[mirror_ubuntu-artful-kernel.git] / fs / pstore / ram_core.c

/*
 * Copyright (C) 2012 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#define pr_fmt(fmt) "persistent_ram: " fmt

#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/memblock.h>
#include <linux/pstore_ram.h>
#include <linux/rslib.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <asm/page.h>

struct persistent_ram_buffer {
	uint32_t    sig;
	atomic_t    start;
	atomic_t    size;
	uint8_t     data[0];
};

#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */

static inline size_t buffer_size(struct persistent_ram_zone *prz)
{
	return atomic_read(&prz->buffer->size);
}

static inline size_t buffer_start(struct persistent_ram_zone *prz)
{
	return atomic_read(&prz->buffer->start);
}

/* increase and wrap the start pointer, returning the old value */
static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
{
	int old;
	int new;
	unsigned long flags = 0;

	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
		raw_spin_lock_irqsave(&prz->buffer_lock, flags);

	old = atomic_read(&prz->buffer->start);
	new = old + a;
	while (unlikely(new >= prz->buffer_size))
		new -= prz->buffer_size;
	atomic_set(&prz->buffer->start, new);

	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
		raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);

	return old;
}

/* increase the size counter until it hits the max size */
static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
{
	size_t old;
	size_t new;
	unsigned long flags = 0;

	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
		raw_spin_lock_irqsave(&prz->buffer_lock, flags);

	old = atomic_read(&prz->buffer->size);
	if (old == prz->buffer_size)
		goto exit;

	new = old + a;
	if (new > prz->buffer_size)
		new = prz->buffer_size;
	atomic_set(&prz->buffer->size, new);

exit:
	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
		raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
}

static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
	uint8_t *data, size_t len, uint8_t *ecc)
{
	int i;
	uint16_t par[prz->ecc_info.ecc_size];

	/* Initialize the parity buffer */
	memset(par, 0, sizeof(par));
	encode_rs8(prz->rs_decoder, data, len, par, 0);
	for (i = 0; i < prz->ecc_info.ecc_size; i++)
		ecc[i] = par[i];
}

static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	void *data, size_t len, uint8_t *ecc)
{
	int i;
	uint16_t par[prz->ecc_info.ecc_size];

	for (i = 0; i < prz->ecc_info.ecc_size; i++)
		par[i] = ecc[i];
	return decode_rs8(prz->rs_decoder, data, par, len,
				NULL, 0, NULL, 0, NULL);
}

static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
	unsigned int start, unsigned int count)
{
	struct persistent_ram_buffer *buffer = prz->buffer;
	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	uint8_t *block;
	uint8_t *par;
	int ecc_block_size = prz->ecc_info.block_size;
	int ecc_size = prz->ecc_info.ecc_size;
	int size = ecc_block_size;

	if (!ecc_size)
		return;

	block = buffer->data + (start & ~(ecc_block_size - 1));
	par = prz->par_buffer + (start / ecc_block_size) * ecc_size;

	do {
		if (block + ecc_block_size > buffer_end)
			size = buffer_end - block;
		persistent_ram_encode_rs8(prz, block, size, par);
		block += ecc_block_size;
		par += ecc_size;
	} while (block < buffer->data + start + count);
}

static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
{
	struct persistent_ram_buffer *buffer = prz->buffer;

	if (!prz->ecc_info.ecc_size)
		return;

	persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
				  prz->par_header);
}

static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
{
	struct persistent_ram_buffer *buffer = prz->buffer;
	uint8_t *block;
	uint8_t *par;

	if (!prz->ecc_info.ecc_size)
		return;

	block = buffer->data;
	par = prz->par_buffer;
	while (block < buffer->data + buffer_size(prz)) {
		int numerr;
		int size = prz->ecc_info.block_size;
		if (block + size > buffer->data + prz->buffer_size)
			size = buffer->data + prz->buffer_size - block;
		numerr = persistent_ram_decode_rs8(prz, block, size, par);
		if (numerr > 0) {
			pr_devel("error in block %p, %d\n", block, numerr);
			prz->corrected_bytes += numerr;
		} else if (numerr < 0) {
			pr_devel("uncorrectable error in block %p\n", block);
			prz->bad_blocks++;
		}
		block += prz->ecc_info.block_size;
		par += prz->ecc_info.ecc_size;
	}
}

static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
				   struct persistent_ram_ecc_info *ecc_info)
{
	int numerr;
	struct persistent_ram_buffer *buffer = prz->buffer;
	int ecc_blocks;
	size_t ecc_total;

	if (!ecc_info || !ecc_info->ecc_size)
		return 0;

	prz->ecc_info.block_size = ecc_info->block_size ?: 128;
	prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
	prz->ecc_info.symsize = ecc_info->symsize ?: 8;
	prz->ecc_info.poly = ecc_info->poly ?: 0x11d;

	ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
				  prz->ecc_info.block_size +
				  prz->ecc_info.ecc_size);
	ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
	if (ecc_total >= prz->buffer_size) {
		pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
		       __func__, prz->ecc_info.ecc_size,
		       ecc_total, prz->buffer_size);
		return -EINVAL;
	}

	prz->buffer_size -= ecc_total;
	prz->par_buffer = buffer->data + prz->buffer_size;
	prz->par_header = prz->par_buffer +
			  ecc_blocks * prz->ecc_info.ecc_size;

	/*
	 * first consecutive root is 0
	 * primitive element to generate roots = 1
	 */
	prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
				  0, 1, prz->ecc_info.ecc_size);
	if (prz->rs_decoder == NULL) {
		pr_info("init_rs failed\n");
		return -EINVAL;
	}

	prz->corrected_bytes = 0;
	prz->bad_blocks = 0;

	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
					   prz->par_header);
	if (numerr > 0) {
		pr_info("error in header, %d\n", numerr);
		prz->corrected_bytes += numerr;
	} else if (numerr < 0) {
		pr_info("uncorrectable error in header\n");
		prz->bad_blocks++;
	}

	return 0;
}

ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	char *str, size_t len)
{
	ssize_t ret;

	if (!prz->ecc_info.ecc_size)
		return 0;

	if (prz->corrected_bytes || prz->bad_blocks)
		ret = snprintf(str, len, ""
			"\n%d Corrected bytes, %d unrecoverable blocks\n",
			prz->corrected_bytes, prz->bad_blocks);
	else
		ret = snprintf(str, len, "\nNo errors detected\n");

	return ret;
}

static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
	const void *s, unsigned int start, unsigned int count)
{
	struct persistent_ram_buffer *buffer = prz->buffer;
	memcpy_toio(buffer->data + start, s, count);
	persistent_ram_update_ecc(prz, start, count);
}

static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,
	const void __user *s, unsigned int start, unsigned int count)
{
	struct persistent_ram_buffer *buffer = prz->buffer;
	int ret = unlikely(__copy_from_user(buffer->data + start, s, count)) ?
		-EFAULT : 0;
	persistent_ram_update_ecc(prz, start, count);
	return ret;
}

void persistent_ram_save_old(struct persistent_ram_zone *prz)
{
	struct persistent_ram_buffer *buffer = prz->buffer;
	size_t size = buffer_size(prz);
	size_t start = buffer_start(prz);

	if (!size)
		return;

	if (!prz->old_log) {
		persistent_ram_ecc_old(prz);
		prz->old_log = kmalloc(size, GFP_KERNEL);
	}
	if (!prz->old_log) {
		pr_err("failed to allocate buffer\n");
		return;
	}

	prz->old_log_size = size;
	memcpy_fromio(prz->old_log, &buffer->data[start], size - start);
	memcpy_fromio(prz->old_log + size - start, &buffer->data[0], start);
}

int notrace persistent_ram_write(struct persistent_ram_zone *prz,
	const void *s, unsigned int count)
{
	int rem;
	int c = count;
	size_t start;

	if (unlikely(c > prz->buffer_size)) {
		s += c - prz->buffer_size;
		c = prz->buffer_size;
	}

	buffer_size_add(prz, c);

	start = buffer_start_add(prz, c);

	rem = prz->buffer_size - start;
	if (unlikely(rem < c)) {
		persistent_ram_update(prz, s, start, rem);
		s += rem;
		c -= rem;
		start = 0;
	}
	persistent_ram_update(prz, s, start, c);

	persistent_ram_update_header_ecc(prz);

	return count;
}

int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,
	const void __user *s, unsigned int count)
{
	int rem, ret = 0, c = count;
	size_t start;

	if (unlikely(!access_ok(VERIFY_READ, s, count)))
		return -EFAULT;
	if (unlikely(c > prz->buffer_size)) {
		s += c - prz->buffer_size;
		c = prz->buffer_size;
	}

	buffer_size_add(prz, c);

	start = buffer_start_add(prz, c);

