147 lines
5.3 KiB
C
147 lines
5.3 KiB
C
/*
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* Copyright (C) 2015, Intel Corporation. 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
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* are met:
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* 1. 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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* 2. 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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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* 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
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef CPU_X86_MM_SEGMENTATION_H_
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#define CPU_X86_MM_SEGMENTATION_H_
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#include <stdint.h>
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#define SEG_FLAG(lbl, val) \
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(((val) & (~0u >> (32 - SEG_WIDTH_##lbl))) << SEG_SHAMT_##lbl)
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#define SEG_SET_FLAG(desc, lbl, val) \
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(desc).flags = ((desc).flags & ~SEG_FLAG(lbl, ~0u)) | SEG_FLAG(lbl, val)
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#define SEG_WIDTH_TYPE 4
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#define SEG_SHAMT_TYPE 0
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#define SEG_WIDTH_DESCTYPE 1
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#define SEG_SHAMT_DESCTYPE 4
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#define SEG_WIDTH_DPL 2
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#define SEG_SHAMT_DPL 5
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#define SEG_WIDTH_PRESENT 1
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#define SEG_SHAMT_PRESENT 7
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#define SEG_WIDTH_LIMIT_HI 4
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#define SEG_SHAMT_LIMIT_HI 8
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#define SEG_WIDTH_AVL 1
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#define SEG_SHAMT_AVL 12
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#define SEG_WIDTH_LONG_MODE 1
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#define SEG_SHAMT_LONG_MODE 13
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/* also used to indicate default operand and address size */
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#define SEG_WIDTH_DIRECTION 1
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#define SEG_SHAMT_DIRECTION 14
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#define SEG_WIDTH_GRAN 1
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#define SEG_SHAMT_GRAN 15
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#define SEG_TYPE_DATA_RDONLY SEG_FLAG(TYPE, 0x00) /* Read only */
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#define SEG_TYPE_DATA_RDWR SEG_FLAG(TYPE, 0x02) /* Read/Write */
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#define SEG_TYPE_CODE_EXRD SEG_FLAG(TYPE, 0x0A) /* Execute/Read */
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#define SEG_TYPE_CODE_EX SEG_FLAG(TYPE, 0x08) /* Execute only */
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#define SEG_TYPE_LDT SEG_FLAG(TYPE, 0x02)
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#define SEG_TYPE_TSS32_AVAIL SEG_FLAG(TYPE, 0x09)
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#define SEG_DESCTYPE_SYS SEG_FLAG(DESCTYPE, 0)
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#define SEG_DESCTYPE_NSYS SEG_FLAG(DESCTYPE, 1)
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#define SEG_PRESENT SEG_FLAG(PRESENT, 1)
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#define SEG_DEFL_OPSZ_32BIT SEG_FLAG(DIRECTION, 1)
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#define SEG_GRAN_BYTE SEG_FLAG(GRAN, 0)
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#define SEG_GRAN_PAGE SEG_FLAG(GRAN, 1)
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/**
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* Maximum length of segment that can be regulated with a byte-granularity
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* segment limit.
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*/
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#define SEG_MAX_BYTE_GRAN_LEN (1 << 20)
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/**
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* Segment descriptor. See Intel Combined Manual,
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* Vol. 3, Section 3.4.5 for more details.
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*/
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typedef union segment_desc {
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struct {
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uint32_t lim_lo : 16;
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uint32_t base_lo : 16;
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uint32_t base_mid : 8;
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uint32_t flags : 16;
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uint32_t base_hi : 8;
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};
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struct {
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uint32_t raw_lo, raw_hi;
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};
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uint64_t raw;
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} segment_desc_t;
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#define SEG_DESC_NOT_PRESENT 0
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/* The next two functions are invoked by boot code, so they must always be
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* inlined to avoid being placed in a different address space than the initial,
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* flat address space.
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*/
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static inline void __attribute__((always_inline))
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segment_desc_set_limit(segment_desc_t *c_this, uint32_t len)
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{
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uint32_t limit = len - 1;
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SEG_SET_FLAG(*c_this, LIMIT_HI, limit >> 16); /* set limit bits 19:16 */
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c_this->lim_lo = limit; /* set limit bits 15:0 */
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}
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/**
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* \brief Initialize a segment descriptor.
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* \param c_this Segment descriptor to be initialized.
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* \param base Base address of region to be covered by segment descriptor.
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* \param len Length to be specified by segment descriptor. The units may
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* be bytes or pages, depending on the flags.
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* \param flags Flags to be added to the default flags: present, default
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* operand size of 32 bits, and high limit bits.
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*/
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static inline void __attribute__((always_inline))
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segment_desc_init(segment_desc_t *c_this,
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uint32_t base, uint32_t len, uint16_t flags)
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{
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c_this->raw = 0;
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/* Create the high 32 bit segment */
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c_this->base_mid = base >> 16; /* set base bits 23:16 */
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c_this->base_hi = base >> 24; /* set base bits 31:24 */
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/* Create the low 32 bit segment */
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c_this->base_lo = base; /* set base bits 15:0 */
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c_this->flags = SEG_FLAG(PRESENT, 1) | SEG_DEFL_OPSZ_32BIT | flags;
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/* This must be done after setting the other flags, or else it
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* would be partially overridden.
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*/
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segment_desc_set_limit(c_this, len);
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}
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#endif /* CPU_X86_MM_SEGMENTATION_H_ */
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