[U-Boot] [RFC 3/6] efi_loader: support convert_pointer at runtime

[Heinrich Schuchardt]

On 6/5/19 6:21 AM, AKASHI Takahiro wrote:
> With this patch, ConvertPointer runtime service is enabled.
> This function will be useful only after SetVirtualAddressMap is called
> and before it exits according to UEFI specification.

ConvertPointer() is called by drivers upon calling the notification
functions of events registered as EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE.

We still lack support for these events.

>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---
>   lib/efi_loader/Kconfig       |  8 ++++
>   lib/efi_loader/efi_runtime.c | 81 ++++++++++++++++++++++++++----------
>   2 files changed, 66 insertions(+), 23 deletions(-)
>
> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> index bb9c7582b14d..e2ef43157568 100644
> --- a/lib/efi_loader/Kconfig
> +++ b/lib/efi_loader/Kconfig
> @@ -51,6 +51,14 @@ config EFI_RUNTIME_SET_VIRTUAL_ADDRESS_MAP
>   	  Enable SetVirtualAddressMap runtime service. This API will be
>   	  called by OS just before it enters into virtual address mode.
>
> +config EFI_RUNTIME_CONVERT_POINTER
> +	bool "runtime service: ConvertPointer"
> +	default n
> +	help
> +	  Enable ConvertPointer runtime service. This API will be expected
> +	  to be called by UEFI drivers in relocating themselves to virtual
> +	  address space.
> +
>   config EFI_DEVICE_PATH_TO_TEXT
>   	bool "Device path to text protocol"
>   	default y
> diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
> index cf202bb9ec07..ff3684a4b692 100644
> --- a/lib/efi_loader/efi_runtime.c
> +++ b/lib/efi_loader/efi_runtime.c
> @@ -27,7 +27,6 @@ LIST_HEAD(efi_runtime_mmio);
>
>   static efi_status_t __efi_runtime EFIAPI efi_unimplemented(void);
>   static efi_status_t __efi_runtime EFIAPI efi_device_error(void);
> -static efi_status_t __efi_runtime EFIAPI efi_invalid_parameter(void);
>
>   /*
>    * TODO(sjg at chromium.org): These defines and structures should come from the ELF
> @@ -108,6 +107,10 @@ efi_status_t efi_init_runtime_supported(void)
>   	efi_runtime_services_supported |=
>   				EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP;
>   #endif
> +#ifdef CONFIG_EFI_RUNTIME_CONVERT_POINTER
> +	efi_runtime_services_supported |=
> +				EFI_RT_SUPPORTED_CONVERT_POINTER;
> +#endif
>
>   	return EFI_CALL(efi_set_variable(L"RuntimeServicesSupported",
>   					 &efi_global_variable_guid,
> @@ -392,6 +395,39 @@ efi_status_t __weak __efi_runtime EFIAPI efi_set_time(struct efi_time *time)
>   	return EFI_UNSUPPORTED;
>   }
>
> +#ifdef CONFIG_EFI_RUNTIME_CONVERT_POINTER
> +static struct efi_mem_desc *efi_virtmap __efi_runtime_data;
> +static int efi_virtmap_num __efi_runtime_data;
> +

Please, put a description of the function and its parameters here.
> +static efi_status_t __efi_runtime EFIAPI efi_convert_pointer(unsigned long dbg,
> +							     void **address)
> +{
> +	struct efi_mem_desc *map;
> +	efi_physical_addr_t addr;
> +	int i;
> +
> +	if (!efi_virtmap)
> +		return EFI_UNSUPPORTED;
> +
> +	if (!address)
> +		return EFI_INVALID_PARAMETER;
> +
> +	for (i = 0, map = efi_virtmap; i < efi_virtmap_num; i++, map++) {
> +		addr = (efi_physical_addr_t)*address;
This line should be before the loop.

> +		if (addr >= map->physical_start &&
> +		    (addr < (map->physical_start

%s/(addr/addr/  No need for that extra parenthesis.

> +			     + (map->num_pages << EFI_PAGE_SHIFT)))) {
> +			*address = (void *)map->virtual_start;

I guess on 32bit this will end in a warning? Wouldn't you need to
convert to uintptr_t first?

