csky: Atomic operations
authorGuo Ren <ren_guo@c-sky.com>
Wed, 5 Sep 2018 06:25:16 +0000 (14:25 +0800)
committerGuo Ren <ren_guo@c-sky.com>
Thu, 25 Oct 2018 16:54:23 +0000 (00:54 +0800)
This patch adds atomic, cmpxchg, spinlock files.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Andrea Parri <andrea.parri@amarulasolutions.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
arch/csky/include/asm/atomic.h [new file with mode: 0644]
arch/csky/include/asm/cmpxchg.h [new file with mode: 0644]
arch/csky/include/asm/spinlock.h [new file with mode: 0644]
arch/csky/include/asm/spinlock_types.h [new file with mode: 0644]
arch/csky/kernel/atomic.S [new file with mode: 0644]

diff --git a/arch/csky/include/asm/atomic.h b/arch/csky/include/asm/atomic.h
new file mode 100644 (file)
index 0000000..e369d73
--- /dev/null
@@ -0,0 +1,212 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_CSKY_ATOMIC_H
+#define __ASM_CSKY_ATOMIC_H
+
+#include <linux/version.h>
+#include <asm/cmpxchg.h>
+#include <asm/barrier.h>
+
+#ifdef CONFIG_CPU_HAS_LDSTEX
+
+#define __atomic_add_unless __atomic_add_unless
+static inline int __atomic_add_unless(atomic_t *v, int a, int u)
+{
+       unsigned long tmp, ret;
+
+       smp_mb();
+
+       asm volatile (
+       "1:     ldex.w          %0, (%3) \n"
+       "       mov             %1, %0   \n"
+       "       cmpne           %0, %4   \n"
+       "       bf              2f       \n"
+       "       add             %0, %2   \n"
+       "       stex.w          %0, (%3) \n"
+       "       bez             %0, 1b   \n"
+       "2:                              \n"
+               : "=&r" (tmp), "=&r" (ret)
+               : "r" (a), "r"(&v->counter), "r"(u)
+               : "memory");
+
+       if (ret != u)
+               smp_mb();
+
+       return ret;
+}
+
+#define ATOMIC_OP(op, c_op)                                            \
+static inline void atomic_##op(int i, atomic_t *v)                     \
+{                                                                      \
+       unsigned long tmp;                                              \
+                                                                       \
+       asm volatile (                                                  \
+       "1:     ldex.w          %0, (%2) \n"                            \
+       "       " #op "         %0, %1   \n"                            \
+       "       stex.w          %0, (%2) \n"                            \
+       "       bez             %0, 1b   \n"                            \
+               : "=&r" (tmp)                                           \
+               : "r" (i), "r"(&v->counter)                             \
+               : "memory");                                            \
+}
+
+#define ATOMIC_OP_RETURN(op, c_op)                                     \
+static inline int atomic_##op##_return(int i, atomic_t *v)             \
+{                                                                      \
+       unsigned long tmp, ret;                                         \
+                                                                       \
+       smp_mb();                                                       \
+       asm volatile (                                                  \
+       "1:     ldex.w          %0, (%3) \n"                            \
+       "       " #op "         %0, %2   \n"                            \
+       "       mov             %1, %0   \n"                            \
+       "       stex.w          %0, (%3) \n"                            \
+       "       bez             %0, 1b   \n"                            \
+               : "=&r" (tmp), "=&r" (ret)                              \
+               : "r" (i), "r"(&v->counter)                             \
+               : "memory");                                            \
+       smp_mb();                                                       \
+                                                                       \
+       return ret;                                                     \
+}
+
+#define ATOMIC_FETCH_OP(op, c_op)                                      \
+static inline int atomic_fetch_##op(int i, atomic_t *v)                        \
+{                                                                      \
+       unsigned long tmp, ret;                                         \
+                                                                       \
+       smp_mb();                                                       \
+       asm volatile (                                                  \
+       "1:     ldex.w          %0, (%3) \n"                            \
+       "       mov             %1, %0   \n"                            \
+       "       " #op "         %0, %2   \n"                            \
+       "       stex.w          %0, (%3) \n"                            \
+       "       bez             %0, 1b   \n"                            \
+               : "=&r" (tmp), "=&r" (ret)                              \