	rem = prz->buffer_size - start;
	if (unlikely(rem < c)) {
		ret = persistent_ram_update_user(prz, s, start, rem);
		s += rem;
		c -= rem;
		start = 0;
	}
	if (likely(!ret))
		ret = persistent_ram_update_user(prz, s, start, c);

	persistent_ram_update_header_ecc(prz);

	return unlikely(ret) ? ret : count;
}

size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
{
	return prz->old_log_size;
}

void *persistent_ram_old(struct persistent_ram_zone *prz)
{
	return prz->old_log;
}

void persistent_ram_free_old(struct persistent_ram_zone *prz)
{
	kfree(prz->old_log);
	prz->old_log = NULL;
	prz->old_log_size = 0;
}

void persistent_ram_zap(struct persistent_ram_zone *prz)
{
	atomic_set(&prz->buffer->start, 0);
	atomic_set(&prz->buffer->size, 0);
	persistent_ram_update_header_ecc(prz);
}

static void *persistent_ram_vmap(phys_addr_t start, size_t size,
		unsigned int memtype)
{
	struct page **pages;
	phys_addr_t page_start;
	unsigned int page_count;
	pgprot_t prot;
	unsigned int i;
	void *vaddr;

	page_start = start - offset_in_page(start);
	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);

	if (memtype)
		prot = pgprot_noncached(PAGE_KERNEL);
	else
		prot = pgprot_writecombine(PAGE_KERNEL);

	pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
	if (!pages) {
		pr_err("%s: Failed to allocate array for %u pages\n",
		       __func__, page_count);
		return NULL;
	}

	for (i = 0; i < page_count; i++) {
		phys_addr_t addr = page_start + i * PAGE_SIZE;
		pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	}
	vaddr = vmap(pages, page_count, VM_MAP, prot);
	kfree(pages);

	return vaddr;
}

static void *persistent_ram_iomap(phys_addr_t start, size_t size,
		unsigned int memtype)
{
	void *va;

	if (!request_mem_region(start, size, "persistent_ram")) {
		pr_err("request mem region (0x%llx@0x%llx) failed\n",
			(unsigned long long)size, (unsigned long long)start);
		return NULL;
	}

	if (memtype)
		va = ioremap(start, size);
	else
		va = ioremap_wc(start, size);

	return va;
}

static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
		struct persistent_ram_zone *prz, int memtype)
{
	prz->paddr = start;
	prz->size = size;

	if (pfn_valid(start >> PAGE_SHIFT))
		prz->vaddr = persistent_ram_vmap(start, size, memtype);
	else
		prz->vaddr = persistent_ram_iomap(start, size, memtype);

	if (!prz->vaddr) {
		pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
			(unsigned long long)size, (unsigned long long)start);
		return -ENOMEM;
	}

	prz->buffer = prz->vaddr + offset_in_page(start);
	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);

	return 0;
}

static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
				    struct persistent_ram_ecc_info *ecc_info)
{
	int ret;

	ret = persistent_ram_init_ecc(prz, ecc_info);
	if (ret)
		return ret;

	sig ^= PERSISTENT_RAM_SIG;

	if (prz->buffer->sig == sig) {
		if (buffer_size(prz) > prz->buffer_size ||
		    buffer_start(prz) > buffer_size(prz))
			pr_info("found existing invalid buffer, size %zu, start %zu\n",
				buffer_size(prz), buffer_start(prz));
		else {
			pr_debug("found existing buffer, size %zu, start %zu\n",
				 buffer_size(prz), buffer_start(prz));
			persistent_ram_save_old(prz);
			return 0;
		}
	} else {
		pr_debug("no valid data in buffer (sig = 0x%08x)\n",
			 prz->buffer->sig);
	}

	/* Rewind missing or invalid memory area. */
	prz->buffer->sig = sig;
	persistent_ram_zap(prz);

	return 0;
}

void persistent_ram_free(struct persistent_ram_zone *prz)
{
	if (!prz)
		return;

	if (prz->vaddr) {
		if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
			vunmap(prz->vaddr);
		} else {
			iounmap(prz->vaddr);
			release_mem_region(prz->paddr, prz->size);
		}
		prz->vaddr = NULL;
	}
	persistent_ram_free_old(prz);
	kfree(prz);
}

struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
			u32 sig, struct persistent_ram_ecc_info *ecc_info,
			unsigned int memtype, u32 flags)
{
	struct persistent_ram_zone *prz;
	int ret = -ENOMEM;

