linux/drivers/char/tpm/tpm.h
Duncan Laurie 32d33b29ba TPM: Retry SaveState command in suspend path
If the TPM has already been sent a SaveState command before the driver
is loaded it may have problems sending that same command again later.

This issue is seen with the Chromebook Pixel due to a firmware bug in
the legacy mode boot path which is sending the SaveState command
before booting the kernel.  More information is available at
http://crbug.com/203524

This change introduces a retry of the SaveState command in the suspend
path in order to work around this issue.  A future firmware update
should fix this but this is also a trivial workaround in the driver
that has no effect on systems that do not show this problem.

When this does happen the TPM responds with a non-fatal TPM_RETRY code
that is defined in the specification:

  The TPM is too busy to respond to the command immediately, but the
  command could be resubmitted at a later time.  The TPM MAY return
  TPM_RETRY for any command at any time.

It can take several seconds before the TPM will respond again.  I
measured a typical time between 3 and 4 seconds and the timeout is set
at a safe 5 seconds.

It is also possible to reproduce this with commands via /dev/tpm0.
The bug linked above has a python script attached which can be used to
test for this problem.  I tested a variety of TPMs from Infineon,
Nuvoton, Atmel, and STMicro but was only able to reproduce this with
LPC and I2C TPMs from Infineon.

The TPM specification only loosely defines this behavior:

  TPM Main Level 2 Part 3 v1.2 r116, section 3.3. TPM_SaveState:
  The TPM MAY declare all preserved values invalid in response to any
  command other than TPM_Init.

  TCG PC Client BIOS Spec 1.21 section 8.3.1.
  After issuing a TPM_SaveState command, the OS SHOULD NOT issue TPM
  commands before transitioning to S3 without issuing another
  TPM_SaveState command.

  TCG PC Client TIS 1.21, section 4. Power Management:
  The TPM_SaveState command allows a Static OS to indicate to the TPM
  that the platform may enter a low power state where the TPM will be
  required to enter into the D3 power state.  The use of the term "may"
  is significant in that there is no requirement for the platform to
  actually enter the low power state after sending the TPM_SaveState
  command.  The software may, in fact, send subsequent commands after
  sending the TPM_SaveState command.

Change-Id: I52b41e826412688e5b6c8ddd3bb16409939704e9
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
2013-04-17 09:31:32 -05:00

