diff --git a/BasiliskII/src/Unix/configure.ac b/BasiliskII/src/Unix/configure.ac index 6ece0de2..1a4fba91 100755 --- a/BasiliskII/src/Unix/configure.ac +++ b/BasiliskII/src/Unix/configure.ac @@ -1479,6 +1479,10 @@ if [[ "x$OS_TYPE" = "xdarwin" ]]; then LDFLAGS="$LDFLAGS -Wl,-no_pie -pagezero_size 0x1000" fi +if [[ "x$OS_TYPE" = "xlinux" ]]; then + LDFLAGS="$LDFLAGS -no-pie" +fi + dnl Enable VOSF screen updates with this feature is requested and feasible if [[ "x$WANT_VOSF" = "xyes" -a "x$CAN_VOSF" = "xyes" ]]; then AC_DEFINE(ENABLE_VOSF, 1, [Define if using video enabled on SEGV signals.]) diff --git a/SheepShaver/src/CrossPlatform/vm_alloc.cpp b/SheepShaver/src/CrossPlatform/vm_alloc.cpp deleted file mode 120000 index cc80e1bc..00000000 --- a/SheepShaver/src/CrossPlatform/vm_alloc.cpp +++ /dev/null @@ -1 +0,0 @@ -../../../BasiliskII/src/CrossPlatform/vm_alloc.cpp \ No newline at end of file diff --git a/SheepShaver/src/CrossPlatform/vm_alloc.cpp b/SheepShaver/src/CrossPlatform/vm_alloc.cpp new file mode 100644 index 00000000..176060c0 --- /dev/null +++ b/SheepShaver/src/CrossPlatform/vm_alloc.cpp @@ -0,0 +1,619 @@ +/* + * vm_alloc.cpp - Wrapper to various virtual memory allocation schemes + * (supports mmap, vm_allocate or fallbacks to malloc) + * + * Basilisk II (C) 1997-2008 Christian Bauer + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#ifdef HAVE_FCNTL_H +#include +#endif + +#ifdef HAVE_WIN32_VM +#define WIN32_LEAN_AND_MEAN /* avoid including junk */ +#include +#endif + +#include +#include +#include +#include +#include +#include "vm_alloc.h" + +#if defined(__APPLE__) && defined(__MACH__) +#include +#endif + +#ifdef HAVE_MACH_VM +#ifndef HAVE_MACH_TASK_SELF +#ifdef HAVE_TASK_SELF +#define mach_task_self task_self +#else +#error "No task_self(), you lose." +#endif +#endif +#endif + +#ifdef HAVE_WIN32_VM +/* Windows is either ILP32 or LLP64 */ +typedef UINT_PTR vm_uintptr_t; +#else +/* Other systems are sane as they are either ILP32 or LP64 */ +typedef unsigned long vm_uintptr_t; +#endif + +/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII + because the emulated target is 32-bit and this helps to allocate + memory so that branches could be resolved more easily (32-bit + displacement to code in .text), on AMD64 for example. */ +#if defined(__hpux) +#define MAP_32BIT MAP_ADDR32 +#endif +#ifndef MAP_32BIT +#define MAP_32BIT 0 +#endif +#ifdef __FreeBSD__ +#define FORCE_MAP_32BIT MAP_FIXED +#else +#define FORCE_MAP_32BIT MAP_32BIT +#endif +#ifndef MAP_ANON +#define MAP_ANON 0 +#endif +#ifndef MAP_ANONYMOUS +#define MAP_ANONYMOUS 0 +#endif + +/* NOTE: on linux MAP_32BIT is only implemented on AMD64 + it is a null op on all other architectures + thus the MAP_BASE setting below is the only thing + ensuring low addresses on aarch64 for example */ +#define MAP_EXTRA_FLAGS (MAP_32BIT) + +#ifdef HAVE_MMAP_VM +#if (defined(__linux__) && defined(__i386__)) || defined(__FreeBSD__) || HAVE_LINKER_SCRIPT +/* Force a reasonnable address below 0x80000000 on x86 so that we + don't get addresses above when the program is run on AMD64. + NOTE: this is empirically determined on Linux/x86. */ +#define MAP_BASE 0x10000000 +#elif DIRECT_ADDRESSING +/* linux does not implement any useful fallback behavior + such as allocating the next available address + and the first 4k-64k of address space is marked unavailable + for security