@@ -0,0 +1,282 @@
+/*
+ * Load ELF vmlinux file for the kexec_file_load syscall.
+ *
+ * Copyright (C) 2004 Adam Litke (agl@us.ibm.com)
+ * Copyright (C) 2004 IBM Corp.
+ * Copyright (C) 2005 R Sharada (sharada@in.ibm.com)
+ * Copyright (C) 2006 Mohan Kumar M (mohan@in.ibm.com)
+ * Copyright (C) 2016 IBM Corporation
+ *
+ * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c.
+ * Heavily modified for the kernel by
+ * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation (version 2 of the License).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) "kexec_elf: " fmt
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/elf.h>
+#include <linux/kexec.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
+#include <asm/elf_util.h>
+
+extern size_t kexec_purgatory_size;
+
+#define PURGATORY_STACK_SIZE (16 * 1024)
+
+/**
+ * build_elf_exec_info - read ELF executable and check that we can use it
+ */
+static int build_elf_exec_info(const char *buf, size_t len, struct elfhdr *ehdr,
+ struct elf_info *elf_info)
+{
+ int i;
+ int ret;
+
+ ret = elf_read_from_buffer(buf, len, ehdr, elf_info);
+ if (ret)
+ return ret;
+
+ /* Big endian vmlinux has type ET_DYN. */
+ if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) {
+ pr_err("Not an ELF executable.\n");
+ goto error;
+ } else if (!elf_info->proghdrs) {
+ pr_err("No ELF program header.\n");
+ goto error;
+ }
+
+ for (i = 0; i < ehdr->e_phnum; i++) {
+ /*
+ * Kexec does not support loading interpreters.
+ * In addition this check keeps us from attempting
+ * to kexec ordinay executables.
+ */
+ if (elf_info->proghdrs[i].p_type == PT_INTERP) {
+ pr_err("Requires an ELF interpreter.\n");
+ goto error;
+ }
+ }
+
+ return 0;
+error:
+ elf_free_info(elf_info);
+ return -ENOEXEC;
+}
+
+static int elf64_probe(const char *buf, unsigned long len)
+{
+ struct elfhdr ehdr;
+ struct elf_info elf_info;
+ int ret;
+
+ ret = build_elf_exec_info(buf, len, &ehdr, &elf_info);
+ if (ret)
+ return ret;
+
+ elf_free_info(&elf_info);
+
+ return elf_check_arch(&ehdr) ? 0 : -ENOEXEC;
+}
+
+/**
+ * elf_exec_load - load ELF executable image
+ * @lowest_load_addr: On return, will be the address where the first PT_LOAD
+ * section will be loaded in memory.
+ *
+ * Return:
+ * 0 on success, negative value on failure.
+ */
+static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr,
+ struct elf_info *elf_info,
+ unsigned long *lowest_load_addr)
+{
+ unsigned long base = 0, lowest_addr = UINT_MAX;
+ int ret;
+ size_t i;
+ struct kexec_buf kbuf = { .image = image, .buf_max = ppc64_rma_size,
+ .top_down = false };
+
+ /* Read in the PT_LOAD segments. */
+ for (i = 0; i < ehdr->e_phnum; i++) {
+ unsigned long load_addr;
+ size_t size;
+ const struct elf_phdr *phdr;
+
+ phdr = &elf_info->proghdrs[i];
+ if (phdr->p_type != PT_LOAD)
+ continue;
+
+ size = phdr->p_filesz;
+ if (size > phdr->p_memsz)
+ size = phdr->p_memsz;
+
+ kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset;
+ kbuf.bufsz = size;
+ kbuf.memsz = phdr->p_memsz;
+ kbuf.buf_align = phdr->p_align;
+ kbuf.buf_min = phdr->p_paddr + base;
+ ret = kexec_add_buffer(&kbuf);
+ if (ret)
+ goto out;
+ load_addr = kbuf.mem;
+
+ if (load_addr < lowest_addr)
+ lowest_addr = load_addr;
+ }
+
+ /* Update entry point to reflect new load address. */
+ ehdr->e_entry += base;
+
+ *lowest_load_addr = lowest_addr;
+ ret = 0;
+ out:
+ return ret;
+}
+
+void *elf64_load(struct kimage *image, char *kernel_buf,
+ unsigned long kernel_len, char *initrd,
+ unsigned long initrd_len, char *cmdline,