+               : "r" (i), "r"(&v->counter)                             \
+               : "memory");                                            \
+       smp_mb();                                                       \
+                                                                       \
+       return ret;                                                     \
+}
+
+#else /* CONFIG_CPU_HAS_LDSTEX */
+
+#include <linux/irqflags.h>
+
+#define __atomic_add_unless __atomic_add_unless
+static inline int __atomic_add_unless(atomic_t *v, int a, int u)
+{
+       unsigned long tmp, ret, flags;
+
+       raw_local_irq_save(flags);
+
+       asm volatile (
+       "       ldw             %0, (%3) \n"
+       "       mov             %1, %0   \n"
+       "       cmpne           %0, %4   \n"
+       "       bf              2f       \n"
+       "       add             %0, %2   \n"
+       "       stw             %0, (%3) \n"
+       "2:                              \n"
+               : "=&r" (tmp), "=&r" (ret)
+               : "r" (a), "r"(&v->counter), "r"(u)
+               : "memory");
+
+       raw_local_irq_restore(flags);
+
+       return ret;
+}
+
+#define ATOMIC_OP(op, c_op)                                            \
+static inline void atomic_##op(int i, atomic_t *v)                     \
+{                                                                      \
+       unsigned long tmp, flags;                                       \
+                                                                       \
+       raw_local_irq_save(flags);                                      \
+                                                                       \
+       asm volatile (                                                  \
+       "       ldw             %0, (%2) \n"                            \
+       "       " #op "         %0, %1   \n"                            \
+       "       stw             %0, (%2) \n"                            \
+               : "=&r" (tmp)                                           \
+               : "r" (i), "r"(&v->counter)                             \
+               : "memory");                                            \
+                                                                       \
+       raw_local_irq_restore(flags);                                   \
+}
+
+#define ATOMIC_OP_RETURN(op, c_op)                                     \
+static inline int atomic_##op##_return(int i, atomic_t *v)             \
+{                                                                      \
+       unsigned long tmp, ret, flags;                                  \
+                                                                       \
+       raw_local_irq_save(flags);                                      \
+                                                                       \
+       asm volatile (                                                  \
+       "       ldw             %0, (%3) \n"                            \
+       "       " #op "         %0, %2   \n"                            \
+       "       stw             %0, (%3) \n"                            \
+       "       mov             %1, %0   \n"                            \
+               : "=&r" (tmp), "=&r" (ret)                              \
+               : "r" (i), "r"(&v->counter)                             \
+               : "memory");                                            \
+                                                                       \
+       raw_local_irq_restore(flags);                                   \
+                                                                       \
+       return ret;                                                     \
+}
+
+#define ATOMIC_FETCH_OP(op, c_op)                                      \
+static inline int atomic_fetch_##op(int i, atomic_t *v)                        \
+{                                                                      \
+       unsigned long tmp, ret, flags;                                  \
+                                                                       \
+       raw_local_irq_save(flags);                                      \
+                                                                       \
+       asm volatile (                                                  \
+       "       ldw             %0, (%3) \n"                            \
+       "       mov             %1, %0   \n"                            \
+       "       " #op "         %0, %2   \n"                            \
+       "       stw             %0, (%3) \n"                            \
+               : "=&r" (tmp), "=&r" (ret)                              \
+               : "r" (i), "r"(&v->counter)                             \
+               : "memory");                                            \
+                                                                       \
+       raw_local_irq_restore(flags);                                   \
+                                                                       \
+       return ret;                                                     \