> +			*address += addr - map->physical_start;

I think a single assignment is enough. Here you are updating a 32bit
pointer with the difference of two u64. I would expect a warning.

*address = (void *)(uintptr_t)
(addr - map->physical_start + map->virtual_start);

Or do all calculation with addr before copying to *address.

> +
> +			return EFI_SUCCESS;
> +		}
> +	}
> +
> +	return EFI_NOT_FOUND;
> +}
> +#endif
> +
>   struct efi_runtime_detach_list_struct {
>   	void *ptr;
>   	void *patchto;
> @@ -599,6 +635,10 @@ static efi_status_t EFIAPI efi_set_virtual_address_map(
>   		return EFI_EXIT(EFI_INVALID_PARAMETER);
>   	}
>
> +	efi_virtmap = virtmap;
> +	efi_virtmap_num = n;
> +
> +#if 0 /* FIXME: This code is fragile as calloc is used in add_runtime_mmio */
>   	/* Rebind mmio pointers */
>   	for (i = 0; i < n; i++) {
>   		struct efi_mem_desc *map = (void*)virtmap +
> @@ -622,14 +662,14 @@ static efi_status_t EFIAPI efi_set_virtual_address_map(
>   				*lmmio->ptr = (void *)new_addr;
>   			}
>   		}
> -		if ((map_start <= (uintptr_t)systab.tables) &&
> -		    (map_end >= (uintptr_t)systab.tables)) {
> -			char *ptr = (char *)systab.tables;
> -
> -			ptr += off;
> -			systab.tables = (struct efi_configuration_table *)ptr;
> -		}

This looks like an unrelated change.

Put it into a separate patch, please.

Best regards

Heinrich

>   	}
> +#endif
> +
> +	/* FIXME */
> +	efi_convert_pointer(0, (void **)&systab.tables);
> +
> +	/* All fixes must be done before this line */
> +	efi_virtmap = NULL;
>
>   	/* Move the actual runtime code over */
>   	for (i = 0; i < n; i++) {
> @@ -644,6 +684,11 @@ static efi_status_t EFIAPI efi_set_virtual_address_map(
>   			/* Once we're virtual, we can no longer handle
>   			   complex callbacks */
>   			efi_runtime_detach(new_offset);
> +
> +			/*
> +			 * FIXME:
> +			 * We can no longer update RuntimeServicesSupported.
> +			 */
>   			return EFI_EXIT(EFI_SUCCESS);
>   		}
>   	}
> @@ -733,20 +778,6 @@ static efi_status_t __efi_runtime EFIAPI efi_device_error(void)
>   	return EFI_DEVICE_ERROR;
>   }
>
> -/**
> - * efi_invalid_parameter() - replacement function, returns EFI_INVALID_PARAMETER
> - *
> - * This function is used after SetVirtualAddressMap() is called as replacement
> - * for services that are not available anymore due to constraints of the U-Boot
> - * implementation.
> - *
> - * Return:	EFI_INVALID_PARAMETER
> - */
> -static efi_status_t __efi_runtime EFIAPI efi_invalid_parameter(void)
> -{
> -	return EFI_INVALID_PARAMETER;
> -}
> -
>   /**
>    * efi_update_capsule() - process information from operating system
>    *
> @@ -833,7 +864,11 @@ struct efi_runtime_services __efi_runtime_data efi_runtime_services = {
>   #else
>   	.set_virtual_address_map = (void *)&efi_unimplemented,
>   #endif
> -	.convert_pointer = (void *)&efi_invalid_parameter,
> +#ifdef CONFIG_EFI_RUNTIME_CONVERT_POINTER
> +	.convert_pointer = &efi_convert_pointer,
> +#else
> +	.convert_pointer = (void *)&efi_unimplemented,

I feel uneasy using a function efi_unimplemented() with a different
number of parameters here. Depending on the ABI this may lead to a crash.

Best regards

Heinrich

> +#endif
>   	.get_variable = efi_get_variable,
>   	.get_next_variable_name = efi_get_next_variable_name,
>   	.set_variable = efi_set_variable,
>