xref: /openbmc/qemu/hw/misc/tz-msc.c (revision effd60c8) 
1 /*
2  * ARM TrustZone master security controller emulation
3  *
4  * Copyright (c) 2018 Linaro Limited
5  * Written by Peter Maydell
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 or
9  * (at your option) any later version.
10  */
11 
12 #include "qemu/osdep.h"
13 #include "qemu/log.h"
14 #include "qemu/module.h"
15 #include "qapi/error.h"
16 #include "trace.h"
17 #include "hw/sysbus.h"
18 #include "migration/vmstate.h"
19 #include "hw/registerfields.h"
20 #include "hw/irq.h"
21 #include "hw/misc/tz-msc.h"
22 #include "hw/qdev-properties.h"
23 
24 static void tz_msc_update_irq(TZMSC *s)
25 {
26     bool level = s->irq_status;
27 
28     trace_tz_msc_update_irq(level);
29     qemu_set_irq(s->irq, level);
30 }
31 
32 static void tz_msc_cfg_nonsec(void *opaque, int n, int level)
33 {
34     TZMSC *s = TZ_MSC(opaque);
35 
36     trace_tz_msc_cfg_nonsec(level);
37     s->cfg_nonsec = level;
38 }
39 
40 static void tz_msc_cfg_sec_resp(void *opaque, int n, int level)
41 {
42     TZMSC *s = TZ_MSC(opaque);
43 
44     trace_tz_msc_cfg_sec_resp(level);
45     s->cfg_sec_resp = level;
46 }
47 
48 static void tz_msc_irq_clear(void *opaque, int n, int level)
49 {
50     TZMSC *s = TZ_MSC(opaque);
51 
52     trace_tz_msc_irq_clear(level);
53 
54     s->irq_clear = level;
55     if (level) {
56         s->irq_status = false;
57         tz_msc_update_irq(s);
58     }
59 }
60 
61 /* The MSC may either block a transaction by aborting it, block a
62  * transaction by making it RAZ/WI, allow it through with
63  * MemTxAttrs indicating a secure transaction, or allow it with
64  * MemTxAttrs indicating a non-secure transaction.
65  */
66 typedef enum MSCAction {
67     MSCBlockAbort,
68     MSCBlockRAZWI,
69     MSCAllowSecure,
70     MSCAllowNonSecure,
71 } MSCAction;
72 
73 static MSCAction tz_msc_check(TZMSC *s, hwaddr addr)
74 {
75     /*
76      * Check whether to allow an access from the bus master, returning
77      * an MSCAction indicating the required behaviour. If the transaction
78      * is blocked, the caller must check cfg_sec_resp to determine
79      * whether to abort or RAZ/WI the transaction.
80      */
81     IDAUInterfaceClass *iic = IDAU_INTERFACE_GET_CLASS(s->idau);
82     IDAUInterface *ii = IDAU_INTERFACE(s->idau);
83     bool idau_exempt = false, idau_ns = true, idau_nsc = true;
84     int idau_region = IREGION_NOTVALID;
85 
86     iic->check(ii, addr, &idau_region, &idau_exempt, &idau_ns, &idau_nsc);
87 
88     if (idau_exempt) {
89         /*
90          * Uncheck region -- OK, transaction type depends on
91          * whether bus master is configured as Secure or NonSecure
92          */
93         return s->cfg_nonsec ? MSCAllowNonSecure : MSCAllowSecure;
94     }
95 
96     if (idau_ns) {
97         /* NonSecure region -- always forward as NS transaction */
98         return MSCAllowNonSecure;
99     }
100 
101     if (!s->cfg_nonsec) {
102         /* Access to Secure region by Secure bus master: OK */
103         return MSCAllowSecure;
104     }
105 
106     /* Attempted access to Secure region by NS bus master: block */
107     trace_tz_msc_access_blocked(addr);
108     if (!s->cfg_sec_resp) {
109         return MSCBlockRAZWI;
110     }
111 
112     /*
113      * The TRM isn't clear on behaviour if irq_clear is high when a
114      * transaction is blocked. We assume that the MSC behaves like the
115      * PPC, where holding irq_clear high suppresses the interrupt.