+ unsigned long cmdline_len)
+{
+ int i, ret;
+ unsigned int fdt_size;
+ unsigned long kernel_load_addr, purgatory_load_addr;
+ unsigned long initrd_load_addr, fdt_load_addr, stack_top;
+ void *fdt;
+ const void *slave_code;
+ struct elfhdr ehdr;
+ struct elf_info elf_info;
+ struct fdt_reserve_entry *rsvmap;
+ struct kexec_buf kbuf = { .image = image, .buf_min = 0,
+ .buf_max = ppc64_rma_size };
+
+ ret = build_elf_exec_info(kernel_buf, kernel_len, &ehdr, &elf_info);
+ if (ret)
+ goto out;
+
+ ret = elf_exec_load(image, &ehdr, &elf_info, &kernel_load_addr);
+ if (ret)
+ goto out;
+
+ pr_debug("Loaded the kernel at 0x%lx\n", kernel_load_addr);
+
+ ret = kexec_load_purgatory(image, 0, ppc64_rma_size, true,
+ &purgatory_load_addr);
+ if (ret) {
+ pr_err("Loading purgatory failed.\n");
+ goto out;
+ }
+
+ pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
+
+ if (initrd != NULL) {
+ kbuf.buffer = initrd;
+ kbuf.bufsz = kbuf.memsz = initrd_len;
+ kbuf.buf_align = PAGE_SIZE;
+ kbuf.top_down = false;
+ ret = kexec_add_buffer(&kbuf);
+ if (ret)
+ goto out;
+ initrd_load_addr = kbuf.mem;
+
+ pr_debug("Loaded initrd at 0x%lx\n", initrd_load_addr);
+ }
+
+ fdt_size = fdt_totalsize(initial_boot_params) * 2;
+ fdt = kmalloc(fdt_size, GFP_KERNEL);
+ if (!fdt) {
+ pr_err("Not enough memory for the device tree.\n");
+ ret = -ENOMEM;
+ goto out;
+ }
+ ret = fdt_open_into(initial_boot_params, fdt, fdt_size);
+ if (ret < 0) {
+ pr_err("Error setting up the new device tree.\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = setup_new_fdt(fdt, initrd_load_addr, initrd_len, cmdline);
+ if (ret)
+ goto out;
+
+ /*
+ * Documentation/devicetree/booting-without-of.txt says we need to
+ * add a reservation entry for the device tree block, but
+ * early_init_fdt_reserve_self reserves the memory even if there's no
+ * such entry. We'll add a reservation entry anyway, to be safe and
+ * compliant.
+ *
+ * Use dummy values, we will correct them in a moment.
+ */
+ ret = fdt_add_mem_rsv(fdt, 1, 1);
+ if (ret) {
+ pr_err("Error reserving device tree memory: %s\n",
+ fdt_strerror(ret));
+ ret = -EINVAL;
+ goto out;
+ }
+ fdt_pack(fdt);
+
+ kbuf.buffer = fdt;
+ kbuf.bufsz = kbuf.memsz = fdt_size;
+ kbuf.buf_align = PAGE_SIZE;
+ kbuf.top_down = true;
+ ret = kexec_add_buffer(&kbuf);
+ if (ret)
+ goto out;
+ fdt_load_addr = kbuf.mem;
+
+ /*
+ * Fix fdt reservation, now that we now where it will be loaded
+ * and how big it is.
+ */
+ rsvmap = fdt + fdt_off_mem_rsvmap(fdt);
+ i = fdt_num_mem_rsv(fdt) - 1;
+ rsvmap[i].address = cpu_to_fdt64(fdt_load_addr);
+ rsvmap[i].size = cpu_to_fdt64(fdt_totalsize(fdt));
+
+ pr_debug("Loaded device tree at 0x%lx\n", fdt_load_addr);
+
+ kbuf.memsz = PURGATORY_STACK_SIZE;
+ kbuf.buf_align = PAGE_SIZE;
+ kbuf.top_down = true;
+ ret = kexec_locate_mem_hole(&kbuf);
+ if (ret) {
+ pr_err("Couldn't find free memory for the purgatory stack.\n");
+ ret = -ENOMEM;
+ goto out;
+ }
+ stack_top = kbuf.mem + PURGATORY_STACK_SIZE - 1;
+ pr_debug("Purgatory stack is at 0x%lx\n", stack_top);
+
+ slave_code = elf_info.buffer + elf_info.proghdrs[0].p_offset;
+ ret = setup_purgatory(image, slave_code, fdt, kernel_load_addr,
+ fdt_load_addr, stack_top,
+ find_debug_console(fdt));
+ if (ret)
+ pr_err("Error setting up the purgatory.\n");
+
+out:
+ elf_free_info(&elf_info);
+
+ /* Make kimage_file_post_load_cleanup free the fdt buffer for us. */
+ return ret ? ERR_PTR(ret) : fdt;
+}
+
+struct kexec_file_ops kexec_elf64_ops = {
+ .probe = elf64_probe,
+ .load = elf64_load,
+};