	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	if (!prz) {
		pr_err("failed to allocate persistent ram zone\n");
		goto err;
	}

	/* Initialize general buffer state. */
	prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock);
	prz->flags = flags;

	ret = persistent_ram_buffer_map(start, size, prz, memtype);
	if (ret)
		goto err;

	ret = persistent_ram_post_init(prz, sig, ecc_info);
	if (ret)
		goto err;

	return prz;
err:
	persistent_ram_free(prz);
	return ERR_PTR(ret);
}
Commit	Line	Data
c672528a CC	1	/*
	2	* 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.
	7	*
	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	*
	13	*/
	14
ef748853 FF	15	#define pr_fmt(fmt) "persistent_ram: " fmt
ef748853 FF	16
404a6043 CC	17	#include <linux/device.h>
404a6043 CC	18	#include <linux/err.h>
c672528a	19	#include <linux/errno.h>
c672528a CC	20	#include <linux/init.h>
c672528a CC	21	#include <linux/io.h>
5bf6d1b9	22	#include <linux/kernel.h>
404a6043 CC	23	#include <linux/list.h>
404a6043 CC	24	#include <linux/memblock.h>
5bf6d1b9	25	#include <linux/pstore_ram.h>
9cc05ad9	26	#include <linux/rslib.h>
c672528a	27	#include <linux/slab.h>
5bf6d1b9	28	#include <linux/uaccess.h>
404a6043	29	#include <linux/vmalloc.h>
24c3d2f3	30	#include <asm/page.h>
c672528a	31
c672528a CC	32	struct persistent_ram_buffer {
c672528a CC	33	uint32_t sig;
808d0387 CC	34	atomic_t start;
808d0387 CC	35	atomic_t size;
c672528a CC	36	uint8_t data[0];
	37	};
	38
	39	#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
	40
808d0387 CC	41	static inline size_t buffer_size(struct persistent_ram_zone *prz)
	42	{
	43	return atomic_read(&prz->buffer->size);
	44	}
	45
	46	static inline size_t buffer_start(struct persistent_ram_zone *prz)
	47	{
	48	return atomic_read(&prz->buffer->start);
	49	}
	50
0405a5ce	51	/* increase and wrap the start pointer, returning the old value */
d5a9bf0b	52	static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
0405a5ce RH	53	{
	54	int old;
	55	int new;
663deb47	56	unsigned long flags = 0;
0405a5ce	57
663deb47 JF	58	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
663deb47 JF	59	raw_spin_lock_irqsave(&prz->buffer_lock, flags);
0405a5ce RH	60
	61	old = atomic_read(&prz->buffer->start);
	62	new = old + a;
017321cf	63	while (unlikely(new >= prz->buffer_size))
0405a5ce RH	64	new -= prz->buffer_size;
	65	atomic_set(&prz->buffer->start, new);
	66
663deb47 JF	67	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
663deb47 JF	68	raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
0405a5ce RH	69
	70	return old;
	71	}
	72
	73	/* increase the size counter until it hits the max size */
d5a9bf0b	74	static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
0405a5ce RH	75	{
	76	size_t old;
	77	size_t new;
663deb47	78	unsigned long flags = 0;
0405a5ce	79
663deb47 JF	80	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
663deb47 JF	81	raw_spin_lock_irqsave(&prz->buffer_lock, flags);
0405a5ce RH	82
	83	old = atomic_read(&prz->buffer->size);
	84	if (old == prz->buffer_size)
	85	goto exit;
	86
	87	new = old + a;
	88	if (new > prz->buffer_size)
	89	new = prz->buffer_size;
	90	atomic_set(&prz->buffer->size, new);
	91
	92	exit:
663deb47 JF	93	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
663deb47 JF	94	raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
0405a5ce RH	95	}
0405a5ce RH	96
a15d0b36	97	static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
c672528a CC	98	uint8_t data, size_t len, uint8_t ecc)
	99	{
	100	int i;
c31ad081	101	uint16_t par[prz->ecc_info.ecc_size];
9cc05ad9	102
c672528a CC	103	/* Initialize the parity buffer */
	104	memset(par, 0, sizeof(par));
