[PATCH v2 2/4] lib: sbi: fwft: add support for SBI_FWFT_MISALIGNED_EXC_DELEG

[Clément Léger]

On 18/06/2024 17:54, Anup Patel wrote:
> On Tue, Jun 18, 2024 at 9:23 PM Anup Patel <anup at brainfault.org> wrote:
>>
>> On Mon, Jun 17, 2024 at 9:11 PM Clément Léger <cleger at rivosinc.com> wrote:
>>>
>>> Add support for SBI_FWFT_MISALIGNED_EXC_DELEG withing FWFT support. This
>>> support allows to delegate misaligned accesses traps.
>>>
>>> Signed-off-by: Clément Léger <cleger at rivosinc.com>
>>> ---
>>>  lib/sbi/sbi_fwft.c | 39 ++++++++++++++++++++++++++++++++++++++-
>>>  lib/sbi/sbi_hsm.c  |  3 +++
>>>  2 files changed, 41 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/sbi/sbi_fwft.c b/lib/sbi/sbi_fwft.c
>>> index b302b5d..289a344 100644
>>> --- a/lib/sbi/sbi_fwft.c
>>> +++ b/lib/sbi/sbi_fwft.c
>>> @@ -32,6 +32,8 @@ static unsigned long fwft_ptr_offset;
>>>  #define fwft_set_hart_state_ptr(__scratch, __phs)                      \
>>>         sbi_scratch_write_type((__scratch), void *, fwft_ptr_offset, (__phs))
>>>
>>> +#define MIS_DELEG (1UL << CAUSE_MISALIGNED_LOAD | 1UL << CAUSE_MISALIGNED_STORE)
>>> +
>>>  struct fwft_config;
>>>
>>>  struct fwft_feature {
>>> @@ -71,6 +73,33 @@ static bool fwft_is_defined_feature(enum sbi_fwft_feature_t feature)
>>>         return false;
>>>  }
>>>
>>> +static int fwft_misaligned_delegation_supported(struct fwft_config *conf)
>>> +{
>>> +       if (!misa_extension('S'))
>>> +               return SBI_ENOTSUPP;
>>> +
>>> +       return SBI_OK;
>>> +}
>>> +
>>> +static int fwft_set_misaligned_delegation(struct fwft_config *conf,
>>> +                                        unsigned long value)
>>> +{
>>> +       if (value)
>>> +               csr_set(CSR_MEDELEG, MIS_DELEG);
>>> +       else
>>> +               csr_clear(CSR_MEDELEG, MIS_DELEG);
>>> +
>>> +       return SBI_OK;
>>> +}
>>> +
>>> +static int fwft_get_misaligned_delegation(struct fwft_config *conf,
>>> +                                        unsigned long *value)
>>> +{
>>> +       *value = (csr_read(CSR_MEDELEG) & MIS_DELEG) != 0;
>>> +
>>> +       return SBI_OK;
>>> +}
>>> +
>>>  static struct fwft_config* get_feature_config(enum sbi_fwft_feature_t feature)
>>>  {
>>>         int i;
>>> @@ -148,7 +177,15 @@ int sbi_fwft_get(enum sbi_fwft_feature_t feature, unsigned long *out_val)
>>>         return conf->feature->get(conf, out_val);
>>>  }
>>>
>>> -static const struct fwft_feature features[] = {};
>>> +static const struct fwft_feature features[] =
>>> +{
>>> +       {
>>> +               .id = SBI_FWFT_MISALIGNED_EXC_DELEG,
>>> +               .supported = fwft_misaligned_delegation_supported,
>>> +               .set = fwft_set_misaligned_delegation,
>>> +               .get = fwft_get_misaligned_delegation,
>>> +       },
>>> +};
>>>
>>>  int sbi_fwft_init(struct sbi_scratch *scratch, bool cold_boot)
>>>  {
>>> diff --git a/lib/sbi/sbi_hsm.c b/lib/sbi/sbi_hsm.c
>>> index be48d64..47edab2 100644
>>> --- a/lib/sbi/sbi_hsm.c
>>> +++ b/lib/sbi/sbi_hsm.c
>>> @@ -44,6 +44,7 @@ struct sbi_hsm_data {
>>>         unsigned long suspend_type;
>>>         unsigned long saved_mie;
>>>         unsigned long saved_mip;
>>> +       unsigned long saved_hedeleg;
>>>         atomic_t start_ticket;
>>>  };
>>>
>>> @@ -417,6 +418,7 @@ void __sbi_hsm_suspend_non_ret_save(struct sbi_scratch *scratch)
>>>
>>>         hdata->saved_mie = csr_read(CSR_MIE);
>>>         hdata->saved_mip = csr_read(CSR_MIP) & (MIP_SSIP | MIP_STIP);
>>> +       hdata->saved_hedeleg = csr_read(CSR_HEDELEG);
>>>  }
>>>
>>>  static void __sbi_hsm_suspend_non_ret_restore(struct sbi_scratch *scratch)
>>> @@ -424,6 +426,7 @@ static void __sbi_hsm_suspend_non_ret_restore(struct sbi_scratch *scratch)
>>>         struct sbi_hsm_data *hdata = sbi_scratch_offset_ptr(scratch,
>>>                                                             hart_data_offset);
>>>
>>> +       csr_write(CSR_HEDELEG, hdata->saved_hedeleg);
>>
>> These changes in sbi_hsm.c look like a separate patch.
>> Why is it here ?
> 
> I think you meant to save/restore medeleg here. right ?

Yep, that was meant to be MEDELEG instead of HEDELEG. Thanks for
catching this.

Clément

> 
> Regards,
> Anup
> 
>>
>>>         csr_write(CSR_MIE, hdata->saved_mie);
>>>         csr_set(CSR_MIP, (hdata->saved_mip & (MIP_SSIP | MIP_STIP)));
>>>  }
>>> --
>>> 2.45.2
>>>
>>>
>>> --
>>> opensbi mailing list
>>> opensbi at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/opensbi
>>
>> Regards,
>> Anup