1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *    Copyright IBM Corp. 2015
4  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
5  */
6 
7 #include <linux/kernel.h>
8 #include <asm/processor.h>
9 #include <asm/lowcore.h>
10 #include <asm/ebcdic.h>
11 #include <asm/irq.h>
12 #include <asm/sections.h>
13 #include <asm/mem_detect.h>
14 #include <asm/facility.h>
15 #include "sclp.h"
16 #include "sclp_rw.h"
17 
18 static struct read_info_sccb __bootdata(sclp_info_sccb);
19 static int __bootdata(sclp_info_sccb_valid);
20 char *__bootdata_preserved(sclp_early_sccb);
21 int sclp_init_state = sclp_init_state_uninitialized;
22 /*
23  * Used to keep track of the size of the event masks. Qemu until version 2.11
24  * only supports 4 and needs a workaround.
25  */
26 bool sclp_mask_compat_mode;
27 
28 void sclp_early_wait_irq(void)
29 {
30 	unsigned long psw_mask, addr;
31 	psw_t psw_ext_save, psw_wait;
32 	union ctlreg0 cr0, cr0_new;
33 
34 	__ctl_store(cr0.val, 0, 0);
35 	cr0_new.val = cr0.val & ~CR0_IRQ_SUBCLASS_MASK;
36 	cr0_new.lap = 0;
37 	cr0_new.sssm = 1;
38 	__ctl_load(cr0_new.val, 0, 0);
39 
40 	psw_ext_save = S390_lowcore.external_new_psw;
41 	psw_mask = __extract_psw();
42 	S390_lowcore.external_new_psw.mask = psw_mask;
43 	psw_wait.mask = psw_mask | PSW_MASK_EXT | PSW_MASK_WAIT;
44 	S390_lowcore.ext_int_code = 0;
45 
46 	do {
47 		asm volatile(
48 			"	larl	%[addr],0f\n"
49 			"	stg	%[addr],%[psw_wait_addr]\n"
50 			"	stg	%[addr],%[psw_ext_addr]\n"
51 			"	lpswe	%[psw_wait]\n"
52 			"0:\n"
53 			: [addr] "=&d" (addr),
54 			  [psw_wait_addr] "=Q" (psw_wait.addr),
55 			  [psw_ext_addr] "=Q" (S390_lowcore.external_new_psw.addr)
56 			: [psw_wait] "Q" (psw_wait)
57 			: "cc", "memory");
58 	} while (S390_lowcore.ext_int_code != EXT_IRQ_SERVICE_SIG);
59 
60 	S390_lowcore.external_new_psw = psw_ext_save;
61 	__ctl_load(cr0.val, 0, 0);
62 }
63 
64 int sclp_early_cmd(sclp_cmdw_t cmd, void *sccb)
65 {
66 	unsigned long flags;
67 	int rc;
68 
69 	flags = arch_local_irq_save();
70 	rc = sclp_service_call(cmd, sccb);
71 	if (rc)
72 		goto out;
73 	sclp_early_wait_irq();
74 out:
75 	arch_local_irq_restore(flags);
76 	return rc;
77 }
78 
79 struct write_sccb {
80 	struct sccb_header header;
81 	struct msg_buf msg;
82 } __packed;
83 
84 /* Output multi-line text using SCLP Message interface. */
85 static void sclp_early_print_lm(const char *str, unsigned int len)
86 {
87 	unsigned char *ptr, *end, ch;
88 	unsigned int count, offset;
89 	struct write_sccb *sccb;
90 	struct msg_buf *msg;
91 	struct mdb *mdb;
92 	struct mto *mto;
93 	struct go *go;
94 
95 	sccb = (struct write_sccb *) sclp_early_sccb;
96 	end = (unsigned char *) sccb + EARLY_SCCB_SIZE - 1;
97 	memset(sccb, 0, sizeof(*sccb));
98 	ptr = (unsigned char *) &sccb->msg.mdb.mto;
99 	offset = 0;
100 	do {
101 		for (count = sizeof(*mto); offset < len; count++) {
