From patchwork Mon Jan 23 12:49:15 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: multiboot: mh_load_end_addr and mh_bss_end_addr may be zero Date: Mon, 23 Jan 2012 02:49:15 -0000 From: =?utf-8?q?G=C3=B6ran_Weinholt?= X-Patchwork-Id: 137353 Message-Id: <87mx9ezir8.fsf@industria.weinholt.se> To: qemu-devel@nongnu.org Cc: Kevin Wolf , "Justin M. Forbes" , =?utf-8?Q?Ren=C3=A9?= Rebe , Alexander Graf , qemu-stable@nongnu.org There are two special cases in the address fields of the multiboot format. If mh_load_end_addr is zero then the whole image file should be loaded and if mh_bss_end_addr is zero then there is no bss segment. With this change it is again possible to boot kernels where these fields are zero. Signed-off-by: Göran Weinholt Tested-by: Alexander Graf --- hw/multiboot.c | 15 ++++++++++++++- 1 files changed, 14 insertions(+), 1 deletions(-) diff --git a/hw/multiboot.c b/hw/multiboot.c index b4484a3..db28328 100644 --- a/hw/multiboot.c +++ b/hw/multiboot.c @@ -202,10 +202,23 @@ int load_multiboot(void *fw_cfg, uint32_t mh_bss_end_addr = ldl_p(header+i+24); mh_load_addr = ldl_p(header+i+16); uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr); - uint32_t mb_load_size = mh_load_end_addr - mh_load_addr; + uint32_t mb_load_size; + + /* A load end address of zero indicates that the whole file + * should be loaded. */ + if (!mh_load_end_addr) { + mh_load_end_addr = kernel_file_size + mh_load_addr; + } + + /* A bss end address of zero indicates that there is no bss + * segment. */ + if (!mh_bss_end_addr) { + mh_bss_end_addr = mh_load_end_addr; + } mh_entry_addr = ldl_p(header+i+28); mb_kernel_size = mh_bss_end_addr - mh_load_addr; + mb_load_size = mh_load_end_addr - mh_load_addr; /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE. uint32_t mh_mode_type = ldl_p(header+i+32);