src/Unix/vm_alloc.cpp

/*
 *  vm_alloc.cpp - Wrapper to various virtual memory allocation schemes
 *                 (supports mmap, vm_allocate or fallbacks to malloc)
 *
 *  Basilisk II (C) 1997-2002 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

// TODO: Win32 VMs ?
#include <stdlib.h>
#include <string.h>
#include "vm_alloc.h"

#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

/* 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.  */
#ifndef MAP_32BIT
#define MAP_32BIT 0
#endif

#define MAP_EXTRA_FLAGS (MAP_32BIT)

#ifdef HAVE_MMAP_VM
#if defined(__linux__) && defined(__i386__)
/* 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
#else
#define MAP_BASE        0x00000000
#endif
static char * next_address = (char *)MAP_BASE;
#ifdef HAVE_MMAP_ANON
#define map_flags       (MAP_PRIVATE | MAP_ANON | MAP_EXTRA_FLAGS)
#define zero_fd         -1
#else
#ifdef HAVE_MMAP_ANONYMOUS
#define map_flags       (MAP_PRIVATE | MAP_ANONYMOUS | MAP_EXTRA_FLAGS)
#define zero_fd         -1
#else
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#define map_flags       (MAP_PRIVATE | MAP_EXTRA_FLAGS)
static int zero_fd      = -1;
#endif
#endif
#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
        return 0;
}

/* Deallocate all internal data used to wrap virtual memory allocators.  */

void vm_exit(void)
{
#ifdef HAVE_MMAP_VM
#ifndef zero_fd
        close(zero_fd);
#endif
#endif
}

/* 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)
{
        void * addr;
        
#ifdef HAVE_MACH_VM
        // vm_allocate() returns a zero-filled memory region
        if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
                return VM_MAP_FAILED;
#else
#ifdef HAVE_MMAP_VM
        if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, map_flags, zero_fd, 0)) == MAP_FAILED)
                return VM_MAP_FAILED;
        
        next_address = (char *)addr + size;
        
        // Since I don't know the standard behavior of mmap(), zero-fill here
        if (memset(addr, 0, size) != addr)
                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
#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)
{
#ifdef HAVE_MACH_VM
        // vm_allocate() returns a zero-filled memory region
        if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
                return -1;
#else
#ifdef HAVE_MMAP_VM
        if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, map_flags | MAP_FIXED, zero_fd, 0) == MAP_FAILED)
                return -1;
        
        // Since I don't know the standard behavior of mmap(), zero-fill here
        if (memset(addr, 0, size) != addr)
                return -1;
#else
        // Unsupported
        return -1;
#endif
#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
        free(addr);
#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
        // Unsupported
        return -1;
#endif
#endif
}

#ifdef CONFIGURE_TEST_VM_MAP
/* 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();
        
#define page_align(address) ((char *)((unsigned long)(address) & -page_size))
        unsigned long page_size = getpagesize();
        
        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
Revision:	1.9
Committed:	2003-10-03T18:18:12Z (21 years, 1 month ago) by gbeauche
Branch:	MAIN
Changes since 1.8:	+22 -4 lines
Log Message:	Make sure a 32-bit B2/JIT works reasonnably well on AMD64 too. This implies to force RAMBaseHost < 0x80000000. This is empirically determined to work on Linux/x86 and Linux/amd64.
#	User	Rev	Content
1	gbeauche	1.1	/*
2			* vm_alloc.cpp - Wrapper to various virtual memory allocation schemes
3			* (supports mmap, vm_allocate or fallbacks to malloc)
4			*
5	cebix	1.5	* Basilisk II (C) 1997-2002 Christian Bauer
6	gbeauche	1.1	*
7			* This program is free software; you can redistribute it and/or modify
8			* it under the terms of the GNU General Public License as published by
9			* the Free Software Foundation; either version 2 of the License, or
10			* (at your option) any later version.
11			*
12			* This program is distributed in the hope that it will be useful,
13			* but WITHOUT ANY WARRANTY; without even the implied warranty of
14			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15			* GNU General Public License for more details.
16			*
17			* You should have received a copy of the GNU General Public License
18			* along with this program; if not, write to the Free Software
19			* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20			*/
21
22			#ifdef HAVE_CONFIG_H
23			#include "config.h"
24			#endif
25
26			// TODO: Win32 VMs ?
27			#include <stdlib.h>
28			#include <string.h>
29			#include "vm_alloc.h"
30
31			#ifdef HAVE_MACH_VM
32			#ifndef HAVE_MACH_TASK_SELF
33			#ifdef HAVE_TASK_SELF
34			#define mach_task_self task_self
35			#else
36			#error "No task_self(), you lose."
37			#endif
38			#endif
39			#endif
40
41	gbeauche	1.9	/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII
42			because the emulated target is 32-bit and this helps to allocate
43			memory so that branches could be resolved more easily (32-bit
44			displacement to code in .text), on AMD64 for example. */
45			#ifndef MAP_32BIT
46			#define MAP_32BIT 0
47			#endif
48
49			#define MAP_EXTRA_FLAGS (MAP_32BIT)
50
51	gbeauche	1.1	#ifdef HAVE_MMAP_VM
52	gbeauche	1.9	#if defined(__linux__) && defined(__i386__)
53			/* Force a reasonnable address below 0x80000000 on x86 so that we
54			don't get addresses above when the program is run on AMD64.
55			NOTE: this is empirically determined on Linux/x86. */
56			#define MAP_BASE 0x10000000
57			#else
58			#define MAP_BASE 0x00000000
59			#endif
60			static char * next_address = (char *)MAP_BASE;
61	gbeauche	1.1	#ifdef HAVE_MMAP_ANON
62	gbeauche	1.9	#define map_flags (MAP_PRIVATE \| MAP_ANON \| MAP_EXTRA_FLAGS)
63	gbeauche	1.1	#define zero_fd -1
64			#else
65			#ifdef HAVE_MMAP_ANONYMOUS
66	gbeauche	1.9	#define map_flags (MAP_PRIVATE \| MAP_ANONYMOUS \| MAP_EXTRA_FLAGS)
67	gbeauche	1.1	#define zero_fd -1
68			#else
69			#ifdef HAVE_FCNTL_H
70			#include <fcntl.h>
71			#endif
72	gbeauche	1.9	#define map_flags (MAP_PRIVATE \| MAP_EXTRA_FLAGS)
73	gbeauche	1.1	static int zero_fd = -1;
74			#endif
75			#endif
76			#endif
77
78			/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
79
80			int vm_init(void)
81			{
82			#ifdef HAVE_MMAP_VM
83			#ifndef zero_fd
84			zero_fd = open("/dev/zero", O_RDWR);
85			if (zero_fd < 0)
86			return -1;
87			#endif
88			#endif
89			return 0;
90			}
91
92			/* Deallocate all internal data used to wrap virtual memory allocators. */
93
94			void vm_exit(void)
95			{
96			#ifdef HAVE_MMAP_VM
97			#ifndef zero_fd
98			close(zero_fd);
99			#endif
100			#endif
101			}
102
103			/* Allocate zero-filled memory of SIZE bytes. The mapping is private
104			and default protection bits are read / write. The return value
105			is the actual mapping address chosen or VM_MAP_FAILED for errors. */
106
107			void * vm_acquire(size_t size)
108			{
109			void * addr;
110
111			#ifdef HAVE_MACH_VM
112			// vm_allocate() returns a zero-filled memory region
113			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
114			return VM_MAP_FAILED;
115			#else
116			#ifdef HAVE_MMAP_VM
117	gbeauche	1.7	if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, map_flags, zero_fd, 0)) == MAP_FAILED)
118	gbeauche	1.1	return VM_MAP_FAILED;
119
120	gbeauche	1.3	next_address = (char *)addr + size;
121
122	gbeauche	1.1	// Since I don't know the standard behavior of mmap(), zero-fill here
123			if (memset(addr, 0, size) != addr)
124			return VM_MAP_FAILED;
125			#else
126			if ((addr = calloc(size, 1)) == 0)
127			return VM_MAP_FAILED;
128
