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Subject[PATCH V8 11/21] csky: Atomic operations
Date
This patch adds atomic, cmpxchg, spinlock files.

Changlog:
- SMP supported
- ticklock supported
- queue-rwlock supported

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Parri <andrea.parri@amarulasolutions.com>
---
arch/csky/include/asm/atomic.h | 212 +++++++++++++++++++++++++
arch/csky/include/asm/cmpxchg.h | 73 +++++++++
arch/csky/include/asm/spinlock.h | 274 +++++++++++++++++++++++++++++++++
arch/csky/include/asm/spinlock_types.h | 37 +++++
arch/csky/kernel/atomic.S | 87 +++++++++++
5 files changed, 683 insertions(+)
create mode 100644 arch/csky/include/asm/atomic.h
create mode 100644 arch/csky/include/asm/cmpxchg.h
create mode 100644 arch/csky/include/asm/spinlock.h
create mode 100644 arch/csky/include/asm/spinlock_types.h
create mode 100644 arch/csky/kernel/atomic.S

diff --git a/arch/csky/include/asm/atomic.h b/arch/csky/include/asm/atomic.h
new file mode 100644
index 0000000..e369d73
--- /dev/null
+++ b/arch/csky/include/asm/atomic.h
@@ -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
index 0000000..8922453
--- /dev/null
+++ b/arch/csky/include/asm/cmpxchg.h
@@ -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
index 0000000..0474603
--- /dev/null
+++ b/arch/csky/include/asm/spinlock.h
@@ -0,0 +1,274 @@
+/* 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();
+ lock->tickets.owner++;
+}
+
+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)
+{
+ u32 *p = &lock->lock;
+ u32 tmp;
+
+ smp_mb();
+ asm volatile (
+ " movi %0, 0 \n"
+ " stw %0, (%1) \n"
+ : "=&r" (tmp)
+ : "r"(p)
+ : "cc");
+}
+
+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)
+{
+ u32 *p = &lock->lock;
+ u32 tmp;
+
+ smp_mb();
+ asm volatile (
+ "1: ldex.w %0, (%1) \n"
+ " movi %0, 0 \n"
+ " stex.w %0, (%1) \n"
+ " bez %0, 1b \n"
+ : "=&r" (tmp)
+ : "r"(p)
+ : "cc");
+}
+
+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
index 0000000..88b8243
--- /dev/null
+++ b/arch/csky/include/asm/spinlock_types.h
@@ -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
index 0000000..d2357c8
--- /dev/null
+++ b/arch/csky/kernel/atomic.S
@@ -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
--
2.7.4
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