drivers/char/tpm/eventlog/of.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2012 IBM Corporation
   4  *
   5  * Author: Ashley Lai <ashleydlai@gmail.com>
   6  *         Nayna Jain <nayna@linux.vnet.ibm.com>
   7  *
   8  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
   9  *
  10  * Read the event log created by the firmware on PPC64
  11  */
  12
  13 #include <linux/device.h>
  14 #include <linux/slab.h>
  15 #include <linux/io.h>
  16 #include <linux/ioport.h>
  17 #include <linux/of.h>
  18 #include <linux/of_address.h>
  19 #include <linux/of_reserved_mem.h>
  20 #include <linux/tpm_eventlog.h>
  21
  22 #include "../tpm.h"
  23 #include "common.h"
  24
  25 static int tpm_read_log_memory_region(struct tpm_chip *chip)
  26 {
  27         struct device_node *node;
  28         struct resource res;
  29         int rc;
  30
  31         node = of_parse_phandle(chip->dev.parent->of_node, "memory-region", 0);
  32         if (!node)
  33                 return -ENODEV;
  34
  35         rc = of_address_to_resource(node, 0, &res);
  36         of_node_put(node);
  37         if (rc)
  38                 return rc;
  39
  40         chip->log.bios_event_log = devm_memremap(&chip->dev, res.start, resource_size(&res),
  41                                                  MEMREMAP_WB);
  42         if (IS_ERR(chip->log.bios_event_log))
  43                 return -ENOMEM;
  44
  45         chip->log.bios_event_log_end = chip->log.bios_event_log + resource_size(&res);
  46
  47         return chip->flags & TPM_CHIP_FLAG_TPM2 ? EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 :
  48                 EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
  49 }
  50
  51 int tpm_read_log_of(struct tpm_chip *chip)
  52 {
  53         struct device_node *np;
  54         const u32 *sizep;
  55         const u64 *basep;
  56         struct tpm_bios_log *log;
  57         u32 size;
  58         u64 base;
  59
  60         log = &chip->log;
  61         if (chip->dev.parent && chip->dev.parent->of_node)
  62                 np = chip->dev.parent->of_node;
  63         else
  64                 return -ENODEV;
  65
  66         if (of_property_read_bool(np, "powered-while-suspended"))
  67                 chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
  68
  69         sizep = of_get_property(np, "linux,sml-size", NULL);
  70         basep = of_get_property(np, "linux,sml-base", NULL);
  71         if (sizep == NULL && basep == NULL)
  72                 return tpm_read_log_memory_region(chip);
  73         if (sizep == NULL || basep == NULL)
  74                 return -EIO;
  75
  76         /*
  77          * For both vtpm/tpm, firmware has log addr and log size in big
  78          * endian format. But in case of vtpm, there is a method called
  79          * sml-handover which is run during kernel init even before
  80          * device tree is setup. This sml-handover function takes care
  81          * of endianness and writes to sml-base and sml-size in little
  82          * endian format. For this reason, vtpm doesn't need conversion
  83          * but physical tpm needs the conversion.
  84          */
  85         if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
  86             of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
  87                 size = be32_to_cpup((__force __be32 *)sizep);
  88                 base = be64_to_cpup((__force __be64 *)basep);
  89         } else {
  90                 size = *sizep;
  91                 base = *basep;
  92         }
  93
  94         if (size == 0) {
  95                 dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
  96                 return -EIO;
  97         }
  98
  99         log->bios_event_log = devm_kmemdup(&chip->dev, __va(base), size, GFP_KERNEL);
 100         if (!log->bios_event_log)
 101                 return -ENOMEM;
 102
 103         log->bios_event_log_end = log->bios_event_log + size;
 104
 105         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 106                 return EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
 107         return EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
 108 }