reasons (see https://wiki.debian.org/mmap_min_addr) + so we must start requesting after the first page + or we get a high 64bit address that will crash direct addressing + + leaving NULL unmapped is a good idea anyway for debugging reasons */ +#define MAP_BASE 0x00010000 +#else +#define MAP_BASE 0x00000000 +#endif +static char * next_address = (char *)MAP_BASE; +#ifdef HAVE_MMAP_ANON +#define map_flags (MAP_ANON | MAP_EXTRA_FLAGS) +#define zero_fd -1 +#else +#ifdef HAVE_MMAP_ANONYMOUS +#define map_flags (MAP_ANONYMOUS | MAP_EXTRA_FLAGS) +#define zero_fd -1 +#else +#define map_flags (MAP_EXTRA_FLAGS) +static int zero_fd = -1; +#endif +#endif +#endif + +/* Translate generic VM map flags to host values. */ + +#ifdef HAVE_MMAP_VM +static int translate_map_flags(int vm_flags) +{ + int flags = 0; + if (vm_flags & VM_MAP_SHARED) + flags |= MAP_SHARED; + if (vm_flags & VM_MAP_PRIVATE) + flags |= MAP_PRIVATE; + if (vm_flags & VM_MAP_FIXED) + flags |= MAP_FIXED; + if (vm_flags & VM_MAP_32BIT) + flags |= FORCE_MAP_32BIT; + return flags; +} +#endif + +/* Align ADDR and SIZE to 64K boundaries. */ + +#ifdef HAVE_WIN32_VM +static inline LPVOID align_addr_segment(LPVOID addr) +{ + return LPVOID(vm_uintptr_t(addr) & ~vm_uintptr_t(0xFFFF)); +} + +static inline DWORD align_size_segment(LPVOID addr, DWORD size) +{ + return size + ((vm_uintptr_t)addr - (vm_uintptr_t)align_addr_segment(addr)); +} +#endif + +/* Translate generic VM prot flags to host values. */ + +#ifdef HAVE_WIN32_VM +static int translate_prot_flags(int prot_flags) +{ + int prot = PAGE_READWRITE; + if (prot_flags == (VM_PAGE_EXECUTE | VM_PAGE_READ | VM_PAGE_WRITE)) + prot = PAGE_EXECUTE_READWRITE; + else if (prot_flags == (VM_PAGE_EXECUTE | VM_PAGE_READ)) + prot = PAGE_EXECUTE_READ; + else if (prot_flags == (VM_PAGE_READ | VM_PAGE_WRITE)) + prot = PAGE_READWRITE; + else if (prot_flags == VM_PAGE_READ) + prot = PAGE_READONLY; + else if (prot_flags == 0) + prot = PAGE_NOACCESS; + return prot; +} +#endif + +/* Translate Mach return codes to POSIX errno values. */ +#ifdef HAVE_MACH_VM +static int vm_error(kern_return_t ret_code) +{ + switch (ret_code) { + case KERN_SUCCESS: + return 0; + case KERN_INVALID_ADDRESS: + case KERN_NO_SPACE: + return ENOMEM; + case KERN_PROTECTION_FAILURE: + return EACCES; + default: + return EINVAL; + } +} +#endif + +/* Initialize the VM system. Returns 0 if successful, -1 for errors. */ + +int vm_init(void) +{ +#ifdef HAVE_MMAP_VM +#ifndef zero_fd + zero_fd = open("/dev/zero", O_RDWR); + if (zero_fd < 0) + return -1; +#endif +#endif + +// On 10.4 and earlier, reset CrashReporter's task signal handler to +// avoid having it show up for signals that get handled. +#if defined(__APPLE__) && defined(__MACH__) + struct utsname info; + + if (!uname(&info) && atoi(info.release) <= 8) { + task_set_exception_ports(mach_task_self(), + EXC_MASK_BAD_ACCESS | EXC_MASK_ARITHMETIC, + MACH_PORT_NULL, + EXCEPTION_STATE_IDENTITY, + MACHINE_THREAD_STATE); + } +#endif + + return 0; +} + +/* Deallocate all internal data used to wrap virtual memory allocators. */ + +void vm_exit(void) +{ +#ifdef HAVE_MMAP_VM +#ifndef zero_fd + if (zero_fd != -1) { + close(zero_fd); + zero_fd = -1; + } +#endif +#endif +} + +static void *reserved_buf; +static const size_t RESERVED_SIZE = 64 * 1024 * 1024; // for 5K Retina + +void *vm_acquire_reserved(size_t size) { + return reserved_buf && size <= RESERVED_SIZE ? reserved_buf : VM_MAP_FAILED; +} + +int vm_init_reserved(void *hostAddress) { + int result = vm_acquire_fixed(hostAddress, RESERVED_SIZE); + if (result >= 0) + reserved_buf = hostAddress; + return result; +} + +/* Allocate zero-filled memory of SIZE bytes. The mapping is private + and default protection bits are read / write. The return value + is the actual mapping address chosen or VM_MAP_FAILED for errors. */ + +void * vm_acquire(size_t size, int options) +{ + void * addr; + + errno = 0; + + // VM_MAP_FIXED are to be used with vm_acquire_fixed() only + if (options & VM_MAP_FIXED) + return VM_MAP_FAILED; + +#ifndef HAVE_VM_WRITE_WATCH + if (options & VM_MAP_WRITE_WATCH) + return VM_MAP_FAILED; +#endif + +#if defined(HAVE_MACH_VM) + // vm_allocate() returns a zero-filled memory region + kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, reserved_buf ? size : size + RESERVED_SIZE, TRUE); + if (ret_code != KERN_SUCCESS) { + errno = vm_error(ret_code); + return VM_MAP_FAILED; + } + if (!reserved_buf) + reserved_buf = (char *)addr + size; +#elif defined(HAVE_MMAP_VM) + int fd = zero_fd; + int the_map_flags = translate_map_flags(options) | map_flags; + + if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED) + return VM_MAP_FAILED; + +#if DIRECT_ADDRESSING + // If MAP_32BIT and MAP_BASE fail to ensure + // a 32-bit address crash now instead of later. + // FIXME: make everything 64-bit clean and tear this all out. + if(sizeof(void *) > 4 && (options & VM_MAP_32BIT)) + assert((size_t)addr<0xffffffffL); +#endif + + next_address = (char *)addr + size; +#elif defined(HAVE_WIN32_VM) + int alloc_type = MEM_RESERVE | MEM_COMMIT; + if (options & VM_MAP_WRITE_WATCH) + alloc_type |= MEM_WRITE_WATCH; + + if ((addr = VirtualAlloc(NULL, size, alloc_type, PAGE_EXECUTE_READWRITE)) == NULL) + return VM_MAP_FAILED; +#else + if ((addr = calloc(size, 1)) == 0) + return VM_MAP_FAILED; + + // Omit changes for protections because they are not supported in this mode + return addr; +#endif + + // Explicitely protect the newly mapped region here because on some systems, + // say MacOS X, mmap() doesn't honour the requested protection flags. + if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0) + return VM_MAP_FAILED; + + return addr; +} + +/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned). + Retuns 0 if successful, -1 on errors. */ + +int vm_acquire_fixed(void * addr, size_t size, int options) +{ + errno = 0; + + // Fixed mappings are required to be private + if (options & VM_MAP_SHARED) + return -1; + +#ifndef HAVE_VM_WRITE_WATCH + if (options & VM_MAP_WRITE_WATCH) + return -1; +#endif + +#if defined(HAVE_MACH_VM) + // vm_allocate() returns a zero-filled memory region + kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0); + if (ret_code != KERN_SUCCESS) { + errno = vm_error(ret_code); + return -1; + } +#elif defined(HAVE_MMAP_VM) + int fd = zero_fd; + int the_map_flags = translate_map_flags(options) | map_flags | MAP_FIXED; + + if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED) + return -1; +#elif defined(HAVE_WIN32_VM) + // Windows cannot allocate Low Memory + if (addr == NULL) + return -1; + + int alloc_type = MEM_RESERVE | MEM_COMMIT; + if (options & VM_MAP_WRITE_WATCH) + alloc_type |= MEM_WRITE_WATCH; + + // Allocate a possibly offset region to align on 64K boundaries + LPVOID req_addr = align_addr_segment(addr); + DWORD req_size = align_size_segment(addr, size); + LPVOID ret_addr = VirtualAlloc(req_addr, req_size, alloc_type, PAGE_EXECUTE_READWRITE); + if (ret_addr != req_addr) + return -1; +#else + // Unsupported + return -1; +#endif + + // Explicitely protect the newly mapped region here because on some systems, + // say MacOS X, mmap() doesn't honour the requested protection flags. + if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0) + return -1; + + return 0; +} + +/* Deallocate any mapping for the region starting at ADDR and extending + LEN bytes. Returns 0 if successful, -1 on errors. */ + +int vm_release(void * addr, size_t size) +{ + // Safety check: don't try to release memory that was not allocated + if (addr == VM_MAP_FAILED) + return 0; + +#ifdef HAVE_MACH_VM + if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS) + return -1; +#else +#ifdef HAVE_MMAP_VM + if (munmap((caddr_t)addr, size) != 0) + return -1; +#else +#ifdef HAVE_WIN32_VM + if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0) + return -1; +#else + free(addr); +#endif +#endif +#endif + + return 0; +} + +/* Change the memory protection of the region starting at ADDR and + extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */ + +int vm_protect(void * addr, size_t size, int prot) +{ +#ifdef HAVE_MACH_VM + int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot); + return ret_code == KERN_SUCCESS ? 0 : -1; +#else +#ifdef HAVE_MMAP_VM + int ret_code = mprotect((caddr_t)addr, size, prot); + return ret_code == 0 ? 0 : -1; +#else +#ifdef HAVE_WIN32_VM + DWORD old_prot; + int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot); + return ret_code != 0 ? 0 : -1; +#else + // Unsupported + return -1; +#endif +#endif +#endif +} + +/* Return the addresses of the pages that got modified in the + specified range [ ADDR, ADDR + SIZE [ since the last reset of the watch + bits. Returns 0 if successful, -1 for errors. */ + +int vm_get_write_watch(void * addr, size_t size, + void ** pages, unsigned int * n_pages, + int options) +{ +#ifdef HAVE_VM_WRITE_WATCH +#ifdef HAVE_WIN32_VM + DWORD flags = 0; + if (options & VM_WRITE_WATCH_RESET) + flags |= WRITE_WATCH_FLAG_RESET; + + ULONG page_size; + ULONG_PTR count = *n_pages; + int ret_code = GetWriteWatch(flags, addr, size, pages, &count, &page_size); + if (ret_code != 0) + return -1; + + *n_pages = count; + return 0; +#endif +#endif + // Unsupported + return -1; +} + +/* Reset the write-tracking state for the specified range [ ADDR, ADDR + + SIZE [. Returns 0 if successful, -1 for errors. */ + +int vm_reset_write_watch(void * addr, size_t size) +{ +#ifdef HAVE_VM_WRITE_WATCH +#ifdef HAVE_WIN32_VM + int ret_code = ResetWriteWatch(addr, size); + return ret_code == 0 ? 0 : -1; +#endif +#endif + // Unsupported + return -1; +} + +/* Returns the size of a page. */ + +int vm_get_page_size(void) +{ +#ifdef HAVE_WIN32_VM + static vm_uintptr_t page_size = 0; + if (page_size == 0) { + SYSTEM_INFO si; + GetSystemInfo(&si); + page_size = si.dwAllocationGranularity; + } + return page_size; +#else + return getpagesize(); +#endif +} + +#ifdef CONFIGURE_TEST_VM_WRITE_WATCH +int main(void) +{ + int i, j; + + vm_init(); + + vm_uintptr_t page_size = vm_get_page_size(); + + char *area; + const int n_pages = 7; + const int area_size = n_pages * page_size; + const int map_options = VM_MAP_DEFAULT | VM_MAP_WRITE_WATCH; + if ((area = (char *)vm_acquire(area_size, map_options)) == VM_MAP_FAILED) + return 1; + + unsigned int n_modified_pages_expected = 0; + static const int touch_page[n_pages] = { 0, 1, 1, 0, 1, 0, 1 }; + for (i = 0; i < n_pages; i++) { + if (touch_page[i]) { + area[i * page_size] = 1; + ++n_modified_pages_expected; + } + } + + char *modified_pages[n_pages]; + unsigned int n_modified_pages = n_pages; + if (vm_get_write_watch(area, area_size, (void **)modified_pages, &n_modified_pages) < 0) + return 2; + if (n_modified_pages != n_modified_pages_expected) + return 3; + for (i = 0, j = 0; i < n_pages; i++) { + char v = area[i * page_size]; + if ((touch_page[i] && !v) || (!touch_page[i] && v)) + return 4; + if (!touch_page[i]) + continue; + if (modified_pages[j] != (area + i * page_size)) + return 5; + ++j; + } + + vm_release(area, area_size); + return 0; +} +#endif + +#ifdef CONFIGURE_TEST_VM_MAP +#include +#include + +static void fault_handler(int sig) +{ + exit(1); +} + +/* Tests covered here: + - TEST_VM_PROT_* program slices actually succeeds when a crash occurs + - TEST_VM_MAP_ANON* program slices succeeds when it could be compiled +*/ +int main(void) +{ + vm_init(); + + signal(SIGSEGV, fault_handler); +#ifdef SIGBUS + signal(SIGBUS, fault_handler); +#endif + +#define page_align(address) ((char *)((vm_uintptr_t)(address) & -page_size)) + vm_uintptr_t page_size = vm_get_page_size(); + + const int area_size = 6 * page_size; + volatile char * area = (volatile char *) vm_acquire(area_size); + volatile char * fault_address = area + (page_size * 7) / 2; + +#if defined(TEST_VM_MMAP_ANON) || defined(TEST_VM_MMAP_ANONYMOUS) + if (area == VM_MAP_FAILED) + return 1; + + if (vm_release((char *)area, area_size) < 0) + return 1; + + return 0; +#endif + +#if defined(TEST_VM_PROT_NONE_READ) || defined(TEST_VM_PROT_NONE_WRITE) + if (area == VM_MAP_FAILED) + return 0; + + if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0) + return 0; +#endif + +#if defined(TEST_VM_PROT_RDWR_WRITE) + if (area == VM_MAP_FAILED) + return 1; + + if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0) + return 1; + + if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ | VM_PAGE_WRITE) < 0) + return 1; +#endif + +#if defined(TEST_VM_PROT_READ_WRITE) + if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0) + return 0; +#endif + +#if defined(TEST_VM_PROT_NONE_READ) + // this should cause a core dump + char foo = *fault_address; + return 0; +#endif + +#if defined(TEST_VM_PROT_NONE_WRITE) || defined(TEST_VM_PROT_READ_WRITE) + // this should cause a core dump + *fault_address = 'z'; + return 0; +#endif + +#if defined(TEST_VM_PROT_RDWR_WRITE) + // this should not cause a core dump + *fault_address = 'z'; + return 0; +#endif +} +#endif diff --git a/SheepShaver/src/CrossPlatform/vm_alloc.h b/SheepShaver/src/CrossPlatform/vm_alloc.h deleted file mode 120000 index ef65a561..00000000 --- a/SheepShaver/src/CrossPlatform/vm_alloc.h +++ /dev/null @@ -1 +0,0 @@ -../../../BasiliskII/src/CrossPlatform/vm_alloc.h \ No newline at end of file diff --git a/SheepShaver/src/CrossPlatform/vm_alloc.h b/SheepShaver/src/CrossPlatform/vm_alloc.h new file mode 100644 index 00000000..41dd949d --- /dev/null +++ b/SheepShaver/src/CrossPlatform/vm_alloc.h @@ -0,0 +1,138 @@ +/* + * vm_alloc.h - Wrapper to various virtual memory allocation schemes + * (supports