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Message-ID: <e8e7f70e-ec93-58a1-cd2e-f446e935e0b5@xen0n.name>
Date: Sun, 1 May 2022 19:16:15 +0800
From: WANG Xuerui <kernel@...0n.name>
To: Huacai Chen <chenhuacai@...ngson.cn>,
Arnd Bergmann <arnd@...db.de>,
Andy Lutomirski <luto@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <peterz@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>,
David Airlie <airlied@...ux.ie>,
Jonathan Corbet <corbet@....net>,
Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-arch@...r.kernel.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, Xuefeng Li <lixuefeng@...ngson.cn>,
Yanteng Si <siyanteng@...ngson.cn>,
Huacai Chen <chenhuacai@...il.com>,
Guo Ren <guoren@...nel.org>, Xuerui Wang <kernel@...0n.name>,
Jiaxun Yang <jiaxun.yang@...goat.com>
Subject: Re: [PATCH V9 07/24] LoongArch: Add atomic/locking headers
On 4/30/22 17:05, Huacai Chen wrote:
> This patch adds common headers (atomic, bitops, barrier and locking)
> for basic LoongArch support.
>
> LoongArch has no native sub-word xchg/cmpxchg instructions now, but
> LoongArch-based CPUs support NUMA (e.g., quad-core Loongson-3A5000
> supports as many as 16 nodes, 64 cores in total). So, we emulate sub-
> word xchg/cmpxchg in software and use qspinlock/qrwlock rather than
> ticket locks.
I'd leave the details for others more familiar with the intricate art of
locking to review; here's only a couple minor suggestions.
> Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
> ---
> arch/loongarch/include/asm/atomic.h | 358 ++++++++++++++++++++
> arch/loongarch/include/asm/barrier.h | 51 +++
> arch/loongarch/include/asm/bitops.h | 33 ++
> arch/loongarch/include/asm/bitrev.h | 34 ++
> arch/loongarch/include/asm/cmpxchg.h | 135 ++++++++
> arch/loongarch/include/asm/local.h | 138 ++++++++
> arch/loongarch/include/asm/percpu.h | 20 ++
> arch/loongarch/include/asm/spinlock.h | 12 +
> arch/loongarch/include/asm/spinlock_types.h | 11 +
> 9 files changed, 792 insertions(+)
> create mode 100644 arch/loongarch/include/asm/atomic.h
> create mode 100644 arch/loongarch/include/asm/barrier.h
> create mode 100644 arch/loongarch/include/asm/bitops.h
> create mode 100644 arch/loongarch/include/asm/bitrev.h
> create mode 100644 arch/loongarch/include/asm/cmpxchg.h
> create mode 100644 arch/loongarch/include/asm/local.h
> create mode 100644 arch/loongarch/include/asm/percpu.h
> create mode 100644 arch/loongarch/include/asm/spinlock.h
> create mode 100644 arch/loongarch/include/asm/spinlock_types.h
>
> diff --git a/arch/loongarch/include/asm/atomic.h b/arch/loongarch/include/asm/atomic.h
> new file mode 100644
> index 000000000000..f0ed7f9c08c9
> --- /dev/null
> +++ b/arch/loongarch/include/asm/atomic.h
> @@ -0,0 +1,358 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Atomic operations.
> + *
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +#ifndef _ASM_ATOMIC_H
> +#define _ASM_ATOMIC_H
> +
> +#include <linux/types.h>
> +#include <asm/barrier.h>
> +#include <asm/cmpxchg.h>
> +#include <asm/compiler.h>
> +
> +#if _LOONGARCH_SZLONG == 32
Please don't use the MIPS-like macros, as they *may* go away (once my
https://github.com/loongson/LoongArch-Documentation/pull/28 is merged);
you may use the architecture-independent macro __SIZEOF_LONG__ instead
(this would become "__SIZEOF_LONG__ == 4"). Or use
__loongarch32/__loongarch64.
> +#define __LL "ll.w "
> +#define __SC "sc.w "
> +#define __AMADD "amadd.w "
> +#define __AMAND_SYNC "amand_db.w "
"__AMADD_DB" would better match the instruction mnemonic... IIRC
"amadd_sync" is the old LoongISA-era name!
