[qemu.git] / linux-user / mmap.c

/*
 *  mmap support for qemu
 * 
 *  Copyright (c) 2003 Fabrice Bellard
 *
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>

#include "qemu.h"

//#define DEBUG_MMAP

/* NOTE: all the constants are the HOST ones */
int target_mprotect(unsigned long start, unsigned long len, int prot)
{
    unsigned long end, host_start, host_end, addr;
    int prot1, ret;

#ifdef DEBUG_MMAP
    printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len,
           prot & PROT_READ ? 'r' : '-',
           prot & PROT_WRITE ? 'w' : '-',
           prot & PROT_EXEC ? 'x' : '-');
#endif

    if ((start & ~TARGET_PAGE_MASK) != 0)
        return -EINVAL;
    len = TARGET_PAGE_ALIGN(len);
    end = start + len;
    if (end < start)
        return -EINVAL;
    if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
        return -EINVAL;
    if (len == 0)
        return 0;
    
    host_start = start & host_page_mask;
    host_end = HOST_PAGE_ALIGN(end);
    if (start > host_start) {
        /* handle host page containing start */
        prot1 = prot;
        for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
            prot1 |= page_get_flags(addr);
        }
        if (host_end == host_start + host_page_size) {
            for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
                prot1 |= page_get_flags(addr);
            }
            end = host_end;
        }
        ret = mprotect((void *)host_start, host_page_size, prot1 & PAGE_BITS);
        if (ret != 0)
            return ret;
        host_start += host_page_size;
    }
    if (end < host_end) {
        prot1 = prot;
        for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
            prot1 |= page_get_flags(addr);
        }
        ret = mprotect((void *)(host_end - host_page_size), host_page_size, 
                       prot1 & PAGE_BITS);
        if (ret != 0)
            return ret;
        host_end -= host_page_size;
    }
    
    /* handle the pages in the middle */
    if (host_start < host_end) {
        ret = mprotect((void *)host_start, host_end - host_start, prot);
        if (ret != 0)
            return ret;
    }
    page_set_flags(start, start + len, prot | PAGE_VALID);
    return 0;
}

/* map an incomplete host page */
int mmap_frag(unsigned long host_start, 
               unsigned long start, unsigned long end, 
               int prot, int flags, int fd, unsigned long offset)
{
    unsigned long host_end, ret, addr;
    int prot1, prot_new;

    host_end = host_start + host_page_size;

    /* get the protection of the target pages outside the mapping */
    prot1 = 0;
    for(addr = host_start; addr < host_end; addr++) {
        if (addr < start || addr >= end)
            prot1 |= page_get_flags(addr);
    }
    
    if (prot1 == 0) {
        /* no page was there, so we allocate one */
        ret = (long)mmap((void *)host_start, host_page_size, prot, 
                         flags | MAP_ANONYMOUS, -1, 0);
        if (ret == -1)
            return ret;
    }
    prot1 &= PAGE_BITS;

    prot_new = prot | prot1;
    if (!(flags & MAP_ANONYMOUS)) {
        /* msync() won't work here, so we return an error if write is
           possible while it is a shared mapping */
        if ((flags & MAP_TYPE) == MAP_SHARED &&
            (prot & PROT_WRITE))
            return -EINVAL;

        /* adjust protection to be able to read */
        if (!(prot1 & PROT_WRITE))
            mprotect((void *)host_start, host_page_size, prot1 | PROT_WRITE);
        
        /* read the corresponding file data */
        pread(fd, (void *)start, end - start, offset);
        
        /* put final protection */
        if (prot_new != (prot1 | PROT_WRITE))
            mprotect((void *)host_start, host_page_size, prot_new);
    } else {
        /* just update the protection */
        if (prot_new != prot1) {
            mprotect((void *)host_start, host_page_size, prot_new);
        }
    }
    return 0;
}

/* NOTE: all the constants are the HOST ones */
long target_mmap(unsigned long start, unsigned long len, int prot, 
                 int flags, int fd, unsigned long offset)
{
    unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;