+}
+
+#endif /* CONFIG_CPU_HAS_LDSTEX */
+
+#define atomic_add_return atomic_add_return
+ATOMIC_OP_RETURN(add, +)
+#define atomic_sub_return atomic_sub_return
+ATOMIC_OP_RETURN(sub, -)
+
+#define atomic_fetch_add atomic_fetch_add
+ATOMIC_FETCH_OP(add, +)
+#define atomic_fetch_sub atomic_fetch_sub
+ATOMIC_FETCH_OP(sub, -)
+#define atomic_fetch_and atomic_fetch_and
+ATOMIC_FETCH_OP(and, &)
+#define atomic_fetch_or atomic_fetch_or
+ATOMIC_FETCH_OP(or, |)
+#define atomic_fetch_xor atomic_fetch_xor
+ATOMIC_FETCH_OP(xor, ^)
+
+#define atomic_and atomic_and
+ATOMIC_OP(and, &)
+#define atomic_or atomic_or
+ATOMIC_OP(or, |)
+#define atomic_xor atomic_xor
+ATOMIC_OP(xor, ^)
+
+#undef ATOMIC_FETCH_OP
+#undef ATOMIC_OP_RETURN
+#undef ATOMIC_OP
+
+#include <asm-generic/atomic.h>
+
+#endif /* __ASM_CSKY_ATOMIC_H */
diff --git a/arch/csky/include/asm/cmpxchg.h b/arch/csky/include/asm/cmpxchg.h
new file mode 100644 (file)
index 0000000..8922453
--- /dev/null
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_CSKY_CMPXCHG_H
+#define __ASM_CSKY_CMPXCHG_H
+
+#ifdef CONFIG_CPU_HAS_LDSTEX
+#include <asm/barrier.h>
+
+extern void __bad_xchg(void);
+
+#define __xchg(new, ptr, size)                                 \
+({                                                             \
+       __typeof__(ptr) __ptr = (ptr);                          \
+       __typeof__(new) __new = (new);                          \
+       __typeof__(*(ptr)) __ret;                               \
+       unsigned long tmp;                                      \
+       switch (size) {                                         \
+       case 4:                                                 \
+               smp_mb();                                       \
+               asm volatile (                                  \
+               "1:     ldex.w          %0, (%3) \n"            \
+               "       mov             %1, %2   \n"            \
+               "       stex.w          %1, (%3) \n"            \
+               "       bez             %1, 1b   \n"            \
+                       : "=&r" (__ret), "=&r" (tmp)            \
+                       : "r" (__new), "r"(__ptr)               \
+                       :);                                     \
+               smp_mb();                                       \
+               break;                                          \
+       default:                                                \
+               __bad_xchg();                                   \
+       }                                                       \
+       __ret;                                                  \
+})
+
+#define xchg(ptr, x)   (__xchg((x), (ptr), sizeof(*(ptr))))
+
+#define __cmpxchg(ptr, old, new, size)                         \
+({                                                             \
+       __typeof__(ptr) __ptr = (ptr);                          \
+       __typeof__(new) __new = (new);                          \
+       __typeof__(new) __tmp;                                  \
+       __typeof__(old) __old = (old);                          \
+       __typeof__(*(ptr)) __ret;                               \
+       switch (size) {                                         \
+       case 4:                                                 \
+               smp_mb();                                       \
+               asm volatile (                                  \
+               "1:     ldex.w          %0, (%3) \n"            \
+               "       cmpne           %0, %4   \n"            \
+               "       bt              2f       \n"            \
+               "       mov             %1, %2   \n"            \
+               "       stex.w          %1, (%3) \n"            \
+               "       bez             %1, 1b   \n"            \
+               "2:                              \n"            \
+                       : "=&r" (__ret), "=&r" (__tmp)          \
+                       : "r" (__new), "r"(__ptr), "r"(__old)   \
+                       :);                                     \
+               smp_mb();                                       \
+               break;                                          \
+       default:                                                \
+               __bad_xchg();                                   \
+       }                                                       \
+       __ret;                                                  \
+})
+
+#define cmpxchg(ptr, o, n) \
+       (__cmpxchg((ptr), (o), (n), sizeof(*(ptr))))
+#else
+#include <asm-generic/cmpxchg.h>
+#endif
+
+#endif /* __ASM_CSKY_CMPXCHG_H */
diff --git a/arch/csky/include/asm/spinlock.h b/arch/csky/include/asm/spinlock.h
new file mode 100644 (file)
index 0000000..7cf3f2b
--- /dev/null
@@ -0,0 +1,256 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_CSKY_SPINLOCK_H
+#define __ASM_CSKY_SPINLOCK_H
+
+#include <linux/spinlock_types.h>
+#include <asm/barrier.h>
+
+#ifdef CONFIG_QUEUED_RWLOCKS
+
+/*
+ * Ticket-based spin-locking.
