[RFC PATCH 1/1] riscv/efi_stub: Add support for RISCV_EFI_BOOT_PROTOCOL

[Sunil V L]

On Wed, Jan 26, 2022 at 12:13:42PM +0100, Ard Biesheuvel wrote:
> Hello Sunil,
> 
> On Wed, 26 Jan 2022 at 12:06, Sunil V L <sunilvl at ventanamicro.com> wrote:
> >
> > This patch adds the support for getting the boot hart ID in
> > Linux EFI stub using RISCV_EFI_BOOT_PROTOCOL.
> >
> > Signed-off-by: Sunil V L <sunilvl at ventanamicro.com>
> > ---
> >  drivers/firmware/efi/libstub/efistub.h    | 15 ++++++++++++
> >  drivers/firmware/efi/libstub/riscv-stub.c | 28 ++++++++++++++++++++---
> >  include/linux/efi.h                       |  1 +
> >  3 files changed, 41 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
> > index edb77b0621ea..0428f8816942 100644
> > --- a/drivers/firmware/efi/libstub/efistub.h
> > +++ b/drivers/firmware/efi/libstub/efistub.h
> > @@ -720,6 +720,21 @@ union efi_tcg2_protocol {
> >         } mixed_mode;
> >  };
> >
> > +typedef union riscv_efi_boot_protocol riscv_efi_boot_protocol_t;
> > +
> > +union riscv_efi_boot_protocol {
> > +       struct {
> > +               u64 revision;
> > +               efi_status_t (__efiapi *get_boot_hartid)(
> > +                                                        riscv_efi_boot_protocol_t *,
> > +                                                        size_t *);
> > +       };
> > +       struct {
> > +               u32 revision;
> > +               u32 get_boot_hartid;
> > +       } mixed_mode;
> > +};
> > +
> 
> You don't the mixed mode member here - this is for X64 kernels on IA32
> firmware only.

Ah OK. Thanks for the feedback, Ard. Will remove it in next version.

Thanks
Sunil
> 
> >  typedef union efi_load_file_protocol efi_load_file_protocol_t;
> >  typedef union efi_load_file_protocol efi_load_file2_protocol_t;
> >
> > diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c
> > index 380e4e251399..c7add4eb5453 100644
> > --- a/drivers/firmware/efi/libstub/riscv-stub.c
> > +++ b/drivers/firmware/efi/libstub/riscv-stub.c
> > @@ -46,12 +46,34 @@ static u32 get_boot_hartid_from_fdt(void)
> >         return fdt32_to_cpu(*prop);
> >  }
> >
> > +static u32 get_boot_hartid_from_efi(void)
> > +{
> > +       efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;
> > +       efi_status_t status;
> > +       riscv_efi_boot_protocol_t *boot_protocol;
> > +       size_t boot_hart_id;
> > +
> > +       status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL,
> > +                            (void **)&boot_protocol);
> > +       if (status == EFI_SUCCESS) {
> > +               status = efi_call_proto(boot_protocol,
> > +                                       get_boot_hartid, &boot_hart_id);
> > +               if (status == EFI_SUCCESS) {
> > +                       return (u32)boot_hart_id;
> > +               }
> > +       }
> > +       return U32_MAX;
> > +}
> > +
> >  efi_status_t check_platform_features(void)
> >  {
> > -       hartid = get_boot_hartid_from_fdt();
> > +       hartid = get_boot_hartid_from_efi();
> >         if (hartid == U32_MAX) {
> > -               efi_err("/chosen/boot-hartid missing or invalid!\n");
> > -               return EFI_UNSUPPORTED;
> > +               hartid = get_boot_hartid_from_fdt();
> > +               if (hartid == U32_MAX) {
> > +                       efi_err("/chosen/boot-hartid missing or invalid!\n");
> > +                       return EFI_UNSUPPORTED;
> > +               }
> >         }
> >         return EFI_SUCCESS;
> >  }
> > diff --git a/include/linux/efi.h b/include/linux/efi.h
> > index ccd4d3f91c98..9822c730207c 100644
> > --- a/include/linux/efi.h
> > +++ b/include/linux/efi.h
> > @@ -380,6 +380,7 @@ void efi_native_runtime_setup(void);
> >  #define EFI_CONSOLE_OUT_DEVICE_GUID            EFI_GUID(0xd3b36f2c, 0xd551, 0x11d4,  0x9a, 0x46, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d)
> >  #define APPLE_PROPERTIES_PROTOCOL_GUID         EFI_GUID(0x91bd12fe, 0xf6c3, 0x44fb,  0xa5, 0xb7, 0x51, 0x22, 0xab, 0x30, 0x3a, 0xe0)
> >  #define EFI_TCG2_PROTOCOL_GUID                 EFI_GUID(0x607f766c, 0x7455, 0x42be,  0x93, 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f)
> > +#define RISCV_EFI_BOOT_PROTOCOL_GUID           EFI_GUID(0xccd15fec, 0x6f73, 0x4eec,  0x83, 0x95, 0x3e, 0x69, 0xe4, 0xb9, 0x40, 0xbf)
> >  #define EFI_LOAD_FILE_PROTOCOL_GUID            EFI_GUID(0x56ec3091, 0x954c, 0x11d2,  0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
> >  #define EFI_LOAD_FILE2_PROTOCOL_GUID           EFI_GUID(0x4006c0c1, 0xfcb3, 0x403e,  0x99, 0x6d, 0x4a, 0x6c, 0x87, 0x24, 0xe0, 0x6d)
> >  #define EFI_RT_PROPERTIES_TABLE_GUID           EFI_GUID(0xeb66918a, 0x7eef, 0x402a,  0x84, 0x2e, 0x93, 0x1d, 0x21, 0xc3, 0x8a, 0xe9)
> > --
> > 2.25.1
> >