#ifdef DEBUG_MMAP
    {
        printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
               start, len, 
               prot & PROT_READ ? 'r' : '-',
               prot & PROT_WRITE ? 'w' : '-',
               prot & PROT_EXEC ? 'x' : '-');
        if (flags & MAP_FIXED)
            printf("MAP_FIXED ");
        if (flags & MAP_ANONYMOUS)
            printf("MAP_ANON ");
        switch(flags & MAP_TYPE) {
        case MAP_PRIVATE:
            printf("MAP_PRIVATE ");
            break;
        case MAP_SHARED:
            printf("MAP_SHARED ");
            break;
        default:
            printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
            break;
        }
        printf("fd=%d offset=%lx\n", fd, offset);
    }
#endif

    if (offset & ~TARGET_PAGE_MASK)
        return -EINVAL;

    len = TARGET_PAGE_ALIGN(len);
    if (len == 0)
        return start;
    host_start = start & host_page_mask;

    if (!(flags & MAP_FIXED)) {
#if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
        /* tell the kenel to search at the same place as i386 */
        if (host_start == 0)
            host_start = 0x40000000;
#endif
        if (host_page_size != real_host_page_size) {
            /* NOTE: this code is only for debugging with '-p' option */
            /* reserve a memory area */
            host_len = HOST_PAGE_ALIGN(len) + host_page_size - TARGET_PAGE_SIZE;
            host_start = (long)mmap((void *)host_start, host_len, PROT_NONE, 
                                    MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
            if (host_start == -1)
                return host_start;
            host_end = host_start + host_len;
            start = HOST_PAGE_ALIGN(host_start);
            end = start + HOST_PAGE_ALIGN(len);
            if (start > host_start)
                munmap((void *)host_start, start - host_start);
            if (end < host_end)
                munmap((void *)end, host_end - end);
            /* use it as a fixed mapping */
            flags |= MAP_FIXED;
        } else {
            /* if not fixed, no need to do anything */
            host_offset = offset & host_page_mask;
            host_len = len + offset - host_offset;
            start = (long)mmap((void *)host_start, host_len, 
                               prot, flags, fd, host_offset);
            if (start == -1)
                return start;
            /* update start so that it points to the file position at 'offset' */
            if (!(flags & MAP_ANONYMOUS)) 
                start += offset - host_offset;
            goto the_end1;
        }
    }
    
    if (start & ~TARGET_PAGE_MASK)
        return -EINVAL;
    end = start + len;
    host_end = HOST_PAGE_ALIGN(end);

    /* worst case: we cannot map the file because the offset is not
       aligned, so we read it */
    if (!(flags & MAP_ANONYMOUS) &&
        (offset & ~host_page_mask) != (start & ~host_page_mask)) {
        /* msync() won't work here, so we return an error if write is
           possible while it is a shared mapping */
        if ((flags & MAP_TYPE) == MAP_SHARED &&
            (prot & PROT_WRITE))
            return -EINVAL;
        retaddr = target_mmap(start, len, prot | PROT_WRITE, 
                              MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, 
                              -1, 0);
        if (retaddr == -1)
            return retaddr;
        pread(fd, (void *)start, len, offset);
        if (!(prot & PROT_WRITE)) {
            ret = target_mprotect(start, len, prot);
            if (ret != 0)
                return ret;
        }
        goto the_end;
    }

    /* handle the start of the mapping */
    if (start > host_start) {
        if (host_end == host_start + host_page_size) {
            /* one single host page */
            ret = mmap_frag(host_start, start, end,
                            prot, flags, fd, offset);
            if (ret == -1)
                return ret;
            goto the_end1;
        }
        ret = mmap_frag(host_start, start, host_start + host_page_size,
                        prot, flags, fd, offset);
        if (ret == -1)
            return ret;
        host_start += host_page_size;
    }
    /* handle the end of the mapping */
    if (end < host_end) {
        ret = mmap_frag(host_end - host_page_size, 
                        host_end - host_page_size, host_end,
                        prot, flags, fd, 
                        offset + host_end - host_page_size - start);
        if (ret == -1)
            return ret;
        host_end -= host_page_size;
    }
    