	105	encode_rs8(prz->rs_decoder, data, len, par, 0);
c31ad081	106	for (i = 0; i < prz->ecc_info.ecc_size; i++)
c672528a CC	107	ecc[i] = par[i];
	108	}
	109
	110	static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	111	void data, size_t len, uint8_t ecc)
	112	{
	113	int i;
c31ad081	114	uint16_t par[prz->ecc_info.ecc_size];
9cc05ad9	115
c31ad081	116	for (i = 0; i < prz->ecc_info.ecc_size; i++)
c672528a CC	117	par[i] = ecc[i];
	118	return decode_rs8(prz->rs_decoder, data, par, len,
	119	NULL, 0, NULL, 0, NULL);
	120	}
c672528a	121
a15d0b36	122	static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
808d0387	123	unsigned int start, unsigned int count)
c672528a CC	124	{
c672528a CC	125	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	126	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	127	uint8_t *block;
	128	uint8_t *par;
c31ad081 AH	129	int ecc_block_size = prz->ecc_info.block_size;
	130	int ecc_size = prz->ecc_info.ecc_size;
	131	int size = ecc_block_size;
9cc05ad9	132
c31ad081	133	if (!ecc_size)
9cc05ad9 CC	134	return;
9cc05ad9 CC	135
808d0387	136	block = buffer->data + (start & ~(ecc_block_size - 1));
c31ad081	137	par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
808d0387	138
c672528a	139	do {
9cc05ad9	140	if (block + ecc_block_size > buffer_end)
c672528a CC	141	size = buffer_end - block;
c672528a CC	142	persistent_ram_encode_rs8(prz, block, size, par);
9cc05ad9 CC	143	block += ecc_block_size;
9cc05ad9 CC	144	par += ecc_size;
808d0387	145	} while (block < buffer->data + start + count);
c672528a CC	146	}
c672528a CC	147
9cc05ad9	148	static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
c672528a	149	{
c672528a CC	150	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	151
c31ad081	152	if (!prz->ecc_info.ecc_size)
9cc05ad9 CC	153	return;
9cc05ad9 CC	154
c672528a CC	155	persistent_ram_encode_rs8(prz, (uint8_t )buffer, sizeof(buffer),
c672528a CC	156	prz->par_header);
c672528a CC	157	}
c672528a CC	158
9cc05ad9	159	static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
c672528a CC	160	{
c672528a CC	161	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	162	uint8_t *block;
	163	uint8_t *par;
	164
c31ad081	165	if (!prz->ecc_info.ecc_size)
9cc05ad9 CC	166	return;
9cc05ad9 CC	167
c672528a CC	168	block = buffer->data;
c672528a CC	169	par = prz->par_buffer;
808d0387	170	while (block < buffer->data + buffer_size(prz)) {
c672528a	171	int numerr;
c31ad081	172	int size = prz->ecc_info.block_size;
c672528a CC	173	if (block + size > buffer->data + prz->buffer_size)
	174	size = buffer->data + prz->buffer_size - block;
	175	numerr = persistent_ram_decode_rs8(prz, block, size, par);
	176	if (numerr > 0) {
ef748853	177	pr_devel("error in block %p, %d\n", block, numerr);
c672528a CC	178	prz->corrected_bytes += numerr;
c672528a CC	179	} else if (numerr < 0) {
ef748853	180	pr_devel("uncorrectable error in block %p\n", block);
c672528a CC	181	prz->bad_blocks++;
c672528a CC	182	}
c31ad081 AH	183	block += prz->ecc_info.block_size;
c31ad081 AH	184	par += prz->ecc_info.ecc_size;
9cc05ad9 CC	185	}
	186	}
	187
5ca5d4e6	188	static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
c31ad081	189	struct persistent_ram_ecc_info *ecc_info)
9cc05ad9 CC	190	{
	191	int numerr;
	192	struct persistent_ram_buffer *buffer = prz->buffer;
	193	int ecc_blocks;
1e6a9e56	194	size_t ecc_total;
9cc05ad9	195
c31ad081	196	if (!ecc_info \|\| !ecc_info->ecc_size)
9cc05ad9 CC	197	return 0;
9cc05ad9 CC	198
c31ad081 AH	199	prz->ecc_info.block_size = ecc_info->block_size ?: 128;
	200	prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
	201	prz->ecc_info.symsize = ecc_info->symsize ?: 8;
