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// See LICENSE for license details.
#include "mtrap.h"
#include "bbl.h"
#include "bits.h"
#include "vm.h"
#include <elf.h>
#include <string.h>
void load_kernel_elf(void* blob, size_t size, kernel_elf_info* info)
{
Elf_Ehdr* eh = blob;
if (sizeof(*eh) > size ||
!(eh->e_ident[0] == '\177' && eh->e_ident[1] == 'E' &&
eh->e_ident[2] == 'L' && eh->e_ident[3] == 'F'))
goto fail;
if (IS_ELF64(*eh) != (sizeof(uintptr_t) == 8))
goto fail;
uintptr_t min_vaddr = -1, max_vaddr = 0;
size_t phdr_size = eh->e_phnum * sizeof(Elf_Ehdr);
Elf_Phdr* ph = blob + eh->e_phoff;
if (eh->e_phoff + phdr_size > size)
goto fail;
first_free_paddr = ROUNDUP(first_free_paddr, MEGAPAGE_SIZE);
for (int i = 0; i < eh->e_phnum; i++)
if (ph[i].p_type == PT_LOAD && ph[i].p_memsz && ph[i].p_vaddr < min_vaddr)
min_vaddr = ph[i].p_vaddr;
min_vaddr = ROUNDDOWN(min_vaddr, MEGAPAGE_SIZE);
uintptr_t bias = first_free_paddr - min_vaddr;
for (int i = eh->e_phnum - 1; i >= 0; i--) {
if(ph[i].p_type == PT_LOAD && ph[i].p_memsz) {
uintptr_t prepad = ph[i].p_vaddr % RISCV_PGSIZE;
uintptr_t vaddr = ph[i].p_vaddr + bias;
if (vaddr + ph[i].p_memsz > max_vaddr)
max_vaddr = vaddr + ph[i].p_memsz;
if (ph[i].p_offset + ph[i].p_filesz > size)
goto fail;
memcpy((void*)vaddr, blob + ph[i].p_offset, ph[i].p_filesz);
memset((void*)vaddr - prepad, 0, prepad);
memset((void*)vaddr + ph[i].p_filesz, 0, ph[i].p_memsz - ph[i].p_filesz);
}
}
info->entry = eh->e_entry;
info->load_offset = bias;
info->first_user_vaddr = min_vaddr;
info->first_vaddr_after_user = ROUNDUP(max_vaddr - bias, RISCV_PGSIZE);
return;
fail:
die("failed to load payload");
}
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