    /* map the middle (easier) */
    if (host_start < host_end) {
        unsigned long offset1;
	if (flags & MAP_ANONYMOUS)
	  offset1 = 0;
	else
	  offset1 = offset + host_start - start;
        ret = (long)mmap((void *)host_start, host_end - host_start, 
                         prot, flags, fd, offset1);
        if (ret == -1)
            return ret;
    }
 the_end1:
    page_set_flags(start, start + len, prot | PAGE_VALID);
 the_end:
#ifdef DEBUG_MMAP
    printf("ret=0x%lx\n", (long)start);
    page_dump(stdout);
    printf("\n");
#endif
    return start;
}

int target_munmap(unsigned long start, unsigned long len)
{
    unsigned long end, host_start, host_end, addr;
    int prot, ret;

#ifdef DEBUG_MMAP
    printf("munmap: start=0x%lx len=0x%lx\n", start, len);
#endif
    if (start & ~TARGET_PAGE_MASK)
        return -EINVAL;
    len = TARGET_PAGE_ALIGN(len);
    if (len == 0)
        return -EINVAL;
    end = start + len;
    host_start = start & host_page_mask;
    host_end = HOST_PAGE_ALIGN(end);

    if (start > host_start) {
        /* handle host page containing start */
        prot = 0;
        for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
            prot |= page_get_flags(addr);
        }
        if (host_end == host_start + host_page_size) {
            for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
                prot |= page_get_flags(addr);
            }
            end = host_end;
        }
        if (prot != 0)
            host_start += host_page_size;
    }
    if (end < host_end) {
        prot = 0;
        for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
            prot |= page_get_flags(addr);
        }
        if (prot != 0)
            host_end -= host_page_size;
    }
    
    /* unmap what we can */
    if (host_start < host_end) {
        ret = munmap((void *)host_start, host_end - host_start);
        if (ret != 0)
            return ret;
    }

    page_set_flags(start, start + len, 0);
    return 0;
}

/* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
   blocks which have been allocated starting on a host page */
long target_mremap(unsigned long old_addr, unsigned long old_size, 
                   unsigned long new_size, unsigned long flags,
                   unsigned long new_addr)
{
    int prot;

    /* XXX: use 5 args syscall */
    new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
    if (new_addr == -1)
        return new_addr;
    prot = page_get_flags(old_addr);
    page_set_flags(old_addr, old_addr + old_size, 0);
    page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
    return new_addr;
}

int target_msync(unsigned long start, unsigned long len, int flags)
{
    unsigned long end;

    if (start & ~TARGET_PAGE_MASK)
        return -EINVAL;
    len = TARGET_PAGE_ALIGN(len);
    end = start + len;
    if (end < start)
        return -EINVAL;
    if (end == start)
        return 0;
    
