f9edb09d70
accomplishes a few things: - Makes NULL an invalid address in the kernel, which is useful for catching bugs. - Lays groundwork for radix-tree translation on POWER9, which requires the direct map be at high memory. - Similarly lays groundwork for a direct map on 64-bit Book-E. The new base address is chosen as the base of the fourth radix quadrant (the minimum kernel address in this translation mode) and because all supported CPUs ignore at least the first two bits of addresses in real mode, allowing direct-map addresses to be used in real-mode handlers. This is required by Linux and is part of the architecture standard starting in POWER ISA 3, so can be relied upon. Reviewed by: jhibbits, Breno Leitao Differential Revision: D14499
65 lines
2.4 KiB
C
65 lines
2.4 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (C) 2002 Benno Rice.
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* 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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* THIS SOFTWARE IS PROVIDED BY Benno Rice ``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 TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _MACHINE_SR_H_
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#define _MACHINE_SR_H_
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/*
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* Bit definitions for segment registers.
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*
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* PowerPC Microprocessor Family: The Programming Environments for 32-bit
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* Microprocessors, section 2.3.5
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*/
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#define SR_TYPE 0x80000000 /* Type selector */
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#define SR_KS 0x40000000 /* Supervisor-state protection key */
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#define SR_KP 0x20000000 /* User-state protection key */
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#define SR_N 0x10000000 /* No-execute protection */
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#define SR_VSID_MASK 0x00ffffff /* Virtual Segment ID mask */
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/* Kernel segment register usage */
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#define USER_SR 12
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#define KERNEL_SR 13
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#define KERNEL2_SR 14
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#define KERNEL3_SR 15
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#define KERNEL_VSIDBITS 0xfffffUL
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#define KERNEL_SEGMENT (0xfffff0 + KERNEL_SR)
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#define KERNEL2_SEGMENT (0xfffff0 + KERNEL2_SR)
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#define EMPTY_SEGMENT 0xfffff0
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#ifdef __powerpc64__
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#define USER_ADDR 0xeffffffff0000000UL
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#else
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#define USER_ADDR ((uintptr_t)USER_SR << ADDR_SR_SHFT)
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#endif
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#define SEGMENT_LENGTH 0x10000000UL
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#define SEGMENT_INVMASK 0x0fffffffUL
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#define SEGMENT_MASK ~SEGMENT_INVMASK
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#endif /* !_MACHINE_SR_H_ */
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