Re: [PATCH v2 3/8] tools: riscv: Add header file csr.h

[Andrew Jones]

On Wed, Sep 06, 2023 at 05:09:20PM +0800, Haibo Xu wrote:
> On Wed, Sep 6, 2023 at 3:13 PM Andrew Jones <ajones@xxxxxxxxxxxxxxxx> wrote:
> >
> > On Wed, Sep 06, 2023 at 02:35:42PM +0800, Haibo Xu wrote:
> > > On Mon, Sep 4, 2023 at 9:33 PM Andrew Jones <ajones@xxxxxxxxxxxxxxxx> wrote:
> > > >
> > > > On Sat, Sep 02, 2023 at 08:59:25PM +0800, Haibo Xu wrote:
> > > > > Borrow the csr definitions and operations from kernel's
> > > > > arch/riscv/include/asm/csr.h to tools/ for riscv.
> > > > >
> > > > > Signed-off-by: Haibo Xu <haibo1.xu@xxxxxxxxx>
> > > > > ---
> > > > >  tools/arch/riscv/include/asm/csr.h | 521 +++++++++++++++++++++++++++++
> > > > >  1 file changed, 521 insertions(+)
> > > > >  create mode 100644 tools/arch/riscv/include/asm/csr.h
> > > > >
> > > > > diff --git a/tools/arch/riscv/include/asm/csr.h b/tools/arch/riscv/include/asm/csr.h
> > > > > new file mode 100644
> > > > > index 000000000000..4e86c82aacbd
> > > > > --- /dev/null
> > > > > +++ b/tools/arch/riscv/include/asm/csr.h
> > > > > @@ -0,0 +1,521 @@
> > > > > +/* SPDX-License-Identifier: GPL-2.0-only */
> > > > > +/*
> > > > > + * Copyright (C) 2015 Regents of the University of California
> > > > > + */
> > > > > +
> > > > > +#ifndef _ASM_RISCV_CSR_H
> > > > > +#define _ASM_RISCV_CSR_H
> > > > > +
> > > > > +#include <linux/bits.h>
> > > > > +
> > > > > +/* Status register flags */
> > > > > +#define SR_SIE               _AC(0x00000002, UL) /* Supervisor Interrupt Enable */
> > > > > +#define SR_MIE               _AC(0x00000008, UL) /* Machine Interrupt Enable */
> > > > > +#define SR_SPIE              _AC(0x00000020, UL) /* Previous Supervisor IE */
> > > > > +#define SR_MPIE              _AC(0x00000080, UL) /* Previous Machine IE */
> > > > > +#define SR_SPP               _AC(0x00000100, UL) /* Previously Supervisor */
> > > > > +#define SR_MPP               _AC(0x00001800, UL) /* Previously Machine */
> > > > > +#define SR_SUM               _AC(0x00040000, UL) /* Supervisor User Memory Access */
> > > > > +
> > > > > +#define SR_FS                _AC(0x00006000, UL) /* Floating-point Status */
> > > > > +#define SR_FS_OFF    _AC(0x00000000, UL)
> > > > > +#define SR_FS_INITIAL        _AC(0x00002000, UL)
> > > > > +#define SR_FS_CLEAN  _AC(0x00004000, UL)
> > > > > +#define SR_FS_DIRTY  _AC(0x00006000, UL)
> > > > > +
> > > > > +#define SR_VS                _AC(0x00000600, UL) /* Vector Status */
> > > > > +#define SR_VS_OFF    _AC(0x00000000, UL)
> > > > > +#define SR_VS_INITIAL        _AC(0x00000200, UL)
> > > > > +#define SR_VS_CLEAN  _AC(0x00000400, UL)
> > > > > +#define SR_VS_DIRTY  _AC(0x00000600, UL)
> > > > > +
> > > > > +#define SR_XS                _AC(0x00018000, UL) /* Extension Status */
> > > > > +#define SR_XS_OFF    _AC(0x00000000, UL)
> > > > > +#define SR_XS_INITIAL        _AC(0x00008000, UL)
> > > > > +#define SR_XS_CLEAN  _AC(0x00010000, UL)
> > > > > +#define SR_XS_DIRTY  _AC(0x00018000, UL)
> > > > > +
> > > > > +#define SR_FS_VS     (SR_FS | SR_VS) /* Vector and Floating-Point Unit */
> > > > > +
> > > > > +#ifndef CONFIG_64BIT
> > > >
> > > > How do we ensure CONFIG_64BIT is set?
> > > >
> > >
> > > Currently, no explicit checking for this.
> > > Shall we add a gatekeeper in this file to ensure it is set?
> >
> > Not in this file, since this file is shared by all the tools and...
> >
> > >
> > > #ifndef CONFIG_64BIT
> > > #error "CONFIG_64BIT was not set"
> > > #endif
> >
> > ...we'll surely hit this error right now since nothing is setting
> > CONFIG_64BIT when compiling KVM selftests.
> >
> > We need to define CONFIG_64BIT in the build somewhere prior to any
> > headers which depend on it being included. Maybe we can simply
> > add -DCONFIG_64BIT to CFLAGS, since all KVM selftests supported
> > architectures are 64-bit.
> >
> 
> Make sense! Another option can be just add "#define CONFIG_64BIT" at
> the begin of csr.h

Nope, other tools/tests may want to include csr.h someday and they may or
may not be targeting 64-bit. They'll need to appropriately set
CONFIG_64BIT themselves. We could require

#define CONFIG_64BIT
#include <asm/csr.h>

everywhere we include it, but that's error prone since it'll get forgotten
and nothing will complain unless a define which isn't also present in
!CONFIG_64BIT is used.

Thanks,
drew