1// SPDX-License-Identifier: GPL-2.0
  2/* Copyright (C) 2012-2019 ARM Limited (or its affiliates). */
  3
  4#include <linux/kernel.h>
  5#include <linux/fips.h>
  6#include <linux/notifier.h>
  7
  8#include "cc_driver.h"
  9#include "cc_fips.h"
 10
 11static void fips_dsr(unsigned long devarg);
 12
 13struct cc_fips_handle {
 14	struct tasklet_struct tasklet;
 15	struct notifier_block nb;
 16	struct cc_drvdata *drvdata;
 17};
 18
 19/* The function called once at driver entry point to check
 20 * whether TEE FIPS error occurred.
 21 */
 22static bool cc_get_tee_fips_status(struct cc_drvdata *drvdata)
 23{
 24	u32 reg;
 25
 26	reg = cc_ioread(drvdata, CC_REG(GPR_HOST));
 27	/* Did the TEE report status? */
 28	if (reg & CC_FIPS_SYNC_TEE_STATUS)
 29		/* Yes. Is it OK? */
 30		return (reg & CC_FIPS_SYNC_MODULE_OK);
 31
 32	/* No. It's either not in use or will be reported later */
 33	return true;
 34}
 35
 36/*
 37 * This function should push the FIPS REE library status towards the TEE library
 38 * by writing the error state to HOST_GPR0 register.
 39 */
 40void cc_set_ree_fips_status(struct cc_drvdata *drvdata, bool status)
 41{
 42	int val = CC_FIPS_SYNC_REE_STATUS;
 43
 44	if (drvdata->hw_rev < CC_HW_REV_712)
 45		return;
 46
 47	val |= (status ? CC_FIPS_SYNC_MODULE_OK : CC_FIPS_SYNC_MODULE_ERROR);
 48
 49	cc_iowrite(drvdata, CC_REG(HOST_GPR0), val);
 50}
 51
 52/* Push REE side FIPS test failure to TEE side */
 53static int cc_ree_fips_failure(struct notifier_block *nb, unsigned long unused1,
 54			       void *unused2)
 55{
 56	struct cc_fips_handle *fips_h =
 57				container_of(nb, struct cc_fips_handle, nb);
 58	struct cc_drvdata *drvdata = fips_h->drvdata;
 59	struct device *dev = drvdata_to_dev(drvdata);
 60
 61	cc_set_ree_fips_status(drvdata, false);
 62	dev_info(dev, "Notifying TEE of FIPS test failure...\n");
 63
 64	return NOTIFY_OK;
 65}
 66
 67void cc_fips_fini(struct cc_drvdata *drvdata)
 68{
 69	struct cc_fips_handle *fips_h = drvdata->fips_handle;
 70
 71	if (drvdata->hw_rev < CC_HW_REV_712 || !fips_h)
 72		return;
 73
 74	atomic_notifier_chain_unregister(&fips_fail_notif_chain, &fips_h->nb);
 75
 76	/* Kill tasklet */
 77	tasklet_kill(&fips_h->tasklet);
 78	drvdata->fips_handle = NULL;
 79}
 80
 81void fips_handler(struct cc_drvdata *drvdata)
 82{
 83	struct cc_fips_handle *fips_handle_ptr = drvdata->fips_handle;
 84
 85	if (drvdata->hw_rev < CC_HW_REV_712)
 86		return;
 87
 88	tasklet_schedule(&fips_handle_ptr->tasklet);
 89}
 90
 91static inline void tee_fips_error(struct device *dev)
 92{
 93	if (fips_enabled)
 94		panic("ccree: TEE reported cryptographic error in fips mode!\n");
 95	else
 96		dev_err(dev, "TEE reported error!\n");
 97}
 98
 99/*
100 * This function check if cryptocell tee fips error occurred
101 * and in such case triggers system error
102 */
103void cc_tee_handle_fips_error(struct cc_drvdata *p_drvdata)
104{
105	struct device *dev = drvdata_to_dev(p_drvdata);
106
107	if (!cc_get_tee_fips_status(p_drvdata))
108		tee_fips_error(dev);
109}
110
111/* Deferred service handler, run as interrupt-fired tasklet */
112static void fips_dsr(unsigned long devarg)
113{
114	struct cc_drvdata *drvdata = (struct cc_drvdata *)devarg;
115	u32 irq, val;
116
117	irq = (drvdata->irq & (CC_GPR0_IRQ_MASK));
118
119	if (irq) {
120		cc_tee_handle_fips_error(drvdata);
121	}
122
123	/* after verifying that there is nothing to do,
124	 * unmask AXI completion interrupt.
125	 */
126	val = (CC_REG(HOST_IMR) & ~irq);
127	cc_iowrite(drvdata, CC_REG(HOST_IMR), val);
128}
129
130/* The function called once at driver entry point .*/
131int cc_fips_init(struct cc_drvdata *p_drvdata)
132{
133	struct cc_fips_handle *fips_h;
134	struct device *dev = drvdata_to_dev(p_drvdata);
135
136	if (p_drvdata->hw_rev < CC_HW_REV_712)
137		return 0;
138
139	fips_h = devm_kzalloc(dev, sizeof(*fips_h), GFP_KERNEL);
140	if (!fips_h)
141		return -ENOMEM;
142
143	p_drvdata->fips_handle = fips_h;
144
145	dev_dbg(dev, "Initializing fips tasklet\n");
146	tasklet_init(&fips_h->tasklet, fips_dsr, (unsigned long)p_drvdata);
147	fips_h->drvdata = p_drvdata;
148	fips_h->nb.notifier_call = cc_ree_fips_failure;
149	atomic_notifier_chain_register(&fips_fail_notif_chain, &fips_h->nb);
150
151	cc_tee_handle_fips_error(p_drvdata);
152
153	return 0;
154}