+ */
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+       arch_spinlock_t lockval;
+       u32 ticket_next = 1 << TICKET_NEXT;
+       u32 *p = &lock->lock;
+       u32 tmp;
+
+       asm volatile (
+               "1:     ldex.w          %0, (%2) \n"
+               "       mov             %1, %0   \n"
+               "       add             %0, %3   \n"
+               "       stex.w          %0, (%2) \n"
+               "       bez             %0, 1b   \n"
+               : "=&r" (tmp), "=&r" (lockval)
+               : "r"(p), "r"(ticket_next)
+               : "cc");
+
+       while (lockval.tickets.next != lockval.tickets.owner)
+               lockval.tickets.owner = READ_ONCE(lock->tickets.owner);
+
+       smp_mb();
+}
+
+static inline int arch_spin_trylock(arch_spinlock_t *lock)
+{
+       u32 tmp, contended, res;
+       u32 ticket_next = 1 << TICKET_NEXT;
+       u32 *p = &lock->lock;
+
+       do {
+               asm volatile (
+               "       ldex.w          %0, (%3)   \n"
+               "       movi            %2, 1      \n"
+               "       rotli           %1, %0, 16 \n"
+               "       cmpne           %1, %0     \n"
+               "       bt              1f         \n"
+               "       movi            %2, 0      \n"
+               "       add             %0, %0, %4 \n"
+               "       stex.w          %0, (%3)   \n"
+               "1:                                \n"
+               : "=&r" (res), "=&r" (tmp), "=&r" (contended)
+               : "r"(p), "r"(ticket_next)
+               : "cc");
+       } while (!res);
+
+       if (!contended)
+               smp_mb();
+
+       return !contended;
+}
+
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+       smp_mb();
+       WRITE_ONCE(lock->tickets.owner, lock->tickets.owner + 1);
+}
+
+static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
+{
+       return lock.tickets.owner == lock.tickets.next;
+}
+
+static inline int arch_spin_is_locked(arch_spinlock_t *lock)
+{
+       return !arch_spin_value_unlocked(READ_ONCE(*lock));
+}
+
+static inline int arch_spin_is_contended(arch_spinlock_t *lock)
+{
+       struct __raw_tickets tickets = READ_ONCE(lock->tickets);
+
+       return (tickets.next - tickets.owner) > 1;
+}
+#define arch_spin_is_contended arch_spin_is_contended
+
+#include <asm/qrwlock.h>
+
+/* See include/linux/spinlock.h */
+#define smp_mb__after_spinlock()       smp_mb()
+
+#else /* CONFIG_QUEUED_RWLOCKS */
+
+/*
+ * Test-and-set spin-locking.
