lkml.org 
[lkml]   [2022]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [Linux-stm32] [PATCH 3/3] nvmem: stm32: add OP-TEE support for STM32MP13x
From
Hi Fabrice,


Thanks for the review,

I am preparing a V2 with your remarks.


Patrick


On 11/3/22 14:18, Fabrice Gasnier wrote:
> On 10/28/22 16:52, Patrick Delaunay wrote:
>> For boot with OP-TEE on STM32MP13, the communication with the secure
>> world no more use STMicroelectronics SMC but communication with the
>> BSEC TA, for data access (read/write) or lock operation:
>> - all the request are sent to OP-TEE trusted application,
>> - for upper OTP with ECC protection and with word programming only
>> each OTP are permanently locked when programmed to avoid ECC error
>> on the second write operation
>>
>> Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
>> ---
>>
>> drivers/nvmem/stm32-romem.c | 450 +++++++++++++++++++++++++++++++++++-
>> 1 file changed, 446 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
>> index 6de565639d5f..dfdedbcca9b9 100644
>> --- a/drivers/nvmem/stm32-romem.c
>> +++ b/drivers/nvmem/stm32-romem.c
>> @@ -11,6 +11,7 @@
>> #include <linux/module.h>
>> #include <linux/nvmem-provider.h>
>> #include <linux/of_device.h>
>> +#include <linux/tee_drv.h>
>>
>> /* BSEC secure service access from non-secure */
>> #define STM32_SMC_BSEC 0x82001003
>> @@ -25,14 +26,22 @@
>> struct stm32_romem_cfg {
>> int size;
>> u8 lower;
>> + bool ta;
>> };
>>
>> struct stm32_romem_priv {
>> void __iomem *base;
>> struct nvmem_config cfg;
>> u8 lower;
>> + struct device *ta;
>> };
>>
>> +struct device *stm32_bsec_pta_find(struct device *dev);
>> +static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
>> + size_t bytes);
>> +static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
>> + size_t bytes);
>> +
> Hi Patrick,
>
> Please find some suggestions and few remarks here below.
>
> Adding prototypes could be avoided, by moving these new routines:
> - stm32_bsec_pta_find
> - stm32_bsec_pta_read
> - stm32_bsec_pta_write


ok


>
>> static int stm32_romem_read(void *context, unsigned int offset, void *buf,
>> size_t bytes)
>> {
>> @@ -173,15 +182,25 @@ static int stm32_romem_probe(struct platform_device *pdev)
>> } else {
>> priv->cfg.size = cfg->size;
>> priv->lower = cfg->lower;
>> - priv->cfg.reg_read = stm32_bsec_read;
>> - priv->cfg.reg_write = stm32_bsec_write;
>> + if (cfg->ta) {
>> + priv->ta = stm32_bsec_pta_find(dev);
>> + /* wait for OP-TEE client driver to be up and ready */
>> + if (!priv->ta)
>> + return -EPROBE_DEFER;
>> +
>> + priv->cfg.reg_read = stm32_bsec_pta_read;
>> + priv->cfg.reg_write = stm32_bsec_pta_write;
>> + } else {
>> + priv->cfg.reg_read = stm32_bsec_read;
>> + priv->cfg.reg_write = stm32_bsec_write;
>> + }
>> }
>>
>> return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &priv->cfg));
>> }
>>
>> /*
>> - * STM32MP15 BSEC OTP regions: 4096 OTP bits (with 3072 effective bits)
>> + * STM32MP15/13 BSEC OTP regions: 4096 OTP bits (with 3072 effective bits)
>> * => 96 x 32-bits data words
>> * - Lower: 1K bits, 2:1 redundancy, incremental bit programming
>> * => 32 (x 32-bits) lower shadow registers = words 0 to 31
>> @@ -191,6 +210,13 @@ static int stm32_romem_probe(struct platform_device *pdev)
>> static const struct stm32_romem_cfg stm32mp15_bsec_cfg = {
>> .size = 384,
>> .lower = 32,
>> + .ta = false,
>> +};
>> +
>> +static const struct stm32_romem_cfg stm32mp13_bsec_cfg = {
>> + .size = 384,
>> + .lower = 32,
>> + .ta = true,
>> };
>>
>> static const struct of_device_id stm32_romem_of_match[] = {
>> @@ -198,6 +224,8 @@ static const struct of_device_id stm32_romem_of_match[] = {
>> .compatible = "st,stm32mp15-bsec",
>> .data = (void *)&stm32mp15_bsec_cfg,
>> }, {
>> + .compatible = "st,stm32mp13-bsec",
>> + .data = (void *)&stm32mp13_bsec_cfg,
>> },
>> };
>> MODULE_DEVICE_TABLE(of, stm32_romem_of_match);
>> @@ -209,7 +237,421 @@ static struct platform_driver stm32_romem_driver = {
>> .of_match_table = of_match_ptr(stm32_romem_of_match),
>> },
>> };
>> -module_platform_driver(stm32_romem_driver);
>> +
>> +#if IS_ENABLED(CONFIG_OPTEE)
>> +/*************************************************************************
>> + * BSEC PTA : OP-TEE client driver to pseudo trusted application
>> + *************************************************************************/
> Just suggesting: could improve readability on above comment ?
> (mutli-line comment starting with an emtpy /*. But here there's a single
> line.

