1 files changed, 379 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
new file mode 100644
index 000000000..70e9789ff
--- /dev/null
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * FDT related Helper functions used by the EFI stub on multiple
+ * architectures. This should be #included by the EFI stub
+ * implementation files.
+ *
+ * Copyright 2013 Linaro Limited; author Roy Franz
+ */
+
+#include <linux/efi.h>
+#include <linux/libfdt.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+#define EFI_DT_ADDR_CELLS_DEFAULT 2
+#define EFI_DT_SIZE_CELLS_DEFAULT 2
+
+static void fdt_update_cell_size(void *fdt)
+{
+	int offset;
+
+	offset = fdt_path_offset(fdt, "/");
+	/* Set the #address-cells and #size-cells values for an empty tree */
+
+	fdt_setprop_u32(fdt, offset, "#address-cells", EFI_DT_ADDR_CELLS_DEFAULT);
+	fdt_setprop_u32(fdt, offset, "#size-cells",    EFI_DT_SIZE_CELLS_DEFAULT);
+}
+
+static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size,
+			       void *fdt, int new_fdt_size, char *cmdline_ptr)
+{
+	int node, num_rsv;
+	int status;
+	u32 fdt_val32;
+	u64 fdt_val64;
+
+	/* Do some checks on provided FDT, if it exists: */
+	if (orig_fdt) {
+		if (fdt_check_header(orig_fdt)) {
+			efi_err("Device Tree header not valid!\n");
+			return EFI_LOAD_ERROR;
+		}
+		/*
+		 * We don't get the size of the FDT if we get if from a
+		 * configuration table:
+		 */
+		if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
+			efi_err("Truncated device tree! foo!\n");
+			return EFI_LOAD_ERROR;
+		}
+	}
+
+	if (orig_fdt) {
+		status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
+	} else {
+		status = fdt_create_empty_tree(fdt, new_fdt_size);
+		if (status == 0) {
+			/*
+			 * Any failure from the following function is
+			 * non-critical:
+			 */
+			fdt_update_cell_size(fdt);
+		}
+	}
+
+	if (status != 0)
+		goto fdt_set_fail;
+
+	/*
+	 * Delete all memory reserve map entries. When booting via UEFI,
+	 * kernel will use the UEFI memory map to find reserved regions.
+	 */
+	num_rsv = fdt_num_mem_rsv(fdt);
+	while (num_rsv-- > 0)
+		fdt_del_mem_rsv(fdt, num_rsv);
+
+	node = fdt_subnode_offset(fdt, 0, "chosen");
+	if (node < 0) {
+		node = fdt_add_subnode(fdt, 0, "chosen");
+		if (node < 0) {
+			/* 'node' is an error code when negative: */
+			status = node;
+			goto fdt_set_fail;
+		}
+	}
+
+	if (cmdline_ptr != NULL && strlen(cmdline_ptr) > 0) {
+		status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
+				     strlen(cmdline_ptr) + 1);
+		if (status)
+			goto fdt_set_fail;
+	}
+
+	/* Add FDT entries for EFI runtime services in chosen node. */
+	node = fdt_subnode_offset(fdt, 0, "chosen");
+	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)efi_system_table);
+
+	status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64);
+	if (status)
+		goto fdt_set_fail;
+
+	fdt_val64 = U64_MAX; /* placeholder */
+
+	status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
+	if (status)
+		goto fdt_set_fail;
+
+	fdt_val32 = U32_MAX; /* placeholder */
+
+	status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
+	if (status)
+		goto fdt_set_fail;
+
+	status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
+	if (status)
+		goto fdt_set_fail;
+
+	status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
+	if (status)
+		goto fdt_set_fail;
+
+	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
+		efi_status_t efi_status;
+
+		efi_status = efi_get_random_bytes(sizeof(fdt_val64),
+						  (u8 *)&fdt_val64);
+		if (efi_status == EFI_SUCCESS) {
+			status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64);
+			if (status)
+				goto fdt_set_fail;
+		}
+	}
+
+	/* Shrink the FDT back to its minimum size: */
+	fdt_pack(fdt);
+
+	return EFI_SUCCESS;
+
+fdt_set_fail:
+	if (status == -FDT_ERR_NOSPACE)
+		return EFI_BUFFER_TOO_SMALL;
+
+	return EFI_LOAD_ERROR;
+}
+
+static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
+{
+	int node = fdt_path_offset(fdt, "/chosen");
+	u64 fdt_val64;
+	u32 fdt_val32;
+	int err;
+
+	if (node < 0)
+		return EFI_LOAD_ERROR;
+
+	fdt_val64 = cpu_to_fdt64((unsigned long)map->map);
+
+	err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
+	if (err)
+		return EFI_LOAD_ERROR;
+
+	fdt_val32 = cpu_to_fdt32(map->map_size);
+
+	err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
+	if (err)
+		return EFI_LOAD_ERROR;
+
+	fdt_val32 = cpu_to_fdt32(map->desc_size);
+
+	err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
+	if (err)
+		return EFI_LOAD_ERROR;
+
+	fdt_val32 = cpu_to_fdt32(map->desc_ver);
+
+	err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
+	if (err)
+		return EFI_LOAD_ERROR;
+
+	return EFI_SUCCESS;
+}
+
+struct exit_boot_struct {
+	struct efi_boot_memmap	*boot_memmap;
+	efi_memory_desc_t	*runtime_map;
+	int			runtime_entry_count;
+	void			*new_fdt_addr;
+};
+
+static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv)
+{
+	struct exit_boot_struct *p = priv;
+
+	p->boot_memmap = map;
+
+	/*
+	 * Update the memory map with virtual addresses. The function will also
+	 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
+	 * entries so that we can pass it straight to SetVirtualAddressMap()
+	 */
+	efi_get_virtmap(map->map, map->map_size, map->desc_size,
+			p->runtime_map, &p->runtime_entry_count);
+
+	return update_fdt_memmap(p->new_fdt_addr, map);
+}
+
+#ifndef MAX_FDT_SIZE
+# define MAX_FDT_SIZE SZ_2M
+#endif
+
+/*
+ * Allocate memory for a new FDT, then add EFI and commandline related fields
+ * to the FDT.  This routine increases the FDT allocation size until the
+ * allocated memory is large enough.  EFI allocations are in EFI_PAGE_SIZE
+ * granules, which are fixed at 4K bytes, so in most cases the first allocation
+ * should succeed.  EFI boot services are exited at the end of this function.
+ * There must be no allocations between the get_memory_map() call and the
+ * exit_boot_services() call, so the exiting of boot services is very tightly
+ * tied to the creation of the FDT with the final memory map in it.
+ */
+static
+efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
+					    efi_loaded_image_t *image,
+					    unsigned long *new_fdt_addr,
+					    char *cmdline_ptr)
+{
+	unsigned long desc_size;
+	u32 desc_ver;
+	efi_status_t status;
+	struct exit_boot_struct priv;
+	unsigned long fdt_addr = 0;
+	unsigned long fdt_size = 0;
+
+	if (!efi_novamap) {
+		status = efi_alloc_virtmap(&priv.runtime_map, &desc_size,
+					   &desc_ver);
+		if (status != EFI_SUCCESS) {
+			efi_err("Unable to retrieve UEFI memory map.\n");
+			return status;
+		}
+	}
+
+	/*
+	 * Unauthenticated device tree data is a security hazard, so ignore
+	 * 'dtb=' unless UEFI Secure Boot is disabled.  We assume that secure
+	 * boot is enabled if we can't determine its state.
