From 632b0b5301f67ce54b840d55950707003a489151 Mon Sep 17 00:00:00 2001 From: Rijo Thomas Date: Wed, 4 Dec 2019 11:49:03 +0530 Subject: [PATCH] crypto: ccp - provide in-kernel API to submit TEE commands Extend the functionality of AMD Secure Processor (SP) driver by providing an in-kernel API to submit commands to TEE ring buffer for processing by Trusted OS running on AMD Secure Processor. Following TEE commands are supported by Trusted OS: * TEE_CMD_ID_LOAD_TA : Load Trusted Application (TA) binary into TEE environment * TEE_CMD_ID_UNLOAD_TA : Unload TA binary from TEE environment * TEE_CMD_ID_OPEN_SESSION : Open session with loaded TA * TEE_CMD_ID_CLOSE_SESSION : Close session with loaded TA * TEE_CMD_ID_INVOKE_CMD : Invoke a command with loaded TA * TEE_CMD_ID_MAP_SHARED_MEM : Map shared memory * TEE_CMD_ID_UNMAP_SHARED_MEM : Unmap shared memory Linux AMD-TEE driver will use this API to submit command buffers for processing in Trusted Execution Environment. The AMD-TEE driver shall be introduced in a separate patch. Cc: Jens Wiklander Cc: Tom Lendacky Cc: Ard Biesheuvel Co-developed-by: Devaraj Rangasamy Signed-off-by: Devaraj Rangasamy Signed-off-by: Rijo Thomas Acked-by: Gary R Hook Signed-off-by: Herbert Xu --- drivers/crypto/ccp/tee-dev.c | 126 +++++++++++++++++++++++++++++++++++ drivers/crypto/ccp/tee-dev.h | 1 + include/linux/psp-tee.h | 73 ++++++++++++++++++++ 3 files changed, 200 insertions(+) create mode 100644 include/linux/psp-tee.h diff --git a/drivers/crypto/ccp/tee-dev.c b/drivers/crypto/ccp/tee-dev.c index ccbc2ce59d51..555c8a7c5684 100644 --- a/drivers/crypto/ccp/tee-dev.c +++ b/drivers/crypto/ccp/tee-dev.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "psp-dev.h" #include "tee-dev.h" @@ -38,6 +39,7 @@ static int tee_alloc_ring(struct psp_tee_device *tee, int ring_size) rb_mgr->ring_start = start_addr; rb_mgr->ring_size = ring_size; rb_mgr->ring_pa = __psp_pa(start_addr); + mutex_init(&rb_mgr->mutex); return 0; } @@ -55,6 +57,7 @@ static void tee_free_ring(struct psp_tee_device *tee) rb_mgr->ring_start = NULL; rb_mgr->ring_size = 0; rb_mgr->ring_pa = 0; + mutex_destroy(&rb_mgr->mutex); } static int tee_wait_cmd_poll(struct psp_tee_device *tee, unsigned int timeout, @@ -236,3 +239,126 @@ void tee_dev_destroy(struct psp_device *psp) tee_destroy_ring(tee); } + +static int tee_submit_cmd(struct psp_tee_device *tee, enum tee_cmd_id cmd_id, + void *buf, size_t len, struct tee_ring_cmd **resp) +{ + struct tee_ring_cmd *cmd; + u32 rptr, wptr; + int nloop = 1000, ret = 0; + + *resp = NULL; + + mutex_lock(&tee->rb_mgr.mutex); + + wptr = tee->rb_mgr.wptr; + + /* Check if ring buffer is full */ + do { + rptr = ioread32(tee->io_regs + tee->vdata->ring_rptr_reg); + + if (!(wptr + sizeof(struct tee_ring_cmd) == rptr)) + break; + + dev_info(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u\n", + rptr, wptr); + + /* Wait if ring buffer is full */ + mutex_unlock(&tee->rb_mgr.mutex); + schedule_timeout_interruptible(msecs_to_jiffies(10)); + mutex_lock(&tee->rb_mgr.mutex); + + } while (--nloop); + + if (!nloop && (wptr + sizeof(struct tee_ring_cmd) == rptr)) { + dev_err(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u\n", + rptr, wptr); + ret = -EBUSY; + goto unlock; + } + + /* Pointer to empty data entry in ring buffer */ + cmd = (struct tee_ring_cmd *)(tee->rb_mgr.ring_start + wptr); + + /* Write command data into ring buffer */ + cmd->cmd_id = cmd_id; + cmd->cmd_state = TEE_CMD_STATE_INIT; + memset(&cmd->buf[0], 0, sizeof(cmd->buf)); + memcpy(&cmd->buf[0], buf, len); + + /* Update local copy of write pointer */ + tee->rb_mgr.wptr += sizeof(struct tee_ring_cmd); + if (tee->rb_mgr.wptr >= tee->rb_mgr.ring_size) + tee->rb_mgr.wptr = 0; + + /* Trigger interrupt to Trusted OS */ + iowrite32(tee->rb_mgr.wptr, tee->io_regs + tee->vdata->ring_wptr_reg); + + /* The response is provided by Trusted OS in same + * location as submitted data entry within ring buffer. + */ + *resp = cmd; + +unlock: + mutex_unlock(&tee->rb_mgr.mutex); + + return