Re: [PATCH v2 06/39] xen/riscv: introduce fence.h
On 07.12.2023 10:42, Oleksii wrote: > On Tue, 2023-12-05 at 16:56 +0100, Jan Beulich wrote: >> On 24.11.2023 11:30, Oleksii Kurochko wrote: >>> --- /dev/null >>> +++ b/xen/arch/riscv/include/asm/fence.h >>> @@ -0,0 +1,12 @@ >>> +#ifndef _ASM_RISCV_FENCE_H >>> +#define _ASM_RISCV_FENCE_H >>> + >>> +#ifdef CONFIG_SMP >>> +#define RISCV_ACQUIRE_BARRIER "\tfence r , rw\n" >>> +#define RISCV_RELEASE_BARRIER "\tfence rw, w\n" >>> +#else >>> +#define RISCV_ACQUIRE_BARRIER >>> +#define RISCV_RELEASE_BARRIER >>> +#endif >>> + >>> +#endif /* _ASM_RISCV_FENCE_H */ >> >> Imo such a header would be better to introduce once a use for the >> constructs appears. Otherwise at the very least it wants explaining >> in the description what this is going to be needed for. I can't >> find items of these names in other architectures so far, so this >> must be something RISC-V-specific. > It is going to be used only in RISC-V. The things that use these > definitions are introduced in the patches of this patch series: > * [PATCH v2 18/39] xen/riscv: introduce cmpxchg.h > * [PATCH v2 17/39] xen/riscv: introduce asm/atomic.h Then perhaps fold this patch into patch 17? Jan
Re: [PATCH v2 06/39] xen/riscv: introduce fence.h
On Tue, 2023-12-05 at 16:56 +0100, Jan Beulich wrote: > On 24.11.2023 11:30, Oleksii Kurochko wrote: > > --- /dev/null > > +++ b/xen/arch/riscv/include/asm/fence.h > > @@ -0,0 +1,12 @@ > > +#ifndef _ASM_RISCV_FENCE_H > > +#define _ASM_RISCV_FENCE_H > > + > > +#ifdef CONFIG_SMP > > +#define RISCV_ACQUIRE_BARRIER "\tfence r , rw\n" > > +#define RISCV_RELEASE_BARRIER "\tfence rw, w\n" > > +#else > > +#define RISCV_ACQUIRE_BARRIER > > +#define RISCV_RELEASE_BARRIER > > +#endif > > + > > +#endif /* _ASM_RISCV_FENCE_H */ > > Imo such a header would be better to introduce once a use for the > constructs appears. Otherwise at the very least it wants explaining > in the description what this is going to be needed for. I can't > find items of these names in other architectures so far, so this > must be something RISC-V-specific. It is going to be used only in RISC-V. The things that use these definitions are introduced in the patches of this patch series: * [PATCH v2 18/39] xen/riscv: introduce cmpxchg.h * [PATCH v2 17/39] xen/riscv: introduce asm/atomic.h ~ Oleksii
Re: [PATCH v2 06/39] xen/riscv: introduce fence.h
On 24.11.2023 11:30, Oleksii Kurochko wrote: > --- /dev/null > +++ b/xen/arch/riscv/include/asm/fence.h > @@ -0,0 +1,12 @@ > +#ifndef _ASM_RISCV_FENCE_H > +#define _ASM_RISCV_FENCE_H > + > +#ifdef CONFIG_SMP > +#define RISCV_ACQUIRE_BARRIER"\tfence r , rw\n" > +#define RISCV_RELEASE_BARRIER"\tfence rw, w\n" > +#else > +#define RISCV_ACQUIRE_BARRIER > +#define RISCV_RELEASE_BARRIER > +#endif > + > +#endif /* _ASM_RISCV_FENCE_H */ Imo such a header would be better to introduce once a use for the constructs appears. Otherwise at the very least it wants explaining in the description what this is going to be needed for. I can't find items of these names in other architectures so far, so this must be something RISC-V-specific. Jan
