Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 472 insertions, 0 deletions

diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
new file mode 100644
index 0000000000..68278340ce
--- /dev/null
+++ b/drivers/of/kexec.c
@@ -0,0 +1,472 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Arm Limited
+ *
+ * Based on arch/arm64/kernel/machine_kexec_file.c:
+ *  Copyright (C) 2018 Linaro Limited
+ *
+ * And arch/powerpc/kexec/file_load.c:
+ *  Copyright (C) 2016  IBM Corporation
+ */
+
+#include <linux/ima.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/memblock.h>
+#include <linux/libfdt.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#define RNG_SEED_SIZE		128
+
+/*
+ * Additional space needed for the FDT buffer so that we can add initrd,
+ * bootargs, kaslr-seed, rng-seed, useable-memory-range and elfcorehdr.
+ */
+#define FDT_EXTRA_SPACE 0x1000
+
+/**
+ * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
+ *
+ * @fdt:	Flattened device tree for the current kernel.
+ * @start:	Starting address of the reserved memory.
+ * @size:	Size of the reserved memory.
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
+{
+	int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
+
+	for (i = 0; i < num_rsvs; i++) {
+		u64 rsv_start, rsv_size;
+
+		ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
+		if (ret) {
+			pr_err("Malformed device tree.\n");
+			return -EINVAL;
+		}
+
+		if (rsv_start == start && rsv_size == size) {
+			ret = fdt_del_mem_rsv(fdt, i);
+			if (ret) {
+				pr_err("Error deleting device tree reservation.\n");
+				return -EINVAL;
+			}
+
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+/**
+ * get_addr_size_cells - Get address and size of root node
+ *
+ * @addr_cells: Return address of the root node
+ * @size_cells: Return size of the root node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+static int get_addr_size_cells(int *addr_cells, int *size_cells)
+{
+	struct device_node *root;
+
+	root = of_find_node_by_path("/");
+	if (!root)
+		return -EINVAL;
+
+	*addr_cells = of_n_addr_cells(root);
+	*size_cells = of_n_size_cells(root);
+
+	of_node_put(root);
+
+	return 0;
+}
+
+/**
+ * do_get_kexec_buffer - Get address and size of device tree property
+ *
+ * @prop: Device tree property
+ * @len: Size of @prop
+ * @addr: Return address of the node
+ * @size: Return size of the node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
+			       size_t *size)
+{
+	int ret, addr_cells, size_cells;
+
+	ret = get_addr_size_cells(&addr_cells, &size_cells);
+	if (ret)
+		return ret;
+
+	if (len < 4 * (addr_cells + size_cells))
+		return -ENOENT;
+
+	*addr = of_read_number(prop, addr_cells);
+	*size = of_read_number(prop + 4 * addr_cells, size_cells);
+
+	return 0;
+}
+
+#ifdef CONFIG_HAVE_IMA_KEXEC
+/**
+ * ima_get_kexec_buffer - get IMA buffer from the previous kernel
+ * @addr:	On successful return, set to point to the buffer contents.
+ * @size:	On successful return, set to the buffer size.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int __init ima_get_kexec_buffer(void **addr, size_t *size)
+{
+	int ret, len;
+	unsigned long tmp_addr;
+	unsigned long start_pfn, end_pfn;
+	size_t tmp_size;
+	const void *prop;
+
+	prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
+	if (!prop)
+		return -ENOENT;
+
+	ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
+	if (ret)
+		return ret;
+
+	/* Do some sanity on the returned size for the ima-kexec buffer */
+	if (!tmp_size)
+		return -ENOENT;
+
+	/*
+	 * Calculate the PFNs for the buffer and ensure
+	 * they are with in addressable memory.
