1 // SPDX-License-Identifier: GPL-2.0 1
2 /*
3 * Page Deallocation Table (PDT) support
4 *
5 * The Page Deallocation Table (PDT) is mai
6 * list of memory addresses in which memory
7 * The list contains both single-bit (corre
8 * (uncorrectable) errors.
9 *
10 * Copyright 2017 by Helge Deller <deller@g
11 *
12 * possible future enhancements:
13 * - add userspace interface via procfs or
14 */
15
16 #include <linux/memblock.h>
17 #include <linux/seq_file.h>
18 #include <linux/kthread.h>
19 #include <linux/proc_fs.h>
20 #include <linux/initrd.h>
21 #include <linux/pgtable.h>
22 #include <linux/mm.h>
23
24 #include <asm/pdc.h>
25 #include <asm/pdcpat.h>
26 #include <asm/sections.h>
27 #include <asm/pgtable.h>
28
29 enum pdt_access_type {
30 PDT_NONE,
31 PDT_PDC,
32 PDT_PAT_NEW,
33 PDT_PAT_CELL
34 };
35
36 static enum pdt_access_type pdt_type;
37
38 /* PDT poll interval: 1 minute if errors, 5 mi
39 #define PDT_POLL_INTERVAL_DEFAULT (5*60*
40 #define PDT_POLL_INTERVAL_SHORT (1*60*
41 static unsigned long pdt_poll_interval = PDT_P
42
43 /* global PDT status information */
44 static struct pdc_mem_retinfo pdt_status;
45
46 #define MAX_PDT_TABLE_SIZE PAGE_SIZE
47 #define MAX_PDT_ENTRIES (MAX_PDT_TABLE
48 static unsigned long pdt_entry[MAX_PDT_ENTRIES
49
50 /*
51 * Constants for the pdt_entry format:
52 * A pdt_entry holds the physical address in b
53 * reserved, bit 62 is the perm bit and bit 63
54 * The perm bit indicates whether the error ha
55 * error (value of 1) or has not been verified
56 * of 0). The error_type bit indicates whether
57 * (value of 1) or a multiple bit error.
58 * On non-PAT machines phys_addr is encoded in
59 * 63. Those machines don't provide the perm b
60 */
61
62 #define PDT_ADDR_PHYS_MASK (pdt_type != P
63 #define PDT_ADDR_PERM_ERR (pdt_type != P
64 #define PDT_ADDR_SINGLE_ERR 1UL
65
66 /* report PDT entries via /proc/meminfo */
67 void arch_report_meminfo(struct seq_file *m)
68 {
69 if (pdt_type == PDT_NONE)
70 return;
71
72 seq_printf(m, "PDT_max_entries: %7lu\n
73 pdt_status.pdt_size);
74 seq_printf(m, "PDT_cur_entries: %7lu\n
75 pdt_status.pdt_entries
76 }
77
78 static int get_info_pat_new(void)
79 {
80 struct pdc_pat_mem_retinfo pat_rinfo;
81 int ret;
82
83 /* newer PAT machines like C8000 repor
84 if (is_pdc_pat())
85 ret = pdc_pat_mem_pdt_info(&pa
86 else
87 return PDC_BAD_PROC;
88
89 pdt_status.pdt_size = pat_rinfo.max_pd
90 pdt_status.pdt_entries = pat_rinfo.cur
91 pdt_status.pdt_status = 0;
92 pdt_status.first_dbe_loc = pat_rinfo.f
93 pdt_status.good_mem = pat_rinfo.good_m
94
95 return ret;
96 }
97
98 static int get_info_pat_cell(void)
99 {
100 struct pdc_pat_mem_cell_pdt_retinfo ce
101 int ret;
102
103 /* older PAT machines like rp5470 repo
104 if (is_pdc_pat())
105 ret = pdc_pat_mem_pdt_cell_inf
106 else
107 return PDC_BAD_PROC;
108
109 pdt_status.pdt_size = cell_rinfo.max_p
110 pdt_status.pdt_entries = cell_rinfo.cu
111 pdt_status.pdt_status = 0;
112 pdt_status.first_dbe_loc = cell_rinfo.
113 pdt_status.good_mem = cell_rinfo.good_
114
115 return ret;
116 }
117
118 static void report_mem_err(unsigned long pde)
119 {
120 struct pdc_pat_mem_phys_mem_location l
121 unsigned long addr;
122 char dimm_txt[32];
123
124 addr = pde & PDT_ADDR_PHYS_MASK;
125
126 /* show DIMM slot description on PAT m
127 if (is_pdc_pat()) {
128 pdc_pat_mem_get_dimm_phys_loca
129 sprintf(dimm_txt, "DIMM slot %
130 } else
131 dimm_txt[0] = 0;
132
133 pr_warn("PDT: BAD MEMORY at 0x%08lx, %
134 addr, dimm_txt,
135 pde & PDT_ADDR_PERM_ERR ? "per
136 pde & PDT_ADDR_SINGLE_ERR ? "s
137 }
138
139
140 /*
141 * pdc_pdt_init()
142 *
143 * Initialize kernel PDT structures, read init
144 * report all current PDT entries and mark bad
145 * to avoid that the kernel will use broken me
146 *
147 */
148 void __init pdc_pdt_init(void)
149 {
150 int ret, i;
151 unsigned long entries;
152 struct pdc_mem_read_pdt pdt_read_ret;
153
154 pdt_type = PDT_PAT_NEW;
155 ret = get_info_pat_new();
156
157 if (ret != PDC_OK) {
158 pdt_type = PDT_PAT_CELL;
159 ret = get_info_pat_cell();
160 }
161
162 if (ret != PDC_OK) {
163 pdt_type = PDT_PDC;
164 /* non-PAT machines provide th
165 ret = pdc_mem_pdt_info(&pdt_st
166 }
167
168 if (ret != PDC_OK) {
169 pdt_type = PDT_NONE;
170 pr_info("PDT: Firmware does no
171 " information.\n");
172 return;
173 }
174
175 entries = pdt_status.pdt_entries;
176 if (WARN_ON(entries > MAX_PDT_ENTRIES)
177 entries = pdt_status.pdt_entri
178
179 pr_info("PDT: type %s, size %lu, entri
180 " good_mem %lu MB\n",
181 pdt_type == PDT_PDC ?
