xref: /openbmc/linux/drivers/ras/cec.c (revision 254db5bd075427b0f71ea112b30c924fb22bd0fd)
1011d8261SBorislav Petkov #include <linux/mm.h>
2011d8261SBorislav Petkov #include <linux/gfp.h>
3011d8261SBorislav Petkov #include <linux/kernel.h>
4011d8261SBorislav Petkov 
5011d8261SBorislav Petkov #include <asm/mce.h>
6011d8261SBorislav Petkov 
7011d8261SBorislav Petkov #include "debugfs.h"
8011d8261SBorislav Petkov 
9011d8261SBorislav Petkov /*
10011d8261SBorislav Petkov  * RAS Correctable Errors Collector
11011d8261SBorislav Petkov  *
12011d8261SBorislav Petkov  * This is a simple gadget which collects correctable errors and counts their
13011d8261SBorislav Petkov  * occurrence per physical page address.
14011d8261SBorislav Petkov  *
15011d8261SBorislav Petkov  * We've opted for possibly the simplest data structure to collect those - an
16011d8261SBorislav Petkov  * array of the size of a memory page. It stores 512 u64's with the following
17011d8261SBorislav Petkov  * structure:
18011d8261SBorislav Petkov  *
19011d8261SBorislav Petkov  * [63 ... PFN ... 12 | 11 ... generation ... 10 | 9 ... count ... 0]
20011d8261SBorislav Petkov  *
21011d8261SBorislav Petkov  * The generation in the two highest order bits is two bits which are set to 11b
22011d8261SBorislav Petkov  * on every insertion. During the course of each entry's existence, the
23011d8261SBorislav Petkov  * generation field gets decremented during spring cleaning to 10b, then 01b and
24011d8261SBorislav Petkov  * then 00b.
25011d8261SBorislav Petkov  *
26011d8261SBorislav Petkov  * This way we're employing the natural numeric ordering to make sure that newly
27011d8261SBorislav Petkov  * inserted/touched elements have higher 12-bit counts (which we've manufactured)
28011d8261SBorislav Petkov  * and thus iterating over the array initially won't kick out those elements
29011d8261SBorislav Petkov  * which were inserted last.
30011d8261SBorislav Petkov  *
31011d8261SBorislav Petkov  * Spring cleaning is what we do when we reach a certain number CLEAN_ELEMS of
32011d8261SBorislav Petkov  * elements entered into the array, during which, we're decaying all elements.
33011d8261SBorislav Petkov  * If, after decay, an element gets inserted again, its generation is set to 11b
34011d8261SBorislav Petkov  * to make sure it has higher numerical count than other, older elements and
35011d8261SBorislav Petkov  * thus emulate an an LRU-like behavior when deleting elements to free up space
36011d8261SBorislav Petkov  * in the page.
37011d8261SBorislav Petkov  *
38011d8261SBorislav Petkov  * When an element reaches it's max count of count_threshold, we try to poison
39011d8261SBorislav Petkov  * it by assuming that errors triggered count_threshold times in a single page
40011d8261SBorislav Petkov  * are excessive and that page shouldn't be used anymore. count_threshold is
41011d8261SBorislav Petkov  * initialized to COUNT_MASK which is the maximum.
42011d8261SBorislav Petkov  *
43011d8261SBorislav Petkov  * That error event entry causes cec_add_elem() to return !0 value and thus
44011d8261SBorislav Petkov  * signal to its callers to log the error.
45011d8261SBorislav Petkov  *
46011d8261SBorislav Petkov  * To the question why we've chosen a page and moving elements around with
47011d8261SBorislav Petkov  * memmove(), it is because it is a very simple structure to handle and max data
48011d8261SBorislav Petkov  * movement is 4K which on highly optimized modern CPUs is almost unnoticeable.
49011d8261SBorislav Petkov  * We wanted to avoid the pointer traversal of more complex structures like a
50011d8261SBorislav Petkov  * linked list or some sort of a balancing search tree.
51011d8261SBorislav Petkov  *
52011d8261SBorislav Petkov  * Deleting an element takes O(n) but since it is only a single page, it should
53011d8261SBorislav Petkov  * be fast enough and it shouldn't happen all too often depending on error
54011d8261SBorislav Petkov  * patterns.
