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* Copyright (c) 2007 Pavel Jancik
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* Copyright (c) 2007 Michal Kebrt
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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
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* - The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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/** @addtogroup arm32boot
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* @brief Memory management used while booting the kernel.
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* So called "section" paging is used while booting the kernel. The term
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* "section" comes from the ARM architecture specification and stands for the
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* following: one-level paging, 1MB sized pages, 4096 entries in the page
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#ifndef BOOT_arm32__MM_H
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#define BOOT_arm32__MM_H
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#define FRAME_WIDTH 20
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#define FRAME_SIZE (1 << FRAME_WIDTH)
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/** Page size in 2-level paging which is switched on later after the kernel
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#define KERNEL_PAGE_SIZE (1 << 12)
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/** Converts kernel address to physical address. */
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# define KA2PA(x) (((uintptr_t) (x)) - 0x80000000)
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/** Converts physical address to kernel address. */
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# define PA2KA(x) (((uintptr_t) (x)) + 0x80000000)
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# define KA2PA(x) ((x) - 0x80000000)
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# define PA2KA(x) ((x) + 0x80000000)
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/** Number of entries in PTL0. */
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#define PTL0_ENTRIES (1 << 12) /* 4096 */
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/** Size of an entry in PTL0. */
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#define PTL0_ENTRY_SIZE 4
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/** Returns number of frame the address belongs to. */
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#define ADDR2PFN(addr) (((uintptr_t) (addr)) >> FRAME_WIDTH)
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/** Describes "section" page table entry (one-level paging with 1MB sized pages). */
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#define PTE_DESCRIPTOR_SECTION 0x2
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/** Page table access rights: user - no access, kernel - read/write. */
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#define PTE_AP_USER_NO_KERNEL_RW 0x1
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/** Page table level 0 entry - "section" format is used (one-level paging, 1MB
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* sized pages). Used only while booting the kernel.
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unsigned descriptor_type : 2;
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unsigned bufferable : 1;
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unsigned cacheable : 1;
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unsigned impl_specific : 1;
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unsigned should_be_zero_1 : 1;
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unsigned access_permission : 2;
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unsigned should_be_zero_2 : 8;
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unsigned section_base_addr : 12;
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} __attribute__ ((packed)) pte_level0_section_t;
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/** Page table that holds 1:1 virtual to physical mapping used while booting the
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extern pte_level0_section_t page_table[PTL0_ENTRIES];
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extern void mmu_start(void);
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/** Enables paging. */
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static inline void enable_paging()
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/* c3 - each two bits controls access to the one of domains (16)
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* 0b01 - behave as a client (user) of a domain
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/* behave as a client of domains */
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"ldr r0, =0x55555555\n"
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"mcr p15, 0, r0, c3, c0, 0\n"
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/* current settings */
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"mrc p15, 0, r0, c1, c0, 0\n"
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/* mask to enable paging */
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"ldr r1, =0x00000001\n"
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"mcr p15, 0, r0, c1, c0, 0\n"
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/** Sets the address of level 0 page table to CP15 register 2.
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* @param pt Address of a page table to set.
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static inline void set_ptl0_address(pte_level0_section_t* pt)
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"mcr p15, 0, %0, c2, c0, 0\n"