102 			ch = str[offset++];
103 			if ((ch == 0x0a) || (ptr + count > end))
104 				break;
105 			ptr[count] = _ascebc[ch];
106 		}
107 		mto = (struct mto *) ptr;
108 		memset(mto, 0, sizeof(*mto));
109 		mto->length = count;
110 		mto->type = 4;
111 		mto->line_type_flags = LNTPFLGS_ENDTEXT;
112 		ptr += count;
113 	} while ((offset < len) && (ptr + sizeof(*mto) <= end));
114 	len = ptr - (unsigned char *) sccb;
115 	sccb->header.length = len - offsetof(struct write_sccb, header);
116 	msg = &sccb->msg;
117 	msg->header.type = EVTYP_MSG;
118 	msg->header.length = len - offsetof(struct write_sccb, msg.header);
119 	mdb = &msg->mdb;
120 	mdb->header.type = 1;
121 	mdb->header.tag = 0xD4C4C240;
122 	mdb->header.revision_code = 1;
123 	mdb->header.length = len - offsetof(struct write_sccb, msg.mdb.header);
124 	go = &mdb->go;
125 	go->length = sizeof(*go);
126 	go->type = 1;
127 	sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_DATA, sccb);
128 }
129 
130 struct vt220_sccb {
131 	struct sccb_header header;
132 	struct {
133 		struct evbuf_header header;
134 		char data[];
135 	} msg;
136 } __packed;
137 
138 /* Output multi-line text using SCLP VT220 interface. */
139 static void sclp_early_print_vt220(const char *str, unsigned int len)
140 {
141 	struct vt220_sccb *sccb;
142 
143 	sccb = (struct vt220_sccb *) sclp_early_sccb;
144 	if (sizeof(*sccb) + len >= EARLY_SCCB_SIZE)
145 		len = EARLY_SCCB_SIZE - sizeof(*sccb);
146 	memset(sccb, 0, sizeof(*sccb));
147 	memcpy(&sccb->msg.data, str, len);
148 	sccb->header.length = sizeof(*sccb) + len;
149 	sccb->msg.header.length = sizeof(sccb->msg) + len;
150 	sccb->msg.header.type = EVTYP_VT220MSG;
151 	sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_DATA, sccb);
152 }
153 
154 int sclp_early_set_event_mask(struct init_sccb *sccb,
155 			      sccb_mask_t receive_mask,
156 			      sccb_mask_t send_mask)
157 {
158 retry:
159 	memset(sccb, 0, sizeof(*sccb));
160 	sccb->header.length = sizeof(*sccb);
161 	if (sclp_mask_compat_mode)
162 		sccb->mask_length = SCLP_MASK_SIZE_COMPAT;
163 	else
164 		sccb->mask_length = sizeof(sccb_mask_t);
165 	sccb_set_recv_mask(sccb, receive_mask);
166 	sccb_set_send_mask(sccb, send_mask);
167 	if (sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_MASK, sccb))
168 		return -EIO;
169 	if ((sccb->header.response_code == 0x74f0) && !sclp_mask_compat_mode) {
170 		sclp_mask_compat_mode = true;
171 		goto retry;
172 	}
173 	if (sccb->header.response_code != 0x20)
174 		return -EIO;
175 	return 0;
176 }
177 
178 unsigned int sclp_early_con_check_linemode(struct init_sccb *sccb)
179 {
180 	if (!(sccb_get_sclp_send_mask(sccb) & EVTYP_OPCMD_MASK))
181 		return 0;
182 	if (!(sccb_get_sclp_recv_mask(sccb) & (EVTYP_MSG_MASK | EVTYP_PMSGCMD_MASK)))
183 		return 0;
184 	return 1;
185 }
186 
187 unsigned int sclp_early_con_check_vt220(struct init_sccb *sccb)
