arm64: kexec: !fixup vp_offset calculation

vp_offset is the virtual address of physical address defined by
phys_offset.

/proc/iomem "Kernel Code" start is the physical address of location from
where kernel code starts. ehdr.e_entry is its corresponding virtual
address. Therefore, right definition of vp_offset should be [ehdr.e_entry -
"kernel Code Start PA" + phys_offset].

Signed-off-by: Pratyush Anand <panand@redhat.com>

kexec/arch/arm64/kexec-elf-arm64.c

@@ -43,13 +43,18 @@ int elf_arm64_load(int argc, char **argv, const char *kernel_buf,
 	struct mem_ehdr ehdr;
 	int result;
 	int i;
+	uint64_t kernel_code_start;
 
 	result = build_elf_exec_info(kernel_buf, kernel_size, &ehdr, 0);
 
 	if (result < 0) {
 		dbgprintf("%s: build_elf_exec_info failed\n", __func__);
 		goto exit;
 	}
+	if (parse_iomem_single("Kernel code\n", &kernel_code_start, NULL)) {
+		dbgprintf("%s: Start of kenrel code could not be found\n", __func__);
+		goto exit;
+	}
 
 	/* Find and process the arm64 image header. */
 
@@ -75,7 +80,8 @@ int elf_arm64_load(int argc, char **argv, const char *kernel_buf,
 		if (arm64_process_image_header(h))
 			continue;
 
-		arm64_mem.vp_offset = ehdr.e_entry - arm64_mem.text_offset;
+		arm64_mem.vp_offset = ehdr.e_entry - kernel_code_start +
+					arm64_mem.phys_offset;
 
 		dbgprintf("%s: e_entry:       %016llx -> %016lx\n", __func__,
 			ehdr.e_entry,