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linux-next/fs/pstore/ram_core.c
Anton Vorontsov 201e4aca5a pstore/ram: Should update old dmesg buffer before reading
Without the update, we'll only see the new dmesg buffer after the
reboot, but previously we could see it right away. Making an oops
visible in pstore filesystem before reboot is a somewhat dubious
feature, but removing it wasn't an intentional change, so let's
restore it.

For this we have to make persistent_ram_save_old() safe for calling
multiple times, and also extern it.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-13 16:52:39 -07:00

534 lines
13 KiB
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.
*
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/memblock.h>
#include <linux/rslib.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/pstore_ram.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 __initdata LIST_HEAD(persistent_ram_list);
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 inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
{
int old;
int new;
do {
old = atomic_read(&prz->buffer->start);
new = old + a;
while (unlikely(new > prz->buffer_size))
new -= prz->buffer_size;
} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
return old;
}
/* increase the size counter until it hits the max size */
static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
{
size_t old;
size_t new;
if (atomic_read(&prz->buffer->size) == prz->buffer_size)
return;
do {
old = atomic_read(&prz->buffer->size);
new = old + a;
if (new > prz->buffer_size)
new = prz->buffer_size;
} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
}
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_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_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_size];
for (i = 0; i < prz->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_block_size;
int ecc_size = prz->ecc_size;
int size = prz->ecc_block_size;
if (!prz->ecc)
return;
block = buffer->data + (start & ~(ecc_block_size - 1));
par = prz->par_buffer + (start / ecc_block_size) * prz->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)
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)
return;
block = buffer->data;
par = prz->par_buffer;
while (block < buffer->data + buffer_size(prz)) {
int numerr;
int size = prz->ecc_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("persistent_ram: error in block %p, %d\n",
block, numerr);
prz->corrected_bytes += numerr;
} else if (numerr < 0) {
pr_devel("persistent_ram: uncorrectable error in block %p\n",
block);
prz->bad_blocks++;
}
block += prz->ecc_block_size;
par += prz->ecc_size;
}
}
static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
size_t buffer_size)
{
int numerr;
struct persistent_ram_buffer *buffer = prz->buffer;
int ecc_blocks;
if (!prz->ecc)
return 0;
prz->ecc_block_size = 128;
prz->ecc_size = 16;
prz->ecc_symsize = 8;
prz->ecc_poly = 0x11d;
ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
if (prz->buffer_size > buffer_size) {
pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
buffer_size, prz->buffer_size);
return -EINVAL;
}
prz->par_buffer = buffer->data + prz->buffer_size;
prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
/*
* first consecutive root is 0
* primitive element to generate roots = 1
*/
prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
prz->ecc_size);
if (prz->rs_decoder == NULL) {
pr_info("persistent_ram: 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("persistent_ram: error in header, %d\n", numerr);
prz->corrected_bytes += numerr;
} else if (numerr < 0) {
pr_info("persistent_ram: 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->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(buffer->data + start, s, count);
persistent_ram_update_ecc(prz, start, count);
}
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("persistent_ram: failed to allocate buffer\n");
return;
}
prz->old_log_size = size;
memcpy(prz->old_log, &buffer->data[start], size - start);
memcpy(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;
}
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;
}
static void *persistent_ram_vmap(phys_addr_t start, size_t size)
{
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);
prot = pgprot_noncached(PAGE_KERNEL);
pages = kmalloc(sizeof(struct page *) * page_count, 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)
{
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;
}
return ioremap(start, size);
}
static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
struct persistent_ram_zone *prz)
{
prz->paddr = start;
prz->size = size;
if (pfn_valid(start >> PAGE_SHIFT))
prz->vaddr = persistent_ram_vmap(start, size);
else
prz->vaddr = persistent_ram_iomap(start, size);
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 __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
{
int ret;
prz->ecc = ecc;
ret = persistent_ram_init_ecc(prz, prz->buffer_size);
if (ret)
return ret;
if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
if (buffer_size(prz) > prz->buffer_size ||
buffer_start(prz) > buffer_size(prz))
pr_info("persistent_ram: found existing invalid buffer,"
" size %zu, start %zu\n",
buffer_size(prz), buffer_start(prz));
else {
pr_info("persistent_ram: found existing buffer,"
" size %zu, start %zu\n",
buffer_size(prz), buffer_start(prz));
persistent_ram_save_old(prz);
}
} else {
pr_info("persistent_ram: no valid data in buffer"
" (sig = 0x%08x)\n", prz->buffer->sig);
}
prz->buffer->sig = PERSISTENT_RAM_SIG;
atomic_set(&prz->buffer->start, 0);
atomic_set(&prz->buffer->size, 0);
return 0;
}
void persistent_ram_free(struct persistent_ram_zone *prz)
{
if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
vunmap(prz->vaddr);
} else {
iounmap(prz->vaddr);
release_mem_region(prz->paddr, prz->size);
}
persistent_ram_free_old(prz);
kfree(prz);
}
struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
size_t size,
bool ecc)
{
struct persistent_ram_zone *prz;
int ret = -ENOMEM;
prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
if (!prz) {
pr_err("persistent_ram: failed to allocate persistent ram zone\n");
goto err;
}
ret = persistent_ram_buffer_map(start, size, prz);
if (ret)
goto err;
persistent_ram_post_init(prz, ecc);
persistent_ram_update_header_ecc(prz);
return prz;
err:
kfree(prz);
return ERR_PTR(ret);
}
#ifndef MODULE
static int __init persistent_ram_buffer_init(const char *name,
struct persistent_ram_zone *prz)
{
int i;
struct persistent_ram *ram;
struct persistent_ram_descriptor *desc;
phys_addr_t start;
list_for_each_entry(ram, &persistent_ram_list, node) {
start = ram->start;
for (i = 0; i < ram->num_descs; i++) {
desc = &ram->descs[i];
if (!strcmp(desc->name, name))
return persistent_ram_buffer_map(start,
desc->size, prz);
start += desc->size;
}
}
return -EINVAL;
}
static __init
struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc)
{
struct persistent_ram_zone *prz;
int ret = -ENOMEM;
prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
if (!prz) {
pr_err("persistent_ram: failed to allocate persistent ram zone\n");
goto err;
}
ret = persistent_ram_buffer_init(dev_name(dev), prz);
if (ret) {
pr_err("persistent_ram: failed to initialize buffer\n");
goto err;
}
persistent_ram_post_init(prz, ecc);
return prz;
err:
kfree(prz);
return ERR_PTR(ret);
}
struct persistent_ram_zone * __init
persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
{
return __persistent_ram_init(dev, ecc);
}
int __init persistent_ram_early_init(struct persistent_ram *ram)
{
int ret;
ret = memblock_reserve(ram->start, ram->size);
if (ret) {
pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
(long)ram->start, (long)(ram->start + ram->size - 1));
return ret;
}
list_add_tail(&ram->node, &persistent_ram_list);
pr_info("Initialized persistent memory from %08lx-%08lx\n",
(long)ram->start, (long)(ram->start + ram->size - 1));
return 0;
}
#endif