    start &= host_page_mask;
    return msync((void *)start, end - start, flags);
}
Commit	Line	Data
54936004 FB	1	/*
	2	* mmap support for qemu
	3	*
	4	* Copyright (c) 2003 Fabrice Bellard
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	19	*/
	20	#include <stdlib.h>
	21	#include <stdio.h>
	22	#include <stdarg.h>
	23	#include <string.h>
	24	#include <unistd.h>
	25	#include <errno.h>
	26	#include <sys/mman.h>
	27
	28	#include "qemu.h"
	29
	30	//#define DEBUG_MMAP
	31
	32	/* NOTE: all the constants are the HOST ones */
	33	int target_mprotect(unsigned long start, unsigned long len, int prot)
	34	{
	35	unsigned long end, host_start, host_end, addr;
	36	int prot1, ret;
	37
	38	#ifdef DEBUG_MMAP
	39	printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len,
	40	prot & PROT_READ ? 'r' : '-',
	41	prot & PROT_WRITE ? 'w' : '-',
	42	prot & PROT_EXEC ? 'x' : '-');
	43	#endif
	44
	45	if ((start & ~TARGET_PAGE_MASK) != 0)
	46	return -EINVAL;
	47	len = TARGET_PAGE_ALIGN(len);
	48	end = start + len;
	49	if (end < start)
	50	return -EINVAL;
	51	if (prot & ~(PROT_READ \| PROT_WRITE \| PROT_EXEC))
	52	return -EINVAL;
	53	if (len == 0)
	54	return 0;
	55
	56	host_start = start & host_page_mask;
	57	host_end = HOST_PAGE_ALIGN(end);
	58	if (start > host_start) {
	59	/* handle host page containing start */
	60	prot1 = prot;
	61	for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
	62	prot1 \|= page_get_flags(addr);
	63	}
d418c81e FB	64	if (host_end == host_start + host_page_size) {
	65	for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
	66	prot1 \|= page_get_flags(addr);
	67	}
	68	end = host_end;
	69	}
54936004 FB	70	ret = mprotect((void *)host_start, host_page_size, prot1 & PAGE_BITS);
	71	if (ret != 0)
	72	return ret;
	73	host_start += host_page_size;
	74	}
	75	if (end < host_end) {
54936004 FB	76	prot1 = prot;
	77	for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
	78	prot1 \|= page_get_flags(addr);
	79	}
	80	ret = mprotect((void *)(host_end - host_page_size), host_page_size,
	81	prot1 & PAGE_BITS);
	82	if (ret != 0)
	83	return ret;
	84	host_end -= host_page_size;
	85	}
	86
	87	/* handle the pages in the middle */
	88	if (host_start < host_end) {
	89	ret = mprotect((void *)host_start, host_end - host_start, prot);
	90	if (ret != 0)
	91	return ret;
	92	}
54936004 FB	93	page_set_flags(start, start + len, prot \| PAGE_VALID);
	94	return 0;
	95	}
	96
	97	/* map an incomplete host page */
	98	int mmap_frag(unsigned long host_start,
	99	unsigned long start, unsigned long end,
	100	int prot, int flags, int fd, unsigned long offset)
	101	{
	102	unsigned long host_end, ret, addr;
	103	int prot1, prot_new;
	104
	105	host_end = host_start + host_page_size;
	106
	107	/* get the protection of the target pages outside the mapping */
	108	prot1 = 0;
	109	for(addr = host_start; addr < host_end; addr++) {
	110	if (addr < start \|\| addr >= end)
	111	prot1 \|= page_get_flags(addr);
	112	}
	113
	114	if (prot1 == 0) {
	115	/* no page was there, so we allocate one */
	116	ret = (long)mmap((void *)host_start, host_page_size, prot,
	117	flags \| MAP_ANONYMOUS, -1, 0);
	118	if (ret == -1)
	119	return ret;
	120	}
	121	prot1 &= PAGE_BITS;
	122
	123	prot_new = prot \| prot1;
	124	if (!(flags & MAP_ANONYMOUS)) {
	125	/* msync() won't work here, so we return an error if write is
	126	possible while it is a shared mapping */
	127	if ((flags & MAP_TYPE) == MAP_SHARED &&
	128	(prot & PROT_WRITE))
	129	return -EINVAL;
	130
	131	/* adjust protection to be able to read */
	132	if (!(prot1 & PROT_WRITE))
	133	mprotect((void *)host_start, host_page_size, prot1 \| PROT_WRITE);
	134
	135	/* read the corresponding file data */
	136	pread(fd, (void *)start, end - start, offset);
	137
	138	/* put final protection */
	139	if (prot_new != (prot1 \| PROT_WRITE))
