qemu-lock.h: Remove non-pthreads spinlock implementations
Since configure guarantees us that we have pthreads on all hosts except mingw (which doesn't support a USER_ONLY config), we can and should use the pthread_mutex based implementation of spin_lock() and spin_unlock() in all USER_ONLY cases. This means that all the inline-native-assembly code supporting the "USER_ONLY but not USE_NPTL" case can go away. The not-USER_ONLY case remains as empty implementations; there is no change in behaviour here. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Peter Maydell
Aurelien Jarno
parent
322fd48afb
commit
02615337ef
210
qemu-lock.h
210
qemu-lock.h
|
|
@ -15,15 +15,11 @@
|
||||||
* License along with this library; if not, see <http://www.gnu.org/licenses/>
|
* License along with this library; if not, see <http://www.gnu.org/licenses/>
|
||||||
*/
|
*/
|
||||||
|
|
||||||
/* Locking primitives. Most of this code should be redundant -
|
/* configure guarantees us that we have pthreads on any host except
|
||||||
system emulation doesn't need/use locking, NPTL userspace uses
|
* mingw32, which doesn't support any of the user-only targets.
|
||||||
pthread mutexes, and non-NPTL userspace isn't threadsafe anyway.
|
* So we can simply assume we have pthread mutexes here.
|
||||||
In either case a spinlock is probably the wrong kind of lock.
|
*/
|
||||||
Spinlocks are only good if you know annother CPU has the lock and is
|
#if defined(CONFIG_USER_ONLY)
|
||||||
likely to release it soon. In environments where you have more threads
|
|
||||||
than physical CPUs (the extreme case being a single CPU host) a spinlock
|
|
||||||
simply wastes CPU until the OS decides to preempt it. */
|
|
||||||
#if defined(CONFIG_USE_NPTL)
|
|
||||||
|
|
||||||
#include <pthread.h>
|
#include <pthread.h>
|
||||||
#define spin_lock pthread_mutex_lock
|
#define spin_lock pthread_mutex_lock
|
||||||
|
|
@ -33,198 +29,15 @@
|
||||||
|
|
||||||
#else
|
#else
|
||||||
|
|
||||||
#if defined(__hppa__)
|
/* Empty implementations, on the theory that system mode emulation
|
||||||
|
* is single-threaded. This means that these functions should only
|
||||||
typedef int spinlock_t[4];
|
* be used from code run in the TCG cpu thread, and cannot protect
|
||||||
|
* data structures which might also be accessed from the IO thread
|
||||||
#define SPIN_LOCK_UNLOCKED { 1, 1, 1, 1 }
|
* or from signal handlers.
|
||||||
|
*/
|
||||||
static inline void resetlock (spinlock_t *p)
|
|
||||||
{
|
|
||||||
(*p)[0] = (*p)[1] = (*p)[2] = (*p)[3] = 1;
|
|
||||||
}
|
|
||||||
|
|
||||||
#else
|
|
||||||
|
|
||||||
typedef int spinlock_t;
|
typedef int spinlock_t;
|
||||||
|
|
||||||
#define SPIN_LOCK_UNLOCKED 0
|
#define SPIN_LOCK_UNLOCKED 0
|
||||||
|
|
||||||
static inline void resetlock (spinlock_t *p)
|
|
||||||
{
|
|
||||||
*p = SPIN_LOCK_UNLOCKED;
|
|
||||||
}
|
|
||||||
|
|
||||||
#endif
|
|
||||||
|
|
||||||
#if defined(_ARCH_PPC)
|
|
||||||
static inline int testandset (int *p)
|
|
||||||
{
|
|
||||||
int ret;
|
|
||||||
__asm__ __volatile__ (
|
|
||||||
" lwarx %0,0,%1\n"
|
|
||||||
" xor. %0,%3,%0\n"
|
|
||||||
" bne $+12\n"
|
|
||||||
" stwcx. %2,0,%1\n"
|
|
||||||
" bne- $-16\n"
|
|
||||||
: "=&r" (ret)
|
|
||||||
: "r" (p), "r" (1), "r" (0)
|
|
||||||
: "cr0", "memory");
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
#elif defined(__i386__)
|
|
||||||
static inline int testandset (int *p)
|
|
||||||
{
|
|
||||||
long int readval = 0;
|
|
||||||
|
|
||||||
__asm__ __volatile__ ("lock; cmpxchgl %2, %0"
|
|
||||||
: "+m" (*p), "+a" (readval)
|
|
||||||
: "r" (1)
|
|
||||||
: "cc");
|
|
||||||
return readval;
|
|
||||||
}
|
|
||||||
#elif defined(__x86_64__)
|
|
||||||
static inline int testandset (int *p)
|
|
||||||
{
|
|
||||||
long int readval = 0;
|
|
||||||
|
|
||||||
__asm__ __volatile__ ("lock; cmpxchgl %2, %0"
|
|
||||||
: "+m" (*p), "+a" (readval)
|
|
||||||
: "r" (1)
|
|
||||||
: "cc");
|
|
||||||
return readval;
|
|
||||||
}
|
|
||||||
#elif defined(__s390__)
|
|
||||||
static inline int testandset (int *p)
|
|
||||||
{
|
|
||||||
int ret;
|
|
||||||
|
|
||||||
__asm__ __volatile__ ("0: cs %0,%1,0(%2)\n"
|
|
||||||
" jl 0b"
|
|
||||||
