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From:   Anup Patel <anup@brainfault.org>
Date:   Fri, 29 Nov 2019 10:27:23 +0530
Message-ID: <CAAhSdy2rqz-1nZRdb7GgoAvFmqodOZTF_CAYha5ZwvZ1voXnog@mail.gmail.com>
Subject: Re: [PATCH v5 4/4] RISC-V: Implement new SBI v0.2 extensions
To:     Atish Patra <atish.patra@wdc.com>
Cc:     "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Alexios Zavras <alexios.zavras@intel.com>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        Mao Han <han_mao@c-sky.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Thomas Gleixner <tglx@linutronix.de>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Nov 29, 2019 at 10:21 AM Anup Patel <anup@brainfault.org> wrote:
>
> Hi Atish,
>
> Found few bugs while playing with this patch.
>
> See below ....
>
> On Wed, Nov 27, 2019 at 12:35 AM Atish Patra <atish.patra@wdc.com> wrote:
> >
> > Few v0.1 SBI calls are being replaced by new SBI calls that follows
> > v0.2 calling convention. The specification changes can be found at
> >
> > riscv/riscv-sbi-doc#27
> >
> > Implement the replacement extensions and few additional new SBI
> > function calls that makes way for a better SBI interface in future.
> >
> > Signed-off-by: Atish Patra <atish.patra@wdc.com>
> > Reviewed-by: Anup Patel <anup@brainfault.org>
> > ---
> >  arch/riscv/include/asm/sbi.h |  35 ++++++
> >  arch/riscv/kernel/sbi.c      | 208 +++++++++++++++++++++++++++++++++--
> >  2 files changed, 236 insertions(+), 7 deletions(-)
> >
> > diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
> > index cc82ae63f8e0..54ba9eebec11 100644
> > --- a/arch/riscv/include/asm/sbi.h
> > +++ b/arch/riscv/include/asm/sbi.h
> > @@ -22,6 +22,9 @@ enum sbi_ext_id {
> >         SBI_EXT_0_1_SHUTDOWN = 0x8,
> >  #endif
> >         SBI_EXT_BASE = 0x10,
> > +       SBI_EXT_TIME = 0x54494D45,
> > +       SBI_EXT_IPI = 0x735049,
> > +       SBI_EXT_RFENCE = 0x52464E43,
> >  };
> >
> >  enum sbi_ext_base_fid {
> > @@ -34,6 +37,24 @@ enum sbi_ext_base_fid {
> >         SBI_BASE_GET_MIMPID,
> >  };
> >
> > +enum sbi_ext_time_fid {
> > +       SBI_EXT_TIME_SET_TIMER = 0,
> > +};
> > +
> > +enum sbi_ext_ipi_fid {
> > +       SBI_EXT_IPI_SEND_IPI = 0,
> > +};
> > +
> > +enum sbi_ext_rfence_fid {
> > +       SBI_EXT_RFENCE_REMOTE_FENCE_I = 0,
> > +       SBI_EXT_RFENCE_REMOTE_SFENCE_VMA,
> > +       SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID,
> > +       SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA,
> > +       SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID,
> > +       SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA,
> > +       SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID,
> > +};
> > +
> >  #define SBI_SPEC_VERSION_DEFAULT       0x1
> >  #define SBI_SPEC_VERSION_MAJOR_OFFSET  24
> >  #define SBI_SPEC_VERSION_MAJOR_MASK    0x7f
> > @@ -74,6 +95,20 @@ void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
> >                                 unsigned long start,
> >                                 unsigned long size,
> >                                 unsigned long asid);
> > +int sbi_remote_hfence_gvma(const unsigned long *hart_mask,
> > +                          unsigned long start,
> > +                          unsigned long size);
> > +int sbi_remote_hfence_gvma_vmid(const unsigned long *hart_mask,
> > +                               unsigned long start,
> > +                               unsigned long size,
> > +                               unsigned long vmid);
> > +int sbi_remote_hfence_vvma(const unsigned long *hart_mask,
> > +                          unsigned long start,
> > +                          unsigned long size);
> > +int sbi_remote_hfence_vvma_asid(const unsigned long *hart_mask,
> > +                               unsigned long start,
> > +                               unsigned long size,
> > +                               unsigned long asid);
> >  int sbi_probe_extension(long ext);
> >
> >  /* Check if current SBI specification version is 0.1 or not */
> > diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
> > index ee710bfe0b0e..af3d5f8d8af7 100644
> > --- a/arch/riscv/kernel/sbi.c
> > +++ b/arch/riscv/kernel/sbi.c
> > @@ -205,6 +205,101 @@ static int __sbi_rfence_v01(unsigned long ext, unsigned long fid,
> >  }
> >  #endif /* CONFIG_RISCV_SBI_V01 */
> >
> > +static void __sbi_set_timer_v02(uint64_t stime_value)
> > +{
> > +#if __riscv_xlen == 32
> > +       sbi_ecall(SBI_EXT_TIME, SBI_EXT_TIME_SET_TIMER, stime_value,
> > +                         stime_value >> 32, 0, 0, 0, 0);
> > +#else
> > +       sbi_ecall(SBI_EXT_TIME, SBI_EXT_TIME_SET_TIMER, stime_value, 0,
> > +                 0, 0, 0, 0);
> > +#endif
> > +}
> > +
> > +static int __sbi_send_ipi_v02(const unsigned long *hart_mask)
> > +{
> > +       unsigned long hmask_val;
