blob: 9050d7ba01910388bee79b53d80153974f8033ff [file] [log] [blame]
#include <console/console.h>
#include <part/fallback_boot.h>
#include <boot/elf.h>
#include <boot/elf_boot.h>
#include <boot/linuxbios_tables.h>
#include <ip_checksum.h>
#include <stream/read_bytes.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
/* Maximum physical address we can use for the linuxBIOS bounce buffer.
*/
#ifndef MAX_ADDR
#define MAX_ADDR -1UL
#endif
extern unsigned char _ram_seg;
extern unsigned char _eram_seg;
struct segment {
struct segment *next;
struct segment *prev;
struct segment *phdr_next;
struct segment *phdr_prev;
unsigned long s_addr;
unsigned long s_memsz;
unsigned long s_offset;
unsigned long s_filesz;
};
struct verify_callback {
struct verify_callback *next;
int (*callback)(struct verify_callback *vcb,
Elf_ehdr *ehdr, Elf_phdr *phdr, struct segment *head);
unsigned long desc_offset;
unsigned long desc_addr;
};
struct ip_checksum_vcb {
struct verify_callback data;
unsigned short ip_checksum;
};
int verify_ip_checksum(
struct verify_callback *vcb,
Elf_ehdr *ehdr, Elf_phdr *phdr, struct segment *head)
{
struct ip_checksum_vcb *cb;
struct segment *ptr;
unsigned long bytes;
unsigned long checksum;
unsigned char buff[2], *n_desc;
cb = (struct ip_checksum_vcb *)vcb;
/* zero the checksum so it's value won't
* get in the way of verifying the checksum.
*/
n_desc = 0;
if (vcb->desc_addr) {
n_desc = (unsigned char *)(vcb->desc_addr);
memcpy(buff, n_desc, 2);
memset(n_desc, 0, 2);
}
bytes = 0;
checksum = compute_ip_checksum(ehdr, sizeof(*ehdr));
bytes += sizeof(*ehdr);
checksum = add_ip_checksums(bytes, checksum,
compute_ip_checksum(phdr, ehdr->e_phnum*sizeof(*phdr)));
bytes += ehdr->e_phnum*sizeof(*phdr);
for(ptr = head->phdr_next; ptr != head; ptr = ptr->phdr_next) {
checksum = add_ip_checksums(bytes, checksum,
compute_ip_checksum((void *)ptr->s_addr, ptr->s_memsz));
bytes += ptr->s_memsz;
}
if (n_desc != 0) {
memcpy(n_desc, buff, 2);
}
if (checksum != cb->ip_checksum) {
printk_err("Image checksum: %04x != computed checksum: %04x\n",
cb->ip_checksum, checksum);
}
return checksum == cb->ip_checksum;
}
/* The problem:
* Static executables all want to share the same addresses
* in memory because only a few addresses are reliably present on
* a machine, and implementing general relocation is hard.
*
* The solution:
* - Allocate a buffer twice the size of the linuxBIOS image.
* - Anything that would overwrite linuxBIOS copy into the lower half of
* the buffer.
* - After loading an ELF image copy linuxBIOS to the upper half of the
* buffer.
* - Then jump to the loaded image.
*
* Benefits:
* - Nearly arbitrary standalone executables can be loaded.
* - LinuxBIOS is preserved, so it can be returned to.
* - The implementation is still relatively simple,
* and much simpler then the general case implemented in kexec.
