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https://github.com/brain-hackers/u-boot-brain
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cdcf55584e
Tegra186 currently restricts its DRAM usage to entries in the /memory node in the DTB passed to it. However, the MMU configuration always maps the entire first 2GB of RAM. This could allow the CPU to speculatively access RAM that isn't part of the in-use banks. This patch switches to runtime construction of the table that's used to construct the MMU translation tables, and thus prevents access to RAM that's not part of a valid bank. Note: This patch is intended to prevent access to RAM regions which U-Boot does not need to access, with the primary purpose of avoiding theoretical speculative access to physical regions for which the HW will throw errors (e.g. carve-outs that the CPU has no permission to access at a bus level, bad ECC pages, etc.). In particular, this patch is not deliberately related to the speculation-related security issues that were recently announced. The apparent similarity is a coincidence. Signed-off-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com>
37 lines
841 B
C
37 lines
841 B
C
/*
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* (C) Copyright 2014 - 2015 Xilinx, Inc.
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* Michal Simek <michal.simek@xilinx.com>
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* (This file derived from arch/arm/cpu/armv8/zynqmp/cpu.c)
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*
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* Copyright (c) 2015, NVIDIA CORPORATION. All rights reserved.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <asm/system.h>
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#include <asm/armv8/mmu.h>
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/* size: IO + NR_DRAM_BANKS + terminator */
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struct mm_region tegra_mem_map[1 + CONFIG_NR_DRAM_BANKS + 1] = {
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{
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.virt = 0x0UL,
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.phys = 0x0UL,
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.size = 0x80000000UL,
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.attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
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PTE_BLOCK_NON_SHARE |
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PTE_BLOCK_PXN | PTE_BLOCK_UXN
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}, {
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.virt = 0x80000000UL,
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.phys = 0x80000000UL,
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.size = 0x80000000UL,
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.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
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PTE_BLOCK_INNER_SHARE
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}, {
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/* List terminator */
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0,
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}
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};
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struct mm_region *mem_map = tegra_mem_map;
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