> +#define __AMOR_SYNC "amor_db.w "
> +#define __AMXOR_SYNC "amxor_db.w "
> +#elif _LOONGARCH_SZLONG == 64
> +#define __LL "ll.d "
> +#define __SC "sc.d "
> +#define __AMADD "amadd.d "
> +#define __AMAND_SYNC "amand_db.d "
> +#define __AMOR_SYNC "amor_db.d "
> +#define __AMXOR_SYNC "amxor_db.d "
> +#endif
> +
> +#define ATOMIC_INIT(i) { (i) }
> +
> +/*
> + * arch_atomic_read - read atomic variable
> + * @v: pointer of type atomic_t
> + *
> + * Atomically reads the value of @v.
> + */
> +#define arch_atomic_read(v) READ_ONCE((v)->counter)
> +
> +/*
> + * arch_atomic_set - set atomic variable
> + * @v: pointer of type atomic_t
> + * @i: required value
> + *
> + * Atomically sets the value of @v to @i.
> + */
> +#define arch_atomic_set(v, i) WRITE_ONCE((v)->counter, (i))
> +
> +#define ATOMIC_OP(op, I, asm_op) \
> +static inline void arch_atomic_##op(int i, atomic_t *v) \
> +{ \
> + __asm__ __volatile__( \
> + "am"#asm_op"_db.w" " $zero, %1, %0 \n" \
> + : "+ZB" (v->counter) \
> + : "r" (I) \
> + : "memory"); \
> +}
> +
> +#define ATOMIC_OP_RETURN(op, I, asm_op, c_op) \
> +static inline int arch_atomic_##op##_return_relaxed(int i, atomic_t *v) \
> +{ \
> + int result; \
> + \
> + __asm__ __volatile__( \
> + "am"#asm_op"_db.w" " %1, %2, %0 \n" \
> + : "+ZB" (v->counter), "=&r" (result) \
> + : "r" (I) \
> + : "memory"); \
> + \
> + return result c_op I; \
> +}
> +
> +#define ATOMIC_FETCH_OP(op, I, asm_op) \
> +static inline int arch_atomic_fetch_##op##_relaxed(int i, atomic_t *v) \
> +{ \
> + int result; \
> + \
> + __asm__ __volatile__( \
> + "am"#asm_op"_db.w" " %1, %2, %0 \n" \
> + : "+ZB" (v->counter), "=&r" (result) \
> + : "r" (I) \
> + : "memory"); \
> + \
> + return result; \
> +}
> +
> +#define ATOMIC_OPS(op, I, asm_op, c_op) \
> + ATOMIC_OP(op, I, asm_op) \
> + ATOMIC_OP_RETURN(op, I, asm_op, c_op) \
> + ATOMIC_FETCH_OP(op, I, asm_op)
> +
> +ATOMIC_OPS(add, i, add, +)
> +ATOMIC_OPS(sub, -i, add, +)
> +
> +#define arch_atomic_add_return_relaxed arch_atomic_add_return_relaxed
> +#define arch_atomic_sub_return_relaxed arch_atomic_sub_return_relaxed
> +#define arch_atomic_fetch_add_relaxed arch_atomic_fetch_add_relaxed
> +#define arch_atomic_fetch_sub_relaxed arch_atomic_fetch_sub_relaxed
> +
> +#undef ATOMIC_OPS
> +
> +#define ATOMIC_OPS(op, I, asm_op) \
> + ATOMIC_OP(op, I, asm_op) \
> + ATOMIC_FETCH_OP(op, I, asm_op)
> +
> +ATOMIC_OPS(and, i, and)
> +ATOMIC_OPS(or, i, or)
> +ATOMIC_OPS(xor, i, xor)
> +
> +#define arch_atomic_fetch_and_relaxed arch_atomic_fetch_and_relaxed
> +#define arch_atomic_fetch_or_relaxed arch_atomic_fetch_or_relaxed
> +#define arch_atomic_fetch_xor_relaxed arch_atomic_fetch_xor_relaxed
> +
> +#undef ATOMIC_OPS
> +#undef ATOMIC_FETCH_OP
> +#undef ATOMIC_OP_RETURN
> +#undef ATOMIC_OP
> +
> +static inline int arch_atomic_fetch_add_unless(atomic_t *v, int a, int u)
> +{
> + int prev, rc;
> +
> + __asm__ __volatile__ (
> + "0: ll.w %[p], %[c]\n"
> + " beq %[p], %[u], 1f\n"
> + " add.w %[rc], %[p], %[a]\n"
> + " sc.w %[rc], %[c]\n"
> + " beqz %[rc], 0b\n"
> + " b 2f\n"
> + "1:\n"
> + __WEAK_LLSC_MB
> + "2:\n"
> + : [p]"=&r" (prev), [rc]"=&r" (rc),
> + [c]"=ZB" (v->counter)
> + : [a]"r" (a), [u]"r" (u)
> + : "memory");
> +
> + return prev;
> +}
> +#define arch_atomic_fetch_add_unless arch_atomic_fetch_add_unless
> +
> +/*
> + * arch_atomic_sub_if_positive - conditionally subtract integer from atomic variable
> + * @i: integer value to subtract
> + * @v: pointer of type atomic_t
> + *
> + * Atomically test @v and subtract @i if @v is greater or equal than @i.