: "=&d" (ret)
|
|
||||||
: "r" (1), "a" (p), "0" (*p)
|
|
||||||
: "cc", "memory" );
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
#elif defined(__alpha__)
|
|
||||||
static inline int testandset (int *p)
|
|
||||||
{
|
|
||||||
int ret;
|
|
||||||
unsigned long one;
|
|
||||||
|
|
||||||
__asm__ __volatile__ ("0: mov 1,%2\n"
|
|
||||||
" ldl_l %0,%1\n"
|
|
||||||
" stl_c %2,%1\n"
|
|
||||||
" beq %2,1f\n"
|
|
||||||
".subsection 2\n"
|
|
||||||
"1: br 0b\n"
|
|
||||||
".previous"
|
|
||||||
: "=r" (ret), "=m" (*p), "=r" (one)
|
|
||||||
: "m" (*p));
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
#elif defined(__sparc__)
|
|
||||||
static inline int testandset (int *p)
|
|
||||||
{
|
|
||||||
int ret;
|
|
||||||
|
|
||||||
__asm__ __volatile__("ldstub [%1], %0"
|
|
||||||
: "=r" (ret)
|
|
||||||
: "r" (p)
|
|
||||||
: "memory");
|
|
||||||
|
|
||||||
return (ret ? 1 : 0);
|
|
||||||
}
|
|
||||||
#elif defined(__arm__)
|
|
||||||
static inline int testandset (int *spinlock)
|
|
||||||
{
|
|
||||||
register unsigned int ret;
|
|
||||||
__asm__ __volatile__("swp %0, %1, [%2]"
|
|
||||||
: "=r"(ret)
|
|
||||||
: "0"(1), "r"(spinlock));
|
|
||||||
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
#elif defined(__mc68000)
|
|
||||||
static inline int testandset (int *p)
|
|
||||||
{
|
|
||||||
char ret;
|
|
||||||
__asm__ __volatile__("tas %1; sne %0"
|
|
||||||
: "=r" (ret)
|
|
||||||
: "m" (p)
|
|
||||||
: "cc","memory");
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
#elif defined(__hppa__)
|
|
||||||
|
|
||||||
/* Because malloc only guarantees 8-byte alignment for malloc'd data,
|
|
||||||
and GCC only guarantees 8-byte alignment for stack locals, we can't
|
|
||||||
be assured of 16-byte alignment for atomic lock data even if we
|
|
||||||
specify "__attribute ((aligned(16)))" in the type declaration. So,
|
|
||||||
we use a struct containing an array of four ints for the atomic lock
|
|
||||||
type and dynamically select the 16-byte aligned int from the array
|
|
||||||
for the semaphore. */
|
|
||||||
#define __PA_LDCW_ALIGNMENT 16
|
|
||||||
static inline void *ldcw_align (void *p) {
|
|
||||||
unsigned long a = (unsigned long)p;
|
|
||||||
a = (a + __PA_LDCW_ALIGNMENT - 1) & ~(__PA_LDCW_ALIGNMENT - 1);
|
|
||||||
return (void *)a;
|
|
||||||
}
|
|
||||||
|
|
||||||
static inline int testandset (spinlock_t *p)
|
|
||||||
{
|
|
||||||
unsigned int ret;
|
|
||||||
p = ldcw_align(p);
|
|
||||||
__asm__ __volatile__("ldcw 0(%1),%0"
|
|
||||||
: "=r" (ret)
|
|
||||||
: "r" (p)
|
|
||||||
: "memory" );
|
|
||||||
return !ret;
|
|
||||||
}
|
|
||||||
|
|
||||||
#elif defined(__ia64)
|
|
||||||
|
|
||||||
#include <ia64intrin.h>
|
|
||||||
|
|
||||||
static inline int testandset (int *p)
|
|
||||||
{
|
|
||||||
return __sync_lock_test_and_set (p, 1);
|
|
||||||
}
|
|
||||||
#elif defined(__mips__)
|
|
||||||
static inline int testandset (int *p)
|
|
||||||
{
|
|
||||||
int ret;
|
|
||||||
|
|
||||||
__asm__ __volatile__ (
|
|
||||||
" .set push \n"
|
|
||||||
" .set noat \n"
|
|
||||||
" .set mips2 \n"
|
|
||||||
"1: li $1, 1 \n"
|
|
||||||
" ll %0, %1 \n"
|
|
||||||
" sc $1, %1 \n"
|
|
||||||
" beqz $1, 1b \n"
|
|
||||||
" .set pop "
|
|
||||||
: "=r" (ret), "+R" (*p)
|
|
||||||
:
|
|
||||||
: "memory");
|
|
||||||
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
#else
|
|
||||||
#error unimplemented CPU support
|
|
||||||
#endif
|
|
||||||
|
|
||||||
#if defined(CONFIG_USER_ONLY)
|
|
||||||
static inline void spin_lock(spinlock_t *lock)
|
|
||||||
{
|
|
||||||
while (testandset(lock));
|
|
||||||
}
|
|
||||||
|
|
||||||
static inline void spin_unlock(spinlock_t *lock)
|
|
||||||
{
|
|
||||||
resetlock(lock);
|
|
||||||
}
|
|
||||||
#else
|
|
||||||
static inline void spin_lock(spinlock_t *lock)
|
static inline void spin_lock(spinlock_t *lock)
|
||||||
{
|
{
|
||||||
}
|
}
|
||||||
|
|
@ -232,6 +45,5 @@ static inline void spin_lock(spinlock_t *lock)
|
||||||
static inline void spin_unlock(spinlock_t *lock)
|
static inline void spin_unlock(spinlock_t *lock)
|
||||||
{
|
{
|
||||||
}
|
}
|
||||||
#endif
|
|
||||||
|
|
||||||
#endif
|
#endif
|
||||||
|
|
|
||||||
Loading…
Reference in a new issue