--- /dev/null
+/*
+ * Kexec bzImage loader
+ *
+ * Copyright (C) 2014 Red Hat Inc.
+ * Authors:
+ * Vivek Goyal <vgoyal@redhat.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#define pr_fmt(fmt) "kexec-bzImage64: " fmt
+
+#include <linux/string.h>
+#include <linux/printk.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/kexec.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+
+#include <asm/bootparam.h>
+#include <asm/setup.h>
+
+/*
+ * Defines lowest physical address for various segments. Not sure where
+ * exactly these limits came from. Current bzimage64 loader in kexec-tools
+ * uses these so I am retaining it. It can be changed over time as we gain
+ * more insight.
+ */
+#define MIN_PURGATORY_ADDR 0x3000
+#define MIN_BOOTPARAM_ADDR 0x3000
+#define MIN_KERNEL_LOAD_ADDR 0x100000
+#define MIN_INITRD_LOAD_ADDR 0x1000000
+
+/*
+ * This is a place holder for all boot loader specific data structure which
+ * gets allocated in one call but gets freed much later during cleanup
+ * time. Right now there is only one field but it can grow as need be.
+ */
+struct bzimage64_data {
+ /*
+ * Temporary buffer to hold bootparams buffer. This should be
+ * freed once the bootparam segment has been loaded.
+ */
+ void *bootparams_buf;
+};
+
+static int setup_initrd(struct boot_params *params,
+ unsigned long initrd_load_addr, unsigned long initrd_len)
+{
+ params->hdr.ramdisk_image = initrd_load_addr & 0xffffffffUL;
+ params->hdr.ramdisk_size = initrd_len & 0xffffffffUL;
+
+ params->ext_ramdisk_image = initrd_load_addr >> 32;
+ params->ext_ramdisk_size = initrd_len >> 32;
+
+ return 0;
+}
+
+static int setup_cmdline(struct boot_params *params,
+ unsigned long bootparams_load_addr,
+ unsigned long cmdline_offset, char *cmdline,
+ unsigned long cmdline_len)
+{
+ char *cmdline_ptr = ((char *)params) + cmdline_offset;
+ unsigned long cmdline_ptr_phys;
+ uint32_t cmdline_low_32, cmdline_ext_32;
+
+ memcpy(cmdline_ptr, cmdline, cmdline_len);
+ cmdline_ptr[cmdline_len - 1] = '\0';
+
+ cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
+ cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
+ cmdline_ext_32 = cmdline_ptr_phys >> 32;
+
+ params->hdr.cmd_line_ptr = cmdline_low_32;
+ if (cmdline_ext_32)
+ params->ext_cmd_line_ptr = cmdline_ext_32;
+
+ return 0;
+}
+
+static int setup_memory_map_entries(struct boot_params *params)
+{
+ unsigned int nr_e820_entries;
+
+ nr_e820_entries = e820_saved.nr_map;
+
+ /* TODO: Pass entries more than E820MAX in bootparams setup data */
+ if (nr_e820_entries > E820MAX)
+ nr_e820_entries = E820MAX;
+
+ params->e820_entries = nr_e820_entries;
+ memcpy(¶ms->e820_map, &e820_saved.map,
+ nr_e820_entries * sizeof(struct e820entry));
+
+ return 0;
+}
+
+static int setup_boot_parameters(struct boot_params *params)
+{
+ unsigned int nr_e820_entries;
+ unsigned long long mem_k, start, end;
+ int i;
+
+ /* Get subarch from existing bootparams */
+ params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
+
+ /* Copying screen_info will do? */
+ memcpy(¶ms->screen_info, &boot_params.screen_info,
+ sizeof(struct screen_info));
+
+ /* Fill in memsize later */
+ params->screen_info.ext_mem_k = 0;
+ params->alt_mem_k = 0;
+
+ /* Default APM info */
+ memset(¶ms->apm_bios_info, 0, sizeof(params->apm_bios_info));
+
+ /* Default drive info */
