| 1 | /* $Id: alloc-r0drv-linux.c 5999 2007-12-07 15:05:06Z vboxsync $ */
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| 2 | /** @file
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| 3 | * innotek Portable Runtime - Memory Allocation, Ring-0 Driver, Linux.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2006-2007 innotek GmbH
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | *
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| 17 | * The contents of this file may alternatively be used under the terms
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| 18 | * of the Common Development and Distribution License Version 1.0
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| 19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | * VirtualBox OSE distribution, in which case the provisions of the
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| 21 | * CDDL are applicable instead of those of the GPL.
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| 22 | *
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| 23 | * You may elect to license modified versions of this file under the
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| 24 | * terms and conditions of either the GPL or the CDDL or both.
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| 25 | */
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| 26 |
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| 27 |
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| 28 | /*******************************************************************************
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| 29 | * Header Files *
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| 30 | *******************************************************************************/
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| 31 | #include "the-linux-kernel.h"
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| 32 | #include <iprt/mem.h>
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| 33 | #include <iprt/assert.h>
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| 34 | #include "r0drv/alloc-r0drv.h"
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| 35 |
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| 36 | #if defined(RT_ARCH_AMD64) || defined(__DOXYGEN__)
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| 37 | /**
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| 38 | * We need memory in the module range (~2GB to ~0) this can only be obtained
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| 39 | * thru APIs that are not exported (see module_alloc()).
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| 40 | *
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| 41 | * So, we'll have to create a quick and dirty heap here using BSS memory.
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| 42 | * Very annoying and it's going to restrict us!
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| 43 | */
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| 44 | # define RTMEMALLOC_EXEC_HEAP
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| 45 | #endif
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| 46 | #ifdef RTMEMALLOC_EXEC_HEAP
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| 47 | # include <iprt/heap.h>
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| 48 | # include <iprt/spinlock.h>
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| 49 | # include <iprt/err.h>
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| 50 | #endif
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| 51 |
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| 52 |
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| 53 | /*******************************************************************************
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| 54 | * Global Variables *
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| 55 | *******************************************************************************/
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| 56 | #ifdef RTMEMALLOC_EXEC_HEAP
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| 57 | /** The heap. */
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| 58 | static RTHEAPSIMPLE g_HeapExec = NIL_RTHEAPSIMPLE;
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| 59 | /** Spinlock protecting the heap. */
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| 60 | static RTSPINLOCK g_HeapExecSpinlock = NIL_RTSPINLOCK;
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| 61 |
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| 62 |
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| 63 | /**
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| 64 | * API for cleaning up the heap spinlock on IPRT termination.
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| 65 | * This is as RTMemExecDonate specific to AMD64 Linux/GNU.
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| 66 | */
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| 67 | void rtR0MemExecCleanup(void)
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| 68 | {
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| 69 | RTSpinlockDestroy(g_HeapExecSpinlock);
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| 70 | g_HeapExecSpinlock = NIL_RTSPINLOCK;
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| 71 | }
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| 72 |
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| 73 |
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| 74 | /**
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| 75 | * Donate read+write+execute memory to the exec heap.
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| 76 | *
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| 77 | * This API is specific to AMD64 and Linux/GNU. A kernel module that desires to
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| 78 | * use RTMemExecAlloc on AMD64 Linux/GNU will have to donate some statically
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| 79 | * allocated memory in the module if it wishes for GCC generated code to work.
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| 80 | * GCC can only generate modules that work in the address range ~2GB to ~0
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| 81 | * currently.
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| 82 | *
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| 83 | * The API only accept one single donation.
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| 84 | *
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| 85 | * @returns IPRT status code.
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| 86 | * @param pvMemory Pointer to the memory block.
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| 87 | * @param cb The size of the memory block.
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| 88 | */
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| 89 | RTR0DECL(int) RTR0MemExecDonate(void *pvMemory, size_t cb)
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| 90 | {
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| 91 | int rc;
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| 92 | AssertReturn(g_HeapExec == NIL_RTHEAPSIMPLE, VERR_WRONG_ORDER);
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| 93 |
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| 94 | rc = RTSpinlockCreate(&g_HeapExecSpinlock);
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| 95 | if (RT_SUCCESS(rc))
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| 96 | {
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| 97 | rc = RTHeapSimpleInit(&g_HeapExec, pvMemory, cb);
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| 98 | if (RT_FAILURE(rc))
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| 99 | rtR0MemExecCleanup();
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| 100 | }
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| 101 | return rc;
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| 102 | }
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| 103 | #endif /* RTMEMALLOC_EXEC_HEAP */
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| 104 |
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| 105 |
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| 106 |
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| 107 | /**
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| 108 | * OS specific allocation function.
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| 109 | */
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| 110 | PRTMEMHDR rtMemAlloc(size_t cb, uint32_t fFlags)
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| 111 | {
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| 112 | /*
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| 113 | * Allocate.