> + * The function returns the old value of @v minus @i.
> + */
> +static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
> +{
> + int result;
> + int temp;
> +
> + if (__builtin_constant_p(i)) {
> + __asm__ __volatile__(
> + "1: ll.w %1, %2 # atomic_sub_if_positive\n"
> + " addi.w %0, %1, %3 \n"
> + " or %1, %0, $zero \n"
> + " blt %0, $zero, 2f \n"
> + " sc.w %1, %2 \n"
> + " beq $zero, %1, 1b \n"
> + "2: \n"
> + : "=&r" (result), "=&r" (temp),
> + "+" GCC_OFF_SMALL_ASM() (v->counter)
> + : "I" (-i));
> + } else {
> + __asm__ __volatile__(
> + "1: ll.w %1, %2 # atomic_sub_if_positive\n"
> + " sub.w %0, %1, %3 \n"
> + " or %1, %0, $zero \n"
> + " blt %0, $zero, 2f \n"
> + " sc.w %1, %2 \n"
> + " beq $zero, %1, 1b \n"
> + "2: \n"
> + : "=&r" (result), "=&r" (temp),
> + "+" GCC_OFF_SMALL_ASM() (v->counter)
> + : "r" (i));
> + }
> +
> + return result;
> +}
> +
> +#define arch_atomic_cmpxchg(v, o, n) (arch_cmpxchg(&((v)->counter), (o), (n)))
> +#define arch_atomic_xchg(v, new) (arch_xchg(&((v)->counter), (new)))
> +
> +/*
> + * arch_atomic_dec_if_positive - decrement by 1 if old value positive
> + * @v: pointer of type atomic_t
> + */
> +#define arch_atomic_dec_if_positive(v) arch_atomic_sub_if_positive(1, v)
> +
> +#ifdef CONFIG_64BIT
> +
> +#define ATOMIC64_INIT(i) { (i) }
> +
> +/*
> + * arch_atomic64_read - read atomic variable
> + * @v: pointer of type atomic64_t
> + *
> + */
> +#define arch_atomic64_read(v) READ_ONCE((v)->counter)
> +
> +/*
> + * arch_atomic64_set - set atomic variable
> + * @v: pointer of type atomic64_t
> + * @i: required value
> + */
> +#define arch_atomic64_set(v, i) WRITE_ONCE((v)->counter, (i))
> +
> +#define ATOMIC64_OP(op, I, asm_op) \
> +static inline void arch_atomic64_##op(long i, atomic64_t *v) \
> +{ \
> + __asm__ __volatile__( \
> + "am"#asm_op"_db.d " " $zero, %1, %0 \n" \
> + : "+ZB" (v->counter) \
> + : "r" (I) \
> + : "memory"); \
> +}
> +
> +#define ATOMIC64_OP_RETURN(op, I, asm_op, c_op) \
> +static inline long arch_atomic64_##op##_return_relaxed(long i, atomic64_t *v) \
> +{ \
> + long result; \
> + __asm__ __volatile__( \
> + "am"#asm_op"_db.d " " %1, %2, %0 \n" \
> + : "+ZB" (v->counter), "=&r" (result) \
> + : "r" (I) \
> + : "memory"); \
> + \
> + return result c_op I; \
> +}
> +
