaking ASM files
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* or linker scripts including it.
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*/
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#if !(defined(__LINKER__) || defined(__ASSEMBLY__))
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#include <types.h>
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/*
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* Fill a region of normal memory of size "length" in bytes with zero bytes.
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*
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* WARNING: This function can only operate on normal memory. This means that
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* the MMU must be enabled when using this function. Otherwise, use
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* zeromem.
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*/
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void zero_normalmem(void *mem, u_register_t length);
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/*
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* Fill a region of memory of size "length" in bytes with null bytes.
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*
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* Unlike zero_normalmem, this function has no restriction on the type of
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* memory targeted and can be used for any device memory as well as normal
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* memory. This function must be used instead of zero_normalmem when MMU is
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* disabled.
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*
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* NOTE: When data cache and MMU are enabled, prefer zero_normalmem for faster
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* zeroing.
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*/
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void zeromem(void *mem, u_register_t length);
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#endif /* !(defined(__LINKER__) || defined(__ASSEMBLY__)) */
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#endif /* __UTILS_H__ */
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