253 lines
6.6 KiB
C
253 lines
6.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#include <console/console.h>
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#include <string.h>
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#include <cbfs.h>
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#include <option.h>
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#include <pc80/mc146818rtc.h>
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#include <types.h>
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/* option_table.h is autogenerated */
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#include "option_table.h"
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/* Don't warn for checking >= LB_CKS_RANGE_START even though it may be 0. */
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#pragma GCC diagnostic ignored "-Wtype-limits"
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/*
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* This routine returns the value of the requested bits.
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* input bit = bit count from the beginning of the CMOS image
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* length = number of bits to include in the value
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* ret = a character pointer to where the value is to be returned
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* returns CB_SUCCESS = successful, cb_err code if an error occurred
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*/
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static enum cb_err get_cmos_value(unsigned long bit, unsigned long length,
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void *vret)
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{
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unsigned char *ret;
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unsigned long byte, byte_bit;
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unsigned long i;
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unsigned char uchar;
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/*
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* The table is checked when it is built to ensure all
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* values are valid.
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*/
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ret = vret;
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byte = bit / 8; /* find the byte where the data starts */
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byte_bit = bit % 8; /* find the bit in the byte where the data starts */
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if (length < 9) { /* one byte or less */
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uchar = cmos_read(byte); /* load the byte */
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uchar >>= byte_bit; /* shift the bits to byte align */
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/* clear unspecified bits */
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ret[0] = uchar & ((1 << length) - 1);
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} else { /* more than one byte so transfer the whole bytes */
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for (i = 0; length; i++, length -= 8, byte++) {
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/* load the byte */
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ret[i] = cmos_read(byte);
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}
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}
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return CB_SUCCESS;
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}
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static enum cb_err locate_cmos_layout(struct region_device *rdev)
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{
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uint32_t cbfs_type = CBFS_COMPONENT_CMOS_LAYOUT;
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static struct cbfsf fh;
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/*
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* In case VBOOT is enabled and this function is called from SMM,
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* we have multiple CMOS layout files and to locate them we'd need to
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* include VBOOT into SMM...
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*
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* Support only one CMOS layout in the 'COREBOOT' region for now.
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*/
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if (!region_device_sz(&(fh.data))) {
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if (cbfs_locate_file_in_region(&fh, "COREBOOT", "cmos_layout.bin",
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&cbfs_type)) {
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printk(BIOS_ERR, "RTC: cmos_layout.bin could not be found. "
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"Options are disabled\n");
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return CB_CMOS_LAYOUT_NOT_FOUND;
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}
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}
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cbfs_file_data(rdev, &fh);
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return CB_SUCCESS;
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}
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enum cb_err cmos_get_option(void *dest, const char *name)
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{
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struct cmos_option_table *ct;
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struct region_device rdev;
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struct cmos_entries *ce;
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size_t namelen;
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int found = 0;
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/* Figure out how long name is */
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namelen = strnlen(name, CMOS_MAX_NAME_LENGTH);
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if (locate_cmos_layout(&rdev) != CB_SUCCESS) {
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return CB_CMOS_LAYOUT_NOT_FOUND;
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}
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ct = rdev_mmap_full(&rdev);
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if (!ct) {
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printk(BIOS_ERR, "RTC: cmos_layout.bin could not be mapped. "
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"Options are disabled\n");
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return CB_CMOS_LAYOUT_NOT_FOUND;
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}
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/* find the requested entry record */
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ce = (struct cmos_entries *)((unsigned char *)ct + ct->header_length);
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for (; ce->tag == LB_TAG_OPTION;
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ce = (struct cmos_entries *)((unsigned char *)ce + ce->size)) {
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if (memcmp(ce->name, name, namelen) == 0) {
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found = 1;
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break;
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}
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}
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if (!found) {
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printk(BIOS_DEBUG, "No CMOS option '%s'.\n", name);
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rdev_munmap(&rdev, ct);
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return CB_CMOS_OPTION_NOT_FOUND;
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}
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if (!cmos_checksum_valid(LB_CKS_RANGE_START, LB_CKS_RANGE_END, LB_CKS_LOC)) {
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rdev_munmap(&rdev, ct);
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return CB_CMOS_CHECKSUM_INVALID;
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}
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if (get_cmos_value(ce->bit, ce->length, dest) != CB_SUCCESS) {
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rdev_munmap(&rdev, ct);
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return CB_CMOS_ACCESS_ERROR;
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}
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rdev_munmap(&rdev, ct);