+ memset(¶ms->hd0_info, 0, sizeof(params->hd0_info));
+ memset(¶ms->hd1_info, 0, sizeof(params->hd1_info));
+
+ /* Default sysdesc table */
+ params->sys_desc_table.length = 0;
+
+ setup_memory_map_entries(params);
+ nr_e820_entries = params->e820_entries;
+
+ for (i = 0; i < nr_e820_entries; i++) {
+ if (params->e820_map[i].type != E820_RAM)
+ continue;
+ start = params->e820_map[i].addr;
+ end = params->e820_map[i].addr + params->e820_map[i].size - 1;
+
+ if ((start <= 0x100000) && end > 0x100000) {
+ mem_k = (end >> 10) - (0x100000 >> 10);
+ params->screen_info.ext_mem_k = mem_k;
+ params->alt_mem_k = mem_k;
+ if (mem_k > 0xfc00)
+ params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
+ if (mem_k > 0xffffffff)
+ params->alt_mem_k = 0xffffffff;
+ }
+ }
+
+ /* Setup EDD info */
+ memcpy(params->eddbuf, boot_params.eddbuf,
+ EDDMAXNR * sizeof(struct edd_info));
+ params->eddbuf_entries = boot_params.eddbuf_entries;
+
+ memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
+ EDD_MBR_SIG_MAX * sizeof(unsigned int));
+
+ return 0;
+}
+
+int bzImage64_probe(const char *buf, unsigned long len)
+{
+ int ret = -ENOEXEC;
+ struct setup_header *header;
+
+ /* kernel should be atleast two sectors long */
+ if (len < 2 * 512) {
+ pr_err("File is too short to be a bzImage\n");
+ return ret;
+ }
+
+ header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
+ if (memcmp((char *)&header->header, "HdrS", 4) != 0) {
+ pr_err("Not a bzImage\n");
+ return ret;
+ }
+
+ if (header->boot_flag != 0xAA55) {
+ pr_err("No x86 boot sector present\n");
+ return ret;
+ }
+
+ if (header->version < 0x020C) {
+ pr_err("Must be at least protocol version 2.12\n");
+ return ret;
+ }
+
+ if (!(header->loadflags & LOADED_HIGH)) {
+ pr_err("zImage not a bzImage\n");
+ return ret;
+ }
+
+ if (!(header->xloadflags & XLF_KERNEL_64)) {
+ pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
+ return ret;
+ }
+
+ if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
+ pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
+ return ret;
+ }
+
+ /* I've got a bzImage */
+ pr_debug("It's a relocatable bzImage64\n");
+ ret = 0;
+
+ return ret;
+}
+
+void *bzImage64_load(struct kimage *image, char *kernel,
+ unsigned long kernel_len, char *initrd,
+ unsigned long initrd_len, char *cmdline,
+ unsigned long cmdline_len)
+{
+
+ struct setup_header *header;
+ int setup_sects, kern16_size, ret = 0;
+ unsigned long setup_header_size, params_cmdline_sz;
+ struct boot_params *params;
+ unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
+ unsigned long purgatory_load_addr;
+ unsigned long kernel_bufsz, kernel_memsz, kernel_align;
+ char *kernel_buf;
+ struct bzimage64_data *ldata;
+ struct kexec_entry64_regs regs64;
+ void *stack;
+ unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
+
+ header = (struct setup_header *)(kernel + setup_hdr_offset);
+ setup_sects = header->setup_sects;
+ if (setup_sects == 0)
+ setup_sects = 4;
+
+ kern16_size = (setup_sects + 1) * 512;
+ if (kernel_len < kern16_size) {
+ pr_err("bzImage truncated\n");
+ return ERR_PTR(-ENOEXEC);
+ }
+
+ if (cmdline_len > header->cmdline_size) {
+ pr_err("Kernel command line too long\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ /*
+ * Load purgatory. For 64bit entry point, purgatory code can be
+ * anywhere.
