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.
#	Content
1	/*
2	* vm_alloc.cpp - Wrapper to various virtual memory allocation schemes
3	* (supports mmap, vm_allocate or fallbacks to malloc)
4	*
5	* Basilisk II (C) 1997-2002 Christian Bauer
6	*
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	/* 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	#ifdef HAVE_MMAP_VM
52	#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	#ifdef HAVE_MMAP_ANON
62	#define map_flags (MAP_PRIVATE \| MAP_ANON \| MAP_EXTRA_FLAGS)
63	#define zero_fd -1
64	#else
65	#ifdef HAVE_MMAP_ANONYMOUS
66	#define map_flags (MAP_PRIVATE \| MAP_ANONYMOUS \| MAP_EXTRA_FLAGS)
67	#define zero_fd -1
68	#else
69	#ifdef HAVE_FCNTL_H
70	#include <fcntl.h>
71	#endif
72	#define map_flags (MAP_PRIVATE \| MAP_EXTRA_FLAGS)
73	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	if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, map_flags, zero_fd, 0)) == MAP_FAILED)
118	return VM_MAP_FAILED;
119
120	next_address = (char *)addr + size;
121
122	// 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
134	// 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	if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, map_flags \| MAP_FIXED, zero_fd, 0) == MAP_FAILED)
154	return -1;
155
156	// Since I don't know the standard behavior of mmap(), zero-fill here
157	if (memset(addr, 0, size) != addr)
158	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	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
168	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	// Safety check: don't try to release memory that was not allocated
179	if (addr == VM_MAP_FAILED)
180	return 0;
181
182	#ifdef HAVE_MACH_VM
183	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
184	return -1;
185	#else
186	#ifdef HAVE_MMAP_VM
187	if (munmap((caddr_t)addr, size) != 0)
188	return -1;
189	#else
190	free(addr);
191	#endif
192	#endif
193
194	return 0;
195	}
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	int ret_code = mprotect((caddr_t)addr, size, prot);
208	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