+ */
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+       u32 *p = &lock->lock;
+       u32 tmp;
+
+       asm volatile (
+               "1:     ldex.w          %0, (%1) \n"
+               "       bnez            %0, 1b   \n"
+               "       movi            %0, 1    \n"
+               "       stex.w          %0, (%1) \n"
+               "       bez             %0, 1b   \n"
+               : "=&r" (tmp)
+               : "r"(p)
+               : "cc");
+       smp_mb();
+}
+
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+       smp_mb();
+       WRITE_ONCE(lock->lock, 0);
+}
+
+static inline int arch_spin_trylock(arch_spinlock_t *lock)
+{
+       u32 *p = &lock->lock;
+       u32 tmp;
+
+       asm volatile (
+               "1:     ldex.w          %0, (%1) \n"
+               "       bnez            %0, 2f   \n"
+               "       movi            %0, 1    \n"
+               "       stex.w          %0, (%1) \n"
+               "       bez             %0, 1b   \n"
+               "       movi            %0, 0    \n"
+               "2:                              \n"
+               : "=&r" (tmp)
+               : "r"(p)
+               : "cc");
+
+       if (!tmp)
+               smp_mb();
+
+       return !tmp;
+}
+
+#define arch_spin_is_locked(x) (READ_ONCE((x)->lock) != 0)
+
+/*
+ * read lock/unlock/trylock
+ */
+static inline void arch_read_lock(arch_rwlock_t *lock)
+{
+       u32 *p = &lock->lock;
+       u32 tmp;
+
+       asm volatile (
+               "1:     ldex.w          %0, (%1) \n"
+               "       blz             %0, 1b   \n"
+               "       addi            %0, 1    \n"
+               "       stex.w          %0, (%1) \n"
+               "       bez             %0, 1b   \n"
+               : "=&r" (tmp)
+               : "r"(p)
+               : "cc");
+       smp_mb();
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *lock)
+{
+       u32 *p = &lock->lock;
+       u32 tmp;
+
+       smp_mb();
+       asm volatile (
+               "1:     ldex.w          %0, (%1) \n"
+               "       subi            %0, 1    \n"
+               "       stex.w          %0, (%1) \n"
+               "       bez             %0, 1b   \n"
+               : "=&r" (tmp)
+               : "r"(p)
+               : "cc");
+}
+
+static inline int arch_read_trylock(arch_rwlock_t *lock)
+{
+       u32 *p = &lock->lock;
+       u32 tmp;
+
+       asm volatile (
+               "1:     ldex.w          %0, (%1) \n"
+               "       blz             %0, 2f   \n"
+               "       addi            %0, 1    \n"
+               "       stex.w          %0, (%1) \n"
+               "       bez             %0, 1b   \n"
+               "       movi            %0, 0    \n"
+               "2:                              \n"
+               : "=&r" (tmp)
+               : "r"(p)
+               : "cc");
+
+       if (!tmp)
+               smp_mb();
+
+       return !tmp;
+}
+
+/*
+ * write lock/unlock/trylock
+ */
+static inline void arch_write_lock(arch_rwlock_t *lock)
+{
+       u32 *p = &lock->lock;
+       u32 tmp;
+
+       asm volatile (
+               "1:     ldex.w          %0, (%1) \n"
+               "       bnez            %0, 1b   \n"
+               "       subi            %0, 1    \n"
+               "       stex.w          %0, (%1) \n"
+               "       bez             %0, 1b   \n"
+               : "=&r" (tmp)
+               : "r"(p)
+               : "cc");
+       smp_mb();
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *lock)