> +#define ATOMIC64_FETCH_OP(op, I, asm_op) \
> +static inline long arch_atomic64_fetch_##op##_relaxed(long i, atomic64_t *v) \
> +{ \
> + long result; \
> + \
> + __asm__ __volatile__( \
> + "am"#asm_op"_db.d " " %1, %2, %0 \n" \
> + : "+ZB" (v->counter), "=&r" (result) \
> + : "r" (I) \
> + : "memory"); \
> + \
> + return result; \
> +}
> +
> +#define ATOMIC64_OPS(op, I, asm_op, c_op) \
> + ATOMIC64_OP(op, I, asm_op) \
> + ATOMIC64_OP_RETURN(op, I, asm_op, c_op) \
> + ATOMIC64_FETCH_OP(op, I, asm_op)
> +
> +ATOMIC64_OPS(add, i, add, +)
> +ATOMIC64_OPS(sub, -i, add, +)
> +
> +#define arch_atomic64_add_return_relaxed arch_atomic64_add_return_relaxed
> +#define arch_atomic64_sub_return_relaxed arch_atomic64_sub_return_relaxed
> +#define arch_atomic64_fetch_add_relaxed arch_atomic64_fetch_add_relaxed
> +#define arch_atomic64_fetch_sub_relaxed arch_atomic64_fetch_sub_relaxed
> +
> +#undef ATOMIC64_OPS
> +
> +#define ATOMIC64_OPS(op, I, asm_op) \
> + ATOMIC64_OP(op, I, asm_op) \
> + ATOMIC64_FETCH_OP(op, I, asm_op)
> +
> +ATOMIC64_OPS(and, i, and)
> +ATOMIC64_OPS(or, i, or)
> +ATOMIC64_OPS(xor, i, xor)
> +
> +#define arch_atomic64_fetch_and_relaxed arch_atomic64_fetch_and_relaxed
> +#define arch_atomic64_fetch_or_relaxed arch_atomic64_fetch_or_relaxed
> +#define arch_atomic64_fetch_xor_relaxed arch_atomic64_fetch_xor_relaxed
> +
> +#undef ATOMIC64_OPS
> +#undef ATOMIC64_FETCH_OP
> +#undef ATOMIC64_OP_RETURN
> +#undef ATOMIC64_OP
> +
> +static inline long arch_atomic64_fetch_add_unless(atomic64_t *v, long a, long u)
> +{
> + long prev, rc;
> +
> + __asm__ __volatile__ (
> + "0: ll.d %[p], %[c]\n"
> + " beq %[p], %[u], 1f\n"
> + " add.d %[rc], %[p], %[a]\n"
> + " sc.d %[rc], %[c]\n"
> + " beqz %[rc], 0b\n"
> + " b 2f\n"
> + "1:\n"
> + __WEAK_LLSC_MB
> + "2:\n"
> + : [p]"=&r" (prev), [rc]"=&r" (rc),
> + [c] "=ZB" (v->counter)
> + : [a]"r" (a), [u]"r" (u)
> + : "memory");
> +
> + return prev;
> +}
> +#define arch_atomic64_fetch_add_unless arch_atomic64_fetch_add_unless
> +
> +/*
> + * arch_atomic64_sub_if_positive - conditionally subtract integer from atomic variable
> + * @i: integer value to subtract
> + * @v: pointer of type atomic64_t
> + *
> + * Atomically test @v and subtract @i if @v is greater or equal than @i.
> + * The function returns the old value of @v minus @i.