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| 114 | */
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| 115 | PRTMEMHDR pHdr;
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| 116 | Assert(cb != sizeof(void *)); /* 99% of pointer sized allocations are wrong. */
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| 117 | if (fFlags & RTMEMHDR_FLAG_EXEC)
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| 118 | {
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| 119 | #if defined(RT_ARCH_AMD64)
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| 120 | # ifdef RTMEMALLOC_EXEC_HEAP
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| 121 | if (g_HeapExec != NIL_RTHEAPSIMPLE)
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| 122 | {
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| 123 | RTSPINLOCKTMP SpinlockTmp = RTSPINLOCKTMP_INITIALIZER;
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| 124 | RTSpinlockAcquireNoInts(g_HeapExecSpinlock, &SpinlockTmp);
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| 125 | pHdr = (PRTMEMHDR)RTHeapSimpleAlloc(g_HeapExec, cb + sizeof(*pHdr), 0);
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| 126 | RTSpinlockReleaseNoInts(g_HeapExecSpinlock, &SpinlockTmp);
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| 127 | fFlags |= RTMEMHDR_FLAG_EXEC_HEAP;
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| 128 | }
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| 129 | else
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| 130 | # endif
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| 131 | pHdr = (PRTMEMHDR)__vmalloc(cb + sizeof(*pHdr), GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
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| 132 |
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| 133 | #elif defined(PAGE_KERNEL_EXEC) && defined(CONFIG_X86_PAE)
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| 134 | pHdr = (PRTMEMHDR)__vmalloc(cb + sizeof(*pHdr), GFP_KERNEL | __GFP_HIGHMEM,
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| 135 | __pgprot(cpu_has_pge ? _PAGE_KERNEL_EXEC | _PAGE_GLOBAL : _PAGE_KERNEL_EXEC));
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| 136 | #else
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| 137 | pHdr = (PRTMEMHDR)vmalloc(cb + sizeof(*pHdr));
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| 138 | #endif
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| 139 | }
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| 140 | else
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| 141 | {
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| 142 | if (cb <= PAGE_SIZE)
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| 143 | {
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| 144 | fFlags |= RTMEMHDR_FLAG_KMALLOC;
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| 145 | pHdr = kmalloc(cb + sizeof(*pHdr), GFP_KERNEL);
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| 146 | }
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| 147 | else
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| 148 | pHdr = vmalloc(cb + sizeof(*pHdr));
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| 149 | }
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| 150 |
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| 151 | /*
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| 152 | * Initialize.
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| 153 | */
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| 154 | if (pHdr)
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| 155 | {
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| 156 | pHdr->u32Magic = RTMEMHDR_MAGIC;
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| 157 | pHdr->fFlags = fFlags;
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| 158 | pHdr->cb = cb;
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| 159 | pHdr->u32Padding= 0;
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| 160 | }
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| 161 | return pHdr;
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| 162 | }
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| 163 |
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| 164 |
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| 165 | /**
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| 166 | * OS specific free function.
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| 167 | */
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| 168 | void rtMemFree(PRTMEMHDR pHdr)
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| 169 | {
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| 170 | pHdr->u32Magic += 1;
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| 171 | if (pHdr->fFlags & RTMEMHDR_FLAG_KMALLOC)
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| 172 | kfree(pHdr);
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| 173 | #ifdef RTMEMALLOC_EXEC_HEAP
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| 174 | else if (pHdr->fFlags & RTMEMHDR_FLAG_EXEC_HEAP)
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| 175 | {
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| 176 | RTSPINLOCKTMP SpinlockTmp = RTSPINLOCKTMP_INITIALIZER;
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| 177 | RTSpinlockAcquireNoInts(g_HeapExecSpinlock, &SpinlockTmp);
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| 178 | RTHeapSimpleFree(g_HeapExec, pHdr);
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| 179 | RTSpinlockReleaseNoInts(g_HeapExecSpinlock, &SpinlockTmp);
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| 180 | }
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| 181 | #endif
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| 182 | else
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| 183 | vfree(pHdr);
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| 184 | }
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| 185 |
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| 186 |
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| 187 | /**
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| 188 | * Compute order. Some functions allocate 2^order pages.
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| 189 | *
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| 190 | * @returns order.
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| 191 | * @param cPages Number of pages.
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| 192 | */
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| 193 | static int CalcPowerOf2Order(unsigned long cPages)
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| 194 | {
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| 195 | int iOrder;
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| 196 | unsigned long cTmp;
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| 197 |
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| 198 | for (iOrder = 0, cTmp = cPages; cTmp >>= 1; ++iOrder)
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| 199 | ;
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| 200 | if (cPages & ~(1 << iOrder))
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| 201 | ++iOrder;
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| 202 |
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| 203 | return iOrder;
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| 204 | }
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| 205 |
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| 206 |
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| 207 | /**
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| 208 | * Allocates physical contiguous memory (below 4GB).
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| 209 | * The allocation is page aligned and the content is undefined.
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| 210 | *
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| 211 | * @returns Pointer to the memory block. This is page aligned.
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| 212 | * @param pPhys Where to store the physical address.
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| 213 | * @param cb The allocation size in bytes. This is always
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| 214 | * rounded up to PAGE_SIZE.
