[U-Boot] [PATCH 3/4] efi_loader: implement ConvertPointer()

[AKASHI Takahiro]

On Sat, Jul 27, 2019 at 11:00:03PM +0200, Heinrich Schuchardt wrote:
> Implement the ConvertPointer() runtime service.

I already submitted a similar patch:
https://lists.denx.de/pipermail/u-boot/2019-June/371773.html

Anyhow,

> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
>  lib/efi_loader/efi_runtime.c | 75 ++++++++++++++++++++++++++++++++++--
>  1 file changed, 71 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
> index a8f0b5eae3..2286e847a7 100644
> --- a/lib/efi_loader/efi_runtime.c
> +++ b/lib/efi_loader/efi_runtime.c
> @@ -81,6 +81,10 @@ struct elf_rela {
>  	long addend;
>  };
> 
> +static __efi_runtime_data struct efi_mem_desc *efi_virtmap;
> +static __efi_runtime_data efi_uintn_t efi_descriptor_count;
> +static __efi_runtime_data efi_uintn_t efi_descriptor_size;
> +
>  /*
>   * EFI runtime code lives in two stages. In the first stage, U-Boot and an EFI
>   * payload are running concurrently at the same time. In this mode, we can
> @@ -89,7 +93,9 @@ struct elf_rela {
> 
>  efi_status_t efi_init_runtime_supported(void)
>  {
> -	u16 efi_runtime_services_supported = 0;
> +	u16 efi_runtime_services_supported =
> +				EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP ||

"||" -> "|"

> +				EFI_RT_SUPPORTED_CONVERT_POINTER;
> 
>  	/*
>  	 * This value must be synced with efi_runtime_detach_list
> @@ -98,8 +104,7 @@ efi_status_t efi_init_runtime_supported(void)
>  #ifdef CONFIG_EFI_HAVE_RUNTIME_RESET
>  	efi_runtime_services_supported |= EFI_RT_SUPPORTED_RESET_SYSTEM;
>  #endif
> -	efi_runtime_services_supported |=
> -				EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP;
> +
>  	return EFI_CALL(efi_set_variable(L"RuntimeServicesSupported",
>  					 &efi_global_variable_guid,
>  					 EFI_VARIABLE_BOOTSERVICE_ACCESS |
> @@ -454,6 +459,58 @@ static __efi_runtime efi_status_t EFIAPI efi_convert_pointer_runtime(
>  	return EFI_UNSUPPORTED;
>  }
> 
> +/**
> + * efi_convert_pointer_runtime() - convert from physical to virtual pointer
> + *
> + * This function implements the ConvertPointer() runtime service until
> + * the first call to SetVirtualAddressMap().
> + *
> + * See the Unified Extensible Firmware Interface (UEFI) specification for
> + * details.
> + *
> + * @debug_disposition:	indicates if pointer may be converted to NULL
> + * @address:		pointer to be converted
> + * Return:		status code EFI_UNSUPPORTED
> + */
> +static __efi_runtime efi_status_t EFIAPI efi_convert_pointer(
> +			efi_uintn_t debug_disposition, void **address)
> +{
> +	efi_physical_addr_t addr = (uintptr_t)*address;
> +	efi_uintn_t i;
> +	efi_status_t ret = EFI_NOT_FOUND;
> +
> +	EFI_ENTRY("%zu %p", debug_disposition, address);
> +
> +	if (!efi_virtmap) {
> +		ret = EFI_UNSUPPORTED;
> +		goto out;
> +	}
> +
> +	if (!address) {
> +		ret = EFI_INVALID_PARAMETER;
> +		goto out;
> +	}
> +
> +	for (i = 0; i < efi_descriptor_count; i++) {
> +		struct efi_mem_desc *map = (void *)efi_virtmap +
> +					   (efi_descriptor_size * i);
> +
> +		if (addr >= map->physical_start &&
> +		    (addr < map->physical_start
> +			    + (map->num_pages << EFI_PAGE_SHIFT))) {
> +			*address = (void *)(uintptr_t)
> +				   (addr + map->virtual_start -
> +				    map->physical_start);
> +
> +			ret = EFI_SUCCESS;
> +			break;
> +		}
> +	}
> +
> +out:
> +	return EFI_EXIT(ret);
> +}
> +
>  static __efi_runtime void efi_relocate_runtime_table(ulong offset)
>  {
>  	ulong patchoff;
> @@ -480,6 +537,12 @@ static __efi_runtime void efi_relocate_runtime_table(ulong offset)
>  	 */
>  	efi_runtime_services.convert_pointer = &efi_convert_pointer_runtime;
> 
> +	/*
> +	 * TODO: Update UEFI variable RuntimeServicesSupported removing flags
> +	 * EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP and
> +	 * EFI_RT_SUPPORTED_CONVERT_POINTER as required by the UEFI spec 2.8.
> +	 */
> +
>  	/* Update CRC32 */
>  	efi_update_table_header_crc32(&efi_runtime_services.hdr);
>  }
> @@ -584,6 +647,10 @@ static efi_status_t EFIAPI efi_set_virtual_address_map(
>  	EFI_ENTRY("%zx %zx %x %p", memory_map_size, descriptor_size,
>  		  descriptor_version, virtmap);
> 
> +	efi_virtmap = virtmap;
> +	efi_descriptor_size = descriptor_size;
> +	efi_descriptor_count = n;
> +

As I mentioned in the patch above,

!        /* Rebind mmio pointers */
!                for (i = 0; i < n; i++) {
!       ...

This part of code in efi_set_virtual_address_map() is fragile as 
entries in efi_runtime_mmio belong to memory allocated by calloc(),
which means that they are no longer accessible at runtime.

-Takahiro Akashi

>  	/*
>  	 * TODO:
>  	 * Further down we are cheating. While really we should implement
> @@ -800,7 +867,7 @@ struct efi_runtime_services __efi_runtime_data efi_runtime_services = {
>  	.get_wakeup_time = (void *)&efi_unimplemented,
>  	.set_wakeup_time = (void *)&efi_unimplemented,
>  	.set_virtual_address_map = &efi_set_virtual_address_map,
> -	.convert_pointer = (void *)&efi_unimplemented,
> +	.convert_pointer = efi_convert_pointer,
>  	.get_variable = efi_get_variable,
>  	.get_next_variable_name = efi_get_next_variable_name,
>  	.set_variable = efi_set_variable,
> --
> 2.20.1
>