I remove this comment (not needed).


>
>> +
>> +/*
>> + * Read OTP memory
>> + *
>> + * [in] value[0].a OTP start offset in byte
>> + * [in] value[0].b Access type (0 : shadow,
>> + * 1 : fuse, 2 : lock)
> Suggestion: fits into 100 chars line

done


>
>> + * [out] memref[1].buffer Output buffer to store read values
>> + * [out] memref[1].size Size of OTP to be read
>> + *
>> + * Return codes:
>> + * TEE_SUCCESS - Invoke command success
>> + * TEE_ERROR_BAD_PARAMETERS - Incorrect input param
>> + */
>> +#define PTA_BSEC_READ_MEM 0x0 /* Read OTP */
>> +
>> +/*
>> + * Write OTP memory
>> + *
>> + * [in] value[0].a OTP start offset in byte
>> + * [in] value[0].b Access type (0 : shadow,
>> + * 1 : fuse, 2 : lock)
> same here


done


>
>> + * [in] memref[1].buffer Input buffer to read values
>> + * [in] memref[1].size Size of OTP to be written
>> + *
>> + * Return codes:
>> + * TEE_SUCCESS - Invoke command success
>> + * TEE_ERROR_BAD_PARAMETERS - Incorrect input param
>> + */
>> +#define PTA_BSEC_WRITE_MEM 0x1 /* Write OTP */
>> +
>> +/* value of PTA_BSEC access type = value[in] b */
>> +#define SHADOW_ACCESS 0
>> +#define FUSE_ACCESS 1
>> +#define LOCK_ACCESS 2
>> +
>> +/* Bitfield definition for LOCK status */
>> +#define LOCK_PERM BIT(30)
>> +
>> +/**
>> + * struct stm32_bsec_pta_priv - OP-TEE BSEC TA private data
>> + * @ctx: OP-TEE context handler.
>> + * @session_id: TA session identifier.
>> + */
>> +struct stm32_bsec_pta_priv {
>> + struct tee_context *ctx;
>> + u32 session_id;
>> +};
>> +
>> +/*
>> + * Check whether this driver supports the BSEC TA in the TEE instance
>> + * represented by the params (ver/data) to this function.
>> + */
>> +static int stm32_bsec_pta_match(struct tee_ioctl_version_data *ver, const void *data)
>> +{
>> + /*
>> + * Currently this driver only supports GP compliant, OP-TEE based TA
>> + */
> /* suggestion: single line comment */