> > +       struct sbiret ret = {0};
> > +       int result;
> > +
> > +       if (!hart_mask)
> > +               hmask_val = *(cpumask_bits(cpu_online_mask));
> > +       else
> > +               hmask_val = *hart_mask;
> > +
> > +       ret = sbi_ecall(SBI_EXT_IPI, SBI_EXT_IPI_SEND_IPI, hmask_val,
> > +                       0, 0, 0, 0, 0);
> > +       if (ret.error) {
> > +               pr_err("%s: failed with error [%d]\n", __func__,
> > +                       sbi_err_map_linux_errno(ret.error));
> > +               result = ret.error;
> > +       } else
> > +               result = ret.value;
> > +
> > +       return result;
> > +}
> > +
> > +static int __sbi_rfence_v02(unsigned long extid, unsigned long fid,
> > +                            const unsigned long *hart_mask,
> > +                            unsigned long hbase, unsigned long start,
> > +                            unsigned long size, unsigned long arg4,
> > +                            unsigned long arg5)
> > +{
> > +       unsigned long hmask_val;
> > +       struct sbiret ret = {0};
> > +       int result;
> > +       unsigned long ext = SBI_EXT_RFENCE;
> > +
> > +       if (!hart_mask)
> > +               hmask_val = *(cpumask_bits(cpu_online_mask));
> > +       else
> > +               hmask_val = *hart_mask;
> > +
> > +       switch (fid) {
> > +       case SBI_EXT_RFENCE_REMOTE_FENCE_I:
> > +               ret = sbi_ecall(ext, fid, hmask_val, 0, 0, 0, 0, 0);
> > +               break;
> > +       case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
> > +               ret = sbi_ecall(ext, fid, hmask_val, 0, start,
> > +                               size, 0, 0);
> > +               break;
> > +       case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
> > +               ret = sbi_ecall(ext, fid, hmask_val, 0, start,
> > +                               size, arg4, 0);
> > +               break;
> > +       /*TODO: Handle non zero hbase cases */
> > +       case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA:
> > +               ret = sbi_ecall(ext, fid, hmask_val, 0, start,
> > +                               size, 0, 0);
> > +               break;
> > +       case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID:
> > +               ret = sbi_ecall(ext, fid, hmask_val, 0, start,
> > +                               size, arg4, 0);
> > +               break;
> > +       case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA:
> > +               ret = sbi_ecall(ext, fid, hmask_val, 0, start,
> > +                               size, 0, 0);
> > +               break;
> > +       case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID:
> > +               ret = sbi_ecall(ext, fid, hmask_val, 0, start,
> > +                               size, arg4, 0);
> > +               break;
> > +       default:
> > +               pr_err("unknown function ID [%lu] for SBI extension [%lu]\n",
> > +                       fid, ext);
> > +               result = -EINVAL;
> > +       }
> > +
> > +       if (ret.error) {
> > +               pr_err("%s: failed with error [%d]\n", __func__,
> > +                       sbi_err_map_linux_errno(ret.error));
> > +               result = ret.error;
> > +       } else
> > +               result = ret.value;
> > +
> > +       return result;
> > +}
> > +
> >  /**
> >   * sbi_set_timer() - Program the timer for next timer event.
> >   * @stime_value: The value after which next timer event should fire.
> > @@ -237,7 +332,7 @@ EXPORT_SYMBOL(sbi_send_ipi);
> >   */
> >  void sbi_remote_fence_i(const unsigned long *hart_mask)
> >  {
> > -       __sbi_rfence(SBI_EXT_0_1_REMOTE_FENCE_I, 0,
> > +       __sbi_rfence(SBI_EXT_0_1_REMOTE_FENCE_I, SBI_EXT_RFENCE_REMOTE_FENCE_I,
> >                      hart_mask, 0, 0, 0, 0, 0);
> >  }
> >  EXPORT_SYMBOL(sbi_remote_fence_i);
> > @@ -255,7 +350,8 @@ void sbi_remote_sfence_vma(const unsigned long *hart_mask,
> >                                          unsigned long start,
> >                                          unsigned long size)
> >  {
> > -       __sbi_rfence(SBI_EXT_0_1_REMOTE_SFENCE_VMA, 0,
> > +       __sbi_rfence(SBI_EXT_0_1_REMOTE_SFENCE_VMA,
> > +                    SBI_EXT_RFENCE_REMOTE_SFENCE_VMA,
> >                      hart_mask, 0, start, size, 0, 0);
> >  }
> >  EXPORT_SYMBOL(sbi_remote_sfence_vma);
> > @@ -276,11 +372,93 @@ void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
> >                                               unsigned long size,
> >                                               unsigned long asid)
> >  {
> > -       __sbi_rfence(SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID, 0,
> > +       __sbi_rfence(SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID,
