1 files changed, 124 insertions, 0 deletions
diff --git a/drivers/firmware/efi/fake_mem.c b/drivers/firmware/efi/fake_mem.c
new file mode 100644
index 000000000..6e0f34a38
--- /dev/null
+++ b/drivers/firmware/efi/fake_mem.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fake_mem.c
+ *
+ * Copyright (C) 2015 FUJITSU LIMITED
+ * Author: Taku Izumi <izumi.taku@jp.fujitsu.com>
+ *
+ * This code introduces new boot option named "efi_fake_mem"
+ * By specifying this parameter, you can add arbitrary attribute to
+ * specific memory range by updating original (firmware provided) EFI
+ * memmap.
+ */
+
+#include <linux/kernel.h>
+#include <linux/efi.h>
+#include <linux/init.h>
+#include <linux/memblock.h>
+#include <linux/types.h>
+#include <linux/sort.h>
+#include "fake_mem.h"
+
+struct efi_mem_range efi_fake_mems[EFI_MAX_FAKEMEM];
+int nr_fake_mem;
+
+static int __init cmp_fake_mem(const void *x1, const void *x2)
+{
+	const struct efi_mem_range *m1 = x1;
+	const struct efi_mem_range *m2 = x2;
+
+	if (m1->range.start < m2->range.start)
+		return -1;
+	if (m1->range.start > m2->range.start)
+		return 1;
+	return 0;
+}
+
+static void __init efi_fake_range(struct efi_mem_range *efi_range)
+{
+	struct efi_memory_map_data data = { 0 };
+	int new_nr_map = efi.memmap.nr_map;
+	efi_memory_desc_t *md;
+	void *new_memmap;
+
+	/* count up the number of EFI memory descriptor */
+	for_each_efi_memory_desc(md)
+		new_nr_map += efi_memmap_split_count(md, &efi_range->range);
+
+	/* allocate memory for new EFI memmap */
+	if (efi_memmap_alloc(new_nr_map, &data) != 0)
+		return;
+
+	/* create new EFI memmap */
+	new_memmap = early_memremap(data.phys_map, data.size);
+	if (!new_memmap) {
+		__efi_memmap_free(data.phys_map, data.size, data.flags);
+		return;
+	}
+
+	efi_memmap_insert(&efi.memmap, new_memmap, efi_range);
+
+	/* swap into new EFI memmap */
+	early_memunmap(new_memmap, data.size);
+
+	efi_memmap_install(&data);
+}
+
+void __init efi_fake_memmap(void)
+{
+	int i;
+
+	if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem)
+		return;
+
+	for (i = 0; i < nr_fake_mem; i++)
+		efi_fake_range(&efi_fake_mems[i]);
+
+	/* print new EFI memmap */
+	efi_print_memmap();
+}
+
+static int __init setup_fake_mem(char *p)
+{
+	u64 start = 0, mem_size = 0, attribute = 0;
+	int i;
+
+	if (!p)
+		return -EINVAL;
+
+	while (*p != '\0') {
+		mem_size = memparse(p, &p);
+		if (*p == '@')
+			start = memparse(p+1, &p);
+		else
+			break;
+
+		if (*p == ':')
+			attribute = simple_strtoull(p+1, &p, 0);
+		else
+			break;
+
+		if (nr_fake_mem >= EFI_MAX_FAKEMEM)
+			break;
+
+		efi_fake_mems[nr_fake_mem].range.start = start;
+		efi_fake_mems[nr_fake_mem].range.end = start + mem_size - 1;
+		efi_fake_mems[nr_fake_mem].attribute = attribute;
+		nr_fake_mem++;
+
+		if (*p == ',')
+			p++;
+	}
+
+	sort(efi_fake_mems, nr_fake_mem, sizeof(struct efi_mem_range),
+	     cmp_fake_mem, NULL);
+
+	for (i = 0; i < nr_fake_mem; i++)
+		pr_info("efi_fake_mem: add attr=0x%016llx to [mem 0x%016llx-0x%016llx]",
+			efi_fake_mems[i].attribute, efi_fake_mems[i].range.start,
+			efi_fake_mems[i].range.end);
+
+	return *p == '\0' ? 0 : -EINVAL;
+}
+
+early_param("efi_fake_mem", setup_fake_mem);