done


>
>> + if ((ver->impl_id == TEE_IMPL_ID_OPTEE) &&
>> + (ver->gen_caps & TEE_GEN_CAP_GP))
>> + return 1;
>> + else
>> + return 0;
>> +}
>> +
>> +/**
>> + * stm32_bsec_pta_probe() - initialize the PTA BSEC
>> + * @dev: the platform_device description.
>> + *
>> + * Return:
>> + * On success, 0. On failure, -errno.
>> + */
>> +static int stm32_bsec_pta_probe(struct device *dev)
>> +{
>> + int rc;
>> + struct tee_ioctl_open_session_arg sess_arg;
>> + struct tee_client_device *tee_device = to_tee_client_device(dev);
>> + struct stm32_bsec_pta_priv *priv;
>> +
>> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> + if (!priv)
>> + return -ENOMEM;
>> +
>> + /* Open context with TEE driver */
>> + priv->ctx = tee_client_open_context(NULL, stm32_bsec_pta_match, NULL, NULL);
>> + if (IS_ERR(priv->ctx)) {
>> + if (PTR_ERR(priv->ctx) == -ENOENT)
>> + return -EPROBE_DEFER;
>> + dev_err(dev, "%s: tee_client_open_context failed\n", __func__);
>> + return PTR_ERR(priv->ctx);
>> + }
>> +
>> + /* Open a session with BSEC TA */
>> + memset(&sess_arg, 0, sizeof(sess_arg));
>> + export_uuid(sess_arg.uuid, &tee_device->id.uuid);
>> + sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
>> + sess_arg.num_params = 0;
>> +
>> + rc = tee_client_open_session(priv->ctx, &sess_arg, NULL);
>> + if ((rc < 0) || (sess_arg.ret != 0)) {
>> + dev_err(dev, "%s: tee_client_open_session failed, err=%x\n",
>> + __func__, sess_arg.ret);
>> + rc = -EINVAL;
>> + goto out_tee_session;
>> + }
>> + priv->session_id = sess_arg.session;
>> + dev_set_drvdata(dev, priv);
>> +
>> + return 0;
>> +
>> +out_tee_session:
>> + tee_client_close_context(priv->ctx);
>> + priv->ctx = NULL;
>> +
>> + return rc;
>> +}
>> +
>> +/**
>> + * stm32_bsec_pta_remove() - remove the BSEC TEE device
>> + * @dev: the platform_device description.
>> + *
>> + * Return:
>> + * 0 always.
>> + */
>> +static int stm32_bsec_pta_remove(struct device *dev)
>> +{
>> + struct stm32_bsec_pta_priv *priv = dev_get_drvdata(dev);
>> +
>> + if (!IS_ERR_OR_NULL(priv->ctx)) {
>> + tee_client_close_session(priv->ctx, priv->session_id);
>> + tee_client_close_context(priv->ctx);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> + * stm32_bsec_pta_read() - nvmem read access using PTA client driver
>> + * @context: nvmem context => romem privdate data
>> + * @offset: nvmem offset
>> + * @buf: buffer to fill with nvem values
>> + * @bytes: number of bytes to read
>> + *
>> + * Return:
>> + * On success, 0. On failure, -errno.
>> + */
>> +static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
>> + size_t bytes)
>> +{
>> + struct stm32_romem_priv *romem_priv = context;
>> + struct device *dev;
>> + struct stm32_bsec_pta_priv *priv;
>> + struct tee_shm *shm;
>> + struct tee_ioctl_invoke_arg arg;
>> + struct tee_param param[2];
>> + u8 *shm_buf;
>> + u32 start, num_bytes;
>> + int ret;
>> +
>> + dev = romem_priv->ta;
>> + if (!dev) {
>> + pr_err("TA_BSEC invoke with driver\n");
>> + return -ENXIO;
>> + }
>> +
>> + priv = dev_get_drvdata(dev);
>> +
>> + memset(&arg, 0, sizeof(arg));
>> + memset(&param, 0, sizeof(param));
>> +
>> + arg.func = PTA_BSEC_READ_MEM;
>> + arg.session = priv->session_id;
>> + arg.num_params = 2;
>> +
>> + /* align access on 32bits */
>> + start = ALIGN_DOWN(offset, 4);
>> + num_bytes = round_up(offset + bytes - start, 4);
>> + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
>> + param[0].u.value.a = start;
>> + param[0].u.value.b = SHADOW_ACCESS;
>> +
>> + shm = tee_shm_alloc_kernel_buf(priv->ctx, num_bytes);
>> + if (IS_ERR(shm))
>> + return PTR_ERR(shm);
>> +
>> + param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
>> + param[1].u.memref.shm = shm;
>> + param[1].u.memref.size = num_bytes;
>> +
>> + ret = tee_client_invoke_func(priv->ctx, &arg, param);
>> + if (ret < 0 || arg.ret != 0) {
>> + dev_err(dev, "TA_BSEC invoke failed TEE err: %x, ret:%x\n",
>> + arg.ret, ret);
>> + if (!ret)
>> + ret = -EIO;
>> + }
>> + if (!ret) {
>> + shm_buf = tee_shm_get_va(shm, 0);
>> + if (IS_ERR(shm_buf)) {
>> + dev_err(dev, "tee_shm_get_va failed for transmit\n");
>> + ret = PTR_ERR(shm_buf);
>> + } else {
>> + ret = 0;
> ret = 0; maybe removed ? (ret is already 0 here)


