diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/crypto/ccp/tee-dev.c | 396 |
1 files changed, 396 insertions, 0 deletions
diff --git a/drivers/crypto/ccp/tee-dev.c b/drivers/crypto/ccp/tee-dev.c new file mode 100644 index 000000000..5c9d47f3b --- /dev/null +++ b/drivers/crypto/ccp/tee-dev.c @@ -0,0 +1,396 @@ +// SPDX-License-Identifier: MIT +/* + * AMD Trusted Execution Environment (TEE) interface + * + * Author: Rijo Thomas <Rijo-john.Thomas@amd.com> + * Author: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com> + * + * Copyright (C) 2019,2021 Advanced Micro Devices, Inc. + */ + +#include <linux/types.h> +#include <linux/mutex.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/gfp.h> +#include <linux/psp-sev.h> +#include <linux/psp-tee.h> + +#include "psp-dev.h" +#include "tee-dev.h" + +static bool psp_dead; + +static int tee_alloc_ring(struct psp_tee_device *tee, int ring_size) +{ + struct ring_buf_manager *rb_mgr = &tee->rb_mgr; + void *start_addr; + + if (!ring_size) + return -EINVAL; + + /* We need actual physical address instead of DMA address, since + * Trusted OS running on AMD Secure Processor will map this region + */ + start_addr = (void *)__get_free_pages(GFP_KERNEL, get_order(ring_size)); + if (!start_addr) + return -ENOMEM; + + memset(start_addr, 0x0, 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; +} + +static void tee_free_ring(struct psp_tee_device *tee) +{ + struct ring_buf_manager *rb_mgr = &tee->rb_mgr; + + if (!rb_mgr->ring_start) + return; + + free_pages((unsigned long)rb_mgr->ring_start, + get_order(rb_mgr->ring_size)); + + 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, + unsigned int *reg) +{ + /* ~10ms sleep per loop => nloop = timeout * 100 */ + int nloop = timeout * 100; + + while (--nloop) { + *reg = ioread32(tee->io_regs + tee->vdata->cmdresp_reg); + if (*reg & PSP_CMDRESP_RESP) + return 0; + + usleep_range(10000, 10100); + } + + dev_err(tee->dev, "tee: command timed out, disabling PSP\n"); + psp_dead = true; + + return -ETIMEDOUT; +} + +static +struct tee_init_ring_cmd *tee_alloc_cmd_buffer(struct psp_tee_device *tee) +{ + struct tee_init_ring_cmd *cmd; + + cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); + if (!cmd) + return NULL; + + cmd->hi_addr = upper_32_bits(tee->rb_mgr.ring_pa); + cmd->low_addr = lower_32_bits(tee->rb_mgr.ring_pa); + cmd->size = tee->rb_mgr.ring_size; + + dev_dbg(tee->dev, "tee: ring address: high = 0x%x low = 0x%x size = %u\n", + cmd->hi_addr, cmd->low_addr, cmd->size); + + return cmd; +} + +static inline void tee_free_cmd_buffer(struct tee_init_ring_cmd *cmd) +{ + kfree(cmd); +} + +static int tee_init_ring(struct psp_tee_device *tee) +{ + int ring_size = MAX_RING_BUFFER_ENTRIES * sizeof(struct tee_ring_cmd); + struct tee_init_ring_cmd *cmd; + phys_addr_t cmd_buffer; + unsigned int reg; + int ret; + + BUILD_BUG_ON(sizeof(struct tee_ring_cmd) != 1024); + + ret = tee_alloc_ring(tee, ring_size); + if (ret) { + dev_err(tee->dev, "tee: ring allocation failed %d\n", ret); + return ret; + } + + tee->rb_mgr.wptr = 0; + + cmd = tee_alloc_cmd_buffer(tee); + if (!cmd) { + tee_free_ring(tee); + return -ENOMEM; + } + + cmd_buffer = __psp_pa((void *)cmd); + + /* Send command buffer details to Trusted OS by writing to + * CPU-PSP message registers + */ + + iowrite32(lower_32_bits(cmd_buffer), + tee->io_regs + tee->vdata->cmdbuff_addr_lo_reg); + iowrite32(upper_32_bits(cmd_buffer), + tee->io_regs + tee->vdata->cmdbuff_addr_hi_reg); + iowrite32(TEE_RING_INIT_CMD, + tee->io_regs + tee->vdata->cmdresp_reg); + + ret = tee_wait_cmd_poll(tee, TEE_DEFAULT_TIMEOUT, ®); + if (ret) { + dev_err(tee->dev, "tee: ring init command timed out\n"); + tee_free_ring(tee); + goto free_buf; + } + + if (reg & PSP_CMDRESP_ERR_MASK) { + dev_err(tee->dev, "tee: ring init command failed (%#010x)\n", + reg & PSP_CMDRESP_ERR_MASK); + tee_free_ring(tee); + ret = -EIO; + } + +free_buf: + tee_free_cmd_buffer(cmd); + + return ret; +} + +static void tee_destroy_ring(struct psp_tee_device *tee) +{ + unsigned int reg; + int ret; + + if (!tee->rb_mgr.ring_start) + return; + + if (psp_dead) + goto free_ring; + + iowrite32(TEE_RING_DESTROY_CMD, + tee->io_regs + tee->vdata->cmdresp_reg); + + ret = tee_wait_cmd_poll(tee, TEE_DEFAULT_TIMEOUT, ®); + if (ret) { + dev_err(tee->dev, "tee: ring destroy command timed out\n"); + } else if (reg & PSP_CMDRESP_ERR_MASK) { + dev_err(tee->dev, "tee: ring destroy command failed (%#010x)\n", + reg & PSP_CMDRESP_ERR_MASK); + } + +free_ring: + tee_free_ring(tee); +} + +int tee_dev_init(struct psp_device *psp) +{ + struct device *dev = psp->dev; + struct psp_tee_device *tee; + int ret; + + ret = -ENOMEM; + tee = devm_kzalloc(dev, sizeof(*tee), GFP_KERNEL); + if (!tee) + goto e_err; + + psp->tee_data = tee; + + tee->dev = dev; + tee->psp = psp; + + tee->io_regs = psp->io_regs; + + tee->vdata = (struct tee_vdata *)psp->vdata->tee; + if (!tee->vdata) { + ret = -ENODEV; + dev_err(dev, "tee: missing driver data\n"); + goto e_err; + } + + ret = tee_init_ring(tee); + if (ret) { + dev_err(dev, "tee: failed to init ring buffer\n"); + goto e_err; + } + + dev_notice(dev, "tee enabled\n"); + + return 0; + +e_err: + psp->tee_data = NULL; + + dev_notice(dev, "tee initialization failed\n"); + + return ret; +} + +void tee_dev_destroy(struct psp_device *psp) +{ + struct psp_tee_device *tee = psp->tee_data; + + if (!tee) + return; + + 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; + int nloop = 1000, ret = 0; + u32 rptr; + + *resp = NULL; + + mutex_lock(&tee->rb_mgr.mutex); + + /* Loop until empty entry found in ring buffer */ + do { + /* Get pointer to ring buffer command entry */ + cmd = (struct tee_ring_cmd *) + (tee->rb_mgr.ring_start + tee->rb_mgr.wptr); + + rptr = ioread32(tee->io_regs + tee->vdata->ring_rptr_reg); + + /* Check if ring buffer is full or command entry is waiting + * for response from TEE + */ + if (!(tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr || + cmd->flag == CMD_WAITING_FOR_RESPONSE)) + break; + + dev_dbg(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u\n", + rptr, tee->rb_mgr.wptr); + + /* Wait if ring buffer is full or TEE is processing data */ + mutex_unlock(&tee->rb_mgr.mutex); + schedule_timeout_interruptible(msecs_to_jiffies(10)); + mutex_lock(&tee->rb_mgr.mutex); + + } while (--nloop); + + if (!nloop && + (tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr || + cmd->flag == CMD_WAITING_FOR_RESPONSE)) { + dev_err(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u response flag %u\n", + rptr, tee->rb_mgr.wptr, cmd->flag); + ret = -EBUSY; + goto unlock; + } + + /* Do not submit command if PSP got disabled while processing any + * command in another thread + */ + if (psp_dead) { + ret = -EBUSY; + goto unlock; + } + + /* 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); + + /* Indicate driver is waiting for response */ + cmd->flag = CMD_WAITING_FOR_RESPONSE; + + /* 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) +{ + /* ~1ms sleep per loop => nloop = timeout * 1000 */ + int nloop = timeout * 1000; + + while (--nloop) { + if (resp->cmd_state == TEE_CMD_STATE_COMPLETED) + return 0; + + usleep_range(1000, 1100); + } + + 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) { + resp->flag = CMD_RESPONSE_TIMEDOUT; + return ret; + } + + memcpy(buf, &resp->buf[0], len); + *status = resp->status; + + resp->flag = CMD_RESPONSE_COPIED; + + return 0; +} +EXPORT_SYMBOL(psp_tee_process_cmd); + +int psp_check_tee_status(void) +{ + struct psp_device *psp = psp_get_master_device(); + + if (!psp || !psp->tee_data) + return -ENODEV; + + return 0; +} +EXPORT_SYMBOL(psp_check_tee_status); |