On Sun, 24 Jul 2011, G?ran Weinholt wrote: > Multiboot images can specify a bss segment. The boot loader must clear > the memory of the bss and ensure that no modules or structures are > allocated inside it. Several fields are provided in the Multiboot > header that were previously not used properly. The header is now used > to determine how much data should be read from the image and how much > memory should be reserved to the bss segment. > > Signed-off-by: G?ran Weinholt <go...@weinholt.se> > --- > hw/multiboot.c | 14 +++++++++----- > 1 files changed, 9 insertions(+), 5 deletions(-) > > diff --git a/hw/multiboot.c b/hw/multiboot.c > index 2426e84..a1d3f41 100644 > --- a/hw/multiboot.c > +++ b/hw/multiboot.c > @@ -198,11 +198,14 @@ int load_multiboot(void *fw_cfg, > } else { > /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */ > uint32_t mh_header_addr = ldl_p(header+i+12); > + uint32_t mh_load_end_addr = ldl_p(header+i+20); > + 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; > > mh_entry_addr = ldl_p(header+i+28); > - mb_kernel_size = kernel_file_size - mb_kernel_text_offset; > + mb_kernel_size = mh_bss_end_addr - mh_load_addr; > > /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE. > uint32_t mh_mode_type = ldl_p(header+i+32); > @@ -212,17 +215,18 @@ int load_multiboot(void *fw_cfg, > > mb_debug("multiboot: mh_header_addr = %#x\n", mh_header_addr); > mb_debug("multiboot: mh_load_addr = %#x\n", mh_load_addr); > - mb_debug("multiboot: mh_load_end_addr = %#x\n", ldl_p(header+i+20)); > - mb_debug("multiboot: mh_bss_end_addr = %#x\n", ldl_p(header+i+24)); > + mb_debug("multiboot: mh_load_end_addr = %#x\n", mh_load_end_addr); > + mb_debug("multiboot: mh_bss_end_addr = %#x\n", mh_bss_end_addr); > mb_debug("qemu: loading multiboot kernel (%#x bytes) at %#x\n", > - mb_kernel_size, mh_load_addr); > + mb_load_size, mh_load_addr); > > mbs.mb_buf = qemu_malloc(mb_kernel_size); > fseek(f, mb_kernel_text_offset, SEEK_SET); > - if (fread(mbs.mb_buf, 1, mb_kernel_size, f) != mb_kernel_size) { > + if (fread(mbs.mb_buf, 1, mb_load_size, f) != mb_load_size) {
Not that it matters, but.. you are asking to read mb_load_size records of 1 byte each, it's simple to ask for one record of mb_load_size as a bonus check becomes != 1 thus saving 11 bytes making the earth that much greener. > fprintf(stderr, "fread() failed\n"); > exit(1); > } > + memset(mbs.mb_buf + mb_load_size, 0, mb_kernel_size - mb_load_size); > fclose(f); > } > > -- mailto:av1...@comtv.ru