cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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tpm.c (2685B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (C) 2017 Google, Inc.
      4 *     Thiebaud Weksteen <tweek@google.com>
      5 */
      6
      7#define TPM_MEMREMAP(start, size) early_memremap(start, size)
      8#define TPM_MEMUNMAP(start, size) early_memunmap(start, size)
      9
     10#include <asm/early_ioremap.h>
     11#include <linux/efi.h>
     12#include <linux/init.h>
     13#include <linux/memblock.h>
     14#include <linux/tpm_eventlog.h>
     15
     16int efi_tpm_final_log_size;
     17EXPORT_SYMBOL(efi_tpm_final_log_size);
     18
     19static int __init tpm2_calc_event_log_size(void *data, int count, void *size_info)
     20{
     21	struct tcg_pcr_event2_head *header;
     22	int event_size, size = 0;
     23
     24	while (count > 0) {
     25		header = data + size;
     26		event_size = __calc_tpm2_event_size(header, size_info, true);
     27		if (event_size == 0)
     28			return -1;
     29		size += event_size;
     30		count--;
     31	}
     32
     33	return size;
     34}
     35
     36/*
     37 * Reserve the memory associated with the TPM Event Log configuration table.
     38 */
     39int __init efi_tpm_eventlog_init(void)
     40{
     41	struct linux_efi_tpm_eventlog *log_tbl;
     42	struct efi_tcg2_final_events_table *final_tbl;
     43	int tbl_size;
     44	int ret = 0;
     45
     46	if (efi.tpm_log == EFI_INVALID_TABLE_ADDR) {
     47		/*
     48		 * We can't calculate the size of the final events without the
     49		 * first entry in the TPM log, so bail here.
     50		 */
     51		return 0;
     52	}
     53
     54	log_tbl = early_memremap(efi.tpm_log, sizeof(*log_tbl));
     55	if (!log_tbl) {
     56		pr_err("Failed to map TPM Event Log table @ 0x%lx\n",
     57		       efi.tpm_log);
     58		efi.tpm_log = EFI_INVALID_TABLE_ADDR;
     59		return -ENOMEM;
     60	}
     61
     62	tbl_size = sizeof(*log_tbl) + log_tbl->size;
     63	memblock_reserve(efi.tpm_log, tbl_size);
     64
     65	if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR) {
     66		pr_info("TPM Final Events table not present\n");
     67		goto out;
     68	} else if (log_tbl->version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2) {
     69		pr_warn(FW_BUG "TPM Final Events table invalid\n");
     70		goto out;
     71	}
     72
     73	final_tbl = early_memremap(efi.tpm_final_log, sizeof(*final_tbl));
     74
     75	if (!final_tbl) {
     76		pr_err("Failed to map TPM Final Event Log table @ 0x%lx\n",
     77		       efi.tpm_final_log);
     78		efi.tpm_final_log = EFI_INVALID_TABLE_ADDR;
     79		ret = -ENOMEM;
     80		goto out;
     81	}
     82
     83	tbl_size = 0;
     84	if (final_tbl->nr_events != 0) {
     85		void *events = (void *)efi.tpm_final_log
     86				+ sizeof(final_tbl->version)
     87				+ sizeof(final_tbl->nr_events);
     88
     89		tbl_size = tpm2_calc_event_log_size(events,
     90						    final_tbl->nr_events,
     91						    log_tbl->log);
     92	}
     93
     94	if (tbl_size < 0) {
     95		pr_err(FW_BUG "Failed to parse event in TPM Final Events Log\n");
     96		ret = -EINVAL;
     97		goto out_calc;
     98	}
     99
    100	memblock_reserve((unsigned long)final_tbl,
    101			 tbl_size + sizeof(*final_tbl));
    102	efi_tpm_final_log_size = tbl_size;
    103
    104out_calc:
    105	early_memunmap(final_tbl, sizeof(*final_tbl));
    106out:
    107	early_memunmap(log_tbl, sizeof(*log_tbl));
    108	return ret;
    109}
    110