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From:   Anup Patel <anup@brainfault.org>
Date:   Tue, 27 Aug 2019 13:58:03 +0530
Message-ID: <CAAhSdy0zOtHftesYW9uuM0gjsOcvyhfuBETbtKaR2Kc1-_sCAQ@mail.gmail.com>
Subject: Re: [RFC PATCH 1/2] RISC-V: Mark existing SBI as legacy SBI.
To:     Mike Rapoport <rppt@linux.ibm.com>
Cc:     Atish Patra <atish.patra@wdc.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Alan Kao <alankao@andestech.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Palmer Dabbelt <palmer@sifive.com>,
        "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>,
        Alexios Zavras <alexios.zavras@intel.com>,
        Gary Guo <gary@garyguo.net>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>
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On Tue, Aug 27, 2019 at 1:21 PM Mike Rapoport <rppt@linux.ibm.com> wrote:
>
> On Mon, Aug 26, 2019 at 04:32:55PM -0700, Atish Patra wrote:
> > As per the new SBI specification, current SBI implementation is
> > defined as legacy and will be removed/replaced in future.
> >
> > Rename existing implementation to reflect that. This patch is just
> > a preparatory patch for SBI v0.2 and doesn't introduce any functional
> > changes.
> >
> > Signed-off-by: Atish Patra <atish.patra@wdc.com>
> > ---
> >  arch/riscv/include/asm/sbi.h | 61 +++++++++++++++++++-----------------
> >  1 file changed, 33 insertions(+), 28 deletions(-)
> >
> > diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
> > index 21134b3ef404..7f5ecaaaa0d7 100644
> > --- a/arch/riscv/include/asm/sbi.h
> > +++ b/arch/riscv/include/asm/sbi.h
> > @@ -8,17 +8,18 @@
> >
> >  #include <linux/types.h>
> >
> > -#define SBI_SET_TIMER 0
> > -#define SBI_CONSOLE_PUTCHAR 1
> > -#define SBI_CONSOLE_GETCHAR 2
> > -#define SBI_CLEAR_IPI 3
> > -#define SBI_SEND_IPI 4
> > -#define SBI_REMOTE_FENCE_I 5
> > -#define SBI_REMOTE_SFENCE_VMA 6
> > -#define SBI_REMOTE_SFENCE_VMA_ASID 7
> > -#define SBI_SHUTDOWN 8
> > -
> > -#define SBI_CALL(which, arg0, arg1, arg2, arg3) ({           \
> > +
> > +#define SBI_EXT_LEGACY_SET_TIMER 0x0
> > +#define SBI_EXT_LEGACY_CONSOLE_PUTCHAR 0x1
> > +#define SBI_EXT_LEGACY_CONSOLE_GETCHAR 0x2
> > +#define SBI_EXT_LEGACY_CLEAR_IPI 0x3
> > +#define SBI_EXT_LEGACY_SEND_IPI 0x4
> > +#define SBI_EXT_LEGACY_REMOTE_FENCE_I 0x5
> > +#define SBI_EXT_LEGACY_REMOTE_SFENCE_VMA 0x6
> > +#define SBI_EXT_LEGACY_REMOTE_SFENCE_VMA_ASID 0x7
> > +#define SBI_EXT_LEGACY_SHUTDOWN 0x8
>
> I can't say I'm closely following RISC-V development, but what will happen
> when SBI v0.3 will come out and will render v0.2 legacy?
> Won't we need another similar renaming then?

Going forward with SBI v0.3 and higher, we won't see any calling
convention changes.

The SBI spec will be maintained and improved by RISC-V UNIX
platform spec working group.

My best guess is that, all future SBI releases (v0.3 or higher) will
include more optional SBI extensions (hart hotplug, power management, etc).