359 lines
8.6 KiB
C

/*
* Copyright (C) 2004 IBM Corporation
*
* Authors:
* Leendert van Doorn <leendert@watson.ibm.com>
* Dave Safford <safford@watson.ibm.com>
* Reiner Sailer <sailer@watson.ibm.com>
* Kylene Hall <kjhall@us.ibm.com>
*
* Maintained by: <tpmdd-devel@lists.sourceforge.net>
*
* Device driver for TCG/TCPA TPM (trusted platform module).
* Specifications at www.trustedcomputinggroup.org
*
* 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, version 2 of the
* License.
*
*/
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/miscdevice.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/tpm.h>
enum tpm_const {
TPM_MINOR = 224, /* officially assigned */
TPM_BUFSIZE = 4096,
TPM_NUM_DEVICES = 256,
TPM_RETRY = 50, /* 5 seconds */
};
enum tpm_timeout {
TPM_TIMEOUT = 5, /* msecs */
TPM_TIMEOUT_RETRY = 100 /* msecs */
};
/* TPM addresses */
enum tpm_addr {
TPM_SUPERIO_ADDR = 0x2E,
TPM_ADDR = 0x4E,
};
#define TPM_WARN_RETRY 0x800
#define TPM_WARN_DOING_SELFTEST 0x802
#define TPM_ERR_DEACTIVATED 0x6
#define TPM_ERR_DISABLED 0x7
#define TPM_ERR_INVALID_POSTINIT 38
#define TPM_HEADER_SIZE 10
extern ssize_t tpm_show_pubek(struct device *, struct device_attribute *attr,
char *);
extern ssize_t tpm_show_pcrs(struct device *, struct device_attribute *attr,
char *);
extern ssize_t tpm_show_caps(struct device *, struct device_attribute *attr,
char *);
extern ssize_t tpm_show_caps_1_2(struct device *, struct device_attribute *attr,
char *);
extern ssize_t tpm_store_cancel(struct device *, struct device_attribute *attr,
const char *, size_t);
extern ssize_t tpm_show_enabled(struct device *, struct device_attribute *attr,
char *);
extern ssize_t tpm_show_active(struct device *, struct device_attribute *attr,
char *);
extern ssize_t tpm_show_owned(struct device *, struct device_attribute *attr,
char *);
extern ssize_t tpm_show_temp_deactivated(struct device *,
struct device_attribute *attr, char *);
extern ssize_t tpm_show_durations(struct device *,
struct device_attribute *attr, char *);
extern ssize_t tpm_show_timeouts(struct device *,
struct device_attribute *attr, char *);
struct tpm_chip;
struct tpm_vendor_specific {
const u8 req_complete_mask;
const u8 req_complete_val;
bool (*req_canceled)(struct tpm_chip *chip, u8 status);
void __iomem *iobase; /* ioremapped address */
unsigned long base; /* TPM base address */
int irq;
int probed_irq;
int region_size;
int have_region;
int (*recv) (struct tpm_chip *, u8 *, size_t);
int (*send) (struct tpm_chip *, u8 *, size_t);
void (*cancel) (struct tpm_chip *);
u8 (*status) (struct tpm_chip *);
void (*release) (struct device *);
struct miscdevice miscdev;
struct attribute_group *attr_group;
struct list_head list;
int locality;
unsigned long timeout_a, timeout_b, timeout_c, timeout_d; /* jiffies */
bool timeout_adjusted;
unsigned long duration[3]; /* jiffies */
bool duration_adjusted;
void *priv;
wait_queue_head_t read_queue;
wait_queue_head_t int_queue;
u16 manufacturer_id;
};
#define TPM_VPRIV(c) (c)->vendor.priv
#define TPM_VID_INTEL 0x8086
#define TPM_VID_WINBOND 0x1050
#define TPM_VID_STM 0x104A
struct tpm_chip {
struct device *dev; /* Device stuff */
int dev_num; /* /dev/tpm# */
unsigned long is_open; /* only one allowed */
int time_expired;
/* Data passed to and from the tpm via the read/write calls */
u8 *data_buffer;
atomic_t data_pending;
struct mutex buffer_mutex;
struct timer_list user_read_timer; /* user needs to claim result */
struct work_struct work;
struct mutex tpm_mutex; /* tpm is processing */
struct tpm_vendor_specific vendor;
struct dentry **bios_dir;
struct list_head list;
void (*release) (struct device *);
};
#define to_tpm_chip(n) container_of(n, struct tpm_chip, vendor)
static inline void tpm_chip_put(struct tpm_chip *chip)
{
module_put(chip->dev->driver->owner);
}
static inline int tpm_read_index(int base, int index)
{
outb(index, base);
return inb(base+1) & 0xFF;
}
static inline void tpm_write_index(int base, int index, int value)
{
outb(index, base);
outb(value & 0xFF, base+1);
}
struct tpm_input_header {
__be16 tag;
__be32 length;
__be32 ordinal;
} __packed;
struct tpm_output_header {