55011d8261SBorislav Petkov  */
56011d8261SBorislav Petkov 
57011d8261SBorislav Petkov #undef pr_fmt
58011d8261SBorislav Petkov #define pr_fmt(fmt) "RAS: " fmt
59011d8261SBorislav Petkov 
60011d8261SBorislav Petkov /*
61011d8261SBorislav Petkov  * We use DECAY_BITS bits of PAGE_SHIFT bits for counting decay, i.e., how long
62011d8261SBorislav Petkov  * elements have stayed in the array without having been accessed again.
63011d8261SBorislav Petkov  */
64011d8261SBorislav Petkov #define DECAY_BITS		2
65011d8261SBorislav Petkov #define DECAY_MASK		((1ULL << DECAY_BITS) - 1)
66011d8261SBorislav Petkov #define MAX_ELEMS		(PAGE_SIZE / sizeof(u64))
67011d8261SBorislav Petkov 
68011d8261SBorislav Petkov /*
69011d8261SBorislav Petkov  * Threshold amount of inserted elements after which we start spring
70011d8261SBorislav Petkov  * cleaning.
71011d8261SBorislav Petkov  */
72011d8261SBorislav Petkov #define CLEAN_ELEMS		(MAX_ELEMS >> DECAY_BITS)
73011d8261SBorislav Petkov 
74011d8261SBorislav Petkov /* Bits which count the number of errors happened in this 4K page. */
75011d8261SBorislav Petkov #define COUNT_BITS		(PAGE_SHIFT - DECAY_BITS)
76011d8261SBorislav Petkov #define COUNT_MASK		((1ULL << COUNT_BITS) - 1)
77011d8261SBorislav Petkov #define FULL_COUNT_MASK		(PAGE_SIZE - 1)
78011d8261SBorislav Petkov 
79011d8261SBorislav Petkov /*
80011d8261SBorislav Petkov  * u64: [ 63 ... 12 | DECAY_BITS | COUNT_BITS ]
81011d8261SBorislav Petkov  */
82011d8261SBorislav Petkov 
83011d8261SBorislav Petkov #define PFN(e)			((e) >> PAGE_SHIFT)
84011d8261SBorislav Petkov #define DECAY(e)		(((e) >> COUNT_BITS) & DECAY_MASK)
85011d8261SBorislav Petkov #define COUNT(e)		((unsigned int)(e) & COUNT_MASK)
86011d8261SBorislav Petkov #define FULL_COUNT(e)		((e) & (PAGE_SIZE - 1))
87011d8261SBorislav Petkov 
88011d8261SBorislav Petkov static struct ce_array {
89011d8261SBorislav Petkov 	u64 *array;			/* container page */
90011d8261SBorislav Petkov 	unsigned int n;			/* number of elements in the array */
91011d8261SBorislav Petkov 
92011d8261SBorislav Petkov 	unsigned int decay_count;	/*
93011d8261SBorislav Petkov 					 * number of element insertions/increments
94011d8261SBorislav Petkov 					 * since the last spring cleaning.
95011d8261SBorislav Petkov 					 */
96011d8261SBorislav Petkov 
97011d8261SBorislav Petkov 	u64 pfns_poisoned;		/*
98011d8261SBorislav Petkov 					 * number of PFNs which got poisoned.
99011d8261SBorislav Petkov 					 */
100011d8261SBorislav Petkov 
101011d8261SBorislav Petkov 	u64 ces_entered;		/*
102011d8261SBorislav Petkov 					 * The number of correctable errors
103011d8261SBorislav Petkov 					 * entered into the collector.
104011d8261SBorislav Petkov 					 */
105011d8261SBorislav Petkov 
106011d8261SBorislav Petkov 	u64 decays_done;		/*
107011d8261SBorislav Petkov 					 * Times we did spring cleaning.
108011d8261SBorislav Petkov 					 */
109011d8261SBorislav Petkov 
110011d8261SBorislav Petkov 	union {
111011d8261SBorislav Petkov 		struct {
112011d8261SBorislav Petkov 			__u32	disabled : 1,	/* cmdline disabled */
113011d8261SBorislav Petkov 			__resv   : 31;
114011d8261SBorislav Petkov 		};
115011d8261SBorislav Petkov 		__u32 flags;
116011d8261SBorislav Petkov 	};
117011d8261SBorislav Petkov } ce_arr;
118011d8261SBorislav Petkov 
119011d8261SBorislav Petkov static DEFINE_MUTEX(ce_mutex);
120011d8261SBorislav Petkov static u64 dfs_pfn;
121011d8261SBorislav Petkov 
122011d8261SBorislav Petkov /* Amount of errors after which we offline */
123011d8261SBorislav Petkov static unsigned int count_threshold = COUNT_MASK;
124011d8261SBorislav Petkov 
125011d8261SBorislav Petkov /*
126011d8261SBorislav Petkov  * The timer "decays" element count each timer_interval which is 24hrs by
127011d8261SBorislav Petkov  * default.