> + */
> +static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
> +{
> + long result;
> + long temp;
> +
> + if (__builtin_constant_p(i)) {
> + __asm__ __volatile__(
> + "1: ll.d %1, %2 # atomic64_sub_if_positive \n"
> + " addi.d %0, %1, %3 \n"
> + " or %1, %0, $zero \n"
> + " blt %0, $zero, 2f \n"
> + " sc.d %1, %2 \n"
> + " beq %1, $zero, 1b \n"
> + "2: \n"
> + : "=&r" (result), "=&r" (temp),
> + "+" GCC_OFF_SMALL_ASM() (v->counter)
> + : "I" (-i));
> + } else {
> + __asm__ __volatile__(
> + "1: ll.d %1, %2 # atomic64_sub_if_positive \n"
> + " sub.d %0, %1, %3 \n"
> + " or %1, %0, $zero \n"
> + " blt %0, $zero, 2f \n"
> + " sc.d %1, %2 \n"
> + " beq %1, $zero, 1b \n"
> + "2: \n"
> + : "=&r" (result), "=&r" (temp),
> + "+" GCC_OFF_SMALL_ASM() (v->counter)
> + : "r" (i));
> + }
> +
> + return result;
> +}
> +
> +#define arch_atomic64_cmpxchg(v, o, n) \
> + ((__typeof__((v)->counter))arch_cmpxchg(&((v)->counter), (o), (n)))
> +#define arch_atomic64_xchg(v, new) (arch_xchg(&((v)->counter), (new)))
> +
> +/*
> + * arch_atomic64_dec_if_positive - decrement by 1 if old value positive
> + * @v: pointer of type atomic64_t
> + */
> +#define arch_atomic64_dec_if_positive(v) arch_atomic64_sub_if_positive(1, v)
> +
> +#endif /* CONFIG_64BIT */
> +
> +#endif /* _ASM_ATOMIC_H */
> diff --git a/arch/loongarch/include/asm/barrier.h b/arch/loongarch/include/asm/barrier.h
> new file mode 100644
> index 000000000000..cc6c7e3f5ce6
> --- /dev/null
> +++ b/arch/loongarch/include/asm/barrier.h
> @@ -0,0 +1,51 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +#ifndef __ASM_BARRIER_H
> +#define __ASM_BARRIER_H
> +
> +#define __sync() __asm__ __volatile__("dbar 0" : : : "memory")
> +
> +#define fast_wmb() __sync()
> +#define fast_rmb() __sync()
> +#define fast_mb() __sync()
> +#define fast_iob() __sync()
> +#define wbflush() __sync()
> +
> +#define wmb() fast_wmb()
> +#define rmb() fast_rmb()
> +#define mb() fast_mb()
> +#define iob() fast_iob()
> +
> +/**
> + * array_index_mask_nospec() - generate a ~0 mask when index < size, 0 otherwise
> + * @index: array element index
> + * @size: number of elements in array
> + *
> + * Returns:
> + * 0 - (@index < @size)
> + */
> +#define array_index_mask_nospec array_index_mask_nospec
> +static inline unsigned long array_index_mask_nospec(unsigned long index,
> + unsigned long size)
> +{
> + unsigned long mask;
> +
> + __asm__ __volatile__(
> + "sltu %0, %1, %2\n\t"
> +#if (_LOONGARCH_SZLONG == 32)
> + "sub.w %0, $r0, %0\n\t"
> +#elif (_LOONGARCH_SZLONG == 64)
> + "sub.d %0, $r0, %0\n\t"
> +#endif
> + : "=r" (mask)
> + : "r" (index), "r" (size)
> + :);
> +
> + return mask;
> +}
> +
> +#include <asm-generic/barrier.h>
> +
> +#endif /* __ASM_BARRIER_H */
> diff --git a/arch/loongarch/include/asm/bitops.h b/arch/loongarch/include/asm/bitops.h
> new file mode 100644
> index 000000000000..69e00f8d8034
> --- /dev/null
> +++ b/arch/loongarch/include/asm/bitops.h
> @@ -0,0 +1,33 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +#ifndef _ASM_BITOPS_H
> +#define _ASM_BITOPS_H
> +
> +#include <linux/compiler.h>
> +
> +#ifndef _LINUX_BITOPS_H
> +#error only <linux/bitops.h> can be included directly
> +#endif
> +
> +#include <asm/barrier.h>
> +
> +#include <asm-generic/bitops/builtin-ffs.h>
> +#include <asm-generic/bitops/builtin-fls.h>