__be16 tag;
__be32 length;
__be32 return_code;
} __packed;
struct stclear_flags_t {
__be16 tag;
u8 deactivated;
u8 disableForceClear;
u8 physicalPresence;
u8 physicalPresenceLock;
u8 bGlobalLock;
} __packed;
struct tpm_version_t {
u8 Major;
u8 Minor;
u8 revMajor;
u8 revMinor;
} __packed;
struct tpm_version_1_2_t {
__be16 tag;
u8 Major;
u8 Minor;
u8 revMajor;
u8 revMinor;
} __packed;
struct timeout_t {
__be32 a;
__be32 b;
__be32 c;
__be32 d;
} __packed;
struct duration_t {
__be32 tpm_short;
__be32 tpm_medium;
__be32 tpm_long;
} __packed;
struct permanent_flags_t {
__be16 tag;
u8 disable;
u8 ownership;
u8 deactivated;
u8 readPubek;
u8 disableOwnerClear;
u8 allowMaintenance;
u8 physicalPresenceLifetimeLock;
u8 physicalPresenceHWEnable;
u8 physicalPresenceCMDEnable;
u8 CEKPUsed;
u8 TPMpost;
u8 TPMpostLock;
u8 FIPS;
u8 operator;
u8 enableRevokeEK;
u8 nvLocked;
u8 readSRKPub;
u8 tpmEstablished;
u8 maintenanceDone;
u8 disableFullDALogicInfo;
} __packed;
typedef union {
struct permanent_flags_t perm_flags;
struct stclear_flags_t stclear_flags;
bool owned;
__be32 num_pcrs;
struct tpm_version_t tpm_version;
struct tpm_version_1_2_t tpm_version_1_2;
__be32 manufacturer_id;
struct timeout_t timeout;
struct duration_t duration;
} cap_t;
struct tpm_getcap_params_in {
__be32 cap;
__be32 subcap_size;
__be32 subcap;
} __packed;
struct tpm_getcap_params_out {
__be32 cap_size;
cap_t cap;
} __packed;
struct tpm_readpubek_params_out {
u8 algorithm[4];
u8 encscheme[2];
u8 sigscheme[2];
__be32 paramsize;
u8 parameters[12]; /*assuming RSA*/
__be32 keysize;
u8 modulus[256];
u8 checksum[20];
} __packed;
typedef union {
struct tpm_input_header in;
struct tpm_output_header out;
} tpm_cmd_header;
#define TPM_DIGEST_SIZE 20
struct tpm_pcrread_out {
u8 pcr_result[TPM_DIGEST_SIZE];
} __packed;
struct tpm_pcrread_in {
__be32 pcr_idx;
} __packed;
struct tpm_pcrextend_in {
__be32 pcr_idx;
u8 hash[TPM_DIGEST_SIZE];
} __packed;
/* 128 bytes is an arbitrary cap. This could be as large as TPM_BUFSIZE - 18
* bytes, but 128 is still a relatively large number of random bytes and
* anything much bigger causes users of struct tpm_cmd_t to start getting
* compiler warnings about stack frame size. */
#define TPM_MAX_RNG_DATA 128
struct tpm_getrandom_out {
__be32 rng_data_len;
u8 rng_data[TPM_MAX_RNG_DATA];
} __packed;
struct tpm_getrandom_in {
__be32 num_bytes;
} __packed;
struct tpm_startup_in {
__be16 startup_type;
} __packed;
typedef union {
struct tpm_getcap_params_out getcap_out;
struct tpm_readpubek_params_out readpubek_out;
u8 readpubek_out_buffer[sizeof(struct tpm_readpubek_params_out)];
struct tpm_getcap_params_in getcap_in;
struct tpm_pcrread_in pcrread_in;
struct tpm_pcrread_out pcrread_out;
struct tpm_pcrextend_in pcrextend_in;
struct tpm_getrandom_in getrandom_in;
struct tpm_getrandom_out getrandom_out;
struct tpm_startup_in startup_in;
} tpm_cmd_params;
struct tpm_cmd_t {
tpm_cmd_header header;
tpm_cmd_params params;
} __packed;
ssize_t tpm_getcap(struct device *, __be32, cap_t *, const char *);
extern int tpm_get_timeouts(struct tpm_chip *);
extern void tpm_gen_interrupt(struct tpm_chip *);
extern int tpm_do_selftest(struct tpm_chip *);
extern unsigned long tpm_calc_ordinal_duration(struct tpm_chip *, u32);
extern struct tpm_chip* tpm_register_hardware(struct device *,
const struct tpm_vendor_specific *);
extern int tpm_open(struct inode *, struct file *);
extern int tpm_release(struct inode *, struct file *);
extern void tpm_dev_vendor_release(struct tpm_chip *);
extern ssize_t tpm_write(struct file *, const char __user *, size_t,
loff_t *);
extern ssize_t tpm_read(struct file *, char __user *, size_t, loff_t *);
extern void tpm_remove_hardware(struct device *);
extern int tpm_pm_suspend(struct device *);
extern int tpm_pm_resume(struct device *);
extern int wait_for_tpm_stat(struct tpm_chip *, u8, unsigned long,
wait_queue_head_t *, bool);
#ifdef CONFIG_ACPI
extern int tpm_add_ppi(struct kobject *);
extern void tpm_remove_ppi(struct kobject *);
#else
static inline int tpm_add_ppi(struct kobject *parent)
{
return 0;
}
static inline void tpm_remove_ppi(struct kobject *parent)
{
}
#endif