128011d8261SBorislav Petkov  */
129011d8261SBorislav Petkov 
130011d8261SBorislav Petkov #define CEC_TIMER_DEFAULT_INTERVAL	24 * 60 * 60	/* 24 hrs */
131011d8261SBorislav Petkov #define CEC_TIMER_MIN_INTERVAL		 1 * 60 * 60	/* 1h */
132011d8261SBorislav Petkov #define CEC_TIMER_MAX_INTERVAL	   30 *	24 * 60 * 60	/* one month */
133011d8261SBorislav Petkov static struct timer_list cec_timer;
134011d8261SBorislav Petkov static u64 timer_interval = CEC_TIMER_DEFAULT_INTERVAL;
135011d8261SBorislav Petkov 
136011d8261SBorislav Petkov /*
137011d8261SBorislav Petkov  * Decrement decay value. We're using DECAY_BITS bits to denote decay of an
138011d8261SBorislav Petkov  * element in the array. On insertion and any access, it gets reset to max.
139011d8261SBorislav Petkov  */
140011d8261SBorislav Petkov static void do_spring_cleaning(struct ce_array *ca)
141011d8261SBorislav Petkov {
142011d8261SBorislav Petkov 	int i;
143011d8261SBorislav Petkov 
144011d8261SBorislav Petkov 	for (i = 0; i < ca->n; i++) {
145011d8261SBorislav Petkov 		u8 decay = DECAY(ca->array[i]);
146011d8261SBorislav Petkov 
147011d8261SBorislav Petkov 		if (!decay)
148011d8261SBorislav Petkov 			continue;
149011d8261SBorislav Petkov 
150011d8261SBorislav Petkov 		decay--;
151011d8261SBorislav Petkov 
152011d8261SBorislav Petkov 		ca->array[i] &= ~(DECAY_MASK << COUNT_BITS);
153011d8261SBorislav Petkov 		ca->array[i] |= (decay << COUNT_BITS);
154011d8261SBorislav Petkov 	}
155011d8261SBorislav Petkov 	ca->decay_count = 0;
156011d8261SBorislav Petkov 	ca->decays_done++;
157011d8261SBorislav Petkov }
158011d8261SBorislav Petkov 
159011d8261SBorislav Petkov /*
160011d8261SBorislav Petkov  * @interval in seconds
161011d8261SBorislav Petkov  */
162011d8261SBorislav Petkov static void cec_mod_timer(struct timer_list *t, unsigned long interval)
163011d8261SBorislav Petkov {
164011d8261SBorislav Petkov 	unsigned long iv;
165011d8261SBorislav Petkov 
166011d8261SBorislav Petkov 	iv = interval * HZ + jiffies;
167011d8261SBorislav Petkov 
168011d8261SBorislav Petkov 	mod_timer(t, round_jiffies(iv));
169011d8261SBorislav Petkov }
170011d8261SBorislav Petkov 
171*254db5bdSKees Cook static void cec_timer_fn(struct timer_list *unused)
172011d8261SBorislav Petkov {
173*254db5bdSKees Cook 	do_spring_cleaning(&ce_arr);
174011d8261SBorislav Petkov 
175011d8261SBorislav Petkov 	cec_mod_timer(&cec_timer, timer_interval);
176011d8261SBorislav Petkov }
177011d8261SBorislav Petkov 
178011d8261SBorislav Petkov /*
179011d8261SBorislav Petkov  * @to: index of the smallest element which is >= then @pfn.
180011d8261SBorislav Petkov  *
181011d8261SBorislav Petkov  * Return the index of the pfn if found, otherwise negative value.