188 {
189 	if (sccb_get_sclp_send_mask(sccb) & EVTYP_VT220MSG_MASK)
190 		return 1;
191 	return 0;
192 }
193 
194 static int sclp_early_setup(int disable, int *have_linemode, int *have_vt220)
195 {
196 	unsigned long receive_mask, send_mask;
197 	struct init_sccb *sccb;
198 	int rc;
199 
200 	BUILD_BUG_ON(sizeof(struct init_sccb) > PAGE_SIZE);
201 
202 	*have_linemode = *have_vt220 = 0;
203 	sccb = (struct init_sccb *) sclp_early_sccb;
204 	receive_mask = disable ? 0 : EVTYP_OPCMD_MASK;
205 	send_mask = disable ? 0 : EVTYP_VT220MSG_MASK | EVTYP_MSG_MASK;
206 	rc = sclp_early_set_event_mask(sccb, receive_mask, send_mask);
207 	if (rc)
208 		return rc;
209 	*have_linemode = sclp_early_con_check_linemode(sccb);
210 	*have_vt220 = !!(sccb_get_send_mask(sccb) & EVTYP_VT220MSG_MASK);
211 	return rc;
212 }
213 
214 void sclp_early_set_buffer(void *sccb)
215 {
216 	sclp_early_sccb = sccb;
217 }
218 
219 /*
220  * Output one or more lines of text on the SCLP console (VT220 and /
221  * or line-mode).
222  */
223 void __sclp_early_printk(const char *str, unsigned int len)
224 {
225 	int have_linemode, have_vt220;
226 
227 	if (sclp_init_state != sclp_init_state_uninitialized)
228 		return;
229 	if (sclp_early_setup(0, &have_linemode, &have_vt220) != 0)
230 		return;
231 	if (have_linemode)
232 		sclp_early_print_lm(str, len);
233 	if (have_vt220)
234 		sclp_early_print_vt220(str, len);
235 	sclp_early_setup(1, &have_linemode, &have_vt220);
236 }
237 
238 void sclp_early_printk(const char *str)
239 {
240 	__sclp_early_printk(str, strlen(str));
241 }
242 
243 /*
244  * Use sclp_emergency_printk() to print a string when the system is in a
245  * state where regular console drivers cannot be assumed to work anymore.
246  *
247  * Callers must make sure that no concurrent SCLP requests are outstanding
248  * and all other CPUs are stopped, or at least disabled for external
249  * interrupts.
250  */
251 void sclp_emergency_printk(const char *str)
252 {
253 	int have_linemode, have_vt220;
254 	unsigned int len;
255 
256 	len = strlen(str);
257 	/*
258 	 * Don't care about return values; if requests fail, just ignore and
259 	 * continue to have a rather high chance that anything is printed.
260 	 */
261 	sclp_early_setup(0, &have_linemode, &have_vt220);
262 	sclp_early_print_lm(str, len);
263 	sclp_early_print_vt220(str, len);
264 	sclp_early_setup(1, &have_linemode, &have_vt220);
265 }
266 
267 /*
268  * We can't pass sclp_info_sccb to sclp_early_cmd() here directly,
269  * because it might not fulfil the requiremets for a SCLP communication buffer:
270  *   - lie below 2G in memory
271  *   - be page-aligned
272  * Therefore, we use the buffer sclp_early_sccb (which fulfils all those
273  * requirements) temporarily for communication and copy a received response
274  * back into the buffer sclp_info_sccb upon successful completion.