	202	prz->ecc_info.poly = ecc_info->poly ?: 0x11d;
9cc05ad9	203
c31ad081 AH	204	ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
	205	prz->ecc_info.block_size +
	206	prz->ecc_info.ecc_size);
	207	ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
1e6a9e56 AV	208	if (ecc_total >= prz->buffer_size) {
1e6a9e56 AV	209	pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
c31ad081 AH	210	__func__, prz->ecc_info.ecc_size,
c31ad081 AH	211	ecc_total, prz->buffer_size);
9cc05ad9 CC	212	return -EINVAL;
	213	}
	214
1e6a9e56	215	prz->buffer_size -= ecc_total;
9cc05ad9	216	prz->par_buffer = buffer->data + prz->buffer_size;
c31ad081 AH	217	prz->par_header = prz->par_buffer +
c31ad081 AH	218	ecc_blocks * prz->ecc_info.ecc_size;
9cc05ad9 CC	219
	220	/*
	221	* first consecutive root is 0
	222	* primitive element to generate roots = 1
	223	*/
c31ad081 AH	224	prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
c31ad081 AH	225	0, 1, prz->ecc_info.ecc_size);
9cc05ad9	226	if (prz->rs_decoder == NULL) {
ef748853	227	pr_info("init_rs failed\n");
9cc05ad9	228	return -EINVAL;
c672528a	229	}
9cc05ad9 CC	230
	231	prz->corrected_bytes = 0;
	232	prz->bad_blocks = 0;
	233
	234	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
	235	prz->par_header);
	236	if (numerr > 0) {
ef748853	237	pr_info("error in header, %d\n", numerr);
9cc05ad9 CC	238	prz->corrected_bytes += numerr;
9cc05ad9 CC	239	} else if (numerr < 0) {
ef748853	240	pr_info("uncorrectable error in header\n");
9cc05ad9 CC	241	prz->bad_blocks++;
	242	}
	243
	244	return 0;
	245	}
	246
	247	ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	248	char *str, size_t len)
	249	{
	250	ssize_t ret;
	251
bd08ec33 AH	252	if (!prz->ecc_info.ecc_size)
	253	return 0;
	254
9cc05ad9 CC	255	if (prz->corrected_bytes \|\| prz->bad_blocks)
	256	ret = snprintf(str, len, ""
	257	"\n%d Corrected bytes, %d unrecoverable blocks\n",
	258	prz->corrected_bytes, prz->bad_blocks);
	259	else
	260	ret = snprintf(str, len, "\nNo errors detected\n");
	261
	262	return ret;
	263	}
	264
a15d0b36	265	static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
808d0387	266	const void *s, unsigned int start, unsigned int count)
9cc05ad9 CC	267	{
9cc05ad9 CC	268	struct persistent_ram_buffer *buffer = prz->buffer;
7e75678d	269	memcpy_toio(buffer->data + start, s, count);
808d0387	270	persistent_ram_update_ecc(prz, start, count);
9cc05ad9 CC	271	}
9cc05ad9 CC	272
5bf6d1b9 MS	273	static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,
	274	const void __user *s, unsigned int start, unsigned int count)
	275	{
	276	struct persistent_ram_buffer *buffer = prz->buffer;
	277	int ret = unlikely(__copy_from_user(buffer->data + start, s, count)) ?
	278	-EFAULT : 0;
	279	persistent_ram_update_ecc(prz, start, count);
	280	return ret;
	281	}
	282
201e4aca	283	void persistent_ram_save_old(struct persistent_ram_zone *prz)
9cc05ad9 CC	284	{
9cc05ad9 CC	285	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	286	size_t size = buffer_size(prz);
808d0387 CC	287	size_t start = buffer_start(prz);
9cc05ad9	288
201e4aca AV	289	if (!size)
201e4aca AV	290	return;
c672528a	291
201e4aca AV	292	if (!prz->old_log) {
	293	persistent_ram_ecc_old(prz);
	294	prz->old_log = kmalloc(size, GFP_KERNEL);
	295	}
	296	if (!prz->old_log) {
ef748853	297	pr_err("failed to allocate buffer\n");
c672528a CC	298	return;
	299	}
	300
808d0387	301	prz->old_log_size = size;
d771fdf9 AB	302	memcpy_fromio(prz->old_log, &buffer->data[start], size - start);
d771fdf9 AB	303	memcpy_fromio(prz->old_log + size - start, &buffer->data[0], start);
c672528a CC	304	}
c672528a CC	305
a15d0b36	306	int notrace persistent_ram_write(struct persistent_ram_zone *prz,