182 pdt_type == PDT_PAT_CE
183
184 pdt_status.pdt_size, p
185 pdt_status.pdt_status,
186 pdt_status.good_mem /
187
188 if (entries == 0) {
189 pr_info("PDT: Firmware reports
190 return;
191 }
192
193 if (pdt_status.first_dbe_loc &&
194 pdt_status.first_dbe_loc <= __
195 pr_crit("CRITICAL: Bad memory
196
197 pr_warn("PDT: Firmware reports %lu ent
198 entries);
199
200 if (pdt_type == PDT_PDC)
201 ret = pdc_mem_pdt_read_entries
202 else {
203 #ifdef CONFIG_64BIT
204 struct pdc_pat_mem_read_pd_ret
205
206 if (pdt_type == PDT_PAT_CELL)
207 ret = pdc_pat_mem_read
208 MAX_PDT_ENTRIE
209 else
210 ret = pdc_pat_mem_read
211 MAX_PDT_TABLE_
212 #else
213 ret = PDC_BAD_PROC;
214 #endif
215 }
216
217 if (ret != PDC_OK) {
218 pdt_type = PDT_NONE;
219 pr_warn("PDT: Get PDT entries
220 return;
221 }
222
223 for (i = 0; i < pdt_status.pdt_entries
224 unsigned long addr;
225
226 report_mem_err(pdt_entry[i]);
227
228 addr = pdt_entry[i] & PDT_ADDR
229 if (IS_ENABLED(CONFIG_BLK_DEV_
230 addr >= initrd_start &
231 pr_crit("CRITICAL: ini
232 "due to bad me
233
234 /* mark memory page bad */
235 memblock_reserve(pdt_entry[i]
236 num_poisoned_pages_inc(addr >>
237 }
238 }
239
240
241 /*
242 * This is the PDT kernel thread main loop.
243 */
244
245 static int pdt_mainloop(void *unused)
246 {
247 struct pdc_mem_read_pdt pdt_read_ret;
248 struct pdc_pat_mem_read_pd_retinfo pat
249 unsigned long old_num_entries;
250 unsigned long *bad_mem_ptr;
251 int num, ret;
252
253 for (;;) {
254 set_current_state(TASK_INTERRU
255
256 old_num_entries = pdt_status.p
257
258 schedule_timeout(pdt_poll_inte
259 if (kthread_should_stop())
260 break;
261
262 /* Do we have new PDT entries?
263 switch (pdt_type) {
264 case PDT_PAT_NEW:
265 ret = get_info_pat_new
266 break;
267 case PDT_PAT_CELL:
268 ret = get_info_pat_cel
269 break;
270 default:
271 ret = pdc_mem_pdt_info
272 break;
273 }
274
275 if (ret != PDC_OK) {
276 pr_warn("PDT: unexpect
277 return -EINVAL;
278 }
279
280 /* if no new PDT entries, just
281 num = pdt_status.pdt_entries -
282 if (num <= 0)
283 continue;
284
285 /* decrease poll interval in c
286 if (pdt_status.pdt_entries &&
287 pdt_poll_interval == P
288 pdt_poll_interval = PD
289
290 /* limit entries to get */
291 if (num > MAX_PDT_ENTRIES) {
292 num = MAX_PDT_ENTRIES;
293 pdt_status.pdt_entries
294 }
295
296 /* get new entries */
297 switch (pdt_type) {
298 #ifdef CONFIG_64BIT
299 case PDT_PAT_CELL:
300 if (pdt_status.pdt_ent
301 pr_crit("PDT:
302 return -ENOMEM
303 }
304 ret = pdc_pat_mem_read
305 MAX_PDT_ENTRIE
306 bad_mem_ptr = &pdt_ent
307 break;
308 case PDT_PAT_NEW:
309 ret = pdc_pat_mem_read
310 pdt_entry,
311 num * sizeof(u
312 old_num_entrie
313 bad_mem_ptr = &pdt_ent
314 break;
315 #endif
316 default:
317 ret = pdc_mem_pdt_read
318 pdt_entry);
319 bad_mem_ptr = &pdt_ent
320 break;
321 }
322
323 /* report and mark memory brok
324 while (num--) {
325 unsigned long pde = *b
326
327 report_mem_err(pde);
328
329 #ifdef CONFIG_MEMORY_FAILURE
330 if ((pde & PDT_ADDR_PE
331 ((pde & PDT_ADDR_S
332 memory_failure
333 else
334 soft_offline_p
335 #else
336 pr_crit("PDT: memory e
337 "Rebuild kerne
338 "for real hand
339 pde & PDT_ADDR
340 #endif
341
342 }
343 }
344
345 return 0;
346 }
347
348
349 static int __init pdt_initcall(void)
350 {
351 struct task_struct *kpdtd_task;
352
353 if (pdt_type == PDT_NONE)
354 return -ENODEV;
355
356 kpdtd_task = kthread_run(pdt_mainloop,
357
358 return PTR_ERR_OR_ZERO(kpdtd_task);
359 }
360
361 late_initcall(pdt_initcall);
362
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