116      */
117     if (!s->irq_clear) {
118         s->irq_status = true;
119         tz_msc_update_irq(s);
120     }
121     return MSCBlockAbort;
122 }
123 
124 static MemTxResult tz_msc_read(void *opaque, hwaddr addr, uint64_t *pdata,
125                                unsigned size, MemTxAttrs attrs)
126 {
127     TZMSC *s = opaque;
128     AddressSpace *as = &s->downstream_as;
129     uint64_t data;
130     MemTxResult res;
131 
132     switch (tz_msc_check(s, addr)) {
133     case MSCBlockAbort:
134         return MEMTX_ERROR;
135     case MSCBlockRAZWI:
136         *pdata = 0;
137         return MEMTX_OK;
138     case MSCAllowSecure:
139         attrs.secure = 1;
140         attrs.unspecified = 0;
141         break;
142     case MSCAllowNonSecure:
143         attrs.secure = 0;
144         attrs.unspecified = 0;
145         break;
146     }
147 
148     switch (size) {
149     case 1:
150         data = address_space_ldub(as, addr, attrs, &res);
151         break;
152     case 2:
153         data = address_space_lduw_le(as, addr, attrs, &res);
154         break;
155     case 4:
156         data = address_space_ldl_le(as, addr, attrs, &res);
157         break;
158     case 8:
159         data = address_space_ldq_le(as, addr, attrs, &res);
160         break;
161     default:
162         g_assert_not_reached();
163     }
164     *pdata = data;
165     return res;
166 }
167 
168 static MemTxResult tz_msc_write(void *opaque, hwaddr addr, uint64_t val,
169                                 unsigned size, MemTxAttrs attrs)
170 {
171     TZMSC *s = opaque;
172     AddressSpace *as = &s->downstream_as;
173     MemTxResult res;
174 
175     switch (tz_msc_check(s, addr)) {
176     case MSCBlockAbort:
177         return MEMTX_ERROR;
178     case MSCBlockRAZWI:
179         return MEMTX_OK;
180     case MSCAllowSecure:
181         attrs.secure = 1;
182         attrs.unspecified = 0;
183         break;
184     case MSCAllowNonSecure:
185         attrs.secure = 0;
186         attrs.unspecified = 0;
187         break;
188     }
189 
190     switch (size) {
191     case 1:
192         address_space_stb(as, addr, val, attrs, &res);
193         break;
194     case 2:
195         address_space_stw_le(as, addr, val, attrs, &res);
196         break;
197     case 4:
198         address_space_stl_le(as, addr, val, attrs, &res);
199         break;
200     case 8:
201         address_space_stq_le(as, addr, val, attrs, &res);
202         break;
203     default:
204         g_assert_not_reached();
205     }
206     return res;
207 }
208 
209 static const MemoryRegionOps tz_msc_ops = {
210     .read_with_attrs = tz_msc_read,
211     .write_with_attrs = tz_msc_write,
212     .endianness = DEVICE_LITTLE_ENDIAN,
213 };
214 
215 static void tz_msc_reset(DeviceState *dev)
216 {
217     TZMSC *s = TZ_MSC(dev);
218 
219     trace_tz_msc_reset();
220     s->cfg_sec_resp = false;
221     s->cfg_nonsec = false;
222     s->irq_clear = 0;
223     s->irq_status = 0;
224 }
225 
226 static void tz_msc_init(Object *obj)
227 {
228     DeviceState *dev = DEVICE(obj);
229     TZMSC *s = TZ_MSC(obj);
230 
231     qdev_init_gpio_in_named(dev, tz_msc_cfg_nonsec, "cfg_nonsec", 1);
232     qdev_init_gpio_in_named(dev, tz_msc_cfg_sec_resp, "cfg_sec_resp", 1);
233     qdev_init_gpio_in_named(dev, tz_msc_irq_clear, "irq_clear", 1);
234     qdev_init_gpio_out_named(dev, &s->irq, "irq", 1);
235 }
236 
237 static void tz_msc_realize(DeviceState *dev, Error **errp)
238 {
239     Object *obj = OBJECT(dev);
240     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
241     TZMSC *s = TZ_MSC(dev);
242     const char *name = "tz-msc-downstream";
243     uint64_t size;
244 
245     /*
246      * We can't create the upstream end of the port until realize,
247      * as we don't know the size of the MR used as the downstream until then.
248      * We insist on having a downstream, to avoid complicating the
249      * code with handling the "don't know how big this is" case. It's easy
250      * enough for the user to create an unimplemented_device as downstream
251      * if they have nothing else to plug into this.
252      */
253     if (!s->downstream) {
254         error_setg(errp, "MSC 'downstream' link not set");
255         return;
256     }
257     if (!s->idau) {
258         error_setg(errp, "MSC 'idau' link not set");
259         return;
260     }
261 
262     size = memory_region_size(s->downstream);
263     address_space_init(&s->downstream_as, s->downstream, name);
264     memory_region_init_io(&s->upstream, obj, &tz_msc_ops, s, name, size);
265     sysbus_init_mmio(sbd, &s->upstream);
266 }
267 
268 static const VMStateDescription tz_msc_vmstate = {
269     .name = "tz-msc",
270     .version_id = 1,
271     .minimum_version_id = 1,
272     .fields = (const VMStateField[]) {
273         VMSTATE_BOOL(cfg_nonsec, TZMSC),
274         VMSTATE_BOOL(cfg_sec_resp, TZMSC),
275         VMSTATE_BOOL(irq_clear, TZMSC),
276         VMSTATE_BOOL(irq_status, TZMSC),
277         VMSTATE_END_OF_LIST()
278     }
279 };
280 
281 static Property tz_msc_properties[] = {
282     DEFINE_PROP_LINK("downstream", TZMSC, downstream,
283                      TYPE_MEMORY_REGION, MemoryRegion *),
284     DEFINE_PROP_LINK("idau", TZMSC, idau,
285                      TYPE_IDAU_INTERFACE, IDAUInterface *),
286     DEFINE_PROP_END_OF_LIST(),
287 };
288 
289 static void tz_msc_class_init(ObjectClass *klass, void *data)
290 {
291     DeviceClass *dc = DEVICE_CLASS(klass);
292 
293     dc->realize = tz_msc_realize;
294     dc->vmsd = &tz_msc_vmstate;
295     dc->reset = tz_msc_reset;
296     device_class_set_props(dc, tz_msc_properties);
297 }
298 
299 static const TypeInfo tz_msc_info = {
300     .name = TYPE_TZ_MSC,
301     .parent = TYPE_SYS_BUS_DEVICE,
302     .instance_size = sizeof(TZMSC),
303     .instance_init = tz_msc_init,
304     .class_init = tz_msc_class_init,
305 };
306 
307 static void tz_msc_register_types(void)
308 {
309     type_register_static(&tz_msc_info);
310 }
311 
312 type_init(tz_msc_register_types);
313