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/*
* Intel CPU Microcode Update Driver for Linux
*
* Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
* H Peter Anvin" <hpa@zytor.com>
*
* This driver allows to upgrade microcode on Intel processors
* belonging to IA-32 family - PentiumPro, Pentium II,
* Pentium III, Xeon, Pentium 4, etc.
*
* Reference: Section 8.11 of Volume 3a, IA-32 Intel? Architecture
* Software Developer's Manual
* Order Number 253668 or free download from:
*
* http://developer.intel.com/Assets/PDF/manual/253668.pdf
*
* For more information, go to http://www.urbanmyth.org/microcode
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/firmware.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <asm/microcode_intel.h>
#include <asm/processor.h>
#include <asm/msr.h>
static inline bool cpu_signatures_match(unsigned int s1, unsigned int p1,
unsigned int s2, unsigned int p2)
{
if (s1 != s2)
return false;
/* Processor flags are either both 0 ... */
if (!p1 && !p2)
return true;
/* ... or they intersect. */
return p1 & p2;
}
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;
u32 sum, orig_sum, ext_sigcount = 0, i;
struct extended_signature *ext_sig;
total_size = get_totalsize(mc_header);
data_size = get_datasize(mc_header);
if (data_size + MC_HEADER_SIZE > total_size) {
if (print_err)
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: 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: 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: extended signature table size mismatch.\n");
return -EFAULT;
}
ext_sigcount = ext_header->count;
/*
* 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 / sizeof(u32);
while (i--)
ext_table_sum += ext_tablep[i];
if (ext_table_sum) {
if (print_err)
pr_warn("Bad extended signature table checksum, aborting.\n");
return -EINVAL;
}
}
/*
* 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) / sizeof(u32);
while (i--)
orig_sum += ((u32 *)mc)[i];
if (orig_sum) {
if (print_err)
pr_err("Bad microcode data checksum, aborting.\n");
return -EINVAL;
}
if (!ext_table_size)
return 0;
/*
* 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 = (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("Bad extended signature checksum, aborting.\n");
return -EINVAL;
}
}
return 0;
}
/*
* Returns 1 if update has been found, 0 otherwise.
*/
int find_matching_signature(void *mc, unsigned int csig, int cpf)
{
struct microcode_header_intel *mc_hdr = mc;
struct extended_sigtable *ext_hdr;
struct extended_signature *ext_sig;
int i;
if (cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))
return 1;
/* Look for ext. headers: */
if (get_totalsize(mc_hdr) <= get_datasize(mc_hdr) + MC_HEADER_SIZE)
return 0;
ext_hdr = mc + get_datasize(mc_hdr) + MC_HEADER_SIZE;
ext_sig = (void *)ext_hdr + EXT_HEADER_SIZE;
for (i = 0; i < ext_hdr->count; i++) {
if (cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))
return 1;
ext_sig++;
}
return 0;
}
/*
* Returns 1 if update has been found, 0 otherwise.
*/
int has_newer_microcode(void *mc, unsigned int csig, int cpf, int new_rev)
{
struct microcode_header_intel *mc_hdr = mc;
if (mc_hdr->rev <= new_rev)
return 0;
return find_matching_signature(mc, csig, cpf);
}
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