mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-08-04 08:17:46 +00:00
a37594f198
Enable queued rwlocks for SPARC. Here are the discussions on this feature when this was introduced. https://lwn.net/Articles/572765/ https://lwn.net/Articles/582200/ Cleaned-up the arch_read_xxx and arch_write_xxx definitions in spinlock_64.h. These routines are replaced by the functions in include/asm-generic/qrwlock.h Signed-off-by: Babu Moger <babu.moger@oracle.com> Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com> Reviewed-by: Vijay Kumar <vijay.ac.kumar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
107 lines
2.3 KiB
C
107 lines
2.3 KiB
C
/* spinlock.h: 64-bit Sparc spinlock support.
|
|
*
|
|
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
|
|
*/
|
|
|
|
#ifndef __SPARC64_SPINLOCK_H
|
|
#define __SPARC64_SPINLOCK_H
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
#include <asm/processor.h>
|
|
#include <asm/barrier.h>
|
|
#include <asm/qrwlock.h>
|
|
|
|
/* To get debugging spinlocks which detect and catch
|
|
* deadlock situations, set CONFIG_DEBUG_SPINLOCK
|
|
* and rebuild your kernel.
|
|
*/
|
|
|
|
/* Because we play games to save cycles in the non-contention case, we
|
|
* need to be extra careful about branch targets into the "spinning"
|
|
* code. They live in their own section, but the newer V9 branches
|
|
* have a shorter range than the traditional 32-bit sparc branch
|
|
* variants. The rule is that the branches that go into and out of
|
|
* the spinner sections must be pre-V9 branches.
|
|
*/
|
|
|
|
#define arch_spin_is_locked(lp) ((lp)->lock != 0)
|
|
|
|
static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
|
|
{
|
|
smp_cond_load_acquire(&lock->lock, !VAL);
|
|
}
|
|
|
|
static inline void arch_spin_lock(arch_spinlock_t *lock)
|
|
{
|
|
unsigned long tmp;
|
|
|
|
__asm__ __volatile__(
|
|
"1: ldstub [%1], %0\n"
|
|
" brnz,pn %0, 2f\n"
|
|
" nop\n"
|
|
" .subsection 2\n"
|
|
"2: ldub [%1], %0\n"
|
|
" brnz,pt %0, 2b\n"
|
|
" nop\n"
|
|
" ba,a,pt %%xcc, 1b\n"
|
|
" .previous"
|
|
: "=&r" (tmp)
|
|
: "r" (lock)
|
|
: "memory");
|
|
}
|
|
|
|
static inline int arch_spin_trylock(arch_spinlock_t *lock)
|
|
{
|
|
unsigned long result;
|
|
|
|
__asm__ __volatile__(
|
|
" ldstub [%1], %0\n"
|
|
: "=r" (result)
|
|
: "r" (lock)
|
|
: "memory");
|
|
|
|
return (result == 0UL);
|
|
}
|
|
|
|
static inline void arch_spin_unlock(arch_spinlock_t *lock)
|
|
{
|
|
__asm__ __volatile__(
|
|
" stb %%g0, [%0]"
|
|
: /* No outputs */
|
|
: "r" (lock)
|
|
: "memory");
|
|
}
|
|
|
|
static inline void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags)
|
|
{
|
|
unsigned long tmp1, tmp2;
|
|
|
|
__asm__ __volatile__(
|
|
"1: ldstub [%2], %0\n"
|
|
" brnz,pn %0, 2f\n"
|
|
" nop\n"
|
|
" .subsection 2\n"
|
|
"2: rdpr %%pil, %1\n"
|
|
" wrpr %3, %%pil\n"
|
|
"3: ldub [%2], %0\n"
|
|
" brnz,pt %0, 3b\n"
|
|
" nop\n"
|
|
" ba,pt %%xcc, 1b\n"
|
|
" wrpr %1, %%pil\n"
|
|
" .previous"
|
|
: "=&r" (tmp1), "=&r" (tmp2)
|
|
: "r"(lock), "r"(flags)
|
|
: "memory");
|
|
}
|
|
|
|
#define arch_read_lock_flags(p, f) arch_read_lock(p)
|
|
#define arch_write_lock_flags(p, f) arch_write_lock(p)
|
|
|
|
#define arch_spin_relax(lock) cpu_relax()
|
|
#define arch_read_relax(lock) cpu_relax()
|
|
#define arch_write_relax(lock) cpu_relax()
|
|
|
|
#endif /* !(__ASSEMBLY__) */
|
|
|
|
#endif /* !(__SPARC64_SPINLOCK_H) */
|