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

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Sat, Jun 15, 2019 at 09:41:31PM +0200, Heinrich Schuchardt wrote:
> 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.

So? What do you want me to do here?

> >
> >Signed-off-by: AKASHI Takahiro <takahiro.akashi@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.

Okay.

> >+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.

I will check.

> *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.

It does.
This code should be replaced by:
> >+	/* FIXME */
> >+	efi_convert_pointer(0, (void **)&systab.tables);

-Takahiro Akashi

> 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,
> >
>