275  */
276 int __init sclp_early_read_info(void)
277 {
278 	int i;
279 	int length = test_facility(140) ? EXT_SCCB_READ_SCP : PAGE_SIZE;
280 	struct read_info_sccb *sccb = (struct read_info_sccb *)sclp_early_sccb;
281 	sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
282 				  SCLP_CMDW_READ_SCP_INFO};
283 
284 	for (i = 0; i < ARRAY_SIZE(commands); i++) {
285 		memset(sccb, 0, length);
286 		sccb->header.length = length;
287 		sccb->header.function_code = 0x80;
288 		sccb->header.control_mask[2] = 0x80;
289 		if (sclp_early_cmd(commands[i], sccb))
290 			break;
291 		if (sccb->header.response_code == 0x10) {
292 			memcpy(&sclp_info_sccb, sccb, length);
293 			sclp_info_sccb_valid = 1;
294 			return 0;
295 		}
296 		if (sccb->header.response_code != 0x1f0)
297 			break;
298 	}
299 	return -EIO;
300 }
301 
302 struct read_info_sccb * __init sclp_early_get_info(void)
303 {
304 	if (!sclp_info_sccb_valid)
305 		return NULL;
306 
307 	return &sclp_info_sccb;
308 }
309 
310 int __init sclp_early_get_memsize(unsigned long *mem)
311 {
312 	unsigned long rnmax;
313 	unsigned long rnsize;
314 	struct read_info_sccb *sccb = &sclp_info_sccb;
315 
316 	if (!sclp_info_sccb_valid)
317 		return -EIO;
318 
319 	rnmax = sccb->rnmax ? sccb->rnmax : sccb->rnmax2;
320 	rnsize = sccb->rnsize ? sccb->rnsize : sccb->rnsize2;
321 	rnsize <<= 20;
322 	*mem = rnsize * rnmax;
323 	return 0;
324 }
325 
326 int __init sclp_early_get_hsa_size(unsigned long *hsa_size)
327 {
328 	if (!sclp_info_sccb_valid)
329 		return -EIO;
330 
331 	*hsa_size = 0;
332 	if (sclp_info_sccb.hsa_size)
333 		*hsa_size = (sclp_info_sccb.hsa_size - 1) * PAGE_SIZE;
334 	return 0;
335 }
336 
337 #define SCLP_STORAGE_INFO_FACILITY     0x0000400000000000UL
338 
339 void __weak __init add_mem_detect_block(u64 start, u64 end) {}
340 int __init sclp_early_read_storage_info(void)
341 {
342 	struct read_storage_sccb *sccb = (struct read_storage_sccb *)sclp_early_sccb;
343 	int rc, id, max_id = 0;
344 	unsigned long rn, rzm;
345 	sclp_cmdw_t command;
346 	u16 sn;
347 
348 	if (!sclp_info_sccb_valid)
349 		return -EIO;
350 
351 	if (!(sclp_info_sccb.facilities & SCLP_STORAGE_INFO_FACILITY))
352 		return -EOPNOTSUPP;
353 
354 	rzm = sclp_info_sccb.rnsize ?: sclp_info_sccb.rnsize2;
355 	rzm <<= 20;
356 
357 	for (id = 0; id <= max_id; id++) {
358 		memset(sclp_early_sccb, 0, EARLY_SCCB_SIZE);
359 		sccb->header.length = EARLY_SCCB_SIZE;
360 		command = SCLP_CMDW_READ_STORAGE_INFO | (id << 8);
361 		rc = sclp_early_cmd(command, sccb);
362 		if (rc)
363 			goto fail;
364 
365 		max_id = sccb->max_id;
366 		switch (sccb->header.response_code) {
367 		case 0x0010:
368 			for (sn = 0; sn < sccb->assigned; sn++) {
369 				if (!sccb->entries[sn])
370 					continue;
371 				rn = sccb->entries[sn] >> 16;
372 				add_mem_detect_block((rn - 1) * rzm, rn * rzm);
373 			}
374 			break;
375 		case 0x0310:
376 		case 0x0410:
377 			break;
378 		default:
379 			goto fail;
380 		}
381 	}
382 
383 	return 0;
384 fail:
385 	mem_detect.count = 0;
386 	return -EIO;
387 }
388