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| 215 | */
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| 216 | RTR0DECL(void *) RTMemContAlloc(PRTCCPHYS pPhys, size_t cb)
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| 217 | {
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| 218 | int cOrder;
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| 219 | unsigned cPages;
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| 220 | struct page *paPages;
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| 221 |
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| 222 | /*
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| 223 | * validate input.
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| 224 | */
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| 225 | Assert(VALID_PTR(pPhys));
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| 226 | Assert(cb > 0);
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| 227 |
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| 228 | /*
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| 229 | * Allocate page pointer array.
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| 230 | */
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| 231 | cb = RT_ALIGN_Z(cb, PAGE_SIZE);
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| 232 | cPages = cb >> PAGE_SHIFT;
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| 233 | cOrder = CalcPowerOf2Order(cPages);
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| 234 | #ifdef RT_ARCH_AMD64 /** @todo check out if there is a correct way of getting memory below 4GB (physically). */
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| 235 | paPages = alloc_pages(GFP_DMA, cOrder);
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| 236 | #else
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| 237 | paPages = alloc_pages(GFP_USER, cOrder);
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| 238 | #endif
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| 239 | if (paPages)
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| 240 | {
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| 241 | /*
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| 242 | * Reserve the pages and mark them executable.
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| 243 | */
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| 244 | unsigned iPage;
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| 245 | for (iPage = 0; iPage < cPages; iPage++)
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| 246 | {
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| 247 | Assert(!PageHighMem(&paPages[iPage]));
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| 248 | if (iPage + 1 < cPages)
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| 249 | {
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| 250 | AssertMsg( (uintptr_t)phys_to_virt(page_to_phys(&paPages[iPage])) + PAGE_SIZE
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| 251 | == (uintptr_t)phys_to_virt(page_to_phys(&paPages[iPage + 1]))
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| 252 | && page_to_phys(&paPages[iPage]) + PAGE_SIZE
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| 253 | == page_to_phys(&paPages[iPage + 1]),
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| 254 | ("iPage=%i cPages=%u [0]=%#llx,%p [1]=%#llx,%p\n", iPage, cPages,
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| 255 | (long long)page_to_phys(&paPages[iPage]), phys_to_virt(page_to_phys(&paPages[iPage])),
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| 256 | (long long)page_to_phys(&paPages[iPage + 1]), phys_to_virt(page_to_phys(&paPages[iPage + 1])) ));
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| 257 | }
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| 258 |
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| 259 | SetPageReserved(&paPages[iPage]);
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| 260 | #if LINUX_VERSION_CODE > KERNEL_VERSION(2, 4, 20) /** @todo find the exact kernel where change_page_attr was introduced. */
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| 261 | if (pgprot_val(MY_PAGE_KERNEL_EXEC) != pgprot_val(PAGE_KERNEL))
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| 262 | MY_CHANGE_PAGE_ATTR(&paPages[iPage], 1, MY_PAGE_KERNEL_EXEC);
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| 263 | #endif
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| 264 | }
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| 265 | *pPhys = page_to_phys(paPages);
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| 266 | return phys_to_virt(page_to_phys(paPages));
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| 267 | }
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| 268 |
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| 269 | return NULL;
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| 270 | }
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| 271 |
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| 272 |
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| 273 | /**
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| 274 | * Frees memory allocated ysing RTMemContAlloc().
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| 275 | *
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| 276 | * @param pv Pointer to return from RTMemContAlloc().
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| 277 | * @param cb The cb parameter passed to RTMemContAlloc().
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| 278 | */
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| 279 | RTR0DECL(void) RTMemContFree(void *pv, size_t cb)
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| 280 | {
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| 281 | if (pv)
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| 282 | {
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| 283 | int cOrder;
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| 284 | unsigned cPages;
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| 285 | unsigned iPage;
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| 286 | struct page *paPages;
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| 287 |
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| 288 | /* validate */
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| 289 | AssertMsg(!((uintptr_t)pv & PAGE_OFFSET_MASK), ("pv=%p\n", pv));
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| 290 | Assert(cb > 0);
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| 291 |
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| 292 | /* calc order and get pages */
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| 293 | cb = RT_ALIGN_Z(cb, PAGE_SIZE);
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| 294 | cPages = cb >> PAGE_SHIFT;
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| 295 | cOrder = CalcPowerOf2Order(cPages);
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| 296 | paPages = virt_to_page(pv);
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| 297 |
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| 298 | /*
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| 299 | * Restore page attributes freeing the pages.
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| 300 | */
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| 301 | for (iPage = 0; iPage < cPages; iPage++)
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| 302 | {
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| 303 | ClearPageReserved(&paPages[iPage]);
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| 304 | #if LINUX_VERSION_CODE > KERNEL_VERSION(2, 4, 20) /** @todo find the exact kernel where change_page_attr was introduced. */
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| 305 | if (pgprot_val(MY_PAGE_KERNEL_EXEC) != pgprot_val(PAGE_KERNEL))
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| 306 | MY_CHANGE_PAGE_ATTR(&paPages[iPage], 1, PAGE_KERNEL);
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| 307 | #endif
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| 308 | }
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| 309 | __free_pages(paPages, cOrder);
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| 310 | }
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| 311 | }
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| 312 |
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