/*
* 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,
};
