Commit c8a706fe authored by pbrook's avatar pbrook

Multithreaded locking for mmap().


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4654 c046a42c-6fe2-441c-8c8c-71466251a162
parent 30813cea
......@@ -234,6 +234,7 @@ static void page_init(void)
FILE *f;
int n;
mmap_lock();
last_brk = (unsigned long)sbrk(0);
f = fopen("/proc/self/maps", "r");
if (f) {
......@@ -251,6 +252,7 @@ static void page_init(void)
} while (!feof(f));
fclose(f);
}
mmap_unlock();
}
#endif
}
......@@ -326,6 +328,8 @@ static inline PhysPageDesc *phys_page_find(target_phys_addr_t index)
static void tlb_protect_code(ram_addr_t ram_addr);
static void tlb_unprotect_code_phys(CPUState *env, ram_addr_t ram_addr,
target_ulong vaddr);
#define mmap_lock() do { } while(0)
#define mmap_unlock() do { } while(0)
#endif
#define DEFAULT_CODE_GEN_BUFFER_SIZE (32 * 1024 * 1024)
......@@ -1049,6 +1053,9 @@ void tb_link_phys(TranslationBlock *tb,
unsigned int h;
TranslationBlock **ptb;
/* Grab the mmap lock to stop another thread invalidating this TB
before we are done. */
mmap_lock();
/* add in the physical hash table */
h = tb_phys_hash_func(phys_pc);
ptb = &tb_phys_hash[h];
......@@ -1075,6 +1082,7 @@ void tb_link_phys(TranslationBlock *tb,
#ifdef DEBUG_TB_CHECK
tb_page_check();
#endif
mmap_unlock();
}
/* find the TB 'tb' such that tb[0].tc_ptr <= tc_ptr <
......@@ -2002,6 +2010,7 @@ void page_set_flags(target_ulong start, target_ulong end, int flags)
PageDesc *p;
target_ulong addr;
/* mmap_lock should already be held. */
start = start & TARGET_PAGE_MASK;
end = TARGET_PAGE_ALIGN(end);
if (flags & PAGE_WRITE)
......@@ -2065,11 +2074,18 @@ int page_unprotect(target_ulong address, unsigned long pc, void *puc)
PageDesc *p, *p1;
target_ulong host_start, host_end, addr;
/* Technically this isn't safe inside a signal handler. However we
know this only ever happens in a synchronous SEGV handler, so in
practice it seems to be ok. */
mmap_lock();
host_start = address & qemu_host_page_mask;
page_index = host_start >> TARGET_PAGE_BITS;
p1 = page_find(page_index);
if (!p1)
if (!p1) {
mmap_unlock();
return 0;
}
host_end = host_start + qemu_host_page_size;
p = p1;
prot = 0;
......@@ -2091,9 +2107,11 @@ int page_unprotect(target_ulong address, unsigned long pc, void *puc)
#ifdef DEBUG_TB_CHECK
tb_invalidate_check(address);
#endif
mmap_unlock();
return 1;
}
}
mmap_unlock();
return 0;
}
......
