qemu/bsd-user/mmap.c
Alex Bennée 301e40ed80 translate-all: add DEBUG_LOCKING asserts
This adds asserts to check the locking on the various translation
engines structures. There are two sets of structures that are protected
by locks.

The first the l1map and PageDesc structures used to track which
translation blocks are associated with which physical addresses. In
user-mode this is covered by the mmap_lock.

The second case are TB context related structures which are protected by
tb_lock which is also user-mode only.

Currently the asserts do nothing in SoftMMU mode but this will change
for MTTCG.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-Id: <20161027151030.20863-4-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-10-31 10:24:45 +01:00

499 lines
15 KiB
C

/*
* mmap support for qemu
*
* Copyright (c) 2003 - 2008 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, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu.h"
#include "qemu-common.h"
#include "bsd-mman.h"
//#define DEBUG_MMAP
#if defined(CONFIG_USE_NPTL)
pthread_mutex_t mmap_mutex;
static int __thread mmap_lock_count;
void mmap_lock(void)
{
if (mmap_lock_count++ == 0) {
pthread_mutex_lock(&mmap_mutex);
}
}
void mmap_unlock(void)
{
if (--mmap_lock_count == 0) {
pthread_mutex_unlock(&mmap_mutex);
}
}
bool have_mmap_lock(void)
{
return mmap_lock_count > 0 ? true : false;
}
/* Grab lock to make sure things are in a consistent state after fork(). */
void mmap_fork_start(void)
{
if (mmap_lock_count)
abort();
pthread_mutex_lock(&mmap_mutex);
}
void mmap_fork_end(int child)
{
if (child)
pthread_mutex_init(&mmap_mutex, NULL);
else
pthread_mutex_unlock(&mmap_mutex);
}
#else
/* We aren't threadsafe to start with, so no need to worry about locking. */
void mmap_lock(void)
{
}
void mmap_unlock(void)
{
}
#endif
/* NOTE: all the constants are the HOST ones, but addresses are target. */
int target_mprotect(abi_ulong start, abi_ulong len, int prot)
{
abi_ulong end, host_start, host_end, addr;
int prot1, ret;
#ifdef DEBUG_MMAP
printf("mprotect: start=0x" TARGET_FMT_lx
" len=0x" TARGET_FMT_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;
prot &= PROT_READ | PROT_WRITE | PROT_EXEC;
if (len == 0)
return 0;
mmap_lock();
host_start = start & qemu_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 + qemu_host_page_size) {
for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
prot1 |= page_get_flags(addr);
}
end = host_end;
}
ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
if (ret != 0)
goto error;
host_start += qemu_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(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
prot1 & PAGE_BITS);
if (ret != 0)
goto error;
host_end -= qemu_host_page_size;
}
/* handle the pages in the middle */
if (host_start < host_end) {
ret = mprotect(g2h(host_start), host_end - host_start, prot);
if (ret != 0)
goto error;
}
page_set_flags(start, start + len, prot | PAGE_VALID);
mmap_unlock();
return 0;
error:
mmap_unlock();
return ret;
}
/* map an incomplete host page */
static int mmap_frag(abi_ulong real_start,
abi_ulong start, abi_ulong end,
int prot, int flags, int fd, abi_ulong offset)
{
abi_ulong real_end, addr;
void *host_start;
int prot1, prot_new;
real_end = real_start + qemu_host_page_size;
host_start = g2h(real_start);
/* get the protection of the target pages outside the mapping */
prot1 = 0;
for(addr = real_start; addr < real_end; addr++) {
if (addr < start || addr >= end)
prot1 |= page_get_flags(addr);
}
if (prot1 == 0) {
/* no page was there, so we allocate one */
void *p = mmap(host_start, qemu_host_page_size, prot,