*
*/
static unsigned long get_bounce_buffer(struct lb_memory *mem)
{
unsigned long lb_size;
unsigned long mem_entries;
unsigned long buffer;
int i;
lb_size = (unsigned long)(&_eram_seg - &_ram_seg);
/* Double linuxBIOS size so I have somewhere to place a copy to return to */
lb_size = lb_size + lb_size;
mem_entries = (mem->size - sizeof(*mem))/sizeof(mem->map[0]);
buffer = 0;
for(i = 0; i < mem_entries; i++) {
unsigned long mstart, mend;
unsigned long msize;
unsigned long tbuffer;
if (mem->map[i].type != LB_MEM_RAM)
continue;
if (unpack_lb64(mem->map[i].start) > MAX_ADDR)
continue;
if (unpack_lb64(mem->map[i].size) < lb_size)
continue;
mstart = unpack_lb64(mem->map[i].start);
msize = MAX_ADDR - mstart +1;
if (msize > unpack_lb64(mem->map[i].size))
msize = unpack_lb64(mem->map[i].size);
mend = mstart + msize;
tbuffer = mend - lb_size;
if (tbuffer < buffer)
continue;
buffer = tbuffer;
}
return buffer;
}
static struct verify_callback *process_elf_notes(
unsigned char *header,
unsigned long offset, unsigned long length)
{
struct verify_callback *cb_chain;
unsigned char *note, *end;
char *program, *version;
cb_chain = 0;
note = header + offset;
end = note + length;
program = version = 0;
while(note < end) {
Elf_Nhdr *hdr;
unsigned char *n_name, *n_desc, *next;
hdr = (Elf_Nhdr *)note;
n_name = note + sizeof(*hdr);
n_desc = n_name + ((hdr->n_namesz + 3) & ~3);
next = n_desc + ((hdr->n_descsz + 3) & ~3);
if (next > end) {
break;
}
if ((hdr->n_namesz == sizeof(ELF_NOTE_BOOT)) &&
(memcmp(n_name, ELF_NOTE_BOOT, sizeof(ELF_NOTE_BOOT)) == 0)) {
switch(hdr->n_type) {
case EIN_PROGRAM_NAME:
if (n_desc[hdr->n_descsz -1] == 0) {
program = n_desc;
}
break;
case EIN_PROGRAM_VERSION:
if (n_desc[hdr->n_descsz -1] == 0) {
version = n_desc;
}
break;
case EIN_PROGRAM_CHECKSUM:
{
struct ip_checksum_vcb *cb;
cb = malloc(sizeof(*cb));
cb->ip_checksum = *((uint16_t *)n_desc);
cb->data.callback = verify_ip_checksum;
cb->data.next = cb_chain;
cb->data.desc_offset = n_desc - header;
cb_chain = &cb->data;
break;
}
}
}
printk_spew("n_type: %08x n_name(%d): %-*.*s n_desc(%d): %-*.*s\n",
hdr->n_type,
hdr->n_namesz, hdr->n_namesz, hdr->n_namesz, n_name,
hdr->n_descsz,hdr->n_descsz, hdr->n_descsz, n_desc);
note = next;
}
if (program && version) {
printk_info("Loading %s version: %s\n",
program, version);
}
return cb_chain;
}
static int valid_area(struct lb_memory *mem, unsigned long buffer,
unsigned long start, unsigned long len)
{
/* Check through all of the memory segments and ensure
* the segment that was passed in is completely contained
* in RAM.
*/
int i;
unsigned long end = start + len;
unsigned long mem_entries = (mem->size - sizeof(*mem))/sizeof(mem->map[0]);
/* See if I conflict with the bounce buffer */
if (end >= buffer) {
return 0;
}
/* Walk through the table of valid memory ranges and see if I
* have a match.
*/
for(i = 0; i < mem_entries; i++) {
uint64_t mstart, mend;
uint32_t mtype;
mtype = mem->map[i].type;
mstart = unpack_lb64(mem->map[i].start);
mend = mstart + unpack_lb64(mem->map[i].size);
if ((mtype == LB_MEM_RAM) && (start < mend) && (end > mstart)) {
break;
}
}
if (i == mem_entries) {
printk_err("No matching ram area found for range:\n");
printk_err(" [0x%016lx, 0x%016lx)\n", start, end);
printk_err("Ram areas\n");
for(i = 0; i < mem_entries; i++) {
uint64_t mstart, mend;
uint32_t mtype;
mtype = mem->map[i].type;
mstart = unpack_lb64(mem->map[i].start);
mend = mstart + unpack_lb64(mem->map[i].size);
printk_err(" [0x%016lx, 0x%016lx) %s\n",
(unsigned long)mstart,
(unsigned long)mend,
(mtype == LB_MEM_RAM)?"RAM":"Reserved");
}
return 0;
}
return 1;
}
static void relocate_segment(unsigned long buffer, struct segment *seg)
{
/* Modify all segments that want to load onto linuxBIOS
* to load onto the bounce buffer instead.
