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/* |
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* vm_alloc.cpp - Wrapper to various virtual memory allocation schemes |
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* (supports mmap, vm_allocate or fallbacks to malloc) |
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* |
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* Basilisk II (C) 1997-2008 Christian Bauer |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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|
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#ifdef HAVE_CONFIG_H |
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#include "config.h" |
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#endif |
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|
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#ifdef HAVE_FCNTL_H |
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#include <fcntl.h> |
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#endif |
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|
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#ifdef HAVE_WIN32_VM |
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#define WIN32_LEAN_AND_MEAN /* avoid including junk */ |
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#include <windows.h> |
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#endif |
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|
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <limits.h> |
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#include "vm_alloc.h" |
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|
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#ifdef HAVE_MACH_VM |
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#ifndef HAVE_MACH_TASK_SELF |
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#ifdef HAVE_TASK_SELF |
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#define mach_task_self task_self |
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#else |
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#error "No task_self(), you lose." |
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#endif |
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#endif |
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#endif |
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|
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#ifdef HAVE_WIN32_VM |
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/* Windows is either ILP32 or LLP64 */ |
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typedef UINT_PTR vm_uintptr_t; |
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#else |
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/* Other systems are sane as they are either ILP32 or LP64 */ |
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typedef unsigned long vm_uintptr_t; |
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#endif |
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|
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/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII |
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because the emulated target is 32-bit and this helps to allocate |
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memory so that branches could be resolved more easily (32-bit |
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displacement to code in .text), on AMD64 for example. */ |
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#ifndef MAP_32BIT |
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#define MAP_32BIT 0 |
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#endif |
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#ifndef MAP_ANON |
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#define MAP_ANON 0 |
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#endif |
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#ifndef MAP_ANONYMOUS |
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#define MAP_ANONYMOUS 0 |
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#endif |
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|
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#define MAP_EXTRA_FLAGS (MAP_32BIT) |
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|
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#ifdef HAVE_MMAP_VM |
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#if (defined(__linux__) && defined(__i386__)) || HAVE_LINKER_SCRIPT |
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/* Force a reasonnable address below 0x80000000 on x86 so that we |
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don't get addresses above when the program is run on AMD64. |
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NOTE: this is empirically determined on Linux/x86. */ |
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#define MAP_BASE 0x10000000 |
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#else |
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#define MAP_BASE 0x00000000 |
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#endif |
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static char * next_address = (char *)MAP_BASE; |
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#ifdef HAVE_MMAP_ANON |
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#define map_flags (MAP_ANON | MAP_EXTRA_FLAGS) |
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#define zero_fd -1 |
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#else |
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#ifdef HAVE_MMAP_ANONYMOUS |
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#define map_flags (MAP_ANONYMOUS | MAP_EXTRA_FLAGS) |
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#define zero_fd -1 |
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#else |
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#define map_flags (MAP_EXTRA_FLAGS) |
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static int zero_fd = -1; |
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#endif |
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#endif |
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#endif |
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|
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/* Translate generic VM map flags to host values. */ |
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|
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#ifdef HAVE_MMAP_VM |
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static int translate_map_flags(int vm_flags) |
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{ |
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int flags = 0; |
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if (vm_flags & VM_MAP_SHARED) |
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flags |= MAP_SHARED; |
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if (vm_flags & VM_MAP_PRIVATE) |
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flags |= MAP_PRIVATE; |
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if (vm_flags & VM_MAP_FIXED) |
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flags |= MAP_FIXED; |
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if (vm_flags & VM_MAP_32BIT) |
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flags |= MAP_32BIT; |
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return flags; |
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} |
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#endif |
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|
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/* Align ADDR and SIZE to 64K boundaries. */ |
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|
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#ifdef HAVE_WIN32_VM |
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static inline LPVOID align_addr_segment(LPVOID addr) |
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{ |
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return (LPVOID)(((vm_uintptr_t)addr) & -((vm_uintptr_t)65536)); |
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} |
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|
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static inline DWORD align_size_segment(LPVOID addr, DWORD size) |
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{ |
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return size + ((vm_uintptr_t)addr - (vm_uintptr_t)align_addr_segment(addr)); |
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} |
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#endif |
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|
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/* Translate generic VM prot flags to host values. */ |
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|
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#ifdef HAVE_WIN32_VM |
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static int translate_prot_flags(int prot_flags) |
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{ |
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int prot = PAGE_READWRITE; |
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if (prot_flags == (VM_PAGE_EXECUTE | VM_PAGE_READ | VM_PAGE_WRITE)) |
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prot = PAGE_EXECUTE_READWRITE; |
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else if (prot_flags == (VM_PAGE_EXECUTE | VM_PAGE_READ)) |
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prot = PAGE_EXECUTE_READ; |
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else if (prot_flags == (VM_PAGE_READ | VM_PAGE_WRITE)) |
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prot = PAGE_READWRITE; |
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else if (prot_flags == VM_PAGE_READ) |
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prot = PAGE_READONLY; |
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else if (prot_flags == 0) |
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prot = PAGE_NOACCESS; |
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return prot; |
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} |
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#endif |
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|
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/* Initialize the VM system. Returns 0 if successful, -1 for errors. */ |
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|
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int vm_init(void) |
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{ |
