| 1 | /*
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| 2 | * Copyright (c) 2016 Jakub Jermar
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | /** @addtogroup amd64
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| 30 | * @{
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| 31 | */
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| 32 | /** @file
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| 33 | */
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| 34 |
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| 35 | #include <arch/vreg.h>
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| 36 | #include <arch/pm.h>
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| 37 | #include <config.h>
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| 38 | #include <typedefs.h>
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| 39 | #include <arch/asm.h>
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| 40 | #include <panic.h>
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| 41 | #include <mm/km.h>
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| 42 | #include <mm/frame.h>
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| 43 |
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| 44 | /*
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| 45 | * During initialization, we need to make sure that context_save() and
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| 46 | * context_restore() touch some meaningful address when saving/restoring VREGs.
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| 47 | * When a processor is initialized, we set its FS base to a private page and
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| 48 | * vreg_ptr to zero.
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| 49 | */
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| 50 | static uint64_t vreg_tp_dummy;
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| 51 | uint64_t *vreg_ptr = &vreg_tp_dummy;
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| 52 |
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| 53 | /**
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| 54 | * Allocate and initialize a per-CPU user page to be accessible via the FS
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| 55 | * segment register and to hold the virtual registers.
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| 56 | */
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| 57 | void vreg_init(void)
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| 58 | {
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| 59 | uintptr_t frame;
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| 60 | uint64_t *page;
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| 61 |
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| 62 | frame = frame_alloc(1, FRAME_ATOMIC | FRAME_HIGHMEM, 0);
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| 63 | if (!frame)
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| 64 | frame = frame_alloc(1, FRAME_ATOMIC | FRAME_LOWMEM, 0);
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| 65 | if (!frame)
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| 66 | panic("Cannot allocate VREG frame.");
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| 67 |
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| 68 | page = (uint64_t *) km_map(frame, PAGE_SIZE,
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| 69 | PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_CACHEABLE);
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| 70 |
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| 71 | write_msr(AMD_MSR_FS, (uintptr_t) page);
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| 72 |
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| 73 | vreg_ptr = NULL;
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| 74 | }
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| 75 |
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| 76 | /** @}
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| 77 | */
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