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2023-12-08 01573e231f18eb2d99162747186f59511f56b64d 
 kernel/fs/pstore/ram_core.c
....@@ -1,18 +1,9 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * Copyright (C) 2012 Google, Inc.
3
- *
4
- * This software is licensed under the terms of the GNU General Public
5
- * License version 2, as published by the Free Software Foundation, and
6
- * may be copied, distributed, and modified under those terms.
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- *
8
- * This program is distributed in the hope that it will be useful,
9
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
10
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11
- * GNU General Public License for more details.
12
- *
134  */
145 
15
-#define pr_fmt(fmt) "persistent_ram: " fmt
6
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
167 
178 #include <linux/device.h>
189 #include <linux/err.h>
....@@ -28,6 +19,23 @@
2819 #include <linux/uaccess.h>
2920 #include <linux/vmalloc.h>
3021 #include <asm/page.h>
22
+
23
+/**
24
+ * struct persistent_ram_buffer - persistent circular RAM buffer
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+ *
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+ * @sig:
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+ *	signature to indicate header (PERSISTENT_RAM_SIG xor PRZ-type value)
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+ * @start:
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+ *	offset into @data where the beginning of the stored bytes begin
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+ * @size:
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+ *	number of valid bytes stored in @data
32
+ */
33
+struct persistent_ram_buffer {
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+	uint32_t    sig;
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+	atomic_t    start;
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+	atomic_t    size;
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+	uint8_t     data[];
38
+};
3139 
3240 #define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
3341 
....@@ -275,7 +283,7 @@
275283 	const void __user *s, unsigned int start, unsigned int count)
276284 {
277285 	struct persistent_ram_buffer *buffer = prz->buffer;
278
-	int ret = unlikely(__copy_from_user(buffer->data + start, s, count)) ?
286
+	int ret = unlikely(copy_from_user(buffer->data + start, s, count)) ?
279287 		-EFAULT : 0;
280288 	persistent_ram_update_ecc(prz, start, count);
281289 	return ret;
....@@ -340,8 +348,6 @@
340348 	int rem, ret = 0, c = count;
341349 	size_t start;
342350 
343
-	if (unlikely(!access_ok(VERIFY_READ, s, count)))
344
-		return -EFAULT;
345351 	if (unlikely(c > prz->buffer_size)) {
346352 		s += c - prz->buffer_size;
347353 		c = prz->buffer_size;
....@@ -390,6 +396,10 @@
390396 	persistent_ram_update_header_ecc(prz);
391397 }
392398 
399
+#define MEM_TYPE_WCOMBINE	0
400
+#define MEM_TYPE_NONCACHED	1
401
+#define MEM_TYPE_NORMAL		2
402
+
393403 static void *persistent_ram_vmap(phys_addr_t start, size_t size,
394404 		unsigned int memtype)
395405 {
....@@ -403,10 +413,20 @@
403413 	page_start = start - offset_in_page(start);
404414 	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
405415 
406
-	if (memtype)
416
+	switch (memtype) {
417
+	case MEM_TYPE_NORMAL:
418
+		prot = PAGE_KERNEL;
419
+		break;
420
+	case MEM_TYPE_NONCACHED:
407421 		prot = pgprot_noncached(PAGE_KERNEL);
408
-	else
422
+		break;
423
+	case MEM_TYPE_WCOMBINE:
409424 		prot = pgprot_writecombine(PAGE_KERNEL);
425
+		break;
426
+	default:
427
+		pr_err("invalid mem_type=%d\n", memtype);
428
+		return NULL;
429
+	}
410430 