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return CB_SUCCESS;
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}
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static enum cb_err set_cmos_value(unsigned long bit, unsigned long length,
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void *vret)
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{
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unsigned char *ret;
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unsigned long byte, byte_bit;
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unsigned long i;
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unsigned char uchar, mask;
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unsigned int chksum_update_needed = 0;
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ret = vret;
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byte = bit / 8; /* find the byte where the data starts */
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byte_bit = bit % 8; /* find the bit where the data starts */
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if (length <= 8) { /* one byte or less */
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mask = (1 << length) - 1;
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mask <<= byte_bit;
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uchar = cmos_read(byte);
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uchar &= ~mask;
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uchar |= (ret[0] << byte_bit);
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cmos_write(uchar, byte);
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if (byte >= LB_CKS_RANGE_START && byte <= LB_CKS_RANGE_END)
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chksum_update_needed = 1;
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} else { /* more that one byte so transfer the whole bytes */
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if (byte_bit || length % 8)
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return CB_ERR_ARG;
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for (i = 0; length; i++, length -= 8, byte++) {
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cmos_write(ret[i], byte);
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if (byte >= LB_CKS_RANGE_START &&
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byte <= LB_CKS_RANGE_END)
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chksum_update_needed = 1;
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}
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}
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if (chksum_update_needed) {
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cmos_set_checksum(LB_CKS_RANGE_START, LB_CKS_RANGE_END,
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LB_CKS_LOC);
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}
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return CB_SUCCESS;
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}
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enum cb_err cmos_set_option(const char *name, void *value)
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{
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struct cmos_option_table *ct;
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struct region_device rdev;
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struct cmos_entries *ce;
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unsigned long length;
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size_t namelen;
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int found = 0;
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/* Figure out how long name is */
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namelen = strnlen(name, CMOS_MAX_NAME_LENGTH);
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if (locate_cmos_layout(&rdev) != CB_SUCCESS) {
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return CB_CMOS_LAYOUT_NOT_FOUND;
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}
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ct = rdev_mmap_full(&rdev);
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if (!ct) {
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printk(BIOS_ERR, "RTC: cmos_layout.bin could not be mapped. "
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"Options are disabled\n");
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return CB_CMOS_LAYOUT_NOT_FOUND;
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}
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/* find the requested entry record */
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ce = (struct cmos_entries *)((unsigned char *)ct + ct->header_length);
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for (; ce->tag == LB_TAG_OPTION;
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ce = (struct cmos_entries *)((unsigned char *)ce + ce->size)) {
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if (memcmp(ce->name, name, namelen) == 0) {
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found = 1;
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break;
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}
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}
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if (!found) {
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printk(BIOS_DEBUG, "WARNING: No CMOS option '%s'.\n", name);
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rdev_munmap(&rdev, ct);
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return CB_CMOS_OPTION_NOT_FOUND;
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}
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length = ce->length;
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if (ce->config == 's') {
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length = MAX(strlen((const char *)value) * 8, ce->length - 8);
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/* make sure the string is null terminated */
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if (set_cmos_value(ce->bit + ce->length - 8, 8, &(u8[]){0})
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!= CB_SUCCESS) {
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rdev_munmap(&rdev, ct);
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return CB_CMOS_ACCESS_ERROR;
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}
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}
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if (set_cmos_value(ce->bit, length, value) != CB_SUCCESS) {
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rdev_munmap(&rdev, ct);
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return CB_CMOS_ACCESS_ERROR;
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}
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rdev_munmap(&rdev, ct);
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return CB_SUCCESS;
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}
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int cmos_lb_cks_valid(void)
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{
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return cmos_checksum_valid(LB_CKS_RANGE_START, LB_CKS_RANGE_END, LB_CKS_LOC);
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}
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void sanitize_cmos(void)
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{
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const unsigned char *cmos_default;
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const bool cmos_need_reset =
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CONFIG(STATIC_OPTION_TABLE) || cmos_error() || !cmos_lb_cks_valid();
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size_t length = 128;
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size_t i;
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if (CONFIG(TPM_MEASURED_BOOT) || cmos_need_reset) {
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cmos_default = cbfs_boot_map_with_leak("cmos.default",
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CBFS_COMPONENT_CMOS_DEFAULT, &length);
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if (!cmos_default || !cmos_need_reset)
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return;
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u8 control_state = cmos_disable_rtc();
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for (i = 14; i < MIN(128, length); i++)
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cmos_write_inner(cmos_default[i], i);
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cmos_restore_rtc(control_state);
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}
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}
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