182011d8261SBorislav Petkov  */
183011d8261SBorislav Petkov static int __find_elem(struct ce_array *ca, u64 pfn, unsigned int *to)
184011d8261SBorislav Petkov {
185011d8261SBorislav Petkov 	u64 this_pfn;
186011d8261SBorislav Petkov 	int min = 0, max = ca->n;
187011d8261SBorislav Petkov 
188011d8261SBorislav Petkov 	while (min < max) {
189011d8261SBorislav Petkov 		int tmp = (max + min) >> 1;
190011d8261SBorislav Petkov 
191011d8261SBorislav Petkov 		this_pfn = PFN(ca->array[tmp]);
192011d8261SBorislav Petkov 
193011d8261SBorislav Petkov 		if (this_pfn < pfn)
194011d8261SBorislav Petkov 			min = tmp + 1;
195011d8261SBorislav Petkov 		else if (this_pfn > pfn)
196011d8261SBorislav Petkov 			max = tmp;
197011d8261SBorislav Petkov 		else {
198011d8261SBorislav Petkov 			min = tmp;
199011d8261SBorislav Petkov 			break;
200011d8261SBorislav Petkov 		}
201011d8261SBorislav Petkov 	}
202011d8261SBorislav Petkov 
203011d8261SBorislav Petkov 	if (to)
204011d8261SBorislav Petkov 		*to = min;
205011d8261SBorislav Petkov 
206011d8261SBorislav Petkov 	this_pfn = PFN(ca->array[min]);
207011d8261SBorislav Petkov 
208011d8261SBorislav Petkov 	if (this_pfn == pfn)
209011d8261SBorislav Petkov 		return min;
210011d8261SBorislav Petkov 
211011d8261SBorislav Petkov 	return -ENOKEY;
212011d8261SBorislav Petkov }
213011d8261SBorislav Petkov 
214011d8261SBorislav Petkov static int find_elem(struct ce_array *ca, u64 pfn, unsigned int *to)
215011d8261SBorislav Petkov {
216011d8261SBorislav Petkov 	WARN_ON(!to);
217011d8261SBorislav Petkov 
218011d8261SBorislav Petkov 	if (!ca->n) {
219011d8261SBorislav Petkov 		*to = 0;
220011d8261SBorislav Petkov 		return -ENOKEY;
221011d8261SBorislav Petkov 	}
222011d8261SBorislav Petkov 	return __find_elem(ca, pfn, to);
223011d8261SBorislav Petkov }
224011d8261SBorislav Petkov 
225011d8261SBorislav Petkov static void del_elem(struct ce_array *ca, int idx)
226011d8261SBorislav Petkov {
227011d8261SBorislav Petkov 	/* Save us a function call when deleting the last element. */
228011d8261SBorislav Petkov 	if (ca->n - (idx + 1))
229011d8261SBorislav Petkov 		memmove((void *)&ca->array[idx],
230011d8261SBorislav Petkov 			(void *)&ca->array[idx + 1],
231011d8261SBorislav Petkov 			(ca->n - (idx + 1)) * sizeof(u64));
232011d8261SBorislav Petkov 
233011d8261SBorislav Petkov 	ca->n--;
234011d8261SBorislav Petkov }
235011d8261SBorislav Petkov 
236011d8261SBorislav Petkov static u64 del_lru_elem_unlocked(struct ce_array *ca)
237011d8261SBorislav Petkov {
238011d8261SBorislav Petkov 	unsigned int min = FULL_COUNT_MASK;
239011d8261SBorislav Petkov 	int i, min_idx = 0;
240011d8261SBorislav Petkov 
241011d8261SBorislav Petkov 	for (i = 0; i < ca->n; i++) {
242011d8261SBorislav Petkov 		unsigned int this = FULL_COUNT(ca->array[i]);
243011d8261SBorislav Petkov 
244011d8261SBorislav Petkov 		if (min > this) {
245011d8261SBorislav Petkov 			min = this;
246011d8261SBorislav Petkov 			min_idx = i;
247011d8261SBorislav Petkov 		}
248011d8261SBorislav Petkov 	}
249011d8261SBorislav Petkov 
250011d8261SBorislav Petkov 	del_elem(ca, min_idx);
251011d8261SBorislav Petkov 
252011d8261SBorislav Petkov 	return PFN(ca->array[min_idx]);
253011d8261SBorislav Petkov }
254011d8261SBorislav Petkov 
255011d8261SBorislav Petkov /*
256011d8261SBorislav Petkov  * We return the 0th pfn in the error case under the assumption that it cannot
257011d8261SBorislav Petkov  * be poisoned and excessive CEs in there are a serious deal anyway.
