![Arve Hjønnevåg](/assets/img/avatar_default.png)
This was lost when proc/last_kmsg moved to pstore/console-ramoops. Signed-off-by: Arve Hjønnevåg <arve@android.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Anton Vorontsov <anton@enomsg.org>
479 lines
12 KiB
C
479 lines
12 KiB
C
/*
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* Copyright (C) 2012 Google, Inc.
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/list.h>
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#include <linux/memblock.h>
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#include <linux/rslib.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/pstore_ram.h>
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#include <asm/page.h>
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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[0];
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};
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#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
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static inline size_t buffer_size(struct persistent_ram_zone *prz)
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{
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return atomic_read(&prz->buffer->size);
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}
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static inline size_t buffer_start(struct persistent_ram_zone *prz)
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{
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return atomic_read(&prz->buffer->start);
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}
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/* increase and wrap the start pointer, returning the old value */
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static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
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{
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int old;
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int new;
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do {
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old = atomic_read(&prz->buffer->start);
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new = old + a;
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while (unlikely(new > prz->buffer_size))
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new -= prz->buffer_size;
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} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
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return old;
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}
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/* increase the size counter until it hits the max size */
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static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
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{
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size_t old;
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size_t new;
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if (atomic_read(&prz->buffer->size) == prz->buffer_size)
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return;
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do {
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old = atomic_read(&prz->buffer->size);
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new = old + a;
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if (new > prz->buffer_size)
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new = prz->buffer_size;
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} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
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}
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static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
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uint8_t *data, size_t len, uint8_t *ecc)
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{
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int i;
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uint16_t par[prz->ecc_info.ecc_size];
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/* Initialize the parity buffer */
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memset(par, 0, sizeof(par));
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encode_rs8(prz->rs_decoder, data, len, par, 0);
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for (i = 0; i < prz->ecc_info.ecc_size; i++)
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ecc[i] = par[i];
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}
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static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
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void *data, size_t len, uint8_t *ecc)
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{
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int i;
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uint16_t par[prz->ecc_info.ecc_size];
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for (i = 0; i < prz->ecc_info.ecc_size; i++)
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par[i] = ecc[i];
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return decode_rs8(prz->rs_decoder, data, par, len,
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NULL, 0, NULL, 0, NULL);
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}
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static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
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unsigned int start, unsigned int count)
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{
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struct persistent_ram_buffer *buffer = prz->buffer;
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uint8_t *buffer_end = buffer->data + prz->buffer_size;
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uint8_t *block;
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uint8_t *par;
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int ecc_block_size = prz->ecc_info.block_size;
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int ecc_size = prz->ecc_info.ecc_size;
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int size = ecc_block_size;
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if (!ecc_size)
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return;
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block = buffer->data + (start & ~(ecc_block_size - 1));
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par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
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do {
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if (block + ecc_block_size > buffer_end)
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size = buffer_end - block;
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persistent_ram_encode_rs8(prz, block, size, par);
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block += ecc_block_size;
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par += ecc_size;
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} while (block < buffer->data + start + count);
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}
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static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
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{
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struct persistent_ram_buffer *buffer = prz->buffer;
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if (!prz->ecc_info.ecc_size)
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return;
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persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
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prz->par_header);
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}
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static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
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{
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struct persistent_ram_buffer *buffer = prz->buffer;
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uint8_t *block;
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uint8_t *par;
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if (!prz->ecc_info.ecc_size)
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return;
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block = buffer->data;
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par = prz->par_buffer;
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while (block < buffer->data + buffer_size(prz)) {
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int numerr;
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int size = prz->ecc_info.block_size;
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if (block + size > buffer->data + prz->buffer_size)
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size = buffer->data + prz->buffer_size - block;
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numerr = persistent_ram_decode_rs8(prz, block, size, par);
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if (numerr > 0) {
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pr_devel("persistent_ram: error in block %p, %d\n",
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block, numerr);
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prz->corrected_bytes += numerr;
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} else if (numerr < 0) {
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pr_devel("persistent_ram: uncorrectable error in block %p\n",
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block);
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prz->bad_blocks++;
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}
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block += prz->ecc_info.block_size;
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par += prz->ecc_info.ecc_size;
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}
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}
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static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
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struct persistent_ram_ecc_info *ecc_info)
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{
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int numerr;
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struct persistent_ram_buffer *buffer = prz->buffer;
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int ecc_blocks;
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size_t ecc_total;
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if (!ecc_info || !ecc_info->ecc_size)
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return 0;
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prz->ecc_info.block_size = ecc_info->block_size ?: 128;
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prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
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prz->ecc_info.symsize = ecc_info->symsize ?: 8;
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prz->ecc_info.poly = ecc_info->poly ?: 0x11d;
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ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
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prz->ecc_info.block_size +
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prz->ecc_info.ecc_size);
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ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
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if (ecc_total >= prz->buffer_size) {
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pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
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__func__, prz->ecc_info.ecc_size,
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ecc_total, prz->buffer_size);
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return -EINVAL;
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}
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prz->buffer_size -= ecc_total;
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prz->par_buffer = buffer->data + prz->buffer_size;
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prz->par_header = prz->par_buffer +
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ecc_blocks * prz->ecc_info.ecc_size;
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/*
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* first consecutive root is 0
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* primitive element to generate roots = 1
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*/
