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// SPDX-License-Identifier: GPL-2.0-only
/*
* tools/testing/selftests/kvm/lib/elf.c
*
* Copyright (C) 2018, Google LLC.
*/
#include "test_util.h"
#include <bits/endian.h>
#include <linux/elf.h>
#include "kvm_util.h"
static void elfhdr_get(const char *filename, Elf64_Ehdr *hdrp)
{
off_t offset_rv;
/* Open the ELF file. */
int fd;
fd = open(filename, O_RDONLY);
TEST_ASSERT(fd >= 0, "Failed to open ELF file,\n"
" filename: %s\n"
" rv: %i errno: %i", filename, fd, errno);
/* Read in and validate ELF Identification Record.
* The ELF Identification record is the first 16 (EI_NIDENT) bytes
* of the ELF header, which is at the beginning of the ELF file.
* For now it is only safe to read the first EI_NIDENT bytes. Once
* read and validated, the value of e_ehsize can be used to determine
* the real size of the ELF header.
*/
unsigned char ident[EI_NIDENT];
test_read(fd, ident, sizeof(ident));
TEST_ASSERT((ident[EI_MAG0] == ELFMAG0) && (ident[EI_MAG1] == ELFMAG1)
&& (ident[EI_MAG2] == ELFMAG2) && (ident[EI_MAG3] == ELFMAG3),
"ELF MAGIC Mismatch,\n"
" filename: %s\n"
" ident[EI_MAG0 - EI_MAG3]: %02x %02x %02x %02x\n"
" Expected: %02x %02x %02x %02x",
filename,
ident[EI_MAG0], ident[EI_MAG1], ident[EI_MAG2], ident[EI_MAG3],
ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3);
TEST_ASSERT(ident[EI_CLASS] == ELFCLASS64,
"Current implementation only able to handle ELFCLASS64,\n"
" filename: %s\n"
" ident[EI_CLASS]: %02x\n"
" expected: %02x",
filename,
ident[EI_CLASS], ELFCLASS64);
TEST_ASSERT(((BYTE_ORDER == LITTLE_ENDIAN)
&& (ident[EI_DATA] == ELFDATA2LSB))
|| ((BYTE_ORDER == BIG_ENDIAN)
&& (ident[EI_DATA] == ELFDATA2MSB)), "Current "
"implementation only able to handle\n"
"cases where the host and ELF file endianness\n"
"is the same:\n"
" host BYTE_ORDER: %u\n"
" host LITTLE_ENDIAN: %u\n"
" host BIG_ENDIAN: %u\n"
" ident[EI_DATA]: %u\n"
" ELFDATA2LSB: %u\n"
" ELFDATA2MSB: %u",
BYTE_ORDER, LITTLE_ENDIAN, BIG_ENDIAN,
ident[EI_DATA], ELFDATA2LSB, ELFDATA2MSB);
TEST_ASSERT(ident[EI_VERSION] == EV_CURRENT,
"Current implementation only able to handle current "
"ELF version,\n"
" filename: %s\n"
" ident[EI_VERSION]: %02x\n"
" expected: %02x",
filename, ident[EI_VERSION], EV_CURRENT);
/* Read in the ELF header.
* With the ELF Identification portion of the ELF header
* validated, especially that the value at EI_VERSION is
* as expected, it is now safe to read the entire ELF header.
*/
offset_rv = lseek(fd, 0, SEEK_SET);
TEST_ASSERT(offset_rv == 0, "Seek to ELF header failed,\n"
" rv: %zi expected: %i", offset_rv, 0);
test_read(fd, hdrp, sizeof(*hdrp));
TEST_ASSERT(hdrp->e_phentsize == sizeof(Elf64_Phdr),
"Unexpected physical header size,\n"
" hdrp->e_phentsize: %x\n"
" expected: %zx",
hdrp->e_phentsize, sizeof(Elf64_Phdr));
TEST_ASSERT(hdrp->e_shentsize == sizeof(Elf64_Shdr),
"Unexpected section header size,\n"
" hdrp->e_shentsize: %x\n"
" expected: %zx",
hdrp->e_shentsize, sizeof(Elf64_Shdr));
}
/* VM ELF Load
*
* Input Args:
* filename - Path to ELF file
*
* Output Args: None
*
* Input/Output Args:
* vm - Pointer to opaque type that describes the VM.
