1 files changed, 100 insertions, 0 deletions
diff --git a/drivers/firmware/iscsi_ibft_find.c b/drivers/firmware/iscsi_ibft_find.c
new file mode 100644
index 0000000000..71f51303c2
--- /dev/null
+++ b/drivers/firmware/iscsi_ibft_find.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Copyright 2007-2010 Red Hat, Inc.
+ *  by Peter Jones <pjones@redhat.com>
+ *  Copyright 2007 IBM, Inc.
+ *  by Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
+ *  Copyright 2008
+ *  by Konrad Rzeszutek <ketuzsezr@darnok.org>
+ *
+ * This code finds the iSCSI Boot Format Table.
+ */
+
+#include <linux/memblock.h>
+#include <linux/blkdev.h>
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/efi.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/limits.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/acpi.h>
+#include <linux/iscsi_ibft.h>
+
+#include <asm/mmzone.h>
+
+/*
+ * Physical location of iSCSI Boot Format Table.
+ */
+phys_addr_t ibft_phys_addr;
+EXPORT_SYMBOL_GPL(ibft_phys_addr);
+
+static const struct {
+	char *sign;
+} ibft_signs[] = {
+	{ "iBFT" },
+	{ "BIFT" },	/* Broadcom iSCSI Offload */
+};
+
+#define IBFT_SIGN_LEN 4
+#define VGA_MEM 0xA0000 /* VGA buffer */
+#define VGA_SIZE 0x20000 /* 128kB */
+
+/*
+ * Routine used to find and reserve the iSCSI Boot Format Table
+ */
+void __init reserve_ibft_region(void)
+{
+	unsigned long pos, virt_pos = 0;
+	unsigned int len = 0;
+	void *virt = NULL;
+	int i;
+
+	ibft_phys_addr = 0;
+
+	/* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
+	 * only use ACPI for this
+	 */
+	if (efi_enabled(EFI_BOOT))
+		return;
+
+	for (pos = IBFT_START; pos < IBFT_END; pos += 16) {
+		/* The table can't be inside the VGA BIOS reserved space,
+		 * so skip that area */
+		if (pos == VGA_MEM)
+			pos += VGA_SIZE;
+
+		/* Map page by page */
+		if (offset_in_page(pos) == 0) {
+			if (virt)
+				early_memunmap(virt, PAGE_SIZE);
+			virt = early_memremap_ro(pos, PAGE_SIZE);
+			virt_pos = pos;
+		}
+
+		for (i = 0; i < ARRAY_SIZE(ibft_signs); i++) {
+			if (memcmp(virt + (pos - virt_pos), ibft_signs[i].sign,
+				   IBFT_SIGN_LEN) == 0) {
+				unsigned long *addr =
+				    (unsigned long *)(virt + pos - virt_pos + 4);
+				len = *addr;
+				/* if the length of the table extends past 1M,
+				 * the table cannot be valid. */
+				if (pos + len <= (IBFT_END-1)) {
+					ibft_phys_addr = pos;
+					memblock_reserve(ibft_phys_addr, PAGE_ALIGN(len));
+					pr_info("iBFT found at %pa.\n", &ibft_phys_addr);
+					goto out;
+				}
+			}
+		}
+	}
+
+out:
+	early_memunmap(virt, PAGE_SIZE);
+}