arch/sparc: Enable queued rwlocks for SPARC

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: HÃ¥kon 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>
(cherry picked from commit a37594f198363fd9321ece54440336fd4b2a9c8e)

Conflicts:

        arch/sparc/Kconfig
        arch/sparc/include/asm/spinlock_64.h

Orabug: 26183741
Signed-off-by: Allen Pais <allen.pais@oracle.com>

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index b338d6a4f17ec6db898905238102489e58795622..5acc81b65cc8a2c9548231dd4b0555d80b9cbff8 100644 (file)
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -83,6 +83,7 @@ config SPARC64
        select HAVE_ARCH_AUDITSYSCALL
        select ARCH_SUPPORTS_ATOMIC_RMW
        select ARCH_CLOCKSOURCE_DATA
+       select ARCH_USE_QUEUED_RWLOCKS
 
 config ARCH_DMA_ADDR_T_64BIT
        bool

diff --git a/arch/sparc/include/asm/qrwlock.h b/arch/sparc/include/asm/qrwlock.h
new file mode 100644 (file)
index 0000000..1c0f4ee
--- /dev/null
+++ b/arch/sparc/include/asm/qrwlock.h
@@ -0,0 +1,8 @@
+#ifndef _ASM_SPARC_QRWLOCK_H
+#define _ASM_SPARC_QRWLOCK_H
+
+#include <asm-generic/qrwlock_types.h>
+#include <asm-generic/qrwlock.h>
+
+#endif /* _ASM_SPARC_QRWLOCK_H */
+

diff --git a/arch/sparc/include/asm/spinlock_64.h b/arch/sparc/include/asm/spinlock_64.h
index 9689176949781fc5ae8985a794def4521e6ba72b..9e5d5e10fccb5d260c94e69443a012a951d61e06 100644 (file)
--- a/arch/sparc/include/asm/spinlock_64.h
+++ b/arch/sparc/include/asm/spinlock_64.h
@@ -8,6 +8,8 @@
 
 #ifndef __ASSEMBLY__
 
+#include <asm/qrwlock.h>
+
 /* To get debugging spinlocks which detect and catch
  * deadlock situations, set CONFIG_DEBUG_SPINLOCK
  * and rebuild your kernel.
@@ -90,132 +92,9 @@ static inline void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long fla
        : "memory");
 }
 
