Files
codezero/loader/main.c

131 lines
3.3 KiB
C

#include <elf/elf.h>
#include <elf/elf32.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "arch.h"
/* These symbols are defined by the linker script. */
extern char _start_kernel[];
extern char _end_kernel[];
extern char _start_containers[];
extern char _end_containers[];
/* This is a kernel symbol exported to loader's linker script from kernel build */
extern char bkpt_phys_to_virt[];
int load_elf_image(unsigned long **entry, void *filebuf);
/*
* Given a section that is a valid elf file, look for sections
* and recognise special .img.[0-9] section name and run
* load_elf_image on it.
*/
int load_container_image(void *cont_section)
{
struct Elf32_Header *elf_header = (struct Elf32_Header *)cont_section;
struct Elf32_Shdr *sect_header;
int nsect;
int nimgs = 0;
unsigned long *image_entry;
if (elf32_checkFile(elf_header) < 0) {
printf("%s: Not a valid elf image.\n", __FUNCTION__);
return -1;
}
sect_header = elf32_getSectionTable(elf_header);
nsect = elf32_getNumSections(elf_header);
for (int i = 0; i < nsect; i++) {
char *sectname = elf32_getSectionName(elf_header, i);
if (!strncmp(sectname, ".img.", strlen(".img."))) {
printf("Loading %s section image...\n", sectname);
load_elf_image(&image_entry, elf32_getSection(elf_header, i));
nimgs++;
}
}
printf("Total of %d images in this container.\n", nimgs);
return 0;
}
/*
* From a given offset, recognise special .cont.[0-9] section name
* and run load_container_image on it.
*/
int load_container_images(unsigned long start, unsigned long end)
{
struct Elf32_Header *elf_header = (struct Elf32_Header *)start;
struct Elf32_Shdr *sect_header;
int nsect = 0;
int nconts = 0;
if (elf32_checkFile(elf_header) < 0) {
printf("Not a valid elf image.\n");
return -1;
}
sect_header = elf32_getSectionTable(elf_header);
nsect = elf32_getNumSections(elf_header);
for (int i = 0; i < nsect; i++) {
char *sectname = elf32_getSectionName(elf_header, i);
if (!strncmp(sectname, ".cont.", strlen(".cont."))) {
nconts++;
printf("\nLoading section %s from top-level elf file.\n", sectname);
load_container_image(elf32_getSection(elf_header, i));
}
}
printf("Total of %d container images.\n", nconts);
return 0;
}
int load_elf_image(unsigned long **entry, void *filebuf)
{
if (!elf32_checkFile((struct Elf32_Header *)filebuf)) {
**entry = (unsigned long)elf32_getEntryPoint((struct Elf32_Header *)filebuf);
printf("Entry point: 0x%lx\n", **entry);
} else {
printf("Not a valid elf image.\n");
return -1;
}
if (!elf_loadFile(filebuf, 1)) {
printf("Elf image seems valid, but unable to load.\n");
return -1;
}
return 0;
}
void arch_start_kernel(void *entry)
{
printf("elf-loader:\tStarting kernel\n\r");
void (*func)(unsigned long) = (void (*)(unsigned long)) (*(unsigned long*)entry);
func(0);
}
int main(void)
{
unsigned long *kernel_entry;
printf("ELF Loader: Started.\n");
printf("Loading the kernel...\n");
load_elf_image(&kernel_entry, (void *)_start_kernel);
printf("Loading containers...\n");
load_container_images((unsigned long)_start_containers,
(unsigned long)_end_containers);
printf("elf-loader:\tkernel entry point is %lx\n", *kernel_entry);
arch_start_kernel(kernel_entry);
printf("elf-loader:\tKernel start failed! Looping endless.\n");
while (1)
;
return -1;
}