*/
unsigned long lb_start = (unsigned long)&_ram_seg;
unsigned long lb_end = (unsigned long)&_eram_seg;
unsigned long start, middle, end;
printk_spew("lb: [0x%016lx, 0x%016lx)\n",
lb_start, lb_end);
start = seg->s_addr;
middle = start + seg->s_filesz;
end = start + seg->s_memsz;
/* I don't conflict with linuxBIOS so get out of here */
if ((end <= lb_start) || (start >= lb_end))
return;
printk_spew("segment: [0x%016lx, 0x%016lx, 0x%016lx)\n",
start, middle, end);
/* Slice off a piece at the beginning
* that doesn't conflict with linuxBIOS.
*/
if (start < lb_start) {
struct segment *new;
unsigned long len = lb_start - start;
new = malloc(sizeof(*new));
*new = *seg;
new->s_memsz = len;
seg->s_memsz -= len;
seg->s_addr += len;
seg->s_offset += len;
if (seg->s_filesz > len) {
new->s_filesz = len;
seg->s_filesz -= len;
} else {
seg->s_filesz = 0;
}
/* Order by stream offset */
new->next = seg;
new->prev = seg->prev;
seg->prev->next = new;
seg->prev = new;
/* Order by original program header order */
new->phdr_next = seg;
new->phdr_prev = seg->phdr_prev;
seg->phdr_prev->phdr_next = new;
seg->phdr_prev = new;
/* compute the new value of start */
start = seg->s_addr;
printk_spew(" early: [0x%016lx, 0x%016lx, 0x%016lx)\n",
new->s_addr,
new->s_addr + new->s_filesz,
new->s_addr + new->s_memsz);
}
/* Slice off a piece at the end
* that doesn't conflict with linuxBIOS
*/
if (end > lb_end) {
unsigned long len = lb_end - start;
struct segment *new;
new = malloc(sizeof(*new));
*new = *seg;
seg->s_memsz = len;
new->s_memsz -= len;
new->s_addr += len;
new->s_offset += len;
if (seg->s_filesz > len) {
seg->s_filesz = len;
new->s_filesz -= len;
} else {
new->s_filesz = 0;
}
/* Order by stream offset */
new->next = seg->next;
new->prev = seg;
seg->next->prev = new;
seg->next = new;
/* Order by original program header order */
new->phdr_next = seg->phdr_next;
new->phdr_prev = seg;
seg->phdr_next->phdr_prev = new;
seg->phdr_next = new;
/* compute the new value of end */
end = start + len;
printk_spew(" late: [0x%016lx, 0x%016lx, 0x%016lx)\n",
new->s_addr,
new->s_addr + new->s_filesz,
new->s_addr + new->s_memsz);
}
/* Now retarget this segment onto the bounce buffer */
seg->s_addr = buffer + (seg->s_addr - lb_start);
printk_spew(" bounce: [0x%016lx, 0x%016lx, 0x%016lx)\n",
seg->s_addr,
seg->s_addr + seg->s_filesz,
seg->s_addr + seg->s_memsz);
}
static int build_elf_segment_list(
struct segment *head,
unsigned long bounce_buffer, struct lb_memory *mem,
Elf_phdr *phdr, int headers)
{
struct segment *ptr;
int i;
memset(head, 0, sizeof(*head));
head->phdr_next = head->phdr_prev = head;
head->next = head->prev = head;
for(i = 0; i < headers; i++) {
struct segment *new;
/* Ignore data that I don't need to handle */
if (phdr[i].p_type != PT_LOAD) {
printk_debug("Dropping non PT_LOAD segment\n");
continue;
}
if (phdr[i].p_memsz == 0) {
printk_debug("Dropping empty segment\n");
continue;
}
new = malloc(sizeof(*new));
new->s_addr = phdr[i].p_paddr;
new->s_memsz = phdr[i].p_memsz;
new->s_offset = phdr[i].p_offset;
new->s_filesz = phdr[i].p_filesz;
printk_debug("New segment addr 0x%lx size 0x%lx offset 0x%lx filesize 0x%lx\n",
new->s_addr, new->s_memsz, new->s_offset, new->s_filesz);
/* Clean up the values */
if (new->s_filesz > new->s_memsz) {
new->s_filesz = new->s_memsz;
}
printk_debug("(cleaned up) New segment addr 0x%lx size 0x%lx offset 0x%lx filesize 0x%lx\n",
new->s_addr, new->s_memsz, new->s_offset, new->s_filesz);
for(ptr = head->next; ptr != head; ptr = ptr->next) {
if (new->s_offset < ptr->s_offset)
break;
}
/* Order by stream offset */
new->next = ptr;
new->prev = ptr->prev;
ptr->prev->next = new;
ptr->prev = new;
/* Order by original program header order */
new->phdr_next = head;
new->phdr_prev = head->phdr_prev;
head->phdr_prev->phdr_next = new;
head->phdr_prev = new;
/* Verify the memory addresses in the segment are valid */
if (!valid_area(mem, bounce_buffer, new->s_addr, new->s_memsz))
goto out;
/* Modify the segment to load onto the bounce_buffer if necessary.