129			// Omit changes for protections because they are not supported in this mode
130			return addr;
131			#endif
132			#endif
133	cebix	1.2
134	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
135			// say MacOS X, mmap() doesn't honour the requested protection flags.
136			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
137			return VM_MAP_FAILED;
138
139			return addr;
140			}
141
142			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
143			Retuns 0 if successful, -1 on errors. */
144
145			int vm_acquire_fixed(void * addr, size_t size)
146			{
147			#ifdef HAVE_MACH_VM
148			// vm_allocate() returns a zero-filled memory region
149			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
150			return -1;
151			#else
152			#ifdef HAVE_MMAP_VM
153	gbeauche	1.7	if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, map_flags \| MAP_FIXED, zero_fd, 0) == MAP_FAILED)
154	gbeauche	1.1	return -1;
155
156			// Since I don't know the standard behavior of mmap(), zero-fill here
157	gbeauche	1.8	if (memset(addr, 0, size) != addr)
158	gbeauche	1.1	return -1;
159			#else
160			// Unsupported
161			return -1;
162			#endif
163			#endif
164
165			// Explicitely protect the newly mapped region here because on some systems,
166			// say MacOS X, mmap() doesn't honour the requested protection flags.
167	gbeauche	1.6	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
168	gbeauche	1.1	return -1;
169
170			return 0;
171			}
172
173			/* Deallocate any mapping for the region starting at ADDR and extending
174			LEN bytes. Returns 0 if successful, -1 on errors. */
175
176			int vm_release(void * addr, size_t size)
177			{
178	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
179			if (addr == VM_MAP_FAILED)
180			return 0;
181
182	gbeauche	1.1	#ifdef HAVE_MACH_VM
183	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
184			return -1;
185	gbeauche	1.1	#else
186			#ifdef HAVE_MMAP_VM
187	gbeauche	1.7	if (munmap((caddr_t)addr, size) != 0)
188	gbeauche	1.4	return -1;
189	gbeauche	1.1	#else
190			free(addr);
191			#endif
192			#endif
193	gbeauche	1.4
194			return 0;
195	gbeauche	1.1	}
196
197			/* Change the memory protection of the region starting at ADDR and
198			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
199
200			int vm_protect(void * addr, size_t size, int prot)
201			{
202			#ifdef HAVE_MACH_VM
203			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
204			return ret_code == KERN_SUCCESS ? 0 : -1;
205			#else
206			#ifdef HAVE_MMAP_VM
207	gbeauche	1.7	int ret_code = mprotect((caddr_t)addr, size, prot);
208	gbeauche	1.1	return ret_code == 0 ? 0 : -1;
209			#else
210			// Unsupported
211			return -1;
212			#endif
213			#endif
214			}
215
216			#ifdef CONFIGURE_TEST_VM_MAP
217			/* Tests covered here:
218			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
219			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
220			*/
221			int main(void)
222			{
223			vm_init();
224
225			#define page_align(address) ((char *)((unsigned long)(address) & -page_size))
226			unsigned long page_size = getpagesize();
227
228			const int area_size = 6 * page_size;
229			volatile char * area = (volatile char *) vm_acquire(area_size);
230			volatile char * fault_address = area + (page_size * 7) / 2;
231
232			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
233			if (area == VM_MAP_FAILED)
234			return 1;
235
236			if (vm_release((char *)area, area_size) < 0)
237			return 1;
238
239			return 0;
240			#endif
241
242			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
243			if (area == VM_MAP_FAILED)
244			return 0;
245
246			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
247			return 0;
248			#endif
249
250			#if defined(TEST_VM_PROT_RDWR_WRITE)
251			if (area == VM_MAP_FAILED)
252			return 1;
253
254			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
255			return 1;
256
257			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
258			return 1;
259			#endif
260
261			#if defined(TEST_VM_PROT_READ_WRITE)
262			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
263			return 0;
264			#endif
265
266			#if defined(TEST_VM_PROT_NONE_READ)
267			// this should cause a core dump
268			char foo = *fault_address;
269			return 0;
270			#endif
271
272			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
273			// this should cause a core dump
274			*fault_address = 'z';
275			return 0;
276			#endif
277
278			#if defined(TEST_VM_PROT_RDWR_WRITE)
279			// this should not cause a core dump
280			*fault_address = 'z';
281			return 0;
282			#endif
283			}
284			#endif