+ */
+ ret = kexec_load_purgatory(image, MIN_PURGATORY_ADDR, ULONG_MAX, 1,
+ &purgatory_load_addr);
+ if (ret) {
+ pr_err("Loading purgatory failed\n");
+ return ERR_PTR(ret);
+ }
+
+ pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
+
+ /* Load Bootparams and cmdline */
+ params_cmdline_sz = sizeof(struct boot_params) + cmdline_len;
+ params = kzalloc(params_cmdline_sz, GFP_KERNEL);
+ if (!params)
+ return ERR_PTR(-ENOMEM);
+
+ /* Copy setup header onto bootparams. Documentation/x86/boot.txt */
+ setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
+
+ /* Is there a limit on setup header size? */
+ memcpy(¶ms->hdr, (kernel + setup_hdr_offset), setup_header_size);
+
+ ret = kexec_add_buffer(image, (char *)params, params_cmdline_sz,
+ params_cmdline_sz, 16, MIN_BOOTPARAM_ADDR,
+ ULONG_MAX, 1, &bootparam_load_addr);
+ if (ret)
+ goto out_free_params;
+ pr_debug("Loaded boot_param and command line at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ bootparam_load_addr, params_cmdline_sz, params_cmdline_sz);
+
+ /* Load kernel */
+ kernel_buf = kernel + kern16_size;
+ kernel_bufsz = kernel_len - kern16_size;
+ kernel_memsz = PAGE_ALIGN(header->init_size);
+ kernel_align = header->kernel_alignment;
+
+ ret = kexec_add_buffer(image, kernel_buf,
+ kernel_bufsz, kernel_memsz, kernel_align,
+ MIN_KERNEL_LOAD_ADDR, ULONG_MAX, 1,
+ &kernel_load_addr);
+ if (ret)
+ goto out_free_params;
+
+ pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ kernel_load_addr, kernel_memsz, kernel_memsz);
+
+ /* Load initrd high */
+ if (initrd) {
+ ret = kexec_add_buffer(image, initrd, initrd_len, initrd_len,
+ PAGE_SIZE, MIN_INITRD_LOAD_ADDR,
+ ULONG_MAX, 1, &initrd_load_addr);
+ if (ret)
+ goto out_free_params;
+
+ pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ initrd_load_addr, initrd_len, initrd_len);
+
+ setup_initrd(params, initrd_load_addr, initrd_len);
+ }
+
+ setup_cmdline(params, bootparam_load_addr, sizeof(struct boot_params),
+ cmdline, cmdline_len);
+
+ /* bootloader info. Do we need a separate ID for kexec kernel loader? */
+ params->hdr.type_of_loader = 0x0D << 4;
+ params->hdr.loadflags = 0;
+
+ /* Setup purgatory regs for entry */
+ ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", ®s64,
+ sizeof(regs64), 1);
+ if (ret)
+ goto out_free_params;
+
+ regs64.rbx = 0; /* Bootstrap Processor */
+ regs64.rsi = bootparam_load_addr;
+ regs64.rip = kernel_load_addr + 0x200;
+ stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
+ if (IS_ERR(stack)) {
+ pr_err("Could not find address of symbol stack_end\n");
+ ret = -EINVAL;
+ goto out_free_params;
+ }
+
+ regs64.rsp = (unsigned long)stack;
+ ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", ®s64,
+ sizeof(regs64), 0);
+ if (ret)
+ goto out_free_params;
+
+ setup_boot_parameters(params);
+
+ /* Allocate loader specific data */
+ ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
+ if (!ldata) {
+ ret = -ENOMEM;
+ goto out_free_params;
+ }
+
+ /*
+ * Store pointer to params so that it could be freed after loading
+ * params segment has been loaded and contents have been copied
+ * somewhere else.
+ */
+ ldata->bootparams_buf = params;
+ return ldata;
+
+out_free_params:
+ kfree(params);
+ return ERR_PTR(ret);
+}
+
+/* This cleanup function is called after various segments have been loaded */
+int bzImage64_cleanup(void *loader_data)
+{
+ struct bzimage64_data *ldata = loader_data;
+
+ if (!ldata)
+ return 0;
+
+ kfree(ldata->bootparams_buf);
+ ldata->bootparams_buf = NULL;
+
+ return 0;
+}
+
+struct kexec_file_ops kexec_bzImage64_ops = {
+ .probe = bzImage64_probe,
+ .load = bzImage64_load,
+ .cleanup = bzImage64_cleanup,
+};
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