multiboot: bss_end_addr can be zero

The multiboot spec (https://www.gnu.org/software/grub/manual/multiboot/),
section 3.1.3, allows for bss_end_addr to be zero.

A zero bss_end_addr signifies there is no .bss section.

Suggested-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Jack Schwartz <jack.schwartz@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Jack Schwartz 2017-12-21 09:25:15 -08:00 committed by Kevin Wolf
parent f32408f3b4
commit 2a8fcd119e

View File

@ -233,12 +233,6 @@ int load_multiboot(FWCfgState *fw_cfg,
mh_entry_addr = ldl_p(header+i+28); mh_entry_addr = ldl_p(header+i+28);
if (mh_load_end_addr) { if (mh_load_end_addr) {
if (mh_bss_end_addr < mh_load_addr) {
fprintf(stderr, "invalid mh_bss_end_addr address\n");
exit(1);
}
mb_kernel_size = mh_bss_end_addr - mh_load_addr;
if (mh_load_end_addr < mh_load_addr) { if (mh_load_end_addr < mh_load_addr) {
fprintf(stderr, "invalid mh_load_end_addr address\n"); fprintf(stderr, "invalid mh_load_end_addr address\n");
exit(1); exit(1);
@ -249,8 +243,16 @@ int load_multiboot(FWCfgState *fw_cfg,
fprintf(stderr, "invalid kernel_file_size\n"); fprintf(stderr, "invalid kernel_file_size\n");
exit(1); exit(1);
} }
mb_kernel_size = kernel_file_size - mb_kernel_text_offset; mb_load_size = kernel_file_size - mb_kernel_text_offset;
mb_load_size = mb_kernel_size; }
if (mh_bss_end_addr) {
if (mh_bss_end_addr < (mh_load_addr + mb_load_size)) {
fprintf(stderr, "invalid mh_bss_end_addr address\n");
exit(1);
}
mb_kernel_size = mh_bss_end_addr - mh_load_addr;
} else {
mb_kernel_size = mb_load_size;
} }
/* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE. /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE.