diff options
author | Nick Vaccaro <nvaccaro@google.com> | 2021-10-12 17:26:52 -0700 |
---|---|---|
committer | Nick Vaccaro <nvaccaro@google.com> | 2021-12-07 00:17:27 +0000 |
commit | b6f29c9bf47724168a58c196aa1d2ec65302731e (patch) | |
tree | b99e0d56d9dbfc04c9c6a62c0674e00328623e9c /src/soc | |
parent | eb3260b9715842d5abda28ac920afde696afd88c (diff) |
soc/intel/common: add generic gpio lock mechanism
For added security, there are some gpios that an SoC will want to lock
once initially configured, such as gpios attached to non-host (x86)
controllers, so that they can't be recofigured at a later point in
time by rogue code.
Likewise, a mainboard may have some gpios connected to secure busses
and/or devices that they want to protect from being changed post
initial configuration.
This change adds a generic gpio locking mechanism that allows the SoC
to export a list of GPIOs to be locked down and allows the mainboard
to export a list of GPIOs that it wants locked down once
initialization is complete.
Use the SOC_INTEL_COMMON_BLOCK_SMM_LOCK_GPIO_PADS Kconfig option to
enable this feature.
BUG=b:201430600
TEST='emerge-brya coreboot chromeos-bootimage', flash and verify
brya0 boots successfully to kernel.
Signed-off-by: Nick Vaccaro <nvaccaro@google.com>
Change-Id: I42979fb89567d8bcd9392da4fb8c4113ef427b14
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58351
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Diffstat (limited to 'src/soc')
-rw-r--r-- | src/soc/intel/common/block/gpio/gpio.c | 117 | ||||
-rw-r--r-- | src/soc/intel/common/block/include/intelblocks/gpio.h | 32 | ||||
-rw-r--r-- | src/soc/intel/common/block/smm/Kconfig | 7 | ||||
-rw-r--r-- | src/soc/intel/common/block/smm/smihandler.c | 38 |
4 files changed, 154 insertions, 40 deletions
diff --git a/src/soc/intel/common/block/gpio/gpio.c b/src/soc/intel/common/block/gpio/gpio.c index d4a312bf9a..ce23a2eedc 100644 --- a/src/soc/intel/common/block/gpio/gpio.c +++ b/src/soc/intel/common/block/gpio/gpio.c @@ -447,14 +447,27 @@ int gpio_get(gpio_t gpio_num) return !!(reg & PAD_CFG0_RX_STATE); } -int gpio_lock_pad(const gpio_t pad, enum gpio_lock_action action) +static int sideband_msg_err(int status, int response) { - const struct pad_community *comm = gpio_get_community(pad); - size_t rel_pad; + if (status || response) { + printk(BIOS_ERR, "%s: error status=%x response=%x\n", + __func__, status, response); + return (status == -1) ? -1 : response; + } + + return 0; +} + +int gpio_lock_pads(const struct gpio_lock_config *pad_list, const size_t count) +{ + const struct pad_community *comm; + enum gpio_lock_action action; + int status, err_response = 0; + uint8_t response; uint16_t offset; + size_t rel_pad; uint32_t data; - uint8_t response; - int status; + gpio_t pad; /* * FSP-S will unlock all the GPIO pads and hide the P2SB device. With @@ -468,23 +481,13 @@ int gpio_lock_pad(const gpio_t pad, enum gpio_lock_action action) return -1; } - if (!(action & GPIO_LOCK_FULL)) { - printk(BIOS_ERR, "%s: Error: no action specified!\n", __func__); - return -1; - } - - rel_pad = relative_pad_in_comm(comm, pad); - offset = comm->pad_cfg_lock_offset; - if (!offset) { - printk(BIOS_ERR, "%s: Error: offset is not defined!\n", __func__); + if ((pad_list == NULL) || (count == 0)) { + printk(BIOS_ERR, "%s: Error: pad_list null or count = 0!\n", __func__); return -1; } - offset += gpio_group_index_scaled(comm, rel_pad, 2 * sizeof(uint32_t)); /* We must use the sideband interface in order to lock the pad. */ struct pcr_sbi_msg msg = { - .pid = comm->port, - .offset = offset, .opcode = GPIO_LOCK_UNLOCK, .is_posted = false, .fast_byte_enable = 0xF, @@ -494,35 +497,69 @@ int gpio_lock_pad(const gpio_t pad, enum gpio_lock_action action) p2sb_unhide(); - data = gpio_bitmask_within_group(comm, rel_pad); - - if (action & GPIO_LOCK_CONFIG) { - printk(BIOS_INFO, "%s: Locking pad %d configuration\n", - __func__, pad); - status = pcr_execute_sideband_msg(&msg, &data, &response); - if (status || response) { - printk(BIOS_ERR, "%s: error status=%x response=%x\n", __func__, status, - response); - p2sb_hide(); - return status == -1 ? -1 : response; + for (int x = 0; x < count; x++) { + int err; + + pad = pad_list[x].gpio; + action = pad_list[x].action; + + if (!(action & GPIO_LOCK_FULL)) { + printk(BIOS_ERR, "%s: Error: no action specified for pad %d!\n", + __func__, pad); + continue; + } + + comm = gpio_get_community(pad); + rel_pad = relative_pad_in_comm(comm, pad); + offset = comm->pad_cfg_lock_offset; + if (!offset) { + printk(BIOS_ERR, "%s: Error: offset not defined for pad %d!\n", + __func__, pad); + continue; + } + offset += gpio_group_index_scaled(comm, rel_pad, 2 * sizeof(uint32_t)); + + data = gpio_bitmask_within_group(comm, rel_pad); + msg.pid = comm->port; + msg.offset = offset; + + if (action & GPIO_LOCK_CONFIG) { + if (CONFIG(DEBUG_GPIO)) + printk(BIOS_INFO, "%s: Locking pad %d configuration\n", + __func__, pad); + status = pcr_execute_sideband_msg(&msg, &data, &response); + if ((err = sideband_msg_err(status, response)) != 0) { + err_response = err; + continue; + } } - } - if (action & GPIO_LOCK_TX) { - printk(BIOS_INFO, "%s: Locking pad %d TX state\n", __func__, - pad); - msg.offset = msg.offset + 4; - status = pcr_execute_sideband_msg(&msg, &data, &response); - if (status || response) { - printk(BIOS_ERR, "%s: error status=%x response=%x\n", __func__, status, - response); - p2sb_hide(); - return status == -1 ? -1 : response; + if (action & GPIO_LOCK_TX) { + if (CONFIG(DEBUG_GPIO)) + printk(BIOS_INFO, "%s: Locking pad %d TX state\n", + __func__, pad); + msg.offset += 4; + status = pcr_execute_sideband_msg(&msg, &data, &response); + if ((err = sideband_msg_err(status, response)) != 0) { + err_response = err; + continue; + } } } p2sb_hide(); - return 0; + + return err_response; +} + +int gpio_lock_pad(const gpio_t pad, enum gpio_lock_action action) +{ + const struct gpio_lock_config pads = { + .gpio = pad, + .action = action + }; + + return gpio_lock_pads(&pads, 1); } void gpio_set(gpio_t gpio_num, int value) diff --git a/src/soc/intel/common/block/include/intelblocks/gpio.h b/src/soc/intel/common/block/include/intelblocks/gpio.h index c47f908e8c..91f9abe458 100644 --- a/src/soc/intel/common/block/include/intelblocks/gpio.h +++ b/src/soc/intel/common/block/include/intelblocks/gpio.h @@ -205,6 +205,11 @@ enum gpio_lock_action { GPIO_LOCK_FULL = GPIO_LOCK_CONFIG | GPIO_LOCK_TX, }; +struct gpio_lock_config { + gpio_t gpio; + enum gpio_lock_action action; +}; + /* * Lock a GPIO's configuration. * @@ -232,6 +237,33 @@ enum gpio_lock_action { int gpio_lock_pad(const gpio_t pad, enum gpio_lock_action action); /* + * gpio_lock_pads() can be used to lock an array of gpio pads, avoiding + * the p2sb_unhide() and p2sb_hide() calls between each gpio lock that would + * occur if gpio_lock_pad() were used to lock each pad in the list. + * + * @param pad_list: array of gpio_lock_config structures, one for each gpio to lock + * @param count: number of gpio_lock_config structs in the pad_list array + * @return 0 if successful, + * 1 - unsuccessful + * 2 - powered down + * 3 - multi-cast mixed + * -1 - sideband message failed or other error + */ +int gpio_lock_pads(const struct gpio_lock_config *pad_list, const size_t count); + +/* + * Returns an array of gpio_lock_config entries that the SoC + * deems security risks that should be locked down. + */ +const struct gpio_lock_config *soc_gpio_lock_config(size_t *num); + +/* + * Returns an array of gpio_lock_config entries that the mainboard + * deems security risks that should be locked down. + */ +const struct gpio_lock_config *mb_gpio_lock_config(size_t *num); + +/* * Returns the pmc_gpe to gpio_gpe mapping table * */ diff --git a/src/soc/intel/common/block/smm/Kconfig b/src/soc/intel/common/block/smm/Kconfig index 77ba00c027..2d960d6b47 100644 --- a/src/soc/intel/common/block/smm/Kconfig +++ b/src/soc/intel/common/block/smm/Kconfig @@ -8,6 +8,13 @@ config SOC_INTEL_COMMON_BLOCK_SMM_IO_TRAP help Intel Processor trap flag if it is supported +config SOC_INTEL_COMMON_BLOCK_SMM_LOCK_GPIO_PADS + bool + help + Enable locking of security-sensitive SoC and mainboard GPIOs. + An SoC may provide a list of gpios to lock, and the mainboard + may also provide a list of gpios to lock. + config SOC_INTEL_COMMON_BLOCK_SMM_ESPI_DISABLE bool default n diff --git a/src/soc/intel/common/block/smm/smihandler.c b/src/soc/intel/common/block/smm/smihandler.c index e1eadb6676..32de2f6cf1 100644 --- a/src/soc/intel/common/block/smm/smihandler.c +++ b/src/soc/intel/common/block/smm/smihandler.c @@ -311,6 +311,40 @@ static void southbridge_smi_store( } } +__weak const struct gpio_lock_config *soc_gpio_lock_config(size_t *num) +{ + *num = 0; + return NULL; +} + +__weak const struct gpio_lock_config *mb_gpio_lock_config(size_t *num) +{ + *num = 0; + return NULL; +} + +static void soc_lock_gpios(void) +{ + const struct gpio_lock_config *soc_gpios; + const struct gpio_lock_config *mb_gpios; + size_t soc_gpio_num; + size_t mb_gpio_num; + + /* get list of gpios from SoC */ + soc_gpios = soc_gpio_lock_config(&soc_gpio_num); + + /* get list of gpios from mainboard */ + mb_gpios = mb_gpio_lock_config(&mb_gpio_num); + + /* Lock any soc requested gpios */ + if (soc_gpio_num) + gpio_lock_pads(soc_gpios, soc_gpio_num); + + /* Lock any mainboard requested gpios */ + if (mb_gpio_num) + gpio_lock_pads(mb_gpios, mb_gpio_num); +} + static void finalize(void) { static int finalize_done; @@ -337,6 +371,10 @@ static void finalize(void) */ mainboard_smi_finalize(); + /* Lock down all GPIOs that may have been requested by the SoC and/or the mainboard. */ + if (CONFIG(SOC_INTEL_COMMON_BLOCK_SMM_LOCK_GPIO_PADS)) + soc_lock_gpios(); + /* Specific SOC SMI handler during ramstage finalize phase */ smihandler_soc_at_finalize(); } |