summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/cpu/microcode/intel_lib.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/cpu/microcode/intel_lib.c')
-rw-r--r--arch/x86/kernel/cpu/microcode/intel_lib.c58
1 files changed, 37 insertions, 21 deletions
diff --git a/arch/x86/kernel/cpu/microcode/intel_lib.c b/arch/x86/kernel/cpu/microcode/intel_lib.c
index b96896bcbdaf..2ce1a7dc45b7 100644
--- a/arch/x86/kernel/cpu/microcode/intel_lib.c
+++ b/arch/x86/kernel/cpu/microcode/intel_lib.c
@@ -49,7 +49,7 @@ int microcode_sanity_check(void *mc, int print_err)
unsigned long total_size, data_size, ext_table_size;
struct microcode_header_intel *mc_header = mc;
struct extended_sigtable *ext_header = NULL;
- int sum, orig_sum, ext_sigcount = 0, i;
+ u32 sum, orig_sum, ext_sigcount = 0, i;
struct extended_signature *ext_sig;
total_size = get_totalsize(mc_header);
@@ -57,69 +57,85 @@ int microcode_sanity_check(void *mc, int print_err)
if (data_size + MC_HEADER_SIZE > total_size) {
if (print_err)
- pr_err("error! Bad data size in microcode data file\n");
+ pr_err("Error: bad microcode data file size.\n");
return -EINVAL;
}
if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
if (print_err)
- pr_err("error! Unknown microcode update format\n");
+ pr_err("Error: invalid/unknown microcode update format.\n");
return -EINVAL;
}
+
ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
if (ext_table_size) {
+ u32 ext_table_sum = 0;
+ u32 *ext_tablep;
+
if ((ext_table_size < EXT_HEADER_SIZE)
|| ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
if (print_err)
- pr_err("error! Small exttable size in microcode data file\n");
+ pr_err("Error: truncated extended signature table.\n");
return -EINVAL;
}
+
ext_header = mc + MC_HEADER_SIZE + data_size;
if (ext_table_size != exttable_size(ext_header)) {
if (print_err)
- pr_err("error! Bad exttable size in microcode data file\n");
+ pr_err("Error: extended signature table size mismatch.\n");
return -EFAULT;
}
+
ext_sigcount = ext_header->count;
- }
- /* check extended table checksum */
- if (ext_table_size) {
- int ext_table_sum = 0;
- int *ext_tablep = (int *)ext_header;
+ /*
+ * Check extended table checksum: the sum of all dwords that
+ * comprise a valid table must be 0.
+ */
+ ext_tablep = (u32 *)ext_header;
- i = ext_table_size / DWSIZE;
+ i = ext_table_size / sizeof(u32);
while (i--)
ext_table_sum += ext_tablep[i];
+
if (ext_table_sum) {
if (print_err)
- pr_warn("aborting, bad extended signature table checksum\n");
+ pr_warn("Bad extended signature table checksum, aborting.\n");
return -EINVAL;
}
}
- /* calculate the checksum */
+ /*
+ * Calculate the checksum of update data and header. The checksum of
+ * valid update data and header including the extended signature table
+ * must be 0.
+ */
orig_sum = 0;
- i = (MC_HEADER_SIZE + data_size) / DWSIZE;
+ i = (MC_HEADER_SIZE + data_size) / sizeof(u32);
while (i--)
- orig_sum += ((int *)mc)[i];
+ orig_sum += ((u32 *)mc)[i];
+
if (orig_sum) {
if (print_err)
- pr_err("aborting, bad checksum\n");
+ pr_err("Bad microcode data checksum, aborting.\n");
return -EINVAL;
}
+
if (!ext_table_size)
return 0;
- /* check extended signature checksum */
+
+ /*
+ * Check extended signature checksum: 0 => valid.
+ */
for (i = 0; i < ext_sigcount; i++) {
ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
EXT_SIGNATURE_SIZE * i;
- sum = orig_sum
- - (mc_header->sig + mc_header->pf + mc_header->cksum)
- + (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
+
+ sum = (mc_header->sig + mc_header->pf + mc_header->cksum) -
+ (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
if (sum) {
if (print_err)
- pr_err("aborting, bad checksum\n");
+ pr_err("Bad extended signature checksum, aborting.\n");
return -EINVAL;
}
}