> +#include <asm-generic/bitops/builtin-__ffs.h>
> +#include <asm-generic/bitops/builtin-__fls.h>
> +
> +#include <asm-generic/bitops/ffz.h>
> +#include <asm-generic/bitops/fls64.h>
> +
> +#include <asm-generic/bitops/sched.h>
> +#include <asm-generic/bitops/hweight.h>
> +
> +#include <asm-generic/bitops/atomic.h>
> +#include <asm-generic/bitops/non-atomic.h>
> +#include <asm-generic/bitops/lock.h>
> +#include <asm-generic/bitops/le.h>
> +#include <asm-generic/bitops/ext2-atomic.h>
> +
> +#endif /* _ASM_BITOPS_H */
> diff --git a/arch/loongarch/include/asm/bitrev.h b/arch/loongarch/include/asm/bitrev.h
> new file mode 100644
> index 000000000000..46f275b9cdf7
> --- /dev/null
> +++ b/arch/loongarch/include/asm/bitrev.h
> @@ -0,0 +1,34 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +#ifndef __LOONGARCH_ASM_BITREV_H__
> +#define __LOONGARCH_ASM_BITREV_H__
> +
> +#include <linux/swab.h>
> +
> +static __always_inline __attribute_const__ u32 __arch_bitrev32(u32 x)
> +{
> + u32 ret;
> +
> + asm("bitrev.4b %0, %1" : "=r"(ret) : "r"(__swab32(x)));
> + return ret;
> +}
> +
> +static __always_inline __attribute_const__ u16 __arch_bitrev16(u16 x)
> +{
> + u16 ret;
> +
> + asm("bitrev.4b %0, %1" : "=r"(ret) : "r"(__swab16(x)));
> + return ret;
> +}
> +
> +static __always_inline __attribute_const__ u8 __arch_bitrev8(u8 x)
> +{
> + u8 ret;
> +
> + asm("bitrev.4b %0, %1" : "=r"(ret) : "r"(x));
> + return ret;
> +}
> +
> +#endif /* __LOONGARCH_ASM_BITREV_H__ */
> diff --git a/arch/loongarch/include/asm/cmpxchg.h b/arch/loongarch/include/asm/cmpxchg.h
> new file mode 100644
> index 000000000000..69c3e2b7827d
> --- /dev/null
> +++ b/arch/loongarch/include/asm/cmpxchg.h
> @@ -0,0 +1,135 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +#ifndef __ASM_CMPXCHG_H
> +#define __ASM_CMPXCHG_H
> +
> +#include <linux/build_bug.h>
> +
> +#define __xchg_asm(amswap_db, m, val) \
> +({ \
> + __typeof(val) __ret; \
> + \
> + __asm__ __volatile__ ( \
> + " "amswap_db" %1, %z2, %0 \n" \
> + : "+ZB" (*m), "=&r" (__ret) \
> + : "Jr" (val) \
> + : "memory"); \
> + \
> + __ret; \
> +})
> +
> +extern unsigned long __xchg_small(volatile void *ptr, unsigned long x,
> + unsigned int size);
> +
> +static inline unsigned long __xchg(volatile void *ptr, unsigned long x,
> + int size)
> +{
> + switch (size) {
> + case 1:
> + case 2:
> + return __xchg_small(ptr, x, size);
> +
> + case 4:
> + return __xchg_asm("amswap_db.w", (volatile u32 *)ptr, (u32)x);
> +
> + case 8:
> + return __xchg_asm("amswap_db.d", (volatile u64 *)ptr, (u64)x);
> +
> + default:
> + BUILD_BUG();
> + }
> +
> + return 0;
> +}
> +
> +#define arch_xchg(ptr, x) \
> +({ \
> + __typeof__(*(ptr)) __res; \
> + \
> + __res = (__typeof__(*(ptr))) \
> + __xchg((ptr), (unsigned long)(x), sizeof(*(ptr))); \
> + \
> + __res; \
> +})
> +
> +#define __cmpxchg_asm(ld, st, m, old, new) \
> +({ \
> + __typeof(old) __ret; \
> + \
> + __asm__ __volatile__( \
> + "1: " ld " %0, %2 # __cmpxchg_asm \n" \
> + " bne %0, %z3, 2f \n" \
> + " or $t0, %z4, $zero \n" \
> + " " st " $t0, %1 \n" \
> + " beq $zero, $t0, 1b \n" \
> + "2: \n" \
> + : "=&r" (__ret), "=ZB"(*m) \
> + : "ZB"(*m), "Jr" (old), "Jr" (new) \
> + : "t0", "memory"); \
> + \
> + __ret; \
> +})
> +
> +extern unsigned long __cmpxchg_small(volatile void *ptr, unsigned long old,
> + unsigned long new, unsigned int size);
> +