yes => line removed


>
>> + /* read data from 32 bits aligned buffer */
>> + memcpy(buf, &shm_buf[offset % 4], bytes);
>> + }
>> + }
>> +
>> + tee_shm_free(shm);
>> +
>> + return ret;
>> +}
>> +
>> +/**
>> + * stm32_bsec_pta_write() - nvmem write access using PTA client driver
>> + * @context: nvmem context => romem privdate data
>> + * @offset: nvmem offset
>> + * @buf: buffer with nvem values
>> + * @bytes: number of bytes to write
>> + *
>> + * Return:
>> + * On success, 0. On failure, -errno.
>> + */
>> +static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
>> + size_t bytes)
>> +{
>> + struct stm32_romem_priv *romem_priv = context;
>> + struct device *dev;
>> + struct stm32_bsec_pta_priv *priv;
>> + struct tee_shm *shm;
>> + struct tee_ioctl_invoke_arg arg;
>> + struct tee_param param[2];
>> + u8 *shm_buf;
>> + int ret;
>> +
>> + dev = romem_priv->ta;
>> + if (!dev) {
>> + pr_err("TA_BSEC invoke with driver\n");
>> + return -ENXIO;
>> + }
>> +
>> + /* Allow only writing complete 32-bits aligned words */
>> + if ((bytes % 4) || (offset % 4))
>> + return -EINVAL;
>> +
>> + priv = dev_get_drvdata(dev);
>> +
>> + memset(&arg, 0, sizeof(arg));
>> + memset(&param, 0, sizeof(param));
>> +
>> + arg.func = PTA_BSEC_WRITE_MEM;
>> + arg.session = priv->session_id;
>> + arg.num_params = 2;
>> +
>> + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
>> + param[0].u.value.a = offset;
>> + param[0].u.value.b = FUSE_ACCESS;
>> +
>> + shm = tee_shm_alloc_kernel_buf(priv->ctx, bytes);
>> + if (IS_ERR(shm))
>> + return PTR_ERR(shm);
>> +
>> + param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
>> + param[1].u.memref.shm = shm;
>> + param[1].u.memref.size = bytes;
>> +
>> + shm_buf = tee_shm_get_va(shm, 0);
>> + if (IS_ERR(shm_buf)) {
>> + dev_err(dev, "tee_shm_get_va failed for transmit\n");
> Need to add error handling: tee_shm_free(shm);

done => line added


>
>> + return PTR_ERR(shm_buf);
>> + }
>> +
>> + memcpy(shm_buf, buf, bytes);
>> +
>> + ret = tee_client_invoke_func(priv->ctx, &arg, param);
>> + if (ret < 0 || arg.ret != 0) {
>> + dev_err(dev, "TA_BSEC invoke failed TEE err: %x, ret:%x\n",
>> + arg.ret, ret);
>> + if (!ret)
>> + ret = -EIO;
>> + }
>> + dev_dbg(dev, "Write OTPs %d to %d, ret=%d\n",
>> + offset / 4, (offset + bytes) / 4, ret);
>> +
>> + /* Lock the upper OTPs with ECC protection, word programming only */
>> + if (!ret && ((offset + bytes) >= (romem_priv->lower * 4))) {
>> + u32 start, nb_lock;
>> + u32 *lock = (u32 *)shm_buf;
>> + int i;
>> +
>> + /*
>> + * don't lock the lower OTPs, no ECC protection and incremental
>> + * bit programming, a second write is allowed
>> + */
>> + start = max_t(u32, offset, romem_priv->lower * 4);
>> + nb_lock = (offset + bytes - start) / 4;
>> +
>> + param[0].u.value.a = start;
>> + param[0].u.value.b = LOCK_ACCESS;
>> + param[1].u.memref.size = nb_lock * 4;
>> +
>> + for (i = 0; i < nb_lock; i++)
>> + lock[i] = LOCK_PERM;
>> +
>> + ret = tee_client_invoke_func(priv->ctx, &arg, param);
>> + if (ret < 0 || arg.ret != 0) {
>> + dev_err(dev, "TA_BSEC invoke failed TEE err: %x, ret:%x\n",
>> + arg.ret, ret);
>> + if (!ret)
>> + ret = -EIO;
>> + }
>> + dev_dbg(dev, "Lock upper OTPs %d to %d, ret=%d\n",
>> + start / 4, start / 4 + nb_lock, ret);
>> + }
>> +
>> + tee_shm_free(shm);
>> +
>> + return ret;
>> +}
>> +
>> +static const struct tee_client_device_id stm32_bsec_id_table[] = {
>> + {
>> + UUID_INIT(0x94cf71ad, 0x80e6, 0x40b5,
>> + 0xa7, 0xc6, 0x3d, 0xc5, 0x01, 0xeb, 0x28, 0x03)
>> + },
>> + { }
>> +};
>> +
>> +MODULE_DEVICE_TABLE(tee, stm32_bsec_id_table);
>> +
>> +static struct tee_client_driver stm32_bsec_pta_driver = {
>> + .id_table = stm32_bsec_id_table,
>> + .driver = {
>> + .name = "stm32-bsec-pta",
>> + .bus = &tee_bus_type,
>> + .probe = stm32_bsec_pta_probe,
>> + .remove = stm32_bsec_pta_remove,
>> + },
>> +};
>> +
>> +static void stm32_bsec_put_device(void *data)
>> +{
>> + put_device(data);
>> +}
>> +
>> +struct device *stm32_bsec_pta_find(struct device *dev)
>> +{
>> + struct device *pta_dev;
>> +
>> + pta_dev = driver_find_next_device(&stm32_bsec_pta_driver.driver, NULL);
>> +
>> + if (pta_dev && devm_add_action_or_reset(dev, stm32_bsec_put_device, pta_dev)) {
>> + dev_err(dev, "unable to register cleanup action\n");
> I suggest to improve the error message here, to make it more explicit,
> and also propagate the error code to the caller.
> Something like:
> ret = devm_add_action_or_reset()
> if (ret) {
> dev_err(dev, "devm_add_action_or_reset() failed (%d)\n", ret );
> return ret;
> }
> This may avoid turning a real error here, into a EPROBE_DEFER at the
> caller side, e.g.:
> if (!priv->ta)
> return -EPROBE_DEFER;