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prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
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0, 1, prz->ecc_info.ecc_size);
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if (prz->rs_decoder == NULL) {
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pr_info("persistent_ram: init_rs failed\n");
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return -EINVAL;
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}
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prz->corrected_bytes = 0;
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prz->bad_blocks = 0;
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numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
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prz->par_header);
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if (numerr > 0) {
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pr_info("persistent_ram: error in header, %d\n", numerr);
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prz->corrected_bytes += numerr;
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} else if (numerr < 0) {
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pr_info("persistent_ram: uncorrectable error in header\n");
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prz->bad_blocks++;
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}
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return 0;
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}
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ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
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char *str, size_t len)
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{
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ssize_t ret;
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if (!prz->ecc_info.ecc_size)
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return 0;
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if (prz->corrected_bytes || prz->bad_blocks)
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ret = snprintf(str, len, ""
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"\n%d Corrected bytes, %d unrecoverable blocks\n",
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prz->corrected_bytes, prz->bad_blocks);
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else
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ret = snprintf(str, len, "\nNo errors detected\n");
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return ret;
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}
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static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
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const void *s, unsigned int start, unsigned int count)
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{
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struct persistent_ram_buffer *buffer = prz->buffer;
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memcpy(buffer->data + start, s, count);
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persistent_ram_update_ecc(prz, start, count);
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}
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void persistent_ram_save_old(struct persistent_ram_zone *prz)
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{
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struct persistent_ram_buffer *buffer = prz->buffer;
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size_t size = buffer_size(prz);
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size_t start = buffer_start(prz);
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if (!size)
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return;
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if (!prz->old_log) {
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persistent_ram_ecc_old(prz);
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prz->old_log = kmalloc(size, GFP_KERNEL);
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}
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if (!prz->old_log) {
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pr_err("persistent_ram: failed to allocate buffer\n");
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return;
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}
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prz->old_log_size = size;
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memcpy(prz->old_log, &buffer->data[start], size - start);
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memcpy(prz->old_log + size - start, &buffer->data[0], start);
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}
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int notrace persistent_ram_write(struct persistent_ram_zone *prz,
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const void *s, unsigned int count)
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{
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int rem;
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int c = count;
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size_t start;
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if (unlikely(c > prz->buffer_size)) {
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s += c - prz->buffer_size;
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c = prz->buffer_size;
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}
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buffer_size_add(prz, c);
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start = buffer_start_add(prz, c);
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rem = prz->buffer_size - start;
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if (unlikely(rem < c)) {
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persistent_ram_update(prz, s, start, rem);
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s += rem;
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c -= rem;
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start = 0;
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}
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persistent_ram_update(prz, s, start, c);
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persistent_ram_update_header_ecc(prz);
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return count;
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}
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size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
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{
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return prz->old_log_size;
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}
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void *persistent_ram_old(struct persistent_ram_zone *prz)
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{
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return prz->old_log;
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}
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void persistent_ram_free_old(struct persistent_ram_zone *prz)
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{
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kfree(prz->old_log);
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prz->old_log = NULL;
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prz->old_log_size = 0;
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}
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void persistent_ram_zap(struct persistent_ram_zone *prz)
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{
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atomic_set(&prz->buffer->start, 0);
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atomic_set(&prz->buffer->size, 0);
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persistent_ram_update_header_ecc(prz);
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}
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static void *persistent_ram_vmap(phys_addr_t start, size_t size)
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{
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struct page **pages;
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phys_addr_t page_start;
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unsigned int page_count;
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pgprot_t prot;
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unsigned int i;
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void *vaddr;
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page_start = start - offset_in_page(start);
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page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
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prot = pgprot_noncached(PAGE_KERNEL);
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pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
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if (!pages) {
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pr_err("%s: Failed to allocate array for %u pages\n", __func__,
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page_count);
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return NULL;
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}
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for (i = 0; i < page_count; i++) {
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phys_addr_t addr = page_start + i * PAGE_SIZE;
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pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
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}
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vaddr = vmap(pages, page_count, VM_MAP, prot);
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kfree(pages);
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return vaddr;
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}
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static void *persistent_ram_iomap(phys_addr_t start, size_t size)
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{
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if (!request_mem_region(start, size, "persistent_ram")) {
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pr_err("request mem region (0x%llx@0x%llx) failed\n",
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(unsigned long long)size, (unsigned long long)start);
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return NULL;
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}
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return ioremap(start, size);
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}
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static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
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struct persistent_ram_zone *prz)
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{
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prz->paddr = start;
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prz->size = size;
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if (pfn_valid(start >> PAGE_SHIFT))
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prz->vaddr = persistent_ram_vmap(start, size);
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else
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prz->vaddr = persistent_ram_iomap(start, size);
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if (!prz->vaddr) {
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pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
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(unsigned long long)size, (unsigned long long)start);
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return -ENOMEM;
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}
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prz->buffer = prz->vaddr + offset_in_page(start);
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prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
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return 0;
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}
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static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
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struct persistent_ram_ecc_info *ecc_info)
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{
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int ret;
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ret = persistent_ram_init_ecc(prz, ecc_info);
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if (ret)
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return ret;
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sig ^= PERSISTENT_