> > +                    SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID,
> >                      hart_mask, 0, start, size, asid, 0);
> >  }
> >  EXPORT_SYMBOL(sbi_remote_sfence_vma_asid);
> >
> > +/**
> > + * sbi_remote_hfence_gvma() - Execute HFENCE.GVMA instructions on given remote
> > + *                        harts for the specified guest physical address range.
> > + * @hart_mask: A cpu mask containing all the target harts.
> > + * @start: Start of the guest physical address
> > + * @size: Total size of the guest physical address range.
> > + *
> > + * Return: None
> > + */
> > +int sbi_remote_hfence_gvma(const unsigned long *hart_mask,
> > +                                        unsigned long start,
> > +                                        unsigned long size)
> > +{
> > +       return __sbi_rfence(SBI_EXT_RFENCE, SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA,
> > +                           hart_mask, 0, start, size, 0, 0);
> > +}
> > +EXPORT_SYMBOL_GPL(sbi_remote_hfence_gvma);
> > +
> > +/**
> > + * sbi_remote_hfence_gvma_vmid() - Execute HFENCE.GVMA instructions on given
> > + * remote harts for a guest physical address range belonging to a specific VMID.
> > + *
> > + * @hart_mask: A cpu mask containing all the target harts.
> > + * @start: Start of the guest physical address
> > + * @size: Total size of the guest physical address range.
> > + * @vmid: The value of guest ID (VMID).
> > + *
> > + * Return: 0 if success, Error otherwise.
> > + */
> > +int sbi_remote_hfence_gvma_vmid(const unsigned long *hart_mask,
> > +                                             unsigned long start,
> > +                                             unsigned long size,
> > +                                             unsigned long vmid)
> > +{
> > +       return __sbi_rfence(SBI_EXT_RFENCE,
> > +                           SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID,
> > +                           hart_mask, 0, start, size, vmid, 0);
> > +}
> > +EXPORT_SYMBOL(sbi_remote_hfence_gvma_vmid);
> > +
> > +/**
> > + * sbi_remote_hfence_vvma() - Execute HFENCE.VVMA instructions on given remote
> > + *                          harts for the current guest virtual address range.
> > + * @hart_mask: A cpu mask containing all the target harts.
> > + * @start: Start of the current guest virtual address
> > + * @size: Total size of the current guest virtual address range.
> > + *
> > + * Return: None
> > + */
> > +int sbi_remote_hfence_vvma(const unsigned long *hart_mask,
> > +                                        unsigned long start,
> > +                                        unsigned long size)
> > +{
> > +       return __sbi_rfence(SBI_EXT_RFENCE, SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA,
> > +                           hart_mask, 0, start, size, 0, 0);
> > +}
> > +EXPORT_SYMBOL(sbi_remote_hfence_vvma);
> > +
> > +/**
> > + * sbi_remote_hfence_vvma_asid() - Execute HFENCE.VVMA instructions on given
> > + * remote harts for current guest virtual address range belonging to a specific
> > + * ASID.
> > + *
> > + * @hart_mask: A cpu mask containing all the target harts.
> > + * @start: Start of the current guest virtual address
> > + * @size: Total size of the current guest virtual address range.
> > + * @asid: The value of address space identifier (ASID).
> > + *
> > + * Return: None
> > + */
> > +int sbi_remote_hfence_vvma_asid(const unsigned long *hart_mask,
> > +                                             unsigned long start,
> > +                                             unsigned long size,
> > +                                             unsigned long asid)
> > +{
> > +       return __sbi_rfence(SBI_EXT_RFENCE,
> > +                           SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID,
> > +                           hart_mask, 0, start, size, asid, 0);
> > +}
> > +EXPORT_SYMBOL(sbi_remote_hfence_vvma_asid);
> > +
> >  /**
> >   * sbi_probe_extension() - Check if an SBI extension ID is supported or not.
> >   * @extid: The extension ID to be probed.
> > @@ -356,11 +534,27 @@ int __init sbi_init(void)
> >         if (!sbi_spec_is_0_1()) {
> >                 pr_info("SBI implementation ID=0x%lx Version=0x%lx\n",
> >                         sbi_get_firmware_id(), sbi_get_firmware_version());
> > +               if (sbi_probe_extension(SBI_EXT_TIME) > 0) {
> > +                       __sbi_set_timer = __sbi_set_timer_v02;
> > +                       pr_info("SBI v0.2 TIME extension detected\n");
> > +               } else
> > +                       __sbi_set_timer = __sbi_set_timer_dummy_warn;
> This should be:
>
> #if IS_ENABLED(RISCV_SBI_V01)
>                        __sbi_rfence    = __sbi_set_timer_v01;
> #else
>                        __sbi_rfence    = __sbi_set_timer_dummy_warn;
> #endif