flags | MAP_ANON, -1, 0);
if (p == MAP_FAILED)
return -1;
prot1 = prot;
}
prot1 &= PAGE_BITS;
prot_new = prot | prot1;
if (!(flags & MAP_ANON)) {
/* msync() won't work here, so we return an error if write is
possible while it is a shared mapping */
if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED &&
(prot & PROT_WRITE))
return -1;
/* adjust protection to be able to read */
if (!(prot1 & PROT_WRITE))
mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
/* read the corresponding file data */
pread(fd, g2h(start), end - start, offset);
/* put final protection */
if (prot_new != (prot1 | PROT_WRITE))
mprotect(host_start, qemu_host_page_size, prot_new);
} else {
/* just update the protection */
if (prot_new != prot1) {
mprotect(host_start, qemu_host_page_size, prot_new);
}
}
return 0;
}
#if defined(__CYGWIN__)
/* Cygwin doesn't have a whole lot of address space. */
static abi_ulong mmap_next_start = 0x18000000;
#else
static abi_ulong mmap_next_start = 0x40000000;
#endif
unsigned long last_brk;
/* find a free memory area of size 'size'. The search starts at
'start'. If 'start' == 0, then a default start address is used.
Return -1 if error.
*/
/* page_init() marks pages used by the host as reserved to be sure not
to use them. */
static abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
{
abi_ulong addr, addr1, addr_start;
int prot;
unsigned long new_brk;
new_brk = (unsigned long)sbrk(0);
if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) {
/* This is a hack to catch the host allocating memory with brk().
If it uses mmap then we loose.
FIXME: We really want to avoid the host allocating memory in
the first place, and maybe leave some slack to avoid switching
to mmap. */
page_set_flags(last_brk & TARGET_PAGE_MASK,
TARGET_PAGE_ALIGN(new_brk),
PAGE_RESERVED);
}
last_brk = new_brk;
size = HOST_PAGE_ALIGN(size);
start = start & qemu_host_page_mask;
addr = start;
if (addr == 0)
addr = mmap_next_start;
addr_start = addr;
for(;;) {
prot = 0;
for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) {
prot |= page_get_flags(addr1);
}
if (prot == 0)
break;
addr += qemu_host_page_size;
/* we found nothing */
if (addr == addr_start)
return (abi_ulong)-1;
}
if (start == 0)
mmap_next_start = addr + size;
return addr;
}
/* NOTE: all the constants are the HOST ones */
abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
int flags, int fd, abi_ulong offset)
{
abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
unsigned long host_start;
mmap_lock();
#ifdef DEBUG_MMAP
{
printf("mmap: start=0x" TARGET_FMT_lx
" len=0x" TARGET_FMT_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_ANON)
printf("MAP_ANON ");
switch(flags & TARGET_BSD_MAP_FLAGMASK) {
case MAP_PRIVATE:
printf("MAP_PRIVATE ");
break;
case MAP_SHARED:
printf("MAP_SHARED ");
break;
default:
printf("[MAP_FLAGMASK=0x%x] ", flags & TARGET_BSD_MAP_FLAGMASK);
break;
}
printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset);
}
#endif
if (offset & ~TARGET_PAGE_MASK) {
errno = EINVAL;
goto fail;
}
len = TARGET_PAGE_ALIGN(len);
if (len == 0)
goto the_end;
real_start = start & qemu_host_page_mask;
if (!(flags & MAP_FIXED)) {
abi_ulong mmap_start;
void *p;
host_offset = offset & qemu_host_page_mask;
host_len = len + offset - host_offset;
host_len = HOST_PAGE_ALIGN(host_len);
mmap_start = mmap_find_vma(real_start, host_len);
if (mmap_start == (abi_ulong)-1) {
errno = ENOMEM;
goto fail;
}
/* Note: we prefer to control the mapping address. It is
especially important if qemu_host_page_size >
qemu_real_host_page_size */
p = mmap(g2h(mmap_start),