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#ifdef HAVE_MMAP_VM |
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#ifndef zero_fd |
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zero_fd = open("/dev/zero", O_RDWR); |
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if (zero_fd < 0) |
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return -1; |
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#endif |
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#endif |
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return 0; |
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} |
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|
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/* Deallocate all internal data used to wrap virtual memory allocators. */ |
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|
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void vm_exit(void) |
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{ |
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#ifdef HAVE_MMAP_VM |
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#ifndef zero_fd |
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if (zero_fd != -1) { |
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close(zero_fd); |
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zero_fd = -1; |
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} |
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#endif |
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#endif |
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} |
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|
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/* Allocate zero-filled memory of SIZE bytes. The mapping is private |
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and default protection bits are read / write. The return value |
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is the actual mapping address chosen or VM_MAP_FAILED for errors. */ |
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|
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void * vm_acquire(size_t size, int options) |
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{ |
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void * addr; |
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|
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// VM_MAP_FIXED are to be used with vm_acquire_fixed() only |
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if (options & VM_MAP_FIXED) |
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return VM_MAP_FAILED; |
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|
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#ifdef HAVE_MACH_VM |
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// vm_allocate() returns a zero-filled memory region |
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if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS) |
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return VM_MAP_FAILED; |
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#else |
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#ifdef HAVE_MMAP_VM |
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int fd = zero_fd; |
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int the_map_flags = translate_map_flags(options) | map_flags; |
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|
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if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED) |
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return VM_MAP_FAILED; |
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|
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// Sanity checks for 64-bit platforms |
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if (sizeof(void *) == 8 && (options & VM_MAP_32BIT) && !((char *)addr <= (char *)0xffffffff)) |
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return VM_MAP_FAILED; |
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|
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next_address = (char *)addr + size; |
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#else |
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#ifdef HAVE_WIN32_VM |
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if ((addr = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE)) == NULL) |
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return VM_MAP_FAILED; |
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#else |
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if ((addr = calloc(size, 1)) == 0) |
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return VM_MAP_FAILED; |
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|
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// Omit changes for protections because they are not supported in this mode |
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return addr; |
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#endif |
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#endif |
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#endif |
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|
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// Explicitely protect the newly mapped region here because on some systems, |
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// say MacOS X, mmap() doesn't honour the requested protection flags. |
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if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0) |
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return VM_MAP_FAILED; |
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|
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return addr; |
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} |
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|
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/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned). |
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Retuns 0 if successful, -1 on errors. */ |
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|
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int vm_acquire_fixed(void * addr, size_t size, int options) |
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{ |
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// Fixed mappings are required to be private |
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if (options & VM_MAP_SHARED) |
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return -1; |
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|
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#ifdef HAVE_MACH_VM |
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// vm_allocate() returns a zero-filled memory region |
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if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS) |
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return -1; |
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#else |
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#ifdef HAVE_MMAP_VM |
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int fd = zero_fd; |
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int the_map_flags = translate_map_flags(options) | map_flags | MAP_FIXED; |
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|
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if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED) |
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return -1; |
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#else |
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#ifdef HAVE_WIN32_VM |
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// Windows cannot allocate Low Memory |
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if (addr == NULL) |
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return -1; |
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|
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// Allocate a possibly offset region to align on 64K boundaries |
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LPVOID req_addr = align_addr_segment(addr); |
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DWORD req_size = align_size_segment(addr, size); |
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LPVOID ret_addr = VirtualAlloc(req_addr, req_size, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE); |
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if (ret_addr != req_addr) |
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return -1; |
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#else |
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// Unsupported |
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return -1; |
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#endif |
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#endif |
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#endif |
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|
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// Explicitely protect the newly mapped region here because on some systems, |
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// say MacOS X, mmap() doesn't honour the requested protection flags. |
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if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0) |
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return -1; |
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|
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return 0; |
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} |
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|
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/* Deallocate any mapping for the region starting at ADDR and extending |
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LEN bytes. Returns 0 if successful, -1 on errors. */ |
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|
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int vm_release(void * addr, size_t size) |
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{ |
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// Safety check: don't try to release memory that was not allocated |
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if (addr == VM_MAP_FAILED) |
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return 0; |
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|
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#ifdef HAVE_MACH_VM |
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if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS) |