+	 */
+	start_pfn = PHYS_PFN(tmp_addr);
+	end_pfn = PHYS_PFN(tmp_addr + tmp_size - 1);
+	if (!page_is_ram(start_pfn) || !page_is_ram(end_pfn)) {
+		pr_warn("IMA buffer at 0x%lx, size = 0x%zx beyond memory\n",
+			tmp_addr, tmp_size);
+		return -EINVAL;
+	}
+
+	*addr = __va(tmp_addr);
+	*size = tmp_size;
+
+	return 0;
+}
+
+/**
+ * ima_free_kexec_buffer - free memory used by the IMA buffer
+ */
+int __init ima_free_kexec_buffer(void)
+{
+	int ret;
+	unsigned long addr;
+	size_t size;
+	struct property *prop;
+
+	prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
+	if (!prop)
+		return -ENOENT;
+
+	ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
+	if (ret)
+		return ret;
+
+	ret = of_remove_property(of_chosen, prop);
+	if (ret)
+		return ret;
+
+	memblock_free_late(addr, size);
+	return 0;
+}
+#endif
+
+/**
+ * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
+ *
+ * @fdt: Flattened Device Tree to update
+ * @chosen_node: Offset to the chosen node in the device tree
+ *
+ * The IMA measurement buffer is of no use to a subsequent kernel, so we always
+ * remove it from the device tree.
+ */
+static void remove_ima_buffer(void *fdt, int chosen_node)
+{
+	int ret, len;
+	unsigned long addr;
+	size_t size;
+	const void *prop;
+
+	if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
+		return;
+
+	prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
+	if (!prop)
+		return;
+
+	ret = do_get_kexec_buffer(prop, len, &addr, &size);
+	fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
+	if (ret)
+		return;
+
+	ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
+	if (!ret)
+		pr_debug("Removed old IMA buffer reservation.\n");
+}
+
+#ifdef CONFIG_IMA_KEXEC
+/**
+ * setup_ima_buffer - add IMA buffer information to the fdt
+ * @image:		kexec image being loaded.
+ * @fdt:		Flattened device tree for the next kernel.
+ * @chosen_node:	Offset to the chosen node.
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+static int setup_ima_buffer(const struct kimage *image, void *fdt,
+			    int chosen_node)
+{
+	int ret;
+
+	if (!image->ima_buffer_size)
+		return 0;
+
+	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
+				       "linux,ima-kexec-buffer",
+				       image->ima_buffer_addr,
+				       image->ima_buffer_size);
+	if (ret < 0)
+		return -EINVAL;
+
+	ret = fdt_add_mem_rsv(fdt, image->ima_buffer_addr,
+			      image->ima_buffer_size);
+	if (ret)
+		return -EINVAL;
+
+	pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
+		 image->ima_buffer_addr, image->ima_buffer_size);
+
+	return 0;
+}
+#else /* CONFIG_IMA_KEXEC */
+static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
+				   int chosen_node)
+{
+	return 0;
+}
+#endif /* CONFIG_IMA_KEXEC */
+
+/*
+ * of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree
+ *
+ * @image:		kexec image being loaded.
+ * @initrd_load_addr:	Address where the next initrd will be loaded.
+ * @initrd_len:		Size of the next initrd, or 0 if there will be none.
+ * @cmdline:		Command line for the next kernel, or NULL if there will
+ *			be none.
+ * @extra_fdt_size:	Additional size for the new FDT buffer.
+ *
+ * Return: fdt on success, or NULL errno on error.
+ */
+void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
+				   unsigned long initrd_load_addr,
+				   unsigned long initrd_len,
+				   const char *cmdline, size_t extra_fdt_size)
+{
+	void *fdt;
+	int ret, chosen_node, len;
+	const void *prop;
+	size_t fdt_size;
+
+	fdt_size = fdt_totalsize(initial_boot_params) +
+		   (cmdline ? strlen(cmdline) : 0) +
+		   FDT_EXTRA_SPACE +
+		   extra_fdt_size;
+	fdt = kvmalloc(fdt_size, GFP_KERNEL);
+	if (!fdt)
+		return NULL;
+
+	ret = fdt_open_into(initial_boot_params, fdt, fdt_size);
+	if (ret < 0) {
+		pr_err("Error %d setting up the new device tree.\n", ret);
+		goto out;
+	}
+
+	/* Remove memory reservation for the current device tree. */
+	ret = fdt_find_and_del_mem_rsv(fdt, __pa(initial_boot_params),
+				       fdt_totalsize(initial_boot_params));
+	if (ret == -EINVAL) {
+		pr_err("Error removing memory reservation.\n");
+		goto out;
+	}
+
+	chosen_node = fdt_path_offset(fdt, "/chosen");
+	if (chosen_node == -FDT_ERR_NOTFOUND)
+		chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
+					      "chosen");
+	if (chosen_node < 0) {
+		ret = chosen_node;
+		goto out;
+	}
+
+	ret = fdt_delprop(fdt, chosen_node, "linux,elfcorehdr");
+	if (ret && ret != -FDT_ERR_NOTFOUND)
+		goto out;
+	ret = fdt_delprop(fdt, chosen_node, "linux,usable-memory-range");
+	if (ret && ret != -FDT_ERR_NOTFOUND)
+		goto out;
+
+	/* Did we boot using an initrd? */
+	prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", &len);
+	if (prop) {
+		u64 tmp_start, tmp_end, tmp_size;
+
+		tmp_start = of_read_number(prop, len / 4);
+
+		prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", &len);
+		if (!prop) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		tmp_end = of_read_number(prop, len / 4);
+
+		/*
+		 * kexec reserves exact initrd size, while firmware may
+		 * reserve a multiple of PAGE_SIZE, so check for both.