Yes: no need to probe defer if a error is detected:


staticstructdevice *stm32_bsec_pta_find(structdevice *dev)
{
structdevice *pta_dev;
intret;
pta_dev = driver_find_next_device(&stm32_bsec_pta_driver.driver, NULL);
if(pta_dev) {
ret = devm_add_action_or_reset(dev, stm32_bsec_put_device, pta_dev);
if(ret)
dev_err(dev, "devm_add_action_or_reset() failed (%d)\n", ret );
returnERR_PTR(ret);
}
returnpta_dev;
}
and for caller side:
priv->ta= stm32_bsec_pta_find(dev);
/* wait for OP-TEE client driver to be up and ready */
if(!priv->ta)
return-EPROBE_DEFER;
if(IS_ERR(priv->ta))
returnPTR_ERR(priv->ta);


>
> Thanks & Best Regards,
> Fabrice
>
>> +
>> + return NULL;
>> + }
>> +
>> + return pta_dev;
>> +}
>> +
>> +#else
>> +static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
>> + size_t bytes)
>> +{
>> + pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
>> +
>> + return -ENXIO;
>> +}
>> +
>> +static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
>> + size_t bytes)
>> +{
>> + pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
>> +
>> + return -ENXIO;
>> +}
>> +
>> +struct device *stm32_bsec_pta_find(struct device *dev)
>> +{
>> + pr_debug("%s: TA BSEC request without OPTEE support\n", __func__);
>> +
>> + return NULL;
>> +}
>> +#endif
>> +
>> +static int __init stm32_romem_init(void)
>> +{
>> + int rc;
>> +
>> + rc = platform_driver_register(&stm32_romem_driver);
>> + if (rc)
>> + return rc;
>> +
>> +#if IS_ENABLED(CONFIG_OPTEE)
>> + rc = driver_register(&stm32_bsec_pta_driver.driver);
>> +#endif
>> +
>> + return rc;
>> +}
>> +
>> +static void __exit stm32_romem_exit(void)
>> +{
>> + platform_driver_unregister(&stm32_romem_driver);
>> +#if IS_ENABLED(CONFIG_OPTEE)
>> + driver_unregister(&stm32_bsec_pta_driver.driver);
>> +#endif
>> +}
>> +
>> +module_init(stm32_romem_init);
>> +module_exit(stm32_romem_exit);
>>
>> MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
>> MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM");

\
 
 \ /
  Last update: 2022-11-07 11:19    [W:0.140 / U:1.172 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site