	140	mprotect((void *)host_start, host_page_size, prot_new);
	141	} else {
	142	/* just update the protection */
	143	if (prot_new != prot1) {
	144	mprotect((void *)host_start, host_page_size, prot_new);
	145	}
	146	}
	147	return 0;
	148	}
	149
	150	/* NOTE: all the constants are the HOST ones */
	151	long target_mmap(unsigned long start, unsigned long len, int prot,
	152	int flags, int fd, unsigned long offset)
	153	{
	154	unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;
	155
	156	#ifdef DEBUG_MMAP
157	{
158	printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
159	start, len,
160	prot & PROT_READ ? 'r' : '-',
161	prot & PROT_WRITE ? 'w' : '-',
162	prot & PROT_EXEC ? 'x' : '-');
163	if (flags & MAP_FIXED)
164	printf("MAP_FIXED ");
165	if (flags & MAP_ANONYMOUS)
166	printf("MAP_ANON ");
167	switch(flags & MAP_TYPE) {
168	case MAP_PRIVATE:
169	printf("MAP_PRIVATE ");
170	break;
171	case MAP_SHARED:
172	printf("MAP_SHARED ");
173	break;
174	default:
175	printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
176	break;
177	}
178	printf("fd=%d offset=%lx\n", fd, offset);
179	}
180	#endif
181
182	if (offset & ~TARGET_PAGE_MASK)
183	return -EINVAL;
184
185	len = TARGET_PAGE_ALIGN(len);
186	if (len == 0)
187	return start;
188	host_start = start & host_page_mask;
189
190	if (!(flags & MAP_FIXED)) {
bc51c5c9	191	#if defined(__alpha__) \|\| defined(__sparc__) \|\| defined(__x86_64__)
917f95fd FB	192	/* tell the kenel to search at the same place as i386 */
	193	if (host_start == 0)
	194	host_start = 0x40000000;
	195	#endif
54936004 FB	196	if (host_page_size != real_host_page_size) {
	197	/* NOTE: this code is only for debugging with '-p' option */
	198	/* reserve a memory area */
	199	host_len = HOST_PAGE_ALIGN(len) + host_page_size - TARGET_PAGE_SIZE;
	200	host_start = (long)mmap((void *)host_start, host_len, PROT_NONE,
	201	MAP_PRIVATE \| MAP_ANONYMOUS, -1, 0);
	202	if (host_start == -1)
	203	return host_start;
	204	host_end = host_start + host_len;
	205	start = HOST_PAGE_ALIGN(host_start);
	206	end = start + HOST_PAGE_ALIGN(len);
	207	if (start > host_start)
	208	munmap((void *)host_start, start - host_start);
	209	if (end < host_end)
	210	munmap((void *)end, host_end - end);
	211	/* use it as a fixed mapping */
	212	flags \|= MAP_FIXED;
	213	} else {
	214	/* if not fixed, no need to do anything */
	215	host_offset = offset & host_page_mask;
	216	host_len = len + offset - host_offset;
	217	start = (long)mmap((void *)host_start, host_len,
	218	prot, flags, fd, host_offset);
	219	if (start == -1)
	220	return start;
	221	/* update start so that it points to the file position at 'offset' */
	222	if (!(flags & MAP_ANONYMOUS))
	223	start += offset - host_offset;
	224	goto the_end1;
	225	}
	226	}
	227
	228	if (start & ~TARGET_PAGE_MASK)
	229	return -EINVAL;
	230	end = start + len;
	231	host_end = HOST_PAGE_ALIGN(end);
	232
	233	/* worst case: we cannot map the file because the offset is not
	234	aligned, so we read it */
	235	if (!(flags & MAP_ANONYMOUS) &&
	236	(offset & ~host_page_mask) != (start & ~host_page_mask)) {
	237	/* msync() won't work here, so we return an error if write is
	238	possible while it is a shared mapping */
	239	if ((flags & MAP_TYPE) == MAP_SHARED &&
	240	(prot & PROT_WRITE))
	241	return -EINVAL;
	242	retaddr = target_mmap(start, len, prot \| PROT_WRITE,
	243	MAP_FIXED \| MAP_PRIVATE \| MAP_ANONYMOUS,
	244	-1, 0);
	245	if (retaddr == -1)
	246	return retaddr;
	247	pread(fd, (void *)start, len, offset);
	248	if (!(prot & PROT_WRITE)) {
	249	ret = target_mprotect(start, len, prot);
	250	if (ret != 0)
	251	return ret;
	252	}
	253	goto the_end;
	254	}
	255
	256	/* handle the start of the mapping */
	257	if (start > host_start) {
	258	if (host_end == host_start + host_page_size) {
	259	/* one single host page */
