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authorMatthew Garrett <mjg@redhat.com>2012-02-15 12:12:17 -0500
committerH. Peter Anvin <hpa@linux.intel.com>2012-03-26 14:49:09 -0700
commitead636d9693089bc54f1272552ae50b70d3f3965 (patch)
treecb3a51f92179d751883522b70205ce9e2971beda /utils
parent794ff174175734a0974e1846f0db29040b096e45 (diff)
downloadsyslinux-ead636d9693089bc54f1272552ae50b70d3f3965.tar.gz
syslinux-ead636d9693089bc54f1272552ae50b70d3f3965.tar.xz
syslinux-ead636d9693089bc54f1272552ae50b70d3f3965.zip
isohybrid: Generate MBR even when in EFI mode
Various EFI systems insist that there be no active flag in the pMBR in order to parse the GPT. The only way around this is to also generate a valid MBR - the firmware will then pick that up and use the system partition provided there. In order to deal with other EFI "sanity" checks, the partition type for the non-EFI partitions is set to 0 to skip the firmware bailing because of overlapping partitions. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'utils')
-rw-r--r--utils/isohybrid.c54
1 files changed, 49 insertions, 5 deletions
diff --git a/utils/isohybrid.c b/utils/isohybrid.c
index 1dcbaa11..ac04bfd4 100644
--- a/utils/isohybrid.c
+++ b/utils/isohybrid.c
@@ -54,7 +54,7 @@ enum { VERBOSE = 1 , EFI = 2 , MAC = 4};
uint16_t head = 64; /* 1 <= head <= 256 */
uint8_t sector = 32; /* 1 <= sector <= 63 */
-uint8_t entry = 1; /* partition number: 1 <= entry <= 4 */
+uint8_t entry = 0; /* partition number: 1 <= entry <= 4 */
uint8_t offset = 0; /* partition offset: 0 <= offset <= 64 */
uint16_t type = 0x17; /* partition type: 0 <= type <= 255 */
uint32_t id = 0; /* MBR: 0 <= id <= 0xFFFFFFFF(4294967296) */
@@ -300,6 +300,8 @@ check_option(int argc, char *argv[])
entry = strtoul(optarg, &err, 0);
if (entry < 1 || entry > 4)
errx(1, "invalid entry: `%s', 1 <= entry <= 4", optarg);
+ if (mode & MAC || mode & EFI)
+ errx(1, "setting an entry is unsupported with EFI or Mac");
break;
case 'o':
@@ -334,10 +336,14 @@ check_option(int argc, char *argv[])
case 'u':
mode |= EFI;
+ if (entry)
+ errx(1, "setting an entry is unsupported with EFI or Mac");
break;
case 'm':
mode |= MAC;
+ if (entry)
+ errx(1, "setting an entry is unsupported with EFI or Mac");
break;
case 'v':
@@ -581,6 +587,12 @@ initialise_mbr(uint8_t *mbr)
memcpy(mbr, afp_header, sizeof(afp_header));
}
+ if (!entry)
+ entry = 1;
+
+ if (mode & EFI)
+ type = 0;
+
mbr += MBRSIZE; /* offset 432 */
tmp = lendian_int(de_lba * 4);
@@ -633,6 +645,40 @@ initialise_mbr(uint8_t *mbr)
tmp = lendian_int(psize);
memcpy(&mbr[12], &tmp, sizeof(tmp));
}
+ if (i == 2 && (mode & EFI))
+ {
+ mbr[0] = 0x0;
+ mbr[1] = 0xfe;
+ mbr[2] = 0xff;
+ mbr[3] = 0xff;
+ mbr[4] = 0xef;
+ mbr[5] = 0xfe;
+ mbr[6] = 0xff;
+ mbr[7] = 0xff;
+
+ tmp = lendian_int(efi_lba * 4);
+ memcpy(&mbr[8], &tmp, sizeof(tmp));
+
+ tmp = lendian_int(efi_count);
+ memcpy(&mbr[12], &tmp, sizeof(tmp));
+ }
+ if (i == 3 && (mode & MAC))
+ {
+ mbr[0] = 0x0;
+ mbr[1] = 0xfe;
+ mbr[2] = 0xff;
+ mbr[3] = 0xff;
+ mbr[4] = 0x0;
+ mbr[5] = 0xfe;
+ mbr[6] = 0xff;
+ mbr[7] = 0xff;
+
+ tmp = lendian_int(mac_lba * 4);
+ memcpy(&mbr[8], &tmp, sizeof(tmp));
+
+ tmp = lendian_int(mac_count);
+ memcpy(&mbr[12], &tmp, sizeof(tmp));
+ }
mbr += 16;
}
mbr[0] = 0x55;
@@ -908,8 +954,7 @@ main(int argc, char *argv[])
if (!read_efi_section(buf)) {
buf += 32;
if (!read_efi_catalogue(buf, &efi_count, &efi_lba) && efi_lba) {
- offset = 1;
- type = 0xee;
+ offset = 0;
} else {
errx(1, "%s: invalid efi catalogue", argv[0]);
}
@@ -925,8 +970,7 @@ main(int argc, char *argv[])
if (!read_efi_section(buf)) {
buf += 32;
if (!read_efi_catalogue(buf, &mac_count, &mac_lba) && mac_lba) {
- offset = 1;
- type = 0xee;
+ offset = 0;
} else {
errx(1, "%s: invalid efi catalogue", argv[0]);
}