+{
+       smp_mb();
+       WRITE_ONCE(lock->lock, 0);
+}
+
+static inline int arch_write_trylock(arch_rwlock_t *lock)
+{
+       u32 *p = &lock->lock;
+       u32 tmp;
+
+       asm volatile (
+               "1:     ldex.w          %0, (%1) \n"
+               "       bnez            %0, 2f   \n"
+               "       subi            %0, 1    \n"
+               "       stex.w          %0, (%1) \n"
+               "       bez             %0, 1b   \n"
+               "       movi            %0, 0    \n"
+               "2:                              \n"
+               : "=&r" (tmp)
+               : "r"(p)
+               : "cc");
+
+       if (!tmp)
+               smp_mb();
+
+       return !tmp;
+}
+
+#endif /* CONFIG_QUEUED_RWLOCKS */
+#endif /* __ASM_CSKY_SPINLOCK_H */
diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h
new file mode 100644 (file)
index 0000000..88b8243
--- /dev/null
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_CSKY_SPINLOCK_TYPES_H
+#define __ASM_CSKY_SPINLOCK_TYPES_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+# error "please don't include this file directly"
+#endif
+
+#define TICKET_NEXT    16
+
+typedef struct {
+       union {
+               u32 lock;
+               struct __raw_tickets {
+                       /* little endian */
+                       u16 owner;
+                       u16 next;
+               } tickets;
+       };
+} arch_spinlock_t;
+
+#define __ARCH_SPIN_LOCK_UNLOCKED      { { 0 } }
+
+#ifdef CONFIG_QUEUED_RWLOCKS
+#include <asm-generic/qrwlock_types.h>
+
+#else /* CONFIG_NR_CPUS > 2 */
+
+typedef struct {
+       u32 lock;
+} arch_rwlock_t;
+
+#define __ARCH_RW_LOCK_UNLOCKED                { 0 }
+
+#endif /* CONFIG_QUEUED_RWLOCKS */
+#endif /* __ASM_CSKY_SPINLOCK_TYPES_H */
diff --git a/arch/csky/kernel/atomic.S b/arch/csky/kernel/atomic.S
new file mode 100644 (file)
index 0000000..d2357c8
--- /dev/null
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/linkage.h>
+#include <abi/entry.h>
+
+.text
+
+/*
+ * int csky_cmpxchg(int oldval, int newval, int *ptr)
+ *
+ * If *ptr != oldval && return 1,
+ * else *ptr = newval return 0.
+ */
+#ifdef CONFIG_CPU_HAS_LDSTEX
+ENTRY(csky_cmpxchg)
+       USPTOKSP
+       mfcr    a3, epc
+       INCTRAP a3
+
+       subi    sp, 8
+       stw     a3, (sp, 0)
+       mfcr    a3, epsr
+       stw     a3, (sp, 4)
+
+       psrset  ee
+1:
+       ldex    a3, (a2)
+       cmpne   a0, a3
+       bt16    2f
+       mov     a3, a1
+       stex    a3, (a2)
+       bez     a3, 1b
+2:
+       sync.is
+       mvc     a0
+       ldw     a3, (sp, 0)
+       mtcr    a3, epc
+       ldw     a3, (sp, 4)
+       mtcr    a3, epsr
+       addi    sp, 8
+       KSPTOUSP
+       rte
+END(csky_cmpxchg)
+#else
+ENTRY(csky_cmpxchg)
+       USPTOKSP
+       mfcr    a3, epc
+       INCTRAP a3
+
+       subi    sp, 8
+       stw     a3, (sp, 0)
+       mfcr    a3, epsr
+       stw     a3, (sp, 4)
+
+       psrset  ee
+1:
+       ldw     a3, (a2)
+       cmpne   a0, a3
+       bt16    3f
+2:
+       stw     a1, (a2)
+3:
+       mvc     a0
+       ldw     a3, (sp, 0)
+       mtcr    a3, epc
+       ldw     a3, (sp, 4)
+       mtcr    a3, epsr
+       addi    sp, 8
+       KSPTOUSP
+       rte
+END(csky_cmpxchg)
+
+/*
+ * Called from tlbmodified exception
+ */
+ENTRY(csky_cmpxchg_fixup)
+       mfcr    a0, epc
+       lrw     a1, 2b
+       cmpne   a1, a0
+       bt      1f
+       subi    a1, (2b - 1b)
+       stw     a1, (sp, LSAVE_PC)
+1:
+       rts
+END(csky_cmpxchg_fixup)
+#endif