*
* Return: None, TEST_ASSERT failures for all error conditions
*
* Loads the program image of the ELF file specified by filename,
* into the virtual address space of the VM pointed to by vm. On entry
* the VM needs to not be using any of the virtual address space used
* by the image and it needs to have sufficient available physical pages, to
* back the virtual pages used to load the image.
*/
void kvm_vm_elf_load(struct kvm_vm *vm, const char *filename)
{
off_t offset, offset_rv;
Elf64_Ehdr hdr;
/* Open the ELF file. */
int fd;
fd = open(filename, O_RDONLY);
TEST_ASSERT(fd >= 0, "Failed to open ELF file,\n"
" filename: %s\n"
" rv: %i errno: %i", filename, fd, errno);
/* Read in the ELF header. */
elfhdr_get(filename, &hdr);
/* For each program header.
* The following ELF header members specify the location
* and size of the program headers:
*
* e_phoff - File offset to start of program headers
* e_phentsize - Size of each program header
* e_phnum - Number of program header entries
*/
for (unsigned int n1 = 0; n1 < hdr.e_phnum; n1++) {
/* Seek to the beginning of the program header. */
offset = hdr.e_phoff + (n1 * hdr.e_phentsize);
offset_rv = lseek(fd, offset, SEEK_SET);
TEST_ASSERT(offset_rv == offset,
"Failed to seek to begining of program header %u,\n"
" filename: %s\n"
" rv: %jd errno: %i",
n1, filename, (intmax_t) offset_rv, errno);
/* Read in the program header. */
Elf64_Phdr phdr;
test_read(fd, &phdr, sizeof(phdr));
/* Skip if this header doesn't describe a loadable segment. */
if (phdr.p_type != PT_LOAD)
continue;
/* Allocate memory for this segment within the VM. */
TEST_ASSERT(phdr.p_memsz > 0, "Unexpected loadable segment "
"memsize of 0,\n"
" phdr index: %u p_memsz: 0x%" PRIx64,
n1, (uint64_t) phdr.p_memsz);
vm_vaddr_t seg_vstart = align_down(phdr.p_vaddr, vm->page_size);
vm_vaddr_t seg_vend = phdr.p_vaddr + phdr.p_memsz - 1;
seg_vend |= vm->page_size - 1;
size_t seg_size = seg_vend - seg_vstart + 1;
vm_vaddr_t vaddr = vm_vaddr_alloc(vm, seg_size, seg_vstart);
TEST_ASSERT(vaddr == seg_vstart, "Unable to allocate "
"virtual memory for segment at requested min addr,\n"
" segment idx: %u\n"
" seg_vstart: 0x%lx\n"
" vaddr: 0x%lx",
n1, seg_vstart, vaddr);
memset(addr_gva2hva(vm, vaddr), 0, seg_size);
/* TODO(lhuemill): Set permissions of each memory segment
* based on the least-significant 3 bits of phdr.p_flags.
*/
/* Load portion of initial state that is contained within
* the ELF file.
*/
if (phdr.p_filesz) {
offset_rv = lseek(fd, phdr.p_offset, SEEK_SET);
TEST_ASSERT(offset_rv == phdr.p_offset,
"Seek to program segment offset failed,\n"
" program header idx: %u errno: %i\n"
" offset_rv: 0x%jx\n"
" expected: 0x%jx\n",
n1, errno, (intmax_t) offset_rv,
(intmax_t) phdr.p_offset);
test_read(fd, addr_gva2hva(vm, phdr.p_vaddr),
phdr.p_filesz);
}
}
}
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