src/vendorcode/google/chromeos/vboot.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright (C) 2011 The ChromiumOS Authors.  All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #include <types.h>
  21 #include <console/console.h>
  22 #include <arch/acpi.h>
  23 #include <pc80/tpm.h>
  24 #include <reset.h>
  25 #include "chromeos.h"
  26
  27 //#define EXTRA_LOGGING
  28 #define UBOOT_DOES_TPM_STARTUP
  29
  30 #define TPM_LARGE_ENOUGH_COMMAND_SIZE 256       /* saves space in the firmware */
  31
  32 #define TPM_SUCCESS               ((u32)0x00000000)
  33
  34 #define TPM_E_IOERROR             ((u32)0x0000001f)
  35 #define TPM_E_COMMUNICATION_ERROR ((u32)0x00005004)
  36 #define TPM_E_NON_FATAL           ((u32)0x00000800)
  37 #define TPM_E_INVALID_POSTINIT    ((u32)0x00000026)
  38
  39 #define TPM_E_NEEDS_SELFTEST     ((u32)(TPM_E_NON_FATAL + 1))
  40 #define TPM_E_DOING_SELFTEST     ((u32)(TPM_E_NON_FATAL + 2))
  41
  42 static const struct {
  43         u8 buffer[12];
  44 } tpm_resume_cmd = {
  45         { 0x0, 0xc1, 0x0, 0x0, 0x0, 0xc, 0x0, 0x0, 0x0, 0x99, 0x0, 0x2 }
  46 };
  47
  48 static const struct {
  49         u8 buffer[12];
  50 } tpm_startup_cmd = {
  51         {0x0, 0xc1, 0x0, 0x0, 0x0, 0xc, 0x0, 0x0, 0x0, 0x99, 0x0, 0x1 }
  52 };
  53
  54 static const struct {
  55         u8 buffer[10];
  56 } tpm_continueselftest_cmd = {
  57         { 0x0, 0xc1, 0x0, 0x0, 0x0, 0xa, 0x0, 0x0, 0x0, 0x53 }
  58 };
  59
  60 static inline void FromTpmUint32(const u8 * buffer, u32 * x)
  61 {
  62         *x = ((buffer[0] << 24) |
  63               (buffer[1] << 16) | (buffer[2] << 8) | buffer[3]);
  64 }
  65
  66 static inline int TpmCommandSize(const u8 * buffer)
  67 {
  68         u32 size;
  69         FromTpmUint32(buffer + sizeof(u16), &size);
  70         return (int)size;
  71 }
  72
  73 /* Gets the code field of a TPM command. */
  74 static inline int TpmCommandCode(const u8 * buffer)
  75 {
  76         u32 code;
  77         FromTpmUint32(buffer + sizeof(u16) + sizeof(u32), &code);
  78         return code;
  79 }
  80
  81 /* Gets the return code field of a TPM result. */
  82 static inline int TpmReturnCode(const u8 * buffer)
  83 {
  84         return TpmCommandCode(buffer);
  85 }
  86
  87 /* Like TlclSendReceive below, but do not retry if NEEDS_SELFTEST or
  88  * DOING_SELFTEST errors are returned.
  89  */
  90 static u32 TlclSendReceiveNoRetry(const u8 * request,
  91                                   u8 * response, int max_length)
  92 {
  93         size_t response_length = max_length;
  94         u32 result;
  95
  96 #ifdef EXTRA_LOGGING
  97         printk(BIOS_DEBUG, "TPM: command: %x%x %x%x%x%x %x%x%x%x\n",
  98                request[0], request[1],
  99                request[2], request[3], request[4], request[5],
 100                request[6], request[7], request[8], request[9]);
 101 #endif
 102
 103         result = TPM_SUCCESS;
 104         if (tis_sendrecv
 105             (request, TpmCommandSize(request), response, &response_length))
 106                 result = TPM_E_IOERROR;
 107
 108         if (0 != result) {
 109                 /* Communication with TPM failed, so response is garbage */
 110                 printk(BIOS_DEBUG,
 111                        "TPM: command 0x%x send/receive failed: 0x%x\n",
 112                        TpmCommandCode(request), result);
 113                 return TPM_E_COMMUNICATION_ERROR;
 114         }
 115         /* Otherwise, use the result code from the response */
 116         result = TpmReturnCode(response);
 117
 118 /* TODO: add paranoia about returned response_length vs. max_length
 119  * (and possibly expected length from the response header).  See
 120  * crosbug.com/17017 */
 121
 122 #ifdef EXTRA_LOGGING
 123         printk(BIOS_DEBUG, "TPM: response: %x%x %x%x%x%x %x%x%x%x\n",
 124                response[0], response[1],
 125                response[2], response[3], response[4], response[5],
 126                response[6], response[7], response[8], response[9]);
 127 #endif
 128
 129         printk(BIOS_DEBUG, "TPM: command 0x%x returned 0x%x\n",
 130                TpmCommandCode(request), result);
 131
 132         return result;
 133 }
 134
 135 static inline u32 TlclContinueSelfTest(void)
 136 {
 137         u8 response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