> +static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
> + unsigned long new, unsigned int size)
> +{
> + switch (size) {
> + case 1:
> + case 2:
> + return __cmpxchg_small(ptr, old, new, size);
> +
> + case 4:
> + return __cmpxchg_asm("ll.w", "sc.w", (volatile u32 *)ptr,
> + (u32)old, new);
> +
> + case 8:
> + return __cmpxchg_asm("ll.d", "sc.d", (volatile u64 *)ptr,
> + (u64)old, new);
> +
> + default:
> + BUILD_BUG();
> + }
> +
> + return 0;
> +}
> +
> +#define arch_cmpxchg_local(ptr, old, new) \
> + ((__typeof__(*(ptr))) \
> + __cmpxchg((ptr), \
> + (unsigned long)(__typeof__(*(ptr)))(old), \
> + (unsigned long)(__typeof__(*(ptr)))(new), \
> + sizeof(*(ptr))))
> +
> +#define arch_cmpxchg(ptr, old, new) \
> +({ \
> + __typeof__(*(ptr)) __res; \
> + \
> + __res = arch_cmpxchg_local((ptr), (old), (new)); \
> + \
> + __res; \
> +})
> +
> +#ifdef CONFIG_64BIT
> +#define arch_cmpxchg64_local(ptr, o, n) \
> + ({ \
> + BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
> + arch_cmpxchg_local((ptr), (o), (n)); \
> + })
> +
> +#define arch_cmpxchg64(ptr, o, n) \
> + ({ \
> + BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
> + arch_cmpxchg((ptr), (o), (n)); \
> + })
> +#else
> +#include <asm-generic/cmpxchg-local.h>
> +#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
> +#define arch_cmpxchg64(ptr, o, n) arch_cmpxchg64_local((ptr), (o), (n))
> +#endif
> +
> +#endif /* __ASM_CMPXCHG_H */
> diff --git a/arch/loongarch/include/asm/local.h b/arch/loongarch/include/asm/local.h
> new file mode 100644
> index 000000000000..2052a2267337
> --- /dev/null
> +++ b/arch/loongarch/include/asm/local.h
> @@ -0,0 +1,138 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +#ifndef _ARCH_LOONGARCH_LOCAL_H
> +#define _ARCH_LOONGARCH_LOCAL_H
> +
> +#include <linux/percpu.h>
> +#include <linux/bitops.h>
> +#include <linux/atomic.h>
> +#include <asm/cmpxchg.h>
> +#include <asm/compiler.h>
> +
> +typedef struct {
> + atomic_long_t a;
> +} local_t;
> +
> +#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
> +
> +#define local_read(l) atomic_long_read(&(l)->a)
> +#define local_set(l, i) atomic_long_set(&(l)->a, (i))
> +
> +#define local_add(i, l) atomic_long_add((i), (&(l)->a))
> +#define local_sub(i, l) atomic_long_sub((i), (&(l)->a))
> +#define local_inc(l) atomic_long_inc(&(l)->a)
> +#define local_dec(l) atomic_long_dec(&(l)->a)
> +
> +/*
> + * Same as above, but return the result value
> + */
> +static inline long local_add_return(long i, local_t *l)
> +{
> + unsigned long result;
> +
> + __asm__ __volatile__(
> + " " __AMADD " %1, %2, %0 \n"
> + : "+ZB" (l->a.counter), "=&r" (result)
> + : "r" (i)
> + : "memory");
> + result = result + i;
> +
> + return result;
> +}
> +
> +static inline long local_sub_return(long i, local_t *l)
> +{
> + unsigned long result;
> +
> + __asm__ __volatile__(
> + " " __AMADD "%1, %2, %0 \n"
> + : "+ZB" (l->a.counter), "=&r" (result)
> + : "r" (-i)
> + : "memory");
> +
> + result = result - i;
> +
> + return result;
> +}
> +
> +#define local_cmpxchg(l, o, n) \
> + ((long)cmpxchg_local(&((l)->a.counter), (o), (n)))
> +#define local_xchg(l, n) (atomic_long_xchg((&(l)->a), (n)))
> +
> +/**
> + * local_add_unless - add unless the number is a given value
> + * @l: pointer of type local_t
> + * @a: the amount to add to l...
> + * @u: ...unless l is equal to u.