mmap, vm_allocate or fallbacks to malloc) + * + * Basilisk II (C) 1997-2008 Christian Bauer + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef VM_ALLOC_H +#define VM_ALLOC_H + +#ifdef HAVE_UNISTD_H +#include +#include +#endif +#ifdef HAVE_SYS_MMAN_H +#include +#endif +#ifdef HAVE_MACH_VM +extern "C" { +#include +#include +} +#endif + +#include + +/* Return value of `vm_acquire' in case of an error. */ +#ifdef HAVE_MACH_VM +#define VM_MAP_FAILED ((void *)-1) +#else +#ifdef HAVE_MMAP_VM +#define VM_MAP_FAILED ((void *)-1) +#else +#define VM_MAP_FAILED 0 +#endif +#endif + +/* Option to vm_get_write_watch() to reset the write-tracking state + once it was retrieved. Otherwise, you have to manually call + vm_reset_write_watch() and potentially lose some info. */ +#define VM_WRITE_WATCH_RESET 0x01 + +/* Mapping options. */ +#define VM_MAP_SHARED 0x01 +#define VM_MAP_PRIVATE 0x02 +#define VM_MAP_FIXED 0x04 +#define VM_MAP_32BIT 0x08 +#define VM_MAP_WRITE_WATCH 0x10 + +/* Default mapping options. */ +#define VM_MAP_DEFAULT (VM_MAP_PRIVATE) + +/* Protection bits. */ +#ifdef HAVE_MACH_VM +#define VM_PAGE_NOACCESS VM_PROT_NONE +#define VM_PAGE_READ VM_PROT_READ +#define VM_PAGE_WRITE VM_PROT_WRITE +#define VM_PAGE_EXECUTE VM_PROT_EXECUTE +#else +#ifdef HAVE_MMAP_VM +#define VM_PAGE_NOACCESS PROT_NONE +#define VM_PAGE_READ PROT_READ +#define VM_PAGE_WRITE PROT_WRITE +#define VM_PAGE_EXECUTE PROT_EXEC +#else +#define VM_PAGE_NOACCESS 0x0 +#define VM_PAGE_READ 0x1 +#define VM_PAGE_WRITE 0x2 +#define VM_PAGE_EXECUTE 0x4 +#endif +#endif + +/* Default protection bits. */ +#define VM_PAGE_DEFAULT (VM_PAGE_READ | VM_PAGE_WRITE) + +/* Initialize the VM system. Returns 0 if successful, -1 for errors. */ + +extern int vm_init(void); + +/* Deallocate all internal data used to wrap virtual memory allocators. */ + +extern void vm_exit(void); + +/* Allocate zero-filled memory of SIZE bytes. The mapping is private + and default protection bits are read / write. The return value + is the actual mapping address chosen or VM_MAP_FAILED for errors. */ + +extern void * vm_acquire(size_t size, int options = VM_MAP_DEFAULT); + +extern void * vm_acquire_reserved(size_t size); + +/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned). + Returns 0 if successful, -1 on errors. */ + +extern int vm_acquire_fixed(void * addr, size_t size, int options = VM_MAP_DEFAULT); + +/* Deallocate any mapping for the region starting at ADDR and extending + LEN bytes. Returns 0 if successful, -1 on errors. */ + +extern int vm_release(void * addr, size_t size); + +/* Change the memory protection of the region starting at ADDR and + extending SIZE bytes to PROT. Returns 0 if successful, -1 for errors. */ + +extern int vm_protect(void * addr, size_t size, int prot); + +/* Return the addresses of the pages that got modified since the last + reset of the write-tracking state for the specified range [ ADDR, + ADDR + SIZE [. Returns 0 if successful, -1 for errors. */ + +extern int vm_get_write_watch(void * addr, size_t size, + void ** pages, unsigned int * n_pages, + int options = 0); + +/* Reset the write-tracking state for the specified range [ ADDR, ADDR + + SIZE [. Returns 0 if successful, -1 for errors. */ + +extern int vm_reset_write_watch(void * addr, size_t size); + +/* Returns the size of a page. */ + +extern int vm_get_page_size(void); + +#endif /* VM_ALLOC_H */