258011d8261SBorislav Petkov  */
259011d8261SBorislav Petkov static u64 __maybe_unused del_lru_elem(void)
260011d8261SBorislav Petkov {
261011d8261SBorislav Petkov 	struct ce_array *ca = &ce_arr;
262011d8261SBorislav Petkov 	u64 pfn;
263011d8261SBorislav Petkov 
264011d8261SBorislav Petkov 	if (!ca->n)
265011d8261SBorislav Petkov 		return 0;
266011d8261SBorislav Petkov 
267011d8261SBorislav Petkov 	mutex_lock(&ce_mutex);
268011d8261SBorislav Petkov 	pfn = del_lru_elem_unlocked(ca);
269011d8261SBorislav Petkov 	mutex_unlock(&ce_mutex);
270011d8261SBorislav Petkov 
271011d8261SBorislav Petkov 	return pfn;
272011d8261SBorislav Petkov }
273011d8261SBorislav Petkov 
274011d8261SBorislav Petkov 
275011d8261SBorislav Petkov int cec_add_elem(u64 pfn)
276011d8261SBorislav Petkov {
277011d8261SBorislav Petkov 	struct ce_array *ca = &ce_arr;
278011d8261SBorislav Petkov 	unsigned int to;
279011d8261SBorislav Petkov 	int count, ret = 0;
280011d8261SBorislav Petkov 
281011d8261SBorislav Petkov 	/*
282011d8261SBorislav Petkov 	 * We can be called very early on the identify_cpu() path where we are
283011d8261SBorislav Petkov 	 * not initialized yet. We ignore the error for simplicity.
284011d8261SBorislav Petkov 	 */
285011d8261SBorislav Petkov 	if (!ce_arr.array || ce_arr.disabled)
286011d8261SBorislav Petkov 		return -ENODEV;
287011d8261SBorislav Petkov 
288011d8261SBorislav Petkov 	ca->ces_entered++;
289011d8261SBorislav Petkov 
290011d8261SBorislav Petkov 	mutex_lock(&ce_mutex);
291011d8261SBorislav Petkov 
292011d8261SBorislav Petkov 	if (ca->n == MAX_ELEMS)
293011d8261SBorislav Petkov 		WARN_ON(!del_lru_elem_unlocked(ca));
294011d8261SBorislav Petkov 
295011d8261SBorislav Petkov 	ret = find_elem(ca, pfn, &to);
296011d8261SBorislav Petkov 	if (ret < 0) {
297011d8261SBorislav Petkov 		/*
298011d8261SBorislav Petkov 		 * Shift range [to-end] to make room for one more element.
299011d8261SBorislav Petkov 		 */
300011d8261SBorislav Petkov 		memmove((void *)&ca->array[to + 1],
301011d8261SBorislav Petkov 			(void *)&ca->array[to],
302011d8261SBorislav Petkov 			(ca->n - to) * sizeof(u64));
303011d8261SBorislav Petkov 
304011d8261SBorislav Petkov 		ca->array[to] = (pfn << PAGE_SHIFT) |
305011d8261SBorislav Petkov 				(DECAY_MASK << COUNT_BITS) | 1;
306011d8261SBorislav Petkov 
307011d8261SBorislav Petkov 		ca->n++;
308011d8261SBorislav Petkov 
309011d8261SBorislav Petkov 		ret = 0;
310011d8261SBorislav Petkov 
311011d8261SBorislav Petkov 		goto decay;
312011d8261SBorislav Petkov 	}
313011d8261SBorislav Petkov 
314011d8261SBorislav Petkov 	count = COUNT(ca->array[to]);
315011d8261SBorislav Petkov 
316011d8261SBorislav Petkov 	if (count < count_threshold) {
317011d8261SBorislav Petkov 		ca->array[to] |= (DECAY_MASK << COUNT_BITS);
318011d8261SBorislav Petkov 		ca->array[to]++;
319011d8261SBorislav Petkov 
320011d8261SBorislav Petkov 		ret = 0;
321011d8261SBorislav Petkov 	} else {
322011d8261SBorislav Petkov 		u64 pfn = ca->array[to] >> PAGE_SHIFT;
323011d8261SBorislav Petkov 
324011d8261SBorislav Petkov 		if (!pfn_valid(pfn)) {
325011d8261SBorislav Petkov 			pr_warn("CEC: Invalid pfn: 0x%llx\n", pfn);
326011d8261SBorislav Petkov 		} else {
327011d8261SBorislav Petkov 			/* We have reached max count for this page, soft-offline it. */
328011d8261SBorislav Petkov 			pr_err("Soft-offlining pfn: 0x%llx\n", pfn);
329011d8261SBorislav Petkov 			memory_failure_queue(pfn, 0, MF_SOFT_OFFLINE);
330011d8261SBorislav Petkov 			ca->pfns_poisoned++;
331011d8261SBorislav Petkov 		}
332011d8261SBorislav Petkov 
333011d8261SBorislav Petkov 		del_elem(ca, to);
334011d8261SBorislav Petkov 
335011d8261SBorislav Petkov 		/*
336011d8261SBorislav Petkov 		 * Return a >0 value to denote that we've reached the offlining
337011d8261SBorislav Petkov 		 * threshold.
