drivers/staging/ccree/ssi_fips.c

   1 /*
   2  * Copyright (C) 2012-2017 ARM Limited or its affiliates.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/fips.h>
  19
  20 #include "ssi_config.h"
  21 #include "ssi_driver.h"
  22 #include "cc_hal.h"
  23 #include "ssi_fips.h"
  24
  25 static void fips_dsr(unsigned long devarg);
  26
  27 struct ssi_fips_handle {
  28         struct tasklet_struct tasklet;
  29 };
  30
  31 /* The function called once at driver entry point to check
  32  * whether TEE FIPS error occurred.
  33  */
  34 static bool cc_get_tee_fips_status(struct ssi_drvdata *drvdata)
  35 {
  36         u32 reg;
  37         void __iomem *cc_base = drvdata->cc_base;
  38
  39         reg = CC_HAL_READ_REGISTER(CC_REG_OFFSET(HOST_RGF, GPR_HOST));
  40         return (reg == (CC_FIPS_SYNC_TEE_STATUS | CC_FIPS_SYNC_MODULE_OK));
  41 }
  42
  43 /*
  44  * This function should push the FIPS REE library status towards the TEE library
  45  * by writing the error state to HOST_GPR0 register.
  46  */
  47 void cc_set_ree_fips_status(struct ssi_drvdata *drvdata, bool status)
  48 {
  49         void __iomem *cc_base = drvdata->cc_base;
  50         int val = CC_FIPS_SYNC_REE_STATUS;
  51
  52         val |= (status ? CC_FIPS_SYNC_MODULE_OK : CC_FIPS_SYNC_MODULE_ERROR);
  53
  54         CC_HAL_WRITE_REGISTER(CC_REG_OFFSET(HOST_RGF, HOST_GPR0), val);
  55 }
  56
  57 void ssi_fips_fini(struct ssi_drvdata *drvdata)
  58 {
  59         struct ssi_fips_handle *fips_h = drvdata->fips_handle;
  60
  61         if (!fips_h)
  62                 return; /* Not allocated */
  63
  64         /* Kill tasklet */
  65         tasklet_kill(&fips_h->tasklet);
  66
  67         kfree(fips_h);
  68         drvdata->fips_handle = NULL;
  69 }
  70
  71 void fips_handler(struct ssi_drvdata *drvdata)
  72 {
  73         struct ssi_fips_handle *fips_handle_ptr =
  74                 drvdata->fips_handle;
  75
  76         tasklet_schedule(&fips_handle_ptr->tasklet);
  77 }
  78
  79 static inline void tee_fips_error(void)
  80 {
  81         if (fips_enabled)
  82                 panic("ccree: TEE reported cryptographic error in fips mode!\n");
  83         else
  84                 SSI_LOG_ERR("TEE reported error!\n");
  85 }
  86
  87 /* Deferred service handler, run as interrupt-fired tasklet */
  88 static void fips_dsr(unsigned long devarg)
  89 {
  90         struct ssi_drvdata *drvdata = (struct ssi_drvdata *)devarg;
  91         void __iomem *cc_base = drvdata->cc_base;
  92         u32 irq, state, val;
  93
  94         irq = (drvdata->irq & (SSI_GPR0_IRQ_MASK));
  95
  96         if (irq) {
  97                 state = CC_HAL_READ_REGISTER(CC_REG_OFFSET(HOST_RGF, GPR_HOST));
  98
  99                 if (state != (CC_FIPS_SYNC_TEE_STATUS | CC_FIPS_SYNC_MODULE_OK))
 100                         tee_fips_error();
 101         }
 102
 103         /* after verifing that there is nothing to do,
 104          * unmask AXI completion interrupt.
 105          */
 106         val = (CC_REG_OFFSET(HOST_RGF, HOST_IMR) & ~irq);
 107         CC_HAL_WRITE_REGISTER(CC_REG_OFFSET(HOST_RGF, HOST_IMR), val);
 108 }
 109
 110 /* The function called once at driver entry point .*/
 111 int ssi_fips_init(struct ssi_drvdata *p_drvdata)
 112 {
 113         struct ssi_fips_handle *fips_h;
 114
 115         fips_h = kzalloc(sizeof(*fips_h), GFP_KERNEL);
 116         if (!fips_h)
 117                 return -ENOMEM;
 118
 119         p_drvdata->fips_handle = fips_h;
 120
 121         SSI_LOG_DEBUG("Initializing fips tasklet\n");
 122         tasklet_init(&fips_h->tasklet, fips_dsr, (unsigned long)p_drvdata);
 123
 124         if (!cc_get_tee_fips_status(p_drvdata))
 125                 tee_fips_error();
 126
 127         return 0;
 128 }