411431 	pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
412432 	if (!pages) {
....@@ -431,12 +451,13 @@
431451 }
432452 
433453 static void *persistent_ram_iomap(phys_addr_t start, size_t size,
434
-		unsigned int memtype)
454
+		unsigned int memtype, char *label)
435455 {
436456 	void *va;
437457 
438
-	if (!request_mem_region(start, size, "persistent_ram")) {
439
-		pr_err("request mem region (0x%llx@0x%llx) failed\n",
458
+	if (!request_mem_region(start, size, label ?: "ramoops")) {
459
+		pr_err("request mem region (%s 0x%llx@0x%llx) failed\n",
460
+			label ?: "ramoops",
440461 			(unsigned long long)size, (unsigned long long)start);
441462 		return NULL;
442463 	}
....@@ -463,7 +484,8 @@
463484 	if (pfn_valid(start >> PAGE_SHIFT))
464485 		prz->vaddr = persistent_ram_vmap(start, size, memtype);
465486 	else
466
-		prz->vaddr = persistent_ram_iomap(start, size, memtype);
487
+		prz->vaddr = persistent_ram_iomap(start, size, memtype,
488
+						  prz->label);
467489 
468490 	if (!prz->vaddr) {
469491 		pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
....@@ -481,10 +503,13 @@
481503 				    struct persistent_ram_ecc_info *ecc_info)
482504 {
483505 	int ret;
506
+	bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD);
484507 
485508 	ret = persistent_ram_init_ecc(prz, ecc_info);
486
-	if (ret)
509
+	if (ret) {
510
+		pr_warn("ECC failed %s\n", prz->label);
487511 		return ret;
512
+	}
488513 
489514 	sig ^= PERSISTENT_RAM_SIG;
490515 
....@@ -495,23 +520,25 @@
495520 		}
496521 
497522 		if (buffer_size(prz) > prz->buffer_size ||
498
-		    buffer_start(prz) > buffer_size(prz))
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+		    buffer_start(prz) > buffer_size(prz)) {
499524 			pr_info("found existing invalid buffer, size %zu, start %zu\n",
500525 				buffer_size(prz), buffer_start(prz));
501
-		else {
526
+			zap = true;
527
+		} else {
502528 			pr_debug("found existing buffer, size %zu, start %zu\n",
503529 				 buffer_size(prz), buffer_start(prz));
504530 			persistent_ram_save_old(prz);
505
-			return 0;
506531 		}
507532 	} else {
508533 		pr_debug("no valid data in buffer (sig = 0x%08x)\n",
509534 			 prz->buffer->sig);
535
+		prz->buffer->sig = sig;
536
+		zap = true;
510537 	}
511538 
512
-	/* Rewind missing or invalid memory area. */
513
-	prz->buffer->sig = sig;
514
-	persistent_ram_zap(prz);
539
+	/* Reset missing, invalid, or single-use memory area. */
540
+	if (zap)
541
+		persistent_ram_zap(prz);
515542 
516543 	return 0;
517544 }
....@@ -539,12 +566,13 @@
539566 	prz->ecc_info.par = NULL;
540567 
541568 	persistent_ram_free_old(prz);
569
+	kfree(prz->label);
542570 	kfree(prz);
543571 }
544572 
545573 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
546574 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
547
-			unsigned int memtype, u32 flags)
575
+			unsigned int memtype, u32 flags, char *label)
548576 {
549577 	struct persistent_ram_zone *prz;
550578 	int ret = -ENOMEM;
....@@ -558,6 +586,7 @@
558586 	/* Initialize general buffer state. */
559587 	raw_spin_lock_init(&prz->buffer_lock);
560588 	prz->flags = flags;
589
+	prz->label = kstrdup(label, GFP_KERNEL);
561590 
562591 	ret = persistent_ram_buffer_map(start, size, prz, memtype);
563592 	if (ret)
....@@ -567,6 +596,12 @@
567596 	if (ret)
568597 		goto err;
569598 
599
+	pr_debug("attached %s 0x%zx@0x%llx: %zu header, %zu data, %zu ecc (%d/%d)\n",
600
+		prz->label, prz->size, (unsigned long long)prz->paddr,
601
+		sizeof(*prz->buffer), prz->buffer_size,
602
+		prz->size - sizeof(*prz->buffer) - prz->buffer_size,
603
+		prz->ecc_info.ecc_size, prz->ecc_info.block_size);
604
+
570605 	return prz;
571606 err:
572607 	persistent_ram_free(prz);