74 lines
3.1 KiB
C
74 lines
3.1 KiB
C
/*
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Copyright (C) 2012, Aaron Lindsay <aaron@aclindsay.com>
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This file is part of Aedrix.
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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 as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <print.h>
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#include <types.h>
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#include <arch/properties.h>
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#define SCTLR 15,0,1,0,0
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#define TTBR0 15,0,2,0,0
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#define TTBR1 15,0,2,0,1
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#define TTBCR 15,0,2,0,2
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#define _cp_read(var, cp, opc1, CRn, CRm, opc2) asm("mrc p" #cp ", " #opc1 ", %0, c" #CRn ", c" #CRm ", " #opc2 ";" : "=r"(var) : )
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#define _cp_write(var, cp, opc1, CRn, CRm, opc2) asm("mcr p" #cp ", " #opc1 ", %0, c" #CRn ", c" #CRm ", " #opc2 ";" : : "r"(var) )
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#define cp_read(var, ...) _cp_read(var, __VA_ARGS__)
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#define cp_write(var, ...) _cp_write(var, __VA_ARGS__)
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void print_mapping(void *addr) {
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extern uint32 tt_base_virtual;
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print("%x: %x\n", addr, *(uint32 *)(tt_base_virtual + (((uint32)addr)>>18)));
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}
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static inline int page_intersects(uint32 *page_start, uint32 *lower, uint32 *upper) {
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return (lower >= page_start && lower < (page_start + (CONFIG_INIT_PAGE_SIZE>>2))) ||
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(upper >= page_start && upper < (page_start + (CONFIG_INIT_PAGE_SIZE>>2))) ||
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(lower < page_start && upper >= (page_start + (CONFIG_INIT_PAGE_SIZE>>2)));
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}
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void mmu_reinit() {
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extern uint32 tt_base_virtual;
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uint32 *curr_addr, *curr_tt_entry;
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uint32 virt_phys_offset = kernel_start_virtual() - kernel_start_physical(); /* CAUTION: 1 = 4 bytes */
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//get the current translation table base address
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curr_tt_entry = (uint32 *)tt_base_virtual;
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//do first loop iteration outside the loop, because we have to check against wrapping back around to know we're done
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*curr_tt_entry = 0xc02; /* 0xc02 means read/write at any priviledge level, and that it's a section w/o PXN bit set */
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curr_tt_entry++;
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//create identity mapping for entire address space using sections.
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//BUT, if we've relocated the kernel from where it is in physical
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//memory, make sure we keep those mappings correct, and we'll actually
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//swap the two mappings so all of memory is addressable.
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for (curr_addr = (uint32 *)CONFIG_INIT_PAGE_SIZE; curr_addr != 0; curr_addr += (CONFIG_INIT_PAGE_SIZE>>2)) {
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if (page_intersects(curr_addr, kernel_start_physical(), kernel_end_physical())) {
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*curr_tt_entry = (uint32)(curr_addr + virt_phys_offset) | 0xc02;
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} else if (page_intersects(curr_addr, kernel_start_virtual(), kernel_end_virtual())) {
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*curr_tt_entry = (uint32)(curr_addr - virt_phys_offset) | 0xc02;
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} else {
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*curr_tt_entry = (uint32)curr_addr | 0xc02;
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}
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curr_tt_entry++;
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}
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}
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