On 24.11.2023 11:30, Oleksii Kurochko wrote:
> From: Bobby Eshleman <bobbyeshle...@gmail.com>
>
> Signed-off-by: Oleksii Kurochko <oleksii.kuroc...@gmail.com>
> ---
> Changes in V2:
> - Change an author of commit. I got this header from Bobby's old repo.
Not sure how to deal with that when there's not also an S-o-b.
> --- /dev/null
> +++ b/xen/arch/riscv/include/asm/atomic.h
> @@ -0,0 +1,375 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Taken and modified from Linux.
> + *
> + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
> + * Copyright (C) 2012 Regents of the University of California
> + * Copyright (C) 2017 SiFive
> + * Copyright (C) 2021 Vates SAS
> + */
> +
> +#ifndef _ASM_RISCV_ATOMIC_H
> +#define _ASM_RISCV_ATOMIC_H
> +
> +#include <xen/atomic.h>
> +#include <asm/cmpxchg.h>
This and ...
> +#include <asm/fence.h>
> +#include <asm/io.h>
.. this header are only introduced later. Bad ordering of the series?
> +#include <asm/system.h>
> +
> +void __bad_atomic_size(void);
> +
> +static always_inline void read_atomic_size(const volatile void *p,
> + void *res,
> + unsigned int size)
> +{
> + switch ( size ) {
Nit (style): Brace on its own line (again further down).
> + case 1: *(uint8_t *)res = readb((uint8_t *)p); break;
> + case 2: *(uint16_t *)res = readw((uint16_t *)p); break;
> + case 4: *(uint32_t *)res = readl((uint32_t *)p); break;
> + case 8: *(uint32_t *)res = readq((uint64_t *)p); break;
Please don't cast away const-ness.
> + default: __bad_atomic_size(); break;
> + }
> +}
> +
> +#define read_atomic(p) ({ \
> + union { typeof(*p) val; char c[0]; } x_; \
Hmm, you avoid leading underscores here, but then ...
> + read_atomic_size(p, x_.c, sizeof(*p)); \
> + x_.val; \
> +})
> +
> +
> +#define write_atomic(p, x) ({ \
> + typeof(*p) __x = (x); \
... they're still there here.
> + switch ( sizeof(*p) ) { \
> + case 1: writeb((uint8_t)__x, (uint8_t *) p); break; \
> + case 2: writew((uint16_t)__x, (uint16_t *) p); break; \
> + case 4: writel((uint32_t)__x, (uint32_t *) p); break; \
> + case 8: writeq((uint64_t)__x, (uint64_t *) p); break; \
> + default: __bad_atomic_size(); break; \
> + } \
> + __x; \
> +})
> +
> +/* TODO: Fix this */
> +#define add_sized(p, x) ({ \
> + typeof(*(p)) __x = (x); \
> + switch ( sizeof(*(p)) ) \
> + { \
> + case 1: writeb(read_atomic(p) + __x, (uint8_t *)(p)); break; \
> + case 2: writew(read_atomic(p) + __x, (uint16_t *)(p)); break; \
> + case 4: writel(read_atomic(p) + __x, (uint32_t *)(p)); break; \
Instead of this, considering the comment perhaps better just BUG()?
> + default: __bad_atomic_size(); break; \
> + } \
> +})
> +
> +/*
> + * __unqual_scalar_typeof(x) - Declare an unqualified scalar type, leaving
> + * non-scalar types unchanged.
> + *
> + * Prefer C11 _Generic for better compile-times and simpler code. Note:
> 'char'
> + * is not type-compatible with 'signed char', and we define a separate case.
> + */
> +#define __scalar_type_to_expr_cases(type) \
> + unsigned type: (unsigned type)0, \
> + signed type: (signed type)0
> +
> +#define __unqual_scalar_typeof(x) typeof( \
> + _Generic((x), \
I think you still owe us an update to ./README, clarifying what compiler
versions
may be used for building RISC-V. Unless of course all that exist support
_Generic
(which then would be nice to say in the description).
> + char: (char)0, \
> + __scalar_type_to_expr_cases(char), \
> + __scalar_type_to_expr_cases(short), \
> + __scalar_type_to_expr_cases(int), \
> + __scalar_type_to_expr_cases(long), \
> + __scalar_type_to_expr_cases(long long), \
> + default: (x)))
> +
> +#define READ_ONCE(x) (*(const volatile __unqual_scalar_typeof(x) *)&(x))
> +#define WRITE_ONCE(x, val) \
> + do { \
> + *(volatile typeof(x) *)&(x) = (val); \
Nit (style): Too deep indentation.
> + } while (0)
> +
> +#define __atomic_acquire_fence() \
> + __asm__ __volatile__(RISCV_ACQUIRE_BARRIER "" ::: "memory")
Suddenly using tab indentation here and below? And missing blanks again.
Jan