338011d8261SBorislav Petkov 		 */
339011d8261SBorislav Petkov 		ret = 1;
340011d8261SBorislav Petkov 
341011d8261SBorislav Petkov 		goto unlock;
342011d8261SBorislav Petkov 	}
343011d8261SBorislav Petkov 
344011d8261SBorislav Petkov decay:
345011d8261SBorislav Petkov 	ca->decay_count++;
346011d8261SBorislav Petkov 
347011d8261SBorislav Petkov 	if (ca->decay_count >= CLEAN_ELEMS)
348011d8261SBorislav Petkov 		do_spring_cleaning(ca);
349011d8261SBorislav Petkov 
350011d8261SBorislav Petkov unlock:
351011d8261SBorislav Petkov 	mutex_unlock(&ce_mutex);
352011d8261SBorislav Petkov 
353011d8261SBorislav Petkov 	return ret;
354011d8261SBorislav Petkov }
355011d8261SBorislav Petkov 
356011d8261SBorislav Petkov static int u64_get(void *data, u64 *val)
357011d8261SBorislav Petkov {
358011d8261SBorislav Petkov 	*val = *(u64 *)data;
359011d8261SBorislav Petkov 
360011d8261SBorislav Petkov 	return 0;
361011d8261SBorislav Petkov }
362011d8261SBorislav Petkov 
363011d8261SBorislav Petkov static int pfn_set(void *data, u64 val)
364011d8261SBorislav Petkov {
365011d8261SBorislav Petkov 	*(u64 *)data = val;
366011d8261SBorislav Petkov 
367011d8261SBorislav Petkov 	return cec_add_elem(val);
368011d8261SBorislav Petkov }
369011d8261SBorislav Petkov 
370011d8261SBorislav Petkov DEFINE_DEBUGFS_ATTRIBUTE(pfn_ops, u64_get, pfn_set, "0x%llx\n");
371011d8261SBorislav Petkov 
372011d8261SBorislav Petkov static int decay_interval_set(void *data, u64 val)
373011d8261SBorislav Petkov {
374011d8261SBorislav Petkov 	*(u64 *)data = val;
375011d8261SBorislav Petkov 
376011d8261SBorislav Petkov 	if (val < CEC_TIMER_MIN_INTERVAL)
377011d8261SBorislav Petkov 		return -EINVAL;
378011d8261SBorislav Petkov 
379011d8261SBorislav Petkov 	if (val > CEC_TIMER_MAX_INTERVAL)
380011d8261SBorislav Petkov 		return -EINVAL;
381011d8261SBorislav Petkov 
382011d8261SBorislav Petkov 	timer_interval = val;
383011d8261SBorislav Petkov 
384011d8261SBorislav Petkov 	cec_mod_timer(&cec_timer, timer_interval);
385011d8261SBorislav Petkov 	return 0;
386011d8261SBorislav Petkov }
387011d8261SBorislav Petkov DEFINE_DEBUGFS_ATTRIBUTE(decay_interval_ops, u64_get, decay_interval_set, "%lld\n");
388011d8261SBorislav Petkov 
389011d8261SBorislav Petkov static int count_threshold_set(void *data, u64 val)
390011d8261SBorislav Petkov {
391011d8261SBorislav Petkov 	*(u64 *)data = val;
392011d8261SBorislav Petkov 
393011d8261SBorislav Petkov 	if (val > COUNT_MASK)
394011d8261SBorislav Petkov 		val = COUNT_MASK;
395011d8261SBorislav Petkov 
396011d8261SBorislav Petkov 	count_threshold = val;
397011d8261SBorislav Petkov 
398011d8261SBorislav Petkov 	return 0;
399011d8261SBorislav Petkov }
400011d8261SBorislav Petkov DEFINE_DEBUGFS_ATTRIBUTE(count_threshold_ops, u64_get, count_threshold_set, "%lld\n");
401011d8261SBorislav Petkov 
402011d8261SBorislav Petkov static int array_dump(struct seq_file *m, void *v)
403011d8261SBorislav Petkov {
404011d8261SBorislav Petkov 	struct ce_array *ca = &ce_arr;
405011d8261SBorislav Petkov 	u64 prev = 0;