Regards,
Anup

>
> > +#define SBI_CALL_LEGACY(which, arg0, arg1, arg2, arg3) ({             \
> >       register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);   \
> >       register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);   \
> >       register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);   \
> > @@ -32,58 +33,61 @@
> >  })
> >
> >  /* Lazy implementations until SBI is finalized */
> > -#define SBI_CALL_0(which) SBI_CALL(which, 0, 0, 0, 0)
> > -#define SBI_CALL_1(which, arg0) SBI_CALL(which, arg0, 0, 0, 0)
> > -#define SBI_CALL_2(which, arg0, arg1) SBI_CALL(which, arg0, arg1, 0, 0)
> > -#define SBI_CALL_3(which, arg0, arg1, arg2) \
> > -             SBI_CALL(which, arg0, arg1, arg2, 0)
> > -#define SBI_CALL_4(which, arg0, arg1, arg2, arg3) \
> > -             SBI_CALL(which, arg0, arg1, arg2, arg3)
> > +#define SBI_CALL_LEGACY_0(which) SBI_CALL_LEGACY(which, 0, 0, 0, 0)
> > +#define SBI_CALL_LEGACY_1(which, arg0) SBI_CALL_LEGACY(which, arg0, 0, 0, 0)
> > +#define SBI_CALL_LEGACY_2(which, arg0, arg1) \
> > +             SBI_CALL_LEGACY(which, arg0, arg1, 0, 0)
> > +#define SBI_CALL_LEGACY_3(which, arg0, arg1, arg2) \
> > +             SBI_CALL_LEGACY(which, arg0, arg1, arg2, 0)
> > +#define SBI_CALL_LEGACY_4(which, arg0, arg1, arg2, arg3) \
> > +             SBI_CALL_LEGACY(which, arg0, arg1, arg2, arg3)
> >
> >  static inline void sbi_console_putchar(int ch)
> >  {
> > -     SBI_CALL_1(SBI_CONSOLE_PUTCHAR, ch);
> > +     SBI_CALL_LEGACY_1(SBI_EXT_LEGACY_CONSOLE_PUTCHAR, ch);
> >  }
> >
> >  static inline int sbi_console_getchar(void)
> >  {
> > -     return SBI_CALL_0(SBI_CONSOLE_GETCHAR);
> > +     return SBI_CALL_LEGACY_0(SBI_EXT_LEGACY_CONSOLE_GETCHAR);
> >  }
> >
> >  static inline void sbi_set_timer(uint64_t stime_value)
> >  {
> >  #if __riscv_xlen == 32
> > -     SBI_CALL_2(SBI_SET_TIMER, stime_value, stime_value >> 32);
> > +     SBI_CALL_LEGACY_2(SBI_EXT_LEGACY_SET_TIMER, stime_value,
> > +                       stime_value >> 32);
> >  #else
> > -     SBI_CALL_1(SBI_SET_TIMER, stime_value);
> > +     SBI_CALL_LEGACY_1(SBI_EXT_LEGACY_SET_TIMER, stime_value);
> >  #endif
> >  }
> >
> >  static inline void sbi_shutdown(void)
> >  {
> > -     SBI_CALL_0(SBI_SHUTDOWN);
> > +     SBI_CALL_LEGACY_0(SBI_EXT_LEGACY_SHUTDOWN);
> >  }
> >
> >  static inline void sbi_clear_ipi(void)
> >  {
> > -     SBI_CALL_0(SBI_CLEAR_IPI);
> > +     SBI_CALL_LEGACY_0(SBI_EXT_LEGACY_CLEAR_IPI);
> >  }
> >
> >  static inline void sbi_send_ipi(const unsigned long *hart_mask)
> >  {
> > -     SBI_CALL_1(SBI_SEND_IPI, hart_mask);
> > +     SBI_CALL_LEGACY_1(SBI_EXT_LEGACY_SEND_IPI, hart_mask);
> >  }
> >
> >  static inline void sbi_remote_fence_i(const unsigned long *hart_mask)
> >  {
> > -     SBI_CALL_1(SBI_REMOTE_FENCE_I, hart_mask);
> > +     SBI_CALL_LEGACY_1(SBI_EXT_LEGACY_REMOTE_FENCE_I, hart_mask);
> >  }
> >
> >  static inline void sbi_remote_sfence_vma(const unsigned long *hart_mask,
> >                                        unsigned long start,
> >                                        unsigned long size)
> >  {
> > -     SBI_CALL_3(SBI_REMOTE_SFENCE_VMA, hart_mask, start, size);
> > +     SBI_CALL_LEGACY_3(SBI_EXT_LEGACY_REMOTE_SFENCE_VMA, hart_mask,
> > +                       start, size);
> >  }
> >
> >  static inline void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
> > @@ -91,7 +95,8 @@ static inline void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
> >                                             unsigned long size,
> >                                             unsigned long asid)
> >  {
> > -     SBI_CALL_4(SBI_REMOTE_SFENCE_VMA_ASID, hart_mask, start, size, asid);
> > +     SBI_CALL_LEGACY_4(SBI_EXT_LEGACY_REMOTE_SFENCE_VMA_ASID, hart_mask,
> > +                       start, size, asid);
> >  }
> >
> >  #endif
> > --
> > 2.21.0
> >
> >
> > _______________________________________________
> > linux-riscv mailing list
> > linux-riscv@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-riscv
> >
>
> --
> Sincerely yours,
> Mike.
>
>
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