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Message-ID: <CAAhV-H7ks=uOqM5kaD15-f--sx_F0fGMLe=ng2b93X+yi_DsvQ@mail.gmail.com>
Date: Fri, 20 May 2022 17:50:18 +0800
From: Huacai Chen <chenhuacai@...il.com>
To: Guo Ren <guoren@...nel.org>
Cc: 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>,
linux-arch <linux-arch@...r.kernel.org>,
Linux Doc Mailing List <linux-doc@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Xuefeng Li <lixuefeng@...ngson.cn>,
Yanteng Si <siyanteng@...ngson.cn>,
Xuerui Wang <kernel@...0n.name>,
Jiaxun Yang <jiaxun.yang@...goat.com>,
Stephen Rothwell <sfr@...b.auug.org.au>
Subject: Re: [PATCH V11 07/22] LoongArch: Add atomic/locking headers
Hi, Ren,
On Fri, May 20, 2022 at 3:54 PM Guo Ren <guoren@...nel.org> wrote:
>
> On Wed, May 18, 2022 at 5:34 PM Huacai Chen <chenhuacai@...ngson.cn> wrote:
> >
> > Add common headers (atomic, bitops, barrier and locking) for basic
> > LoongArch support.
> >
> > 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 | 121 +++++++++
> > arch/loongarch/include/asm/local.h | 138 +++++++++++
> > arch/loongarch/include/asm/percpu.h | 20 ++
> > 7 files changed, 755 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
> >
> > diff --git a/arch/loongarch/include/asm/atomic.h b/arch/loongarch/include/asm/atomic.h
> > new file mode 100644
> > index 000000000000..932352342b12
> > --- /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 __SIZEOF_LONG__ == 4
> > +#define __LL "ll.w "
> > +#define __SC "sc.w "
> > +#define __AMADD "amadd.w "
> > +#define __AMAND_DB "amand_db.w "
> > +#define __AMOR_DB "amor_db.w "
> > +#define __AMXOR_DB "amxor_db.w "
> > +#elif __SIZEOF_LONG__ == 8
> > +#define __LL "ll.d "
> > +#define __SC "sc.d "
> > +#define __AMADD "amadd.d "
> > +#define __AMAND_DB "amand_db.d "
> > +#define __AMOR_DB "amor_db.d "
> > +#define __AMXOR_DB "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__ (
> We need __WEAK_LLSC_MB here, to prevent previous access after sc.w.
LoongArch's ll and sc has implied memory barrier. :)
>
> > + "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__(
> Ditto.
> > + "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"
> Need __WEAK_LLSC_MB ?
> > + "2: \n"
> > + : "=&r" (result), "=&r" (temp),
> > + "+" GCC_OFF_SMALL_ASM() (v->counter)
> > + : "I" (-i));
> > + } else {
> > + __asm__ __volatile__(
> Ditto.
> > + "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"
> Need __WEAK_LLSC_MB ?
> > + " 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__ (
> Ditto
> > + "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"
> Ditto
> > + " 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__(
> Ditto
> > + "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"
> Ditto
> > + " beq %1, $zero, 1b \n"
> > + "2: \n"
> > + : "=&r" (result), "=&r" (temp),
> > + "+" GCC_OFF_SMALL_ASM() (v->counter)
> > + : "I" (-i));
> > + } else {
> > + __asm__ __volatile__(
> Ditto
> > + "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"
> Ditto
> > + " 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..e57571bcaf4f
> > --- /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 (__SIZEOF_LONG__ == 4)
> > + "sub.w %0, $r0, %0\n\t"
> > +#elif (__SIZEOF_LONG__ == 8)
> > + "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..699925b8ff27
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/cmpxchg.h
> > @@ -0,0 +1,121 @@
> > +/* 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; \
> > +})
> > +
> > +static inline unsigned long __xchg(volatile void *ptr, unsigned long x,
> relaxed ?
>
> > + int size)
> > +{
> > + switch (size) {
> > + case 4:
> > + return __xchg_asm("amswap_db.w", (volatile u32 *)ptr, (u32)x);
> Your amswap_db don't have any implicit acquire/release, right?
amswap don't have implicit acquire/release, but amswap_db has.
Huacai
>
> > +
> > + 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; \
> > +})
> > +
> > +static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
> > + unsigned long new, unsigned int size)
> > +{
> > + switch (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) \
> Ditto, it's a relaxed implementation, right?
> > +({ \
> > + __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 */
> > --
> > 2.27.0
> >
>
>
> --
> Best Regards
> Guo Ren
>
> ML: https://lore.kernel.org/linux-csky/
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