c672528a CC	307	const void *s, unsigned int count)
	308	{
	309	int rem;
	310	int c = count;
808d0387	311	size_t start;
c672528a	312
808d0387	313	if (unlikely(c > prz->buffer_size)) {
c672528a CC	314	s += c - prz->buffer_size;
	315	c = prz->buffer_size;
	316	}
808d0387	317
484dd30e	318	buffer_size_add(prz, c);
808d0387 CC	319
	320	start = buffer_start_add(prz, c);
	321
	322	rem = prz->buffer_size - start;
	323	if (unlikely(rem < c)) {
	324	persistent_ram_update(prz, s, start, rem);
c672528a CC	325	s += rem;
c672528a CC	326	c -= rem;
808d0387	327	start = 0;
c672528a	328	}
808d0387	329	persistent_ram_update(prz, s, start, c);
c672528a	330
9cc05ad9	331	persistent_ram_update_header_ecc(prz);
c672528a CC	332
	333	return count;
	334	}
	335
5bf6d1b9 MS	336	int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,
	337	const void __user *s, unsigned int count)
	338	{
	339	int rem, ret = 0, c = count;
	340	size_t start;
	341
	342	if (unlikely(!access_ok(VERIFY_READ, s, count)))
	343	return -EFAULT;
	344	if (unlikely(c > prz->buffer_size)) {
	345	s += c - prz->buffer_size;
	346	c = prz->buffer_size;
	347	}
	348
	349	buffer_size_add(prz, c);
	350
	351	start = buffer_start_add(prz, c);
	352
	353	rem = prz->buffer_size - start;
	354	if (unlikely(rem < c)) {
	355	ret = persistent_ram_update_user(prz, s, start, rem);
	356	s += rem;
	357	c -= rem;
	358	start = 0;
	359	}
	360	if (likely(!ret))
	361	ret = persistent_ram_update_user(prz, s, start, c);
	362
	363	persistent_ram_update_header_ecc(prz);
	364
	365	return unlikely(ret) ? ret : count;
	366	}
	367
c672528a CC	368	size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
	369	{
	370	return prz->old_log_size;
	371	}
	372
	373	void persistent_ram_old(struct persistent_ram_zone prz)
	374	{
	375	return prz->old_log;
	376	}
	377
	378	void persistent_ram_free_old(struct persistent_ram_zone *prz)
	379	{
	380	kfree(prz->old_log);
	381	prz->old_log = NULL;
	382	prz->old_log_size = 0;
	383	}
	384
fce39793 AV	385	void persistent_ram_zap(struct persistent_ram_zone *prz)
	386	{
	387	atomic_set(&prz->buffer->start, 0);
	388	atomic_set(&prz->buffer->size, 0);
	389	persistent_ram_update_header_ecc(prz);
	390	}
	391
027bc8b0 TL	392	static void *persistent_ram_vmap(phys_addr_t start, size_t size,
027bc8b0 TL	393	unsigned int memtype)
c672528a	394	{
404a6043 CC	395	struct page **pages;
	396	phys_addr_t page_start;
	397	unsigned int page_count;
	398	pgprot_t prot;
	399	unsigned int i;
2b1321e4	400	void *vaddr;
404a6043 CC	401
	402	page_start = start - offset_in_page(start);
	403	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
	404
027bc8b0 TL	405	if (memtype)
	406	prot = pgprot_noncached(PAGE_KERNEL);
	407	else
	408	prot = pgprot_writecombine(PAGE_KERNEL);
404a6043	409
b8f52d89	410	pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
404a6043	411	if (!pages) {
ef748853 FF	412	pr_err("%s: Failed to allocate array for %u pages\n",
ef748853 FF	413	__func__, page_count);
2b1321e4	414	return NULL;
404a6043 CC	415	}
	416
	417	for (i = 0; i < page_count; i++) {
	418	phys_addr_t addr = page_start + i * PAGE_SIZE;
	419	pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	420	}
2b1321e4	421	vaddr = vmap(pages, page_count, VM_MAP, prot);
404a6043	422	kfree(pages);
2b1321e4 AV	423
	424	return vaddr;
	425	}
	426
027bc8b0 TL	427	static void *persistent_ram_iomap(phys_addr_t start, size_t size,
027bc8b0 TL	428	unsigned int memtype)
24c3d2f3	429	{
027bc8b0 TL	430	void *va;
027bc8b0 TL	431
24c3d2f3 AV	432	if (!request_mem_region(start, size, "persistent_ram")) {
	433	pr_err("request mem region (0x%llx@0x%llx) failed\n",