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return -1; |
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#else |
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#ifdef HAVE_MMAP_VM |
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if (munmap((caddr_t)addr, size) != 0) |
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return -1; |
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#else |
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#ifdef HAVE_WIN32_VM |
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if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0) |
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return -1; |
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#else |
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free(addr); |
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#endif |
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#endif |
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#endif |
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|
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return 0; |
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} |
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|
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/* Change the memory protection of the region starting at ADDR and |
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extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */ |
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|
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int vm_protect(void * addr, size_t size, int prot) |
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{ |
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#ifdef HAVE_MACH_VM |
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int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot); |
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return ret_code == KERN_SUCCESS ? 0 : -1; |
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#else |
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#ifdef HAVE_MMAP_VM |
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int ret_code = mprotect((caddr_t)addr, size, prot); |
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return ret_code == 0 ? 0 : -1; |
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#else |
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#ifdef HAVE_WIN32_VM |
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DWORD old_prot; |
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int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot); |
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return ret_code != 0 ? 0 : -1; |
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#else |
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// Unsupported |
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return -1; |
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#endif |
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#endif |
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#endif |
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} |
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|
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/* Returns the size of a page. */ |
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|
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int vm_get_page_size(void) |
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{ |
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#ifdef HAVE_WIN32_VM |
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static vm_uintptr_t page_size = 0; |
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if (page_size == 0) { |
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SYSTEM_INFO si; |
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GetSystemInfo(&si); |
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page_size = si.dwAllocationGranularity; |
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} |
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return page_size; |
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#else |
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return getpagesize(); |
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#endif |
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} |
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|
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#ifdef CONFIGURE_TEST_VM_MAP |
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#include <stdlib.h> |
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#include <signal.h> |
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|
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static void fault_handler(int sig) |
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{ |
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exit(1); |
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} |
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|
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/* Tests covered here: |
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- TEST_VM_PROT_* program slices actually succeeds when a crash occurs |
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- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled |
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*/ |
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int main(void) |
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{ |
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vm_init(); |
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|
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signal(SIGSEGV, fault_handler); |
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#ifdef SIGBUS |
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signal(SIGBUS, fault_handler); |
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#endif |
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|
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#define page_align(address) ((char *)((vm_uintptr_t)(address) & -page_size)) |
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vm_uintptr_t page_size = vm_get_page_size(); |
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|
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const int area_size = 6 * page_size; |
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volatile char * area = (volatile char *) vm_acquire(area_size); |
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volatile char * fault_address = area + (page_size * 7) / 2; |
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|
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#if defined(TEST_VM_MMAP_ANON) || defined(TEST_VM_MMAP_ANONYMOUS) |
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if (area == VM_MAP_FAILED) |
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return 1; |
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|
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if (vm_release((char *)area, area_size) < 0) |
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return 1; |
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|
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return 0; |
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#endif |
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|
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#if defined(TEST_VM_PROT_NONE_READ) || defined(TEST_VM_PROT_NONE_WRITE) |
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if (area == VM_MAP_FAILED) |
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return 0; |
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|
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if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0) |
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return 0; |
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#endif |
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|
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#if defined(TEST_VM_PROT_RDWR_WRITE) |
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if (area == VM_MAP_FAILED) |
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return 1; |
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|
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if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0) |
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return 1; |
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|
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if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ | VM_PAGE_WRITE) < 0) |
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return 1; |
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#endif |
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|
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#if defined(TEST_VM_PROT_READ_WRITE) |
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if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0) |
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return 0; |
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#endif |
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|
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#if defined(TEST_VM_PROT_NONE_READ) |
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// this should cause a core dump |
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char foo = *fault_address; |
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return 0; |
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#endif |
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|
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#if defined(TEST_VM_PROT_NONE_WRITE) || defined(TEST_VM_PROT_READ_WRITE) |
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// this should cause a core dump |
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*fault_address = 'z'; |
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return 0; |
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#endif |
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|
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#if defined(TEST_VM_PROT_RDWR_WRITE) |
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// this should not cause a core dump |
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*fault_address = 'z'; |
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return 0; |
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#endif |
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} |
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#endif |