260	ret = mmap_frag(host_start, start, end,
261	prot, flags, fd, offset);
262	if (ret == -1)
263	return ret;
264	goto the_end1;
265	}
266	ret = mmap_frag(host_start, start, host_start + host_page_size,
267	prot, flags, fd, offset);
268	if (ret == -1)
269	return ret;
270	host_start += host_page_size;
271	}
272	/* handle the end of the mapping */
273	if (end < host_end) {
274	ret = mmap_frag(host_end - host_page_size,
275	host_end - host_page_size, host_end,
276	prot, flags, fd,
277	offset + host_end - host_page_size - start);
278	if (ret == -1)
279	return ret;
280	host_end -= host_page_size;
281	}
282
283	/* map the middle (easier) */
284	if (host_start < host_end) {
4a585ccb FB	285	unsigned long offset1;
	286	if (flags & MAP_ANONYMOUS)
	287	offset1 = 0;
	288	else
	289	offset1 = offset + host_start - start;
54936004	290	ret = (long)mmap((void *)host_start, host_end - host_start,
4a585ccb	291	prot, flags, fd, offset1);
54936004 FB	292	if (ret == -1)
	293	return ret;
	294	}
	295	the_end1:
	296	page_set_flags(start, start + len, prot \| PAGE_VALID);
	297	the_end:
	298	#ifdef DEBUG_MMAP
917f95fd	299	printf("ret=0x%lx\n", (long)start);
54936004 FB	300	page_dump(stdout);
	301	printf("\n");
	302	#endif
	303	return start;
	304	}
	305
	306	int target_munmap(unsigned long start, unsigned long len)
	307	{
	308	unsigned long end, host_start, host_end, addr;
	309	int prot, ret;
	310
	311	#ifdef DEBUG_MMAP
	312	printf("munmap: start=0x%lx len=0x%lx\n", start, len);
	313	#endif
	314	if (start & ~TARGET_PAGE_MASK)
	315	return -EINVAL;
	316	len = TARGET_PAGE_ALIGN(len);
	317	if (len == 0)
	318	return -EINVAL;
	319	end = start + len;
	320	host_start = start & host_page_mask;
	321	host_end = HOST_PAGE_ALIGN(end);
	322
	323	if (start > host_start) {
	324	/* handle host page containing start */
	325	prot = 0;
	326	for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
	327	prot \|= page_get_flags(addr);
	328	}
d418c81e FB	329	if (host_end == host_start + host_page_size) {
	330	for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
	331	prot \|= page_get_flags(addr);
	332	}
	333	end = host_end;
	334	}
54936004 FB	335	if (prot != 0)
	336	host_start += host_page_size;
	337	}
	338	if (end < host_end) {
54936004 FB	339	prot = 0;
	340	for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
	341	prot \|= page_get_flags(addr);
	342	}
	343	if (prot != 0)
	344	host_end -= host_page_size;
	345	}
	346
	347	/* unmap what we can */
	348	if (host_start < host_end) {
	349	ret = munmap((void *)host_start, host_end - host_start);
	350	if (ret != 0)
	351	return ret;
	352	}
	353
	354	page_set_flags(start, start + len, 0);
	355	return 0;
	356	}
	357
	358	/* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
	359	blocks which have been allocated starting on a host page */
	360	long target_mremap(unsigned long old_addr, unsigned long old_size,
	361	unsigned long new_size, unsigned long flags,
	362	unsigned long new_addr)
	363	{
	364	int prot;
	365
	366	/* XXX: use 5 args syscall */
	367	new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
	368	if (new_addr == -1)
	369	return new_addr;
	370	prot = page_get_flags(old_addr);
	371	page_set_flags(old_addr, old_addr + old_size, 0);
	372	page_set_flags(new_addr, new_addr + new_size, prot \| PAGE_VALID);
	373	return new_addr;
	374	}
	375
	376	int target_msync(unsigned long start, unsigned long len, int flags)
	377	{
	378	unsigned long end;
	379
	380	if (start & ~TARGET_PAGE_MASK)
	381	return -EINVAL;
	382	len = TARGET_PAGE_ALIGN(len);
54936004	383	end = start + len;
d418c81e FB	384	if (end < start)
	385	return -EINVAL;
	386	if (end == start)
	387	return 0;
54936004 FB	388
54936004 FB	389	start &= host_page_mask;
d418c81e	390	return msync((void *)start, end - start, flags);
54936004 FB	391	}
54936004 FB	392