efi: sandbox: Tidy up copy_fdt() to work with sandbox

At present this function takes a pointer as its argument, then passes this
to efi_allocate_pages(), which actually takes an address. It uses casts,
which are not supported on sandbox.

Also the function calculates the FDT size rounded up to the neared EFI
page size, then its caller recalculates the size and adds a bit more to
it.

This function is much better written as something that works with
addresses only, and returns both the address and the size of the relocated
FDT.

Also, copy_fdt() returns NULL on error, but really should propagate the
error from efi_allocate_pages(). To do this it needs to return an
efi_status_t, not a void *.

Update the code in this way, so that it is easier to follow, and also
supports sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

cmd/bootefi.c

@@ -131,17 +131,30 @@ static void set_load_options(struct efi_loaded_image *loaded_image_info,
 	loaded_image_info->load_options_size = size * 2;
 }
 
-static void *copy_fdt(void *fdt)
+/**
+ * copy_fdt() - Copy the device tree to a new location available to EFI
+ *
+ * The FDT is relocated into a suitable location within the EFI memory map.
+ * An additional 12KB is added to the space in case the device tree needs to be
+ * expanded later with fdt_open_into().
+ *
+ * @fdt_addr: On entry, address of start of FDT. On exit, address of relocated
+ *	FDT start
+ * @fdt_sizep: Returns new size of FDT, including
+ * @return new relocated address of FDT
+ */
+static efi_status_t copy_fdt(ulong *fdt_addrp, ulong *fdt_sizep)
 {
-	u64 fdt_size = fdt_totalsize(fdt);
 	unsigned long fdt_ram_start = -1L, fdt_pages;
+	efi_status_t ret = 0;
+	void *fdt, *new_fdt;
 	u64 new_fdt_addr;
-	void *new_fdt;
+	uint fdt_size;
 	int i;
 
-        for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
-                u64 ram_start = gd->bd->bi_dram[i].start;
-                u64 ram_size = gd->bd->bi_dram[i].size;
+	for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
+		u64 ram_start = gd->bd->bi_dram[i].start;
+		u64 ram_size = gd->bd->bi_dram[i].size;
 
 		if (!ram_size)
 			continue;
@@ -154,30 +167,37 @@ static void *copy_fdt(void *fdt)
 	 * Give us at least 4KB of breathing room in case the device tree needs
 	 * to be expanded later. Round up to the nearest EFI page boundary.
 	 */
-	fdt_size += 4096;
+	fdt = map_sysmem(*fdt_addrp, 0);
+	fdt_size = fdt_totalsize(fdt);
+	fdt_size += 4096 * 3;
 	fdt_size = ALIGN(fdt_size + EFI_PAGE_SIZE - 1, EFI_PAGE_SIZE);
 	fdt_pages = fdt_size >> EFI_PAGE_SHIFT;
 
 	/* Safe fdt location is at 127MB */
 	new_fdt_addr = fdt_ram_start + (127 * 1024 * 1024) + fdt_size;
-	if (efi_allocate_pages(EFI_ALLOCATE_MAX_ADDRESS,
-			       EFI_RUNTIME_SERVICES_DATA, fdt_pages,
-			       &new_fdt_addr) != EFI_SUCCESS) {
+	ret = efi_allocate_pages(EFI_ALLOCATE_MAX_ADDRESS,
+				 EFI_RUNTIME_SERVICES_DATA, fdt_pages,
+				 &new_fdt_addr);
+	if (ret != EFI_SUCCESS) {
 		/* If we can't put it there, put it somewhere */
 		new_fdt_addr = (ulong)memalign(EFI_PAGE_SIZE, fdt_size);
-		if (efi_allocate_pages(EFI_ALLOCATE_MAX_ADDRESS,
-				       EFI_RUNTIME_SERVICES_DATA, fdt_pages,
-				       &new_fdt_addr) != EFI_SUCCESS) {
+		ret = efi_allocate_pages(EFI_ALLOCATE_MAX_ADDRESS,
+					 EFI_RUNTIME_SERVICES_DATA, fdt_pages,
+					 &new_fdt_addr);
+		if (ret != EFI_SUCCESS) {
 			printf("ERROR: Failed to reserve space for FDT\n");
-			return NULL;
+			goto done;
 		}
 	}
 
-	new_fdt = (void*)(ulong)new_fdt_addr;
+	new_fdt = map_sysmem(new_fdt_addr, fdt_size);
 	memcpy(new_fdt, fdt, fdt_totalsize(fdt));
 	fdt_set_totalsize(new_fdt, fdt_size);
 
-	return new_fdt;
+	*fdt_addrp = new_fdt_addr;
+	*fdt_sizep = fdt_size;
+done:
+	return ret;
 }
 
 static efi_status_t efi_do_enter(
@@ -250,22 +270,27 @@ static void efi_carve_out_dt_rsv(void *fdt)
 	}
 }
 
-static efi_status_t efi_install_fdt(void *fdt)
+static efi_status_t efi_install_fdt(ulong fdt_addr)
 {
 	bootm_headers_t img = { 0 };
-	ulong fdt_pages, fdt_size, fdt_start, fdt_end;
+	ulong fdt_pages, fdt_size, fdt_start;
 	efi_status_t ret;
+	void *fdt;
 
+	fdt = map_sysmem(fdt_addr, 0);
 	if (fdt_check_header(fdt)) {
 		printf("ERROR: invalid device tree\n");
 		return EFI_INVALID_PARAMETER;
 	}
 
 	/* Prepare fdt for payload */
-	fdt = copy_fdt(fdt);
-	if (!fdt)
-		return EFI_OUT_OF_RESOURCES;
+	ret = copy_fdt(&fdt_addr, &fdt_size);
+	if (ret)
+		return ret;
 
+	unmap_sysmem(fdt);
+	fdt = map_sysmem(fdt_addr, 0);
+	fdt_size = fdt_totalsize(fdt);
 	if (image_setup_libfdt(&img, fdt, 0, NULL)) {
 		printf("ERROR: failed to process device tree\n");
 		return EFI_LOAD_ERROR;
@@ -279,14 +304,12 @@ static efi_status_t efi_install_fdt(void *fdt)
 		return EFI_OUT_OF_RESOURCES;
 
 	/* And reserve the space in the memory map */
-	fdt_start = ((ulong)fdt) & ~EFI_PAGE_MASK;
-	fdt_end = ((ulong)fdt) + fdt_totalsize(fdt);
-	fdt_size = (fdt_end - fdt_start) + EFI_PAGE_MASK;
+	fdt_start = fdt_addr;
 	fdt_pages = fdt_size >> EFI_PAGE_SHIFT;
-	/* Give a bootloader the chance to modify the device tree */
-	fdt_pages += 2;
+
 	ret = efi_add_memory_map(fdt_start, fdt_pages,
 				 EFI_BOOT_SERVICES_DATA, true);
+
 	return ret;
 }
 
@@ -443,7 +466,6 @@ static int do_bootefi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	char *saddr;
 	efi_status_t r;
 	unsigned long fdt_addr;
-	void *fdt;
 
 	/* Allow unaligned memory access */
 	allow_unaligned();
@@ -464,8 +486,7 @@ static int do_bootefi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 		if (!fdt_addr && *argv[2] != '0')
 			return CMD_RET_USAGE;
 		/* Install device tree */
-		fdt = map_sysmem(fdt_addr, 0);
-		r = efi_install_fdt(fdt);
+		r = efi_install_fdt(fdt_addr);
 		if (r != EFI_SUCCESS) {
 			printf("ERROR: failed to install device tree\n");
 			return CMD_RET_FAILURE;