host_len, prot, flags | MAP_FIXED, fd, host_offset);
if (p == MAP_FAILED)
goto fail;
/* update start so that it points to the file position at 'offset' */
host_start = (unsigned long)p;
if (!(flags & MAP_ANON))
host_start += offset - host_offset;
start = h2g(host_start);
} else {
int flg;
target_ulong addr;
if (start & ~TARGET_PAGE_MASK) {
errno = EINVAL;
goto fail;
}
end = start + len;
real_end = HOST_PAGE_ALIGN(end);
for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) {
flg = page_get_flags(addr);
if (flg & PAGE_RESERVED) {
errno = ENXIO;
goto fail;
}
}
/* worst case: we cannot map the file because the offset is not
aligned, so we read it */
if (!(flags & MAP_ANON) &&
(offset & ~qemu_host_page_mask) != (start & ~qemu_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 & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED &&
(prot & PROT_WRITE)) {
errno = EINVAL;
goto fail;
}
retaddr = target_mmap(start, len, prot | PROT_WRITE,
MAP_FIXED | MAP_PRIVATE | MAP_ANON,
-1, 0);
if (retaddr == -1)
goto fail;
pread(fd, g2h(start), len, offset);
if (!(prot & PROT_WRITE)) {
ret = target_mprotect(start, len, prot);
if (ret != 0) {
start = ret;
goto the_end;
}
}
goto the_end;
}
/* handle the start of the mapping */
if (start > real_start) {
if (real_end == real_start + qemu_host_page_size) {
/* one single host page */
ret = mmap_frag(real_start, start, end,
prot, flags, fd, offset);
if (ret == -1)
goto fail;
goto the_end1;
}
ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
prot, flags, fd, offset);
if (ret == -1)
goto fail;
real_start += qemu_host_page_size;
}
/* handle the end of the mapping */
if (end < real_end) {
ret = mmap_frag(real_end - qemu_host_page_size,
real_end - qemu_host_page_size, real_end,
prot, flags, fd,
offset + real_end - qemu_host_page_size - start);
if (ret == -1)
goto fail;
real_end -= qemu_host_page_size;
}
/* map the middle (easier) */
if (real_start < real_end) {
void *p;
unsigned long offset1;
if (flags & MAP_ANON)
offset1 = 0;
else
offset1 = offset + real_start - start;
p = mmap(g2h(real_start), real_end - real_start,
prot, flags, fd, offset1);
if (p == MAP_FAILED)
goto fail;
}
}
the_end1:
page_set_flags(start, start + len, prot | PAGE_VALID);
the_end:
#ifdef DEBUG_MMAP
printf("ret=0x" TARGET_FMT_lx "\n", start);
page_dump(stdout);
printf("\n");
#endif
mmap_unlock();
return start;
fail:
mmap_unlock();
return -1;
}
int target_munmap(abi_ulong start, abi_ulong len)
{
abi_ulong end, real_start, real_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;
mmap_lock();
end = start + len;
real_start = start & qemu_host_page_mask;
real_end = HOST_PAGE_ALIGN(end);
if (start > real_start) {
/* handle host page containing start */
prot = 0;
for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
prot |= page_get_flags(addr);
}
if (real_end == real_start + qemu_host_page_size) {
for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
prot |= page_get_flags(addr);
}
end = real_end;
}
if (prot != 0)
real_start += qemu_host_page_size;
}
if (end < real_end) {
prot = 0;
for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
prot |= page_get_flags(addr);
}
if (prot != 0)
real_end -= qemu_host_page_size;
}
ret = 0;
/* unmap what we can */
if (real_start < real_end) {
ret = munmap(g2h(real_start), real_end - real_start);
}
if (ret == 0)
page_set_flags(start, start + len, 0);
mmap_unlock();
return ret;
}
int target_msync(abi_ulong start, abi_ulong len, int flags)
{
abi_ulong 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 &= qemu_host_page_mask;
return msync(g2h(start), end - start, flags);
}