ret; +} + +static int tee_wait_cmd_completion(struct psp_tee_device *tee, + struct tee_ring_cmd *resp, + unsigned int timeout) +{ + /* ~5ms sleep per loop => nloop = timeout * 200 */ + int nloop = timeout * 200; + + while (--nloop) { + if (resp->cmd_state == TEE_CMD_STATE_COMPLETED) + return 0; + + usleep_range(5000, 5100); + } + + dev_err(tee->dev, "tee: command 0x%x timed out, disabling PSP\n", + resp->cmd_id); + + psp_dead = true; + + return -ETIMEDOUT; +} + +int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, size_t len, + u32 *status) +{ + struct psp_device *psp = psp_get_master_device(); + struct psp_tee_device *tee; + struct tee_ring_cmd *resp; + int ret; + + if (!buf || !status || !len || len > sizeof(resp->buf)) + return -EINVAL; + + *status = 0; + + if (!psp || !psp->tee_data) + return -ENODEV; + + if (psp_dead) + return -EBUSY; + + tee = psp->tee_data; + + ret = tee_submit_cmd(tee, cmd_id, buf, len, &resp); + if (ret) + return ret; + + ret = tee_wait_cmd_completion(tee, resp, TEE_DEFAULT_TIMEOUT); + if (ret) + return ret; + + memcpy(buf, &resp->buf[0], len); + *status = resp->status; + + return 0; +} +EXPORT_SYMBOL(psp_tee_process_cmd); diff --git a/drivers/crypto/ccp/tee-dev.h b/drivers/crypto/ccp/tee-dev.h index b3db0fcb550c..f09960112115 100644 --- a/drivers/crypto/ccp/tee-dev.h +++ b/drivers/crypto/ccp/tee-dev.h @@ -54,6 +54,7 @@ struct tee_init_ring_cmd { * @wptr: index to the last written entry in ring buffer */ struct ring_buf_manager { + struct mutex mutex; /* synchronizes access to ring buffer */ void *ring_start; u32 ring_size; phys_addr_t ring_pa; diff --git a/include/linux/psp-tee.h b/include/linux/psp-tee.h new file mode 100644 index 000000000000..63bb2212fce0 --- /dev/null +++ b/include/linux/psp-tee.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: MIT */ +/* + * AMD Trusted Execution Environment (TEE) interface + * + * Author: Rijo Thomas + * + * Copyright 2019 Advanced Micro Devices, Inc. + * + */ + +#ifndef __PSP_TEE_H_ +#define __PSP_TEE_H_ + +#include +#include + +/* This file defines the Trusted Execution Environment (TEE) interface commands + * and the API exported by AMD Secure Processor driver to communicate with + * AMD-TEE Trusted OS. + */ + +/** + * enum tee_cmd_id - TEE Interface Command IDs + * @TEE_CMD_ID_LOAD_TA: Load Trusted Application (TA) binary into + * TEE environment + * @TEE_CMD_ID_UNLOAD_TA: Unload TA binary from TEE environment + * @TEE_CMD_ID_OPEN_SESSION: Open session with loaded TA + * @TEE_CMD_ID_CLOSE_SESSION: Close session with loaded TA + * @TEE_CMD_ID_INVOKE_CMD: Invoke a command with loaded TA + * @TEE_CMD_ID_MAP_SHARED_MEM: Map shared memory + * @TEE_CMD_ID_UNMAP_SHARED_MEM: Unmap shared memory + */ +enum tee_cmd_id { + TEE_CMD_ID_LOAD_TA = 1, + TEE_CMD_ID_UNLOAD_TA, + TEE_CMD_ID_OPEN_SESSION, + TEE_CMD_ID_CLOSE_SESSION, + TEE_CMD_ID_INVOKE_CMD, + TEE_CMD_ID_MAP_SHARED_MEM, + TEE_CMD_ID_UNMAP_SHARED_MEM, +}; + +#ifdef CONFIG_CRYPTO_DEV_SP_PSP +/** + * psp_tee_process_cmd() - Process command in Trusted Execution Environment + * @cmd_id: TEE command ID (&enum tee_cmd_id) + * @buf: Command buffer for TEE processing. On success, is updated + * with the response + * @len: Length of command buffer in bytes + * @status: On success, holds the TEE command execution status + * + * This function submits a command to the Trusted OS for processing in the + * TEE environment and waits for a response or until the command times out. + * + * Returns: + * 0 if TEE successfully processed the command + * -%ENODEV if PSP device not available + * -%EINVAL if invalid input + * -%ETIMEDOUT if TEE command timed out + * -%EBUSY if PSP device is not responsive + */ +int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, size_t len, + u32 *status); + +#else /* !CONFIG_CRYPTO_DEV_SP_PSP */ + +static inline int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, + size_t len, u32 *status) +{ + return -ENODEV; +} +#endif /* CONFIG_CRYPTO_DEV_SP_PSP */ +#endif /* __PSP_TEE_H_ */