-/* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
-
-static void inline arch_read_lock(arch_rwlock_t *lock)
-{
-       unsigned long tmp1, tmp2;
-
-       __asm__ __volatile__ (
-"1:    ldsw            [%2], %0\n"
-"      brlz,pn         %0, 2f\n"
-"4:     add            %0, 1, %1\n"
-"      cas             [%2], %0, %1\n"
-"      cmp             %0, %1\n"
-"      bne,pn          %%icc, 1b\n"
-"       nop\n"
-"      .subsection     2\n"
-"2:    ldsw            [%2], %0\n"
-"      brlz,pt         %0, 2b\n"
-"       nop\n"
-"      ba,a,pt         %%xcc, 4b\n"
-"      .previous"
-       : "=&r" (tmp1), "=&r" (tmp2)
-       : "r" (lock)
-       : "memory");
-}
-
-static int inline arch_read_trylock(arch_rwlock_t *lock)
-{
-       int tmp1, tmp2;
-
-       __asm__ __volatile__ (
-"1:    ldsw            [%2], %0\n"
-"      brlz,a,pn       %0, 2f\n"
-"       mov            0, %0\n"
-"      add             %0, 1, %1\n"
-"      cas             [%2], %0, %1\n"
-"      cmp             %0, %1\n"
-"      bne,pn          %%icc, 1b\n"
-"       mov            1, %0\n"
-"2:"
-       : "=&r" (tmp1), "=&r" (tmp2)
-       : "r" (lock)
-       : "memory");
-
-       return tmp1;
-}
-
-static void inline arch_read_unlock(arch_rwlock_t *lock)
-{
-       unsigned long tmp1, tmp2;
-
-       __asm__ __volatile__(
-"1:    lduw    [%2], %0\n"
-"      sub     %0, 1, %1\n"
-"      cas     [%2], %0, %1\n"
-"      cmp     %0, %1\n"
-"      bne,pn  %%xcc, 1b\n"
-"       nop"
-       : "=&r" (tmp1), "=&r" (tmp2)
-       : "r" (lock)
-       : "memory");
-}
-
-static void inline arch_write_lock(arch_rwlock_t *lock)
-{
-       unsigned long mask, tmp1, tmp2;
-
-       mask = 0x80000000UL;
-
-       __asm__ __volatile__(
-"1:    lduw            [%2], %0\n"
-"      brnz,pn         %0, 2f\n"
-"4:     or             %0, %3, %1\n"
-"      cas             [%2], %0, %1\n"
-"      cmp             %0, %1\n"
-"      bne,pn          %%icc, 1b\n"
-"       nop\n"
-"      .subsection     2\n"
-"2:    lduw            [%2], %0\n"
-"      brnz,pt         %0, 2b\n"
-"       nop\n"
-"      ba,a,pt         %%xcc, 4b\n"
-"      .previous"
-       : "=&r" (tmp1), "=&r" (tmp2)
-       : "r" (lock), "r" (mask)
-       : "memory");
-}
-
-static void inline arch_write_unlock(arch_rwlock_t *lock)
-{
-       __asm__ __volatile__(
-"      stw             %%g0, [%0]"
-       : /* no outputs */
-       : "r" (lock)
-       : "memory");
-}
-
-static int inline arch_write_trylock(arch_rwlock_t *lock)
-{
-       unsigned long mask, tmp1, tmp2, result;
-
-       mask = 0x80000000UL;
-
-       __asm__ __volatile__(
-"      mov             0, %2\n"
-"1:    lduw            [%3], %0\n"
-"      brnz,pn         %0, 2f\n"
-"       or             %0, %4, %1\n"
-"      cas             [%3], %0, %1\n"
-"      cmp             %0, %1\n"
-"      bne,pn          %%icc, 1b\n"
-"       nop\n"
-"      mov             1, %2\n"
-"2:"
-       : "=&r" (tmp1), "=&r" (tmp2), "=&r" (result)
-       : "r" (lock), "r" (mask)
-       : "memory");
-
-       return result;
-}
-
 #define arch_read_lock_flags(p, f) arch_read_lock(p)
 #define arch_write_lock_flags(p, f) arch_write_lock(p)
 
-#define arch_read_can_lock(rw)         (!((rw)->lock & 0x80000000UL))
-#define arch_write_can_lock(rw)        (!(rw)->lock)
-
 #define arch_spin_relax(lock)  cpu_relax()
 #define arch_read_relax(lock)  cpu_relax()
 #define arch_write_relax(lock) cpu_relax()

diff --git a/arch/sparc/include/asm/spinlock_types.h b/arch/sparc/include/asm/spinlock_types.h
index 019c0855bf8bf4548c9234d829b753720a488ca6..4e0dbed6261351acfb9566e6d97f069f9d80ceac 100644 (file)
--- a/arch/sparc/include/asm/spinlock_types.h
+++ b/arch/sparc/include/asm/spinlock_types.h
@@ -7,10 +7,14 @@ typedef struct {
 
 #define __ARCH_SPIN_LOCK_UNLOCKED      { 0 }
 
+#ifdef CONFIG_QUEUED_RWLOCKS
+#include <asm-generic/qrwlock_types.h>
+#else
 typedef struct {
        volatile unsigned int lock;
 } arch_rwlock_t;
 
 #define __ARCH_RW_LOCK_UNLOCKED                { 0 }
 
+#endif /*CONFIG_QUEUED_RWLOCKS */
 #endif