406011d8261SBorislav Petkov 	int i;
407011d8261SBorislav Petkov 
408011d8261SBorislav Petkov 	mutex_lock(&ce_mutex);
409011d8261SBorislav Petkov 
410011d8261SBorislav Petkov 	seq_printf(m, "{ n: %d\n", ca->n);
411011d8261SBorislav Petkov 	for (i = 0; i < ca->n; i++) {
412011d8261SBorislav Petkov 		u64 this = PFN(ca->array[i]);
413011d8261SBorislav Petkov 
414011d8261SBorislav Petkov 		seq_printf(m, " %03d: [%016llx|%03llx]\n", i, this, FULL_COUNT(ca->array[i]));
415011d8261SBorislav Petkov 
416011d8261SBorislav Petkov 		WARN_ON(prev > this);
417011d8261SBorislav Petkov 
418011d8261SBorislav Petkov 		prev = this;
419011d8261SBorislav Petkov 	}
420011d8261SBorislav Petkov 
421011d8261SBorislav Petkov 	seq_printf(m, "}\n");
422011d8261SBorislav Petkov 
423011d8261SBorislav Petkov 	seq_printf(m, "Stats:\nCEs: %llu\nofflined pages: %llu\n",
424011d8261SBorislav Petkov 		   ca->ces_entered, ca->pfns_poisoned);
425011d8261SBorislav Petkov 
426011d8261SBorislav Petkov 	seq_printf(m, "Flags: 0x%x\n", ca->flags);
427011d8261SBorislav Petkov 
428011d8261SBorislav Petkov 	seq_printf(m, "Timer interval: %lld seconds\n", timer_interval);
429011d8261SBorislav Petkov 	seq_printf(m, "Decays: %lld\n", ca->decays_done);
430011d8261SBorislav Petkov 
431011d8261SBorislav Petkov 	seq_printf(m, "Action threshold: %d\n", count_threshold);
432011d8261SBorislav Petkov 
433011d8261SBorislav Petkov 	mutex_unlock(&ce_mutex);
434011d8261SBorislav Petkov 
435011d8261SBorislav Petkov 	return 0;
436011d8261SBorislav Petkov }
437011d8261SBorislav Petkov 
438011d8261SBorislav Petkov static int array_open(struct inode *inode, struct file *filp)
439011d8261SBorislav Petkov {
440011d8261SBorislav Petkov 	return single_open(filp, array_dump, NULL);
441011d8261SBorislav Petkov }
442011d8261SBorislav Petkov 
443011d8261SBorislav Petkov static const struct file_operations array_ops = {
444011d8261SBorislav Petkov 	.owner	 = THIS_MODULE,
445011d8261SBorislav Petkov 	.open	 = array_open,
446011d8261SBorislav Petkov 	.read	 = seq_read,
447011d8261SBorislav Petkov 	.llseek	 = seq_lseek,
448011d8261SBorislav Petkov 	.release = single_release,
449011d8261SBorislav Petkov };
450011d8261SBorislav Petkov 
451011d8261SBorislav Petkov static int __init create_debugfs_nodes(void)
452011d8261SBorislav Petkov {
453011d8261SBorislav Petkov 	struct dentry *d, *pfn, *decay, *count, *array;
454011d8261SBorislav Petkov 
455011d8261SBorislav Petkov 	d = debugfs_create_dir("cec", ras_debugfs_dir);
456011d8261SBorislav Petkov 	if (!d) {
457011d8261SBorislav Petkov 		pr_warn("Error creating cec debugfs node!\n");
458011d8261SBorislav Petkov 		return -1;
459011d8261SBorislav Petkov 	}
460011d8261SBorislav Petkov 
461011d8261SBorislav Petkov 	pfn = debugfs_create_file("pfn", S_IRUSR | S_IWUSR, d, &dfs_pfn, &pfn_ops);
462011d8261SBorislav Petkov 	if (!pfn) {
463011d8261SBorislav Petkov 		pr_warn("Error creating pfn debugfs node!\n");
464011d8261SBorislav Petkov 		goto err;
465011d8261SBorislav Petkov 	}
466011d8261SBorislav Petkov 
