[PATCH v3 1/4] efi: add EFI_SYSTEM_TABLE_POINTER for debug

[Ilias Apalodimas]

Hi Paul,

[...]


>         bool
>
> +config EFI_DEBUG_SUPPORT_TABLE
> +       bool "EFI Debug Support Table"
> +       help
> +         Select this option if you want to setup the EFI Debug Support
> +         Table which is used by the debug agent or an external debugger to
> +         determine loaded image information in a quiescent manner.
> +
>  menu "UEFI services"
>
>  config EFI_GET_TIME
> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> index dbebb37dc04..5a4349f8679 100644
> --- a/lib/efi_loader/efi_boottime.c
> +++ b/lib/efi_loader/efi_boottime.c
> @@ -4001,6 +4001,8 @@ struct efi_system_table __efi_runtime_data systab = {
>         .tables = NULL,
>  };
>
> +struct efi_system_table_pointer __efi_runtime_data * systab_pointer = NULL;
> +
>  /**
>   * efi_initialize_system_table() - Initialize system table
>   *
> @@ -4035,3 +4037,47 @@ efi_status_t efi_initialize_system_table(void)
>
>         return ret;
>  }
> +
> +/**
> + * efi_initialize_system_table() - Initialize system table pointer
> + *
> + * Return:     status code
> + */
> +efi_status_t efi_initialize_system_table_pointer(void)
> +{
> +       efi_status_t ret;
> +       const int size_4MB = 0x00400000;
> +       int pages = efi_size_in_pages(sizeof(struct efi_system_table_pointer));
> +       int alignment_mask = size_4MB - 1;
> +       int real_pages = pages + efi_size_in_pages(size_4MB);
> +       u64 addr;
> +       u64 aligned_addr;
> +       u32 crc32_value;
> +
> +       /* Allocate configuration table array */
> +       ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
> +                                EFI_RUNTIME_SERVICES_DATA,
> +                                real_pages,
> +                                &addr);
> +
> +       if (ret != EFI_SUCCESS) {
> +               log_err("Installing EFI system table pointer failed\n");
> +               return ret;
> +       }
> +
> +       /* alignment to 4MB boundary */
> +       aligned_addr = (addr + alignment_mask) & ~alignment_mask;

efi_alloc_aligned_pages() does that for you.
But I have similar questions to Heinrich here. Why do you need 4MB?


> +
> +       systab_pointer = (struct efi_system_table_pointer *)aligned_addr;
> +       memset(systab_pointer, 0, sizeof(struct efi_system_table_pointer));
> +
> +       systab_pointer->signature = EFI_SYSTEM_TABLE_SIGNATURE;
> +       systab_pointer->efi_system_table_base = (efi_physical_addr_t)&systab;
> +       systab_pointer->crc32 = 0;

You are assigning this at the end regardless, so I guess you can skip it here.

> +       crc32_value = crc32(0,
> +                           (const unsigned char *)systab_pointer,
> +                           sizeof(struct efi_system_table_pointer));
> +       systab_pointer->crc32 = crc32_value;
> +
> +       return ret;
> +}
> diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
> index 48f91da5df7..a6b37d994f6 100644
> --- a/lib/efi_loader/efi_setup.c
> +++ b/lib/efi_loader/efi_setup.c
> @@ -278,6 +278,14 @@ efi_status_t efi_init_obj_list(void)
>         if (ret != EFI_SUCCESS)
>                 goto out;
>
> +       /* Initialize system table pointer */
> +       if (IS_ENABLED(CONFIG_EFI_DEBUG_SUPPORT_TABLE)) {
> +               ret = efi_initialize_system_table_pointer();
> +               if (ret != EFI_SUCCESS) {
> +                       goto out;
> +               }
> +       }
> +
>         if (IS_ENABLED(CONFIG_EFI_ECPT)) {
>                 ret = efi_ecpt_register();
>                 if (ret != EFI_SUCCESS)
> --
> 2.39.5
>

Thanks
/Ilias