	434	(unsigned long long)size, (unsigned long long)start);
	435	return NULL;
	436	}
	437
027bc8b0 TL	438	if (memtype)
	439	va = ioremap(start, size);
	440	else
	441	va = ioremap_wc(start, size);
	442
	443	return va;
24c3d2f3 AV	444	}
24c3d2f3 AV	445
2b1321e4	446	static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
027bc8b0	447	struct persistent_ram_zone *prz, int memtype)
2b1321e4	448	{
d3b48769 AV	449	prz->paddr = start;
	450	prz->size = size;
	451
24c3d2f3	452	if (pfn_valid(start >> PAGE_SHIFT))
027bc8b0	453	prz->vaddr = persistent_ram_vmap(start, size, memtype);
24c3d2f3	454	else
027bc8b0	455	prz->vaddr = persistent_ram_iomap(start, size, memtype);
24c3d2f3	456
404a6043	457	if (!prz->vaddr) {
2b1321e4 AV	458	pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
2b1321e4 AV	459	(unsigned long long)size, (unsigned long long)start);
404a6043 CC	460	return -ENOMEM;
	461	}
	462
	463	prz->buffer = prz->vaddr + offset_in_page(start);
	464	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
	465
	466	return 0;
	467	}
	468
f568f6ca	469	static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
76d5692a	470	struct persistent_ram_ecc_info *ecc_info)
404a6043	471	{
bb4206f2	472	int ret;
c672528a	473
c31ad081	474	ret = persistent_ram_init_ecc(prz, ecc_info);
9cc05ad9	475	if (ret)
bb4206f2	476	return ret;
c672528a	477
cbe7cbf5 AV	478	sig ^= PERSISTENT_RAM_SIG;
	479
	480	if (prz->buffer->sig == sig) {
808d0387 CC	481	if (buffer_size(prz) > prz->buffer_size \|\|
808d0387 CC	482	buffer_start(prz) > buffer_size(prz))
ef748853 FF	483	pr_info("found existing invalid buffer, size %zu, start %zu\n",
ef748853 FF	484	buffer_size(prz), buffer_start(prz));
c672528a	485	else {
ef748853 FF	486	pr_debug("found existing buffer, size %zu, start %zu\n",
ef748853 FF	487	buffer_size(prz), buffer_start(prz));
c672528a	488	persistent_ram_save_old(prz);
25b63da6	489	return 0;
c672528a CC	490	}
c672528a CC	491	} else {
ef748853 FF	492	pr_debug("no valid data in buffer (sig = 0x%08x)\n",
ef748853 FF	493	prz->buffer->sig);
c672528a CC	494	}
c672528a CC	495
76d5692a	496	/* Rewind missing or invalid memory area. */
cbe7cbf5	497	prz->buffer->sig = sig;
fce39793	498	persistent_ram_zap(prz);
c672528a	499
bb4206f2 AV	500	return 0;
	501	}
	502
d3b48769 AV	503	void persistent_ram_free(struct persistent_ram_zone *prz)
d3b48769 AV	504	{
beeb9432 AV	505	if (!prz)
	506	return;
	507
	508	if (prz->vaddr) {
	509	if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
	510	vunmap(prz->vaddr);
	511	} else {
	512	iounmap(prz->vaddr);
	513	release_mem_region(prz->paddr, prz->size);
	514	}
	515	prz->vaddr = NULL;
d3b48769 AV	516	}
	517	persistent_ram_free_old(prz);
	518	kfree(prz);
	519	}
	520
f568f6ca	521	struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
027bc8b0	522	u32 sig, struct persistent_ram_ecc_info *ecc_info,
663deb47	523	unsigned int memtype, u32 flags)
8cf5aff8 AV	524	{
	525	struct persistent_ram_zone *prz;
	526	int ret = -ENOMEM;
	527
	528	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	529	if (!prz) {
ef748853	530	pr_err("failed to allocate persistent ram zone\n");
8cf5aff8 AV	531	goto err;
	532	}
	533
76d5692a KC	534	/* Initialize general buffer state. */
	535	prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock);
	536	prz->flags = flags;
	537
027bc8b0	538	ret = persistent_ram_buffer_map(start, size, prz, memtype);
8cf5aff8 AV	539	if (ret)
	540	goto err;
	541
76d5692a	542	ret = persistent_ram_post_init(prz, sig, ecc_info);
beeb9432 AV	543	if (ret)
beeb9432 AV	544	goto err;
8cf5aff8 AV	545
	546	return prz;
	547	err:
beeb9432	548	persistent_ram_free(prz);
8cf5aff8 AV	549	return ERR_PTR(ret);
8cf5aff8 AV	550	}