On 24.11.2023 11:30, Oleksii Kurochko wrote:
> --- /dev/null
> +++ b/xen/arch/riscv/include/asm/system.h
> @@ -0,0 +1,79 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef _ASM_RISCV_BARRIER_H
> +#define _ASM_RISCV_BARRIER_H
> +
> +#include <asm/csr.h>
> +
> +#ifndef __ASSEMBLY__
> +
> +#define RISCV_FENCE(p, s) \
> + __asm__ __volatile__ ("fence " #p "," #s : : : "memory")
Nit (style): Missing blanks immediately inside the parentheses.
> +/* These barriers need to enforce ordering on both devices or memory. */
> +#define mb() RISCV_FENCE(iorw,iorw)
> +#define rmb() RISCV_FENCE(ir,ir)
> +#define wmb() RISCV_FENCE(ow,ow)
Nit (style): Missing blanks after the commas (also again below).
> +/* These barriers do not need to enforce ordering on devices, just memory. */
> +#define smp_mb() RISCV_FENCE(rw,rw)
> +#define smp_rmb() RISCV_FENCE(r,r)
> +#define smp_wmb() RISCV_FENCE(w,w)
> +#define smp_mb__before_atomic() smp_mb()
> +#define smp_mb__after_atomic() smp_mb()
> +
> +/*
> +#define __smp_store_release(p, v) \
Is there a need for the double underscores here? We try to not
introduce new instances of undue leading underscores, but there might
be e.g. a strong desire to stay in sync with, say, Linux.
> +do { \
> + compiletime_assert_atomic_type(*p); \
> + RISCV_FENCE(rw,w); \
> + WRITE_ONCE(*p, v); \
Nit: Can the trailing backslashes be aligned, please?
> +} while (0)
> +
> +#define __smp_load_acquire(p) \
> +({ \
> + typeof(*p) ___p1 = READ_ONCE(*p); \
Hmm, yet more leading underscores, and here surely not needed.
> + compiletime_assert_atomic_type(*p); \
> + RISCV_FENCE(r,rw); \
> + ___p1; \
> +})
> +*/
> +
> +static inline unsigned long local_save_flags(void)
> +{
> + return csr_read(sstatus);
> +}
> +
> +static inline void local_irq_enable(void)
> +{
> + csr_set(sstatus, SSTATUS_SIE);
> +}
> +
> +static inline void local_irq_disable(void)
> +{
> + csr_clear(sstatus, SSTATUS_SIE);
> +}
> +
> +#define local_irq_save(x) \
> +({ \
> + x = csr_read_clear(CSR_SSTATUS, SSTATUS_SIE); \
> + local_irq_disable(); \
> +})
> +
> +static inline void local_irq_restore(unsigned long flags)
> +{
> + csr_set(CSR_SSTATUS, flags & SSTATUS_SIE);
> +}
> +
> +static inline int local_irq_is_enabled(void)
> +{
> + unsigned long flags = local_save_flags();
> +
> + return flags & SSTATUS_SIE;
SSTATUS_SIE doesn't even happen to be 1, so I think you're better off
adding != 0, unless you would do as I think I had suggested before and
have the function return bool right away.
Jan