> + *
> + * Atomically adds @a to @l, so long as it was not @u.
> + * Returns non-zero if @l was not @u, and zero otherwise.
> + */
> +#define local_add_unless(l, a, u) \
> +({ \
> + long c, old; \
> + c = local_read(l); \
> + while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \
> + c = old; \
> + c != (u); \
> +})
> +#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
> +
> +#define local_dec_return(l) local_sub_return(1, (l))
> +#define local_inc_return(l) local_add_return(1, (l))
> +
> +/*
> + * local_sub_and_test - subtract value from variable and test result
> + * @i: integer value to subtract
> + * @l: pointer of type local_t
> + *
> + * Atomically subtracts @i from @l and returns
> + * true if the result is zero, or false for all
> + * other cases.
> + */
> +#define local_sub_and_test(i, l) (local_sub_return((i), (l)) == 0)
> +
> +/*
> + * local_inc_and_test - increment and test
> + * @l: pointer of type local_t
> + *
> + * Atomically increments @l by 1
> + * and returns true if the result is zero, or false for all
> + * other cases.
> + */
> +#define local_inc_and_test(l) (local_inc_return(l) == 0)
> +
> +/*
> + * local_dec_and_test - decrement by 1 and test
> + * @l: pointer of type local_t
> + *
> + * Atomically decrements @l by 1 and
> + * returns true if the result is 0, or false for all other
> + * cases.
> + */
> +#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)
> +
> +/*
> + * local_add_negative - add and test if negative
> + * @l: pointer of type local_t
> + * @i: integer value to add
> + *
> + * Atomically adds @i to @l and returns true
> + * if the result is negative, or false when
> + * result is greater than or equal to zero.
> + */
> +#define local_add_negative(i, l) (local_add_return(i, (l)) < 0)
> +
> +/* Use these for per-cpu local_t variables: on some archs they are
> + * much more efficient than these naive implementations. Note they take
> + * a variable, not an address.
> + */
> +
> +#define __local_inc(l) ((l)->a.counter++)
> +#define __local_dec(l) ((l)->a.counter++)
> +#define __local_add(i, l) ((l)->a.counter += (i))
> +#define __local_sub(i, l) ((l)->a.counter -= (i))
> +
> +#endif /* _ARCH_LOONGARCH_LOCAL_H */
> diff --git a/arch/loongarch/include/asm/percpu.h b/arch/loongarch/include/asm/percpu.h
> new file mode 100644
> index 000000000000..7d5b22ebd834
> --- /dev/null
> +++ b/arch/loongarch/include/asm/percpu.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +#ifndef __ASM_PERCPU_H
> +#define __ASM_PERCPU_H
> +
> +/* Use r21 for fast access */
> +register unsigned long __my_cpu_offset __asm__("$r21");
> +
> +static inline void set_my_cpu_offset(unsigned long off)
> +{
> + __my_cpu_offset = off;
> + csr_writeq(off, PERCPU_BASE_KS);
> +}
> +#define __my_cpu_offset __my_cpu_offset
> +
> +#include <asm-generic/percpu.h>
> +
> +#endif /* __ASM_PERCPU_H */
> diff --git a/arch/loongarch/include/asm/spinlock.h b/arch/loongarch/include/asm/spinlock.h
> new file mode 100644
> index 000000000000..7cb3476999be
> --- /dev/null
> +++ b/arch/loongarch/include/asm/spinlock.h
> @@ -0,0 +1,12 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +#ifndef _ASM_SPINLOCK_H
> +#define _ASM_SPINLOCK_H
> +
> +#include <asm/processor.h>
> +#include <asm/qspinlock.h>
> +#include <asm/qrwlock.h>
> +
> +#endif /* _ASM_SPINLOCK_H */
> diff --git a/arch/loongarch/include/asm/spinlock_types.h b/arch/loongarch/include/asm/spinlock_types.h
> new file mode 100644
> index 000000000000..7458d036c161
> --- /dev/null
> +++ b/arch/loongarch/include/asm/spinlock_types.h
> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +#ifndef _ASM_SPINLOCK_TYPES_H
> +#define _ASM_SPINLOCK_TYPES_H
> +
> +#include <asm-generic/qspinlock_types.h>
> +#include <asm-generic/qrwlock_types.h>
> +
> +#endif
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