*/
relocate_segment(bounce_buffer, new);
}
return 1;
out:
return 0;
}
static int load_elf_segments(
struct segment *head, unsigned char *header, unsigned long header_size)
{
unsigned long offset;
struct segment *ptr;
offset = 0;
for(ptr = head->next; ptr != head; ptr = ptr->next) {
unsigned long start_offset;
unsigned long skip_bytes, read_bytes;
unsigned char *dest, *middle, *end;
byte_offset_t result;
printk_debug("Loading Segment: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
ptr->s_addr, ptr->s_memsz, ptr->s_filesz);
/* Compute the boundaries of the segment */
dest = (unsigned char *)(ptr->s_addr);
end = dest + ptr->s_memsz;
middle = dest + ptr->s_filesz;
start_offset = ptr->s_offset;
/* Ignore s_offset if I have a pure bss segment */
if (ptr->s_filesz == 0) {
start_offset = offset;
}
printk_spew("[ 0x%016lx, %016lx, 0x%016lx) <- %016lx\n",
(unsigned long)dest,
(unsigned long)middle,
(unsigned long)end,
(unsigned long)start_offset);
/* Skip intial buffer unused bytes */
if (offset < header_size) {
if (start_offset < header_size) {
offset = start_offset;
} else {
offset = header_size;
}
}
/* Skip the unused bytes */
skip_bytes = start_offset - offset;
if (skip_bytes &&
((result = stream_skip(skip_bytes)) != skip_bytes)) {
printk_err("ERROR: Skip of %ld bytes skipped %ld bytes\n",
skip_bytes, result);
goto out;
}
offset = start_offset;
/* Copy data from the initial buffer */
if (offset < header_size) {
size_t len;
if ((ptr->s_filesz + start_offset) > header_size) {
len = header_size - start_offset;
}
else {
len = ptr->s_filesz;
}
memcpy(dest, &header[start_offset], len);
dest += len;
}
/* Read the segment into memory */
read_bytes = middle - dest;
if (read_bytes &&
((result = stream_read(dest, read_bytes)) != read_bytes)) {
printk_err("ERROR: Read of %ld bytes read %ld bytes...\n",
read_bytes, result);
goto out;
}
offset += ptr->s_filesz;
/* Zero the extra bytes between middle & end */
if (middle < end) {
printk_debug("Clearing Segment: addr: 0x%016lx memsz: 0x%016lx\n",
(unsigned long)middle, end - middle);
/* Zero the extra bytes */
memset(middle, 0, end - middle);
}
}
return 1;
out:
return 0;
}
static int verify_loaded_image(
struct verify_callback *vcb,
Elf_ehdr *ehdr, Elf_phdr *phdr,
struct segment *head
)
{
struct segment *ptr;
int ok;
ok = 1;
for(; ok && vcb ; vcb = vcb->next) {
/* Find where the note is loaded */
/* The whole note must be loaded intact
* so an address of 0 for the descriptor is impossible
*/
vcb->desc_addr = 0;
for(ptr = head->next; ptr != head; ptr = ptr->next) {
unsigned long desc_addr;
desc_addr = ptr->s_addr + vcb->desc_offset - ptr->s_offset;
if ((desc_addr >= ptr->s_addr) &&
(desc_addr < (ptr->s_addr + ptr->s_filesz))) {
vcb->desc_addr = desc_addr;
}
}
ok = vcb->callback(vcb, ehdr, phdr, head);
}
return ok;
}
int elfload(struct lb_memory *mem,
unsigned char *header, unsigned long header_size)
{
Elf_ehdr *ehdr;
Elf_phdr *phdr;
void *entry;
struct segment head;
