[1/1] efi_loader: implement EFI_RT_PROPERTIES_TABLE

On Wed, 19 Feb 2020 at 21:00, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> UEFI spec 2.8 errata A replaces the RuntimeServicesSupported variable
> defined in UEFI spec 2.8 by the configuration table
> EFI_RT_PROPERTIES_TABLE. So let's follow suit.
>
> Cc: Ard Biesheuvel <ardb at kernel.org>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

I have tested this on u-boot+linux/arm64 running on QEMU, with my
kernel patches that take this table into account [0], and compared to
EDK2 (which implements variable services, and doesn't produce this
table), I get

 [    ] clocksource: Switched to clocksource arch_sys_counter

(modulo the timestamps, of course)
So the table is being taken into account, and the EFI variable drivers
are no longer loaded.

Thanks for getting this sorted so quickly, the errata A spec was only
released today :-)


Tested-by: Ard Biesheuvel <ardb at kernel.org>



[0] https://lore.kernel.org/linux-efi/20200219171907.11894-1-ardb at kernel.org/

> ---
>  cmd/efidebug.c               |  4 ++++
>  include/efi_api.h            | 12 ++++++++++++
>  lib/efi_loader/efi_runtime.c | 36 ++++++++++++++++++++++++++++--------
>  lib/efi_loader/efi_setup.c   |  8 ++++----
>  4 files changed, 48 insertions(+), 12 deletions(-)
>
> diff --git a/cmd/efidebug.c b/cmd/efidebug.c
> index 576e95b395..d291ae54af 100644
> --- a/cmd/efidebug.c
> +++ b/cmd/efidebug.c
> @@ -264,6 +264,10 @@ static const struct {
>                 "SMBIOS table",
>                 SMBIOS_TABLE_GUID,
>         },
> +       {
> +               "Runtime properties",
> +               EFI_RT_PROPERTIES_TABLE_GUID,
> +       },
>  };
>
>  /**
> diff --git a/include/efi_api.h b/include/efi_api.h
> index 22396172e1..b7b68cb7a1 100644
> --- a/include/efi_api.h
> +++ b/include/efi_api.h
> @@ -228,6 +228,18 @@ struct efi_capsule_header {
>  #define EFI_RT_SUPPORTED_QUERY_CAPSULE_CAPABILITIES    0x1000
>  #define EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO           0x2000
>
> +#define EFI_RT_PROPERTIES_TABLE_GUID \
> +       EFI_GUID(0xeb66918a, 0x7eef, 0x402a, 0x84, 0x2e, \
> +                0x93, 0x1d, 0x21, 0xc3, 0x8a, 0xe9)
> +
> +#define EFI_RT_PROPERTIES_TABLE_VERSION        0x1
> +
> +struct efi_rt_properties_table {
> +       u16 version;
> +       u16 length;
> +       u32 runtime_services_supported;
> +};
> +
>  struct efi_runtime_services {
>         struct efi_table_hdr hdr;
>         efi_status_t (EFIAPI *get_time)(struct efi_time *time,
> diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
> index 4b3c843b2c..4be51335bc 100644
> --- a/lib/efi_loader/efi_runtime.c
> +++ b/lib/efi_loader/efi_runtime.c
> @@ -18,6 +18,10 @@
>  /* For manual relocation support */
>  DECLARE_GLOBAL_DATA_PTR;
>
> +/* GUID of the runtime properties table */
> +static const efi_guid_t efi_rt_properties_table_guid =
> +                               EFI_RT_PROPERTIES_TABLE_GUID;
> +
>  struct efi_runtime_mmio_list {
>         struct list_head link;
>         void **ptr;
> @@ -94,9 +98,28 @@ static __efi_runtime_data efi_uintn_t efi_descriptor_size;
>   * handle a good number of runtime callbacks
>   */
>
> +/**
> + * efi_init_runtime_supported() - create runtime properties table
> + *
> + * Create a configuration table specifying which services are available at
> + * runtime.
> + *
> + * Return:     status code
> + */
>  efi_status_t efi_init_runtime_supported(void)
>  {
> -       u16 efi_runtime_services_supported =
> +       efi_status_t ret;
> +       struct efi_rt_properties_table *rt_table;
> +
> +       ret = efi_allocate_pool(EFI_RUNTIME_SERVICES_DATA,
> +                               sizeof(struct efi_rt_properties_table),
> +                               (void **)&rt_table);
> +       if (ret != EFI_SUCCESS)
> +               return ret;
> +
> +       rt_table->version = EFI_RT_PROPERTIES_TABLE_VERSION;
> +       rt_table->length = sizeof(struct efi_rt_properties_table);
> +       rt_table->runtime_services_supported =
>                                 EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP |
>                                 EFI_RT_SUPPORTED_CONVERT_POINTER;
>
> @@ -105,15 +128,12 @@ efi_status_t efi_init_runtime_supported(void)
>          * as well as efi_runtime_services.
>          */
>  #ifdef CONFIG_EFI_HAVE_RUNTIME_RESET
> -       efi_runtime_services_supported |= EFI_RT_SUPPORTED_RESET_SYSTEM;
> +       rt_table->runtime_services_supported |= EFI_RT_SUPPORTED_RESET_SYSTEM;
>  #endif
>
> -       return EFI_CALL(efi_set_variable(L"RuntimeServicesSupported",
> -                                        &efi_global_variable_guid,
> -                                        EFI_VARIABLE_BOOTSERVICE_ACCESS |
> -                                        EFI_VARIABLE_RUNTIME_ACCESS,
> -                                        sizeof(efi_runtime_services_supported),
> -                                        &efi_runtime_services_supported));
> +       ret = efi_install_configuration_table(&efi_rt_properties_table_guid,
> +                                             rt_table);
> +       return ret;
>  }
>
>  /**
> diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
> index de7b616c6d..2060307b05 100644
> --- a/lib/efi_loader/efi_setup.c
> +++ b/lib/efi_loader/efi_setup.c
> @@ -122,13 +122,13 @@ efi_status_t efi_init_obj_list(void)
>         if (ret != EFI_SUCCESS)
>                 goto out;
>
> -       /* Indicate supported runtime services */
> -       ret = efi_init_runtime_supported();
> +       /* Initialize system table */
> +       ret = efi_initialize_system_table();
>         if (ret != EFI_SUCCESS)
>                 goto out;
>
> -       /* Initialize system table */
> -       ret = efi_initialize_system_table();
> +       /* Indicate supported runtime services */
> +       ret = efi_init_runtime_supported();
>         if (ret != EFI_SUCCESS)
>                 goto out;
>
> --
> 2.25.0
>