......@@ -29,6 +29,34 @@
//#define DEBUG_MMAP
#if defined(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);
}
}
#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)
{
......@@ -53,6 +81,7 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot)
if (len == 0)
return 0;
mmap_lock();
host_start = start & qemu_host_page_mask;
host_end = HOST_PAGE_ALIGN(end);
if (start > host_start) {
......@@ -69,7 +98,7 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot)
}
ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
if (ret != 0)
return ret;
goto error;
host_start += qemu_host_page_size;
}
if (end < host_end) {
......@@ -80,7 +109,7 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot)
ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
prot1 & PAGE_BITS);
if (ret != 0)
return ret;
goto error;
host_end -= qemu_host_page_size;
}
......@@ -88,10 +117,14 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot)
if (host_start < host_end) {
ret = mprotect(g2h(host_start), host_end - host_start, prot);
if (ret != 0)
return ret;
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 */
......@@ -214,6 +247,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
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
......@@ -243,12 +277,12 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
if (offset & ~TARGET_PAGE_MASK) {
errno = EINVAL;
return -1;
goto fail;
}
len = TARGET_PAGE_ALIGN(len);
if (len == 0)
return start;
goto the_end;
real_start = start & qemu_host_page_mask;
if (!(flags & MAP_FIXED)) {
......@@ -260,7 +294,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
mmap_start = mmap_find_vma(real_start, host_len);
if (mmap_start == (abi_ulong)-1) {
errno = ENOMEM;
return -1;
goto fail;
}
/* Note: we prefer to control the mapping address. It is
especially important if qemu_host_page_size >
......@@ -268,7 +302,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
p = mmap(g2h(mmap_start),
host_len, prot, flags | MAP_FIXED, fd, host_offset);
if (p == MAP_FAILED)
return -1;
goto fail;
/* update start so that it points to the file position at 'offset' */
host_start = (unsigned long)p;
if (!(flags & MAP_ANONYMOUS))
......@@ -280,7 +314,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
if (start & ~TARGET_PAGE_MASK) {
errno = EINVAL;
return -1;
goto fail;
}
end = start + len;
real_end = HOST_PAGE_ALIGN(end);
......@@ -289,7 +323,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
flg = page_get_flags(addr);
if (flg & PAGE_RESERVED) {
errno = ENXIO;
return -1;
goto fail;
}
}
......@@ -302,18 +336,20 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
if ((flags & MAP_TYPE) == MAP_SHARED &&
(prot & PROT_WRITE)) {
errno = EINVAL;
return -1;
goto fail;
}
retaddr = target_mmap(start, len, prot | PROT_WRITE,
MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
-1, 0);
if (retaddr == -1)
return -1;
goto fail;
pread(fd, g2h(start), len, offset);
if (!(prot & PROT_WRITE)) {
ret = target_mprotect(start, len, prot);
if (ret != 0)
return ret;
if (ret != 0) {
start = ret;
goto the_end;
}
}
goto the_end;
}
......@@ -325,13 +361,13 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
ret = mmap_frag(real_start, start, end,
prot, flags, fd, offset);
if (ret == -1)
return ret;
goto fail;
goto the_end1;
}
ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
prot, flags, fd, offset);
if (ret == -1)
return ret;
goto fail;
real_start += qemu_host_page_size;
}
/* handle the end of the mapping */
......@@ -341,7 +377,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
prot, flags, fd,
offset + real_end - qemu_host_page_size - start);
if (ret == -1)
return -1;
goto fail;
real_end -= qemu_host_page_size;
}
......@@ -356,7 +392,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
p = mmap(g2h(real_start), real_end - real_start,
prot, flags, fd, offset1);
if (p == MAP_FAILED)
return -1;
goto fail;
}
}
the_end1:
......@@ -367,7 +403,11 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
page_dump(stdout);
printf("\n");
#endif
mmap_unlock();
return start;
fail:
mmap_unlock();
return -1;
}
int target_munmap(abi_ulong start, abi_ulong len)
......@@ -383,6 +423,7 @@ int target_munmap(abi_ulong start, abi_ulong len)
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);
......@@ -411,15 +452,16 @@ int target_munmap(abi_ulong start, abi_ulong len)
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)
return ret;
}
page_set_flags(start, start + len, 0);
return 0;
if (ret == 0)
page_set_flags(start, start + len, 0);
mmap_unlock();
return ret;
}
/* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
......@@ -431,14 +473,18 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
int prot;
unsigned long host_addr;
mmap_lock();
/* XXX: use 5 args syscall */
host_addr = (long)mremap(g2h(old_addr), old_size, new_size, flags);
if (host_addr == -1)
return -1;
new_addr = h2g(host_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);
if (host_addr == -1) {
new_addr = -1;
} else {
new_addr = h2g(host_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);
}
mmap_unlock();
return new_addr;
}
......
......@@ -233,6 +233,8 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
abi_ulong new_addr);
int target_msync(abi_ulong start, abi_ulong len, int flags);
extern unsigned long last_brk;
void mmap_lock(void);
void mmap_unlock(void);
/* user access */
......@@ -423,4 +425,8 @@ static inline void *lock_user_string(abi_ulong guest_addr)
#define unlock_user_struct(host_ptr, guest_addr, copy) \
unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
#if defined(USE_NPTL)
#include <pthread.h>
#endif
#endif /* QEMU_H */
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