Instead of this, just do the following:
                        __sbi_rfence    = __sbi_set_timer_v01;

>
> > +               if (sbi_probe_extension(SBI_EXT_IPI) > 0) {
> > +                       __sbi_send_ipi  = __sbi_send_ipi_v02;
> > +                       pr_info("SBI v0.2 IPI extension detected\n");
> > +               } else
> > +                       __sbi_send_ipi = __sbi_send_ipi_dummy_warn;
> This should be:
>
> #if IS_ENABLED(RISCV_SBI_V01)
>                        __sbi_rfence    = __sbi_ipi_v01;
> #else
>                        __sbi_rfence    = __sbi_send_ipi_dummy_warn;
> #endif

Instead of this, just do the following:
                        __sbi_rfence    = __sbi_ipi_v01;

>
> > +               if (sbi_probe_extension(SBI_EXT_RFENCE) > 0) {
> > +                       __sbi_rfence    = __sbi_rfence_v02;
> > +                       pr_info("SBI v0.2 RFENCE extension detected\n");
> > +               } else
> > +                       __sbi_rfence    = __sbi_rfence_dummy_warn;
> This should be:
>
> #if IS_ENABLED(RISCV_SBI_V01)
>                        __sbi_rfence    = __sbi_rfence_v01;
> #else
>                        __sbi_rfence    = __sbi_rfence_dummy_warn;
> #endif

Instead of this, just do the following:
                        __sbi_rfence    = __sbi_rfence_v01;
>
> > +
> > +       } else {
> > +               __sbi_set_timer = __sbi_set_timer_v01;
> > +               __sbi_send_ipi  = __sbi_send_ipi_v01;
> > +               __sbi_rfence    = __sbi_rfence_v01;
>
> This should be:
>
> #if IS_ENABLED(RISCV_SBI_V01)
>                __sbi_set_timer = __sbi_set_timer_v01;
>                __sbi_send_ipi  = __sbi_send_ipi_v01;
>                __sbi_rfence    = __sbi_rfence_v01;
> #else
>                __sbi_set_timer = __sbi_set_timer_dummy_warn;
>                __sbi_send_ipi  = __sbi_send_ipi_dummy_warn;
>                __sbi_rfence    = __sbi_rfence_dummy_warn;
> #endif

This is not required.

> >         }
> >
> > -       __sbi_set_timer = __sbi_set_timer_v01;
> > -       __sbi_send_ipi  = __sbi_send_ipi_v01;
> > -       __sbi_rfence    = __sbi_rfence_v01;
> > -
> >         return 0;
> >  }
> > --
> > 2.23.0
> >
>
> Regards,
> Anup

Regards,
Anup