467011d8261SBorislav Petkov 	array = debugfs_create_file("array", S_IRUSR, d, NULL, &array_ops);
468011d8261SBorislav Petkov 	if (!array) {
469011d8261SBorislav Petkov 		pr_warn("Error creating array debugfs node!\n");
470011d8261SBorislav Petkov 		goto err;
471011d8261SBorislav Petkov 	}
472011d8261SBorislav Petkov 
473011d8261SBorislav Petkov 	decay = debugfs_create_file("decay_interval", S_IRUSR | S_IWUSR, d,
474011d8261SBorislav Petkov 				    &timer_interval, &decay_interval_ops);
475011d8261SBorislav Petkov 	if (!decay) {
476011d8261SBorislav Petkov 		pr_warn("Error creating decay_interval debugfs node!\n");
477011d8261SBorislav Petkov 		goto err;
478011d8261SBorislav Petkov 	}
479011d8261SBorislav Petkov 
480011d8261SBorislav Petkov 	count = debugfs_create_file("count_threshold", S_IRUSR | S_IWUSR, d,
481011d8261SBorislav Petkov 				    &count_threshold, &count_threshold_ops);
48232288dafSChristophe JAILLET 	if (!count) {
483011d8261SBorislav Petkov 		pr_warn("Error creating count_threshold debugfs node!\n");
484011d8261SBorislav Petkov 		goto err;
485011d8261SBorislav Petkov 	}
486011d8261SBorislav Petkov 
487011d8261SBorislav Petkov 
488011d8261SBorislav Petkov 	return 0;
489011d8261SBorislav Petkov 
490011d8261SBorislav Petkov err:
491011d8261SBorislav Petkov 	debugfs_remove_recursive(d);
492011d8261SBorislav Petkov 
493011d8261SBorislav Petkov 	return 1;
494011d8261SBorislav Petkov }
495011d8261SBorislav Petkov 
496011d8261SBorislav Petkov void __init cec_init(void)
497011d8261SBorislav Petkov {
498011d8261SBorislav Petkov 	if (ce_arr.disabled)
499011d8261SBorislav Petkov 		return;
500011d8261SBorislav Petkov 
501011d8261SBorislav Petkov 	ce_arr.array = (void *)get_zeroed_page(GFP_KERNEL);
502011d8261SBorislav Petkov 	if (!ce_arr.array) {
503011d8261SBorislav Petkov 		pr_err("Error allocating CE array page!\n");
504011d8261SBorislav Petkov 		return;
505011d8261SBorislav Petkov 	}
506011d8261SBorislav Petkov 
507011d8261SBorislav Petkov 	if (create_debugfs_nodes())
508011d8261SBorislav Petkov 		return;
509011d8261SBorislav Petkov 
510*254db5bdSKees Cook 	timer_setup(&cec_timer, cec_timer_fn, 0);
511011d8261SBorislav Petkov 	cec_mod_timer(&cec_timer, CEC_TIMER_DEFAULT_INTERVAL);
512011d8261SBorislav Petkov 
513011d8261SBorislav Petkov 	pr_info("Correctable Errors collector initialized.\n");
514011d8261SBorislav Petkov }
515011d8261SBorislav Petkov 
516011d8261SBorislav Petkov int __init parse_cec_param(char *str)
517011d8261SBorislav Petkov {
518011d8261SBorislav Petkov 	if (!str)
519011d8261SBorislav Petkov 		return 0;
520011d8261SBorislav Petkov 
521011d8261SBorislav Petkov 	if (*str == '=')
522011d8261SBorislav Petkov 		str++;
523011d8261SBorislav Petkov 
524011d8261SBorislav Petkov 	if (!strncmp(str, "cec_disable", 7))
525011d8261SBorislav Petkov 		ce_arr.disabled = 1;
526011d8261SBorislav Petkov 	else
527011d8261SBorislav Petkov 		return 0;
528011d8261SBorislav Petkov 
529011d8261SBorislav Petkov 	return 1;
530011d8261SBorislav Petkov }
531