 138         printk(BIOS_DEBUG, "TPM: Continue self test\n");
 139         /* Call the No Retry version of SendReceive to avoid recursion. */
 140         return TlclSendReceiveNoRetry(tpm_continueselftest_cmd.buffer,
 141                                       response, sizeof(response));
 142 }
 143
 144 /* Sends a TPM command and gets a response.  Returns 0 if success or the TPM
 145  * error code if error. In the firmware, waits for the self test to complete
 146  * if needed. In the host, reports the first error without retries. */
 147 static u32 TlclSendReceive(const u8 * request, u8 * response, int max_length)
 148 {
 149         u32 result = TlclSendReceiveNoRetry(request, response, max_length);
 150         /* When compiling for the firmware, hide command failures due to the self
 151          * test not having run or completed. */
 152         /* If the command fails because the self test has not completed, try it
 153          * again after attempting to ensure that the self test has completed. */
 154         if (result == TPM_E_NEEDS_SELFTEST || result == TPM_E_DOING_SELFTEST) {
 155                 result = TlclContinueSelfTest();
 156                 if (result != TPM_SUCCESS) {
 157                         return result;
 158                 }
 159 #if defined(TPM_BLOCKING_CONTINUESELFTEST) || defined(VB_RECOVERY_MODE)
 160                 /* Retry only once */
 161                 result = TlclSendReceiveNoRetry(request, response, max_length);
 162 #else
 163                 /* This needs serious testing.  The TPM specification says:
 164                  * "iii. The caller MUST wait for the actions of
 165                  * TPM_ContinueSelfTest to complete before reissuing the
 166                  * command C1."  But, if ContinueSelfTest is non-blocking, how
 167                  * do we know that the actions have completed other than trying
 168                  * again? */
 169                 do {
 170                         result =
 171                             TlclSendReceiveNoRetry(request, response,
 172                                                    max_length);
 173                 } while (result == TPM_E_DOING_SELFTEST);
 174 #endif
 175         }
 176
 177         return result;
 178 }
 179
 180 static void init_vboot(int bootmode)
 181 {
 182         u32 result;
 183         u8 response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
 184
 185 #ifdef UBOOT_DOES_TPM_STARTUP
 186         /* Doing TPM startup when we're not coming in on the S3 resume path
 187          * saves us roughly 20ms in boot time only. This does not seem to
 188          * be worth an API change to vboot_reference-firmware right now, so
 189          * let's keep the code around, but just bail out early:
 190          */
 191         if (bootmode != 2)
 192                 return;
 193 #endif
 194
 195         printk(BIOS_DEBUG, "Verified boot TPM initialization.\n");
 196
 197         printk(BIOS_SPEW, "TPM: Init\n");
 198         if (tis_init())
 199                 return;
 200
 201         printk(BIOS_SPEW, "TPM: Open\n");
 202         if (tis_open())
 203                 return;
 204
 205
 206         if (bootmode == 2) {
 207                 /* S3 Resume */
 208                 printk(BIOS_SPEW, "TPM: Resume\n");
 209                 result = TlclSendReceive(tpm_resume_cmd.buffer,
 210                                         response, sizeof(response));
 211                 if (result == TPM_E_INVALID_POSTINIT) {
 212                         /* We're on a platform where the TPM maintains power
 213                          * in S3, so it's already initialized.
 214                          */
 215                         printk(BIOS_DEBUG, "TPM: Already initialized.\n");
 216                         return;
 217                 }
 218         } else {
 219                 printk(BIOS_SPEW, "TPM: Startup\n");
 220                 result = TlclSendReceive(tpm_startup_cmd.buffer,
 221                                         response, sizeof(response));
 222         }
 223
 224         if (result == TPM_SUCCESS) {
 225                 printk(BIOS_SPEW, "TPM: OK.\n");
 226                 return;
 227         }
 228
 229         printk(BIOS_ERR, "TPM: Error code 0x%x. Hard reset!\n", result);
 230         hard_reset();
 231 }
 232
 233 void init_chromeos(int bootmode)
 234 {
 235         init_vboot(bootmode);
 236 }