struct verify_callback *cb_chain;
unsigned long bounce_buffer;
/* Find a bounce buffer so I can load to linuxBIOS's current location */
bounce_buffer = get_bounce_buffer(mem);
if (!bounce_buffer) {
printk_err("Could not find a bounce buffer...\n");
goto out;
}
ehdr = (Elf_ehdr *)header;
entry = (void *)(ehdr->e_entry);
phdr = (Elf_phdr *)(&header[ehdr->e_phoff]);
/* Digest elf note information... */
cb_chain = 0;
if ((phdr[0].p_type == PT_NOTE) &&
((phdr[0].p_offset + phdr[0].p_filesz) < header_size)) {
cb_chain = process_elf_notes(header,
phdr[0].p_offset, phdr[0].p_filesz);
}
/* Preprocess the elf segments */
if (!build_elf_segment_list(&head,
bounce_buffer, mem, phdr, ehdr->e_phnum))
goto out;
/* Load the segments */
if (!load_elf_segments(&head, header, header_size))
goto out;
printk_spew("Loaded segments\n");
/* Verify the loaded image */
if (!verify_loaded_image(cb_chain, ehdr, phdr, &head))
goto out;
printk_spew("verified segments\n");
/* Shutdown the stream device */
stream_fini();
printk_spew("closed down stream\n");
/* Reset to booting from this image as late as possible */
boot_successful();
printk_debug("Jumping to boot code at 0x%x\n", entry);
post_code(0xfe);
/* Jump to kernel */
jmp_to_elf_entry(entry, bounce_buffer);
return 1;
out:
return 0;
}
int elfboot(struct lb_memory *mem)
{
Elf_ehdr *ehdr;
static unsigned char header[ELF_HEAD_SIZE];
int header_offset;
int i, result;
result = 0;
printk_info("\n");
printk_info("Welcome to %s, the open sourced starter.\n", BOOTLOADER);
printk_info("January 2002, Eric Biederman.\n");
printk_info("Version %s\n", BOOTLOADER_VERSION);
printk_info("\n");
post_code(0xf8);
if (stream_init() < 0) {
printk_err("Could not initialize driver...\n");
goto out;
}
/* Read in the initial ELF_HEAD_SIZE bytes */
if (stream_read(header, ELF_HEAD_SIZE) != ELF_HEAD_SIZE) {
printk_err("Read failed...\n");
goto out;
}
/* Scan for an elf header */
header_offset = -1;
for(i = 0; i < ELF_HEAD_SIZE - (sizeof(Elf_ehdr) + sizeof(Elf_phdr)); i+=16) {
ehdr = (Elf_ehdr *)(&header[i]);
if (memcmp(ehdr->e_ident, ELFMAG, 4) != 0) {
printk_debug("No header at %d\n", i);
continue;
}
printk_debug("Found ELF candidate at offset %d\n", i);
/* Sanity check the elf header */
if ((ehdr->e_type == ET_EXEC) &&
elf_check_arch(ehdr) &&
(ehdr->e_ident[EI_VERSION] == EV_CURRENT) &&
(ehdr->e_version == EV_CURRENT) &&
(ehdr->e_ehsize == sizeof(Elf_ehdr)) &&
(ehdr->e_phentsize = sizeof(Elf_phdr)) &&
(ehdr->e_phoff < (ELF_HEAD_SIZE - i)) &&
((ehdr->e_phoff + (ehdr->e_phentsize * ehdr->e_phnum)) <=
(ELF_HEAD_SIZE - i))) {
header_offset = i;
break;
}
ehdr = 0;
}
printk_debug("header_offset is %d\n", header_offset);
if (header_offset == -1) {
goto out;
}
printk_debug("Try to load at offset 0x%x\n", header_offset);
result = elfload(mem,
header + header_offset , ELF_HEAD_SIZE - header_offset);
out:
if (!result) {
/* Shutdown the stream device */
stream_fini();
printk_err("Can not load ELF Image.\n");
post_code(0xff);
}
return 0;
}