+	 */
+	if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) ||
+	    efi_get_secureboot() != efi_secureboot_mode_disabled) {
+		if (strstr(cmdline_ptr, "dtb="))
+			efi_err("Ignoring DTB from command line.\n");
+	} else {
+		status = efi_load_dtb(image, &fdt_addr, &fdt_size);
+
+		if (status != EFI_SUCCESS && status != EFI_NOT_READY) {
+			efi_err("Failed to load device tree!\n");
+			goto fail;
+		}
+	}
+
+	if (fdt_addr) {
+		efi_info("Using DTB from command line\n");
+	} else {
+		/* Look for a device tree configuration table entry. */
+		fdt_addr = (uintptr_t)get_fdt(&fdt_size);
+		if (fdt_addr)
+			efi_info("Using DTB from configuration table\n");
+	}
+
+	if (!fdt_addr)
+		efi_info("Generating empty DTB\n");
+
+	efi_info("Exiting boot services...\n");
+
+	status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX);
+	if (status != EFI_SUCCESS) {
+		efi_err("Unable to allocate memory for new device tree.\n");
+		goto fail;
+	}
+
+	status = update_fdt((void *)fdt_addr, fdt_size,
+			    (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr);
+
+	if (status != EFI_SUCCESS) {
+		efi_err("Unable to construct new device tree.\n");
+		goto fail_free_new_fdt;
+	}
+
+	priv.new_fdt_addr = (void *)*new_fdt_addr;
+
+	status = efi_exit_boot_services(handle, &priv, exit_boot_func);
+
+	if (status == EFI_SUCCESS) {
+		efi_set_virtual_address_map_t *svam;
+
+		if (efi_novamap)
+			return EFI_SUCCESS;
+
+		/* Install the new virtual address map */
+		svam = efi_system_table->runtime->set_virtual_address_map;
+		status = svam(priv.runtime_entry_count * desc_size, desc_size,
+			      desc_ver, priv.runtime_map);
+
+		/*
+		 * We are beyond the point of no return here, so if the call to
+		 * SetVirtualAddressMap() failed, we need to signal that to the
+		 * incoming kernel but proceed normally otherwise.
+		 */
+		if (status != EFI_SUCCESS) {
+			efi_memory_desc_t *p;
+			int l;
+
+			/*
+			 * Set the virtual address field of all
+			 * EFI_MEMORY_RUNTIME entries to U64_MAX. This will
+			 * signal the incoming kernel that no virtual
+			 * translation has been installed.
+			 */
+			for (l = 0; l < priv.boot_memmap->map_size;
+			     l += priv.boot_memmap->desc_size) {
+				p = (void *)priv.boot_memmap->map + l;
+
+				if (p->attribute & EFI_MEMORY_RUNTIME)
+					p->virt_addr = U64_MAX;
+			}
+		}
+		return EFI_SUCCESS;
+	}
+
+	efi_err("Exit boot services failed.\n");
+
+fail_free_new_fdt:
+	efi_free(MAX_FDT_SIZE, *new_fdt_addr);
+
+fail:
+	efi_free(fdt_size, fdt_addr);
+
+	efi_bs_call(free_pool, priv.runtime_map);
+
+	return EFI_LOAD_ERROR;
+}
+
+efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image,
+			     unsigned long kernel_addr, char *cmdline_ptr)
+{
+	unsigned long fdt_addr;
+	efi_status_t status;
+
+	status = allocate_new_fdt_and_exit_boot(handle, image, &fdt_addr,
+						cmdline_ptr);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to update FDT and exit boot services\n");
+		return status;
+	}
+
+	if (IS_ENABLED(CONFIG_ARM))
+		efi_handle_post_ebs_state();
+
+	efi_enter_kernel(kernel_addr, fdt_addr, fdt_totalsize((void *)fdt_addr));
+	/* not reached */
+}
+
+void *get_fdt(unsigned long *fdt_size)
+{
+	void *fdt;
+
+	fdt = get_efi_config_table(DEVICE_TREE_GUID);
+
+	if (!fdt)
+		return NULL;
+
+	if (fdt_check_header(fdt) != 0) {
+		efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n");
+		return NULL;
+	}
+	*fdt_size = fdt_totalsize(fdt);
+	return fdt;
+}