+		 */
+		tmp_size = tmp_end - tmp_start;
+		ret = fdt_find_and_del_mem_rsv(fdt, tmp_start, tmp_size);
+		if (ret == -ENOENT)
+			ret = fdt_find_and_del_mem_rsv(fdt, tmp_start,
+						       round_up(tmp_size, PAGE_SIZE));
+		if (ret == -EINVAL)
+			goto out;
+	}
+
+	/* add initrd-* */
+	if (initrd_load_addr) {
+		ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-start",
+				      initrd_load_addr);
+		if (ret)
+			goto out;
+
+		ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
+				      initrd_load_addr + initrd_len);
+		if (ret)
+			goto out;
+
+		ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
+		if (ret)
+			goto out;
+
+	} else {
+		ret = fdt_delprop(fdt, chosen_node, "linux,initrd-start");
+		if (ret && (ret != -FDT_ERR_NOTFOUND))
+			goto out;
+
+		ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
+		if (ret && (ret != -FDT_ERR_NOTFOUND))
+			goto out;
+	}
+
+	if (image->type == KEXEC_TYPE_CRASH) {
+		/* add linux,elfcorehdr */
+		ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
+				"linux,elfcorehdr", image->elf_load_addr,
+				image->elf_headers_sz);
+		if (ret)
+			goto out;
+
+		/*
+		 * Avoid elfcorehdr from being stomped on in kdump kernel by
+		 * setting up memory reserve map.
+		 */
+		ret = fdt_add_mem_rsv(fdt, image->elf_load_addr,
+				      image->elf_headers_sz);
+		if (ret)
+			goto out;
+
+		/* add linux,usable-memory-range */
+		ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
+				"linux,usable-memory-range", crashk_res.start,
+				crashk_res.end - crashk_res.start + 1);
+		if (ret)
+			goto out;
+
+		if (crashk_low_res.end) {
+			ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
+					"linux,usable-memory-range",
+					crashk_low_res.start,
+					crashk_low_res.end - crashk_low_res.start + 1);
+			if (ret)
+				goto out;
+		}
+	}
+
+	/* add bootargs */
+	if (cmdline) {
+		ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
+		if (ret)
+			goto out;
+	} else {
+		ret = fdt_delprop(fdt, chosen_node, "bootargs");
+		if (ret && (ret != -FDT_ERR_NOTFOUND))
+			goto out;
+	}
+
+	/* add kaslr-seed */
+	ret = fdt_delprop(fdt, chosen_node, "kaslr-seed");
+	if (ret == -FDT_ERR_NOTFOUND)
+		ret = 0;
+	else if (ret)
+		goto out;
+
+	if (rng_is_initialized()) {
+		u64 seed = get_random_u64();
+
+		ret = fdt_setprop_u64(fdt, chosen_node, "kaslr-seed", seed);
+		if (ret)
+			goto out;
+	} else {
+		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
+			  "kaslr-seed");
+	}
+
+	/* add rng-seed */
+	if (rng_is_initialized()) {
+		void *rng_seed;
+
+		ret = fdt_setprop_placeholder(fdt, chosen_node, "rng-seed",
+				RNG_SEED_SIZE, &rng_seed);
+		if (ret)
+			goto out;
+		get_random_bytes(rng_seed, RNG_SEED_SIZE);
+	} else {
+		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
+			  "rng-seed");
+	}
+
+	ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
+	if (ret)
+		goto out;
+
+	remove_ima_buffer(fdt, chosen_node);
+	ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
+
+out:
+	if (ret) {
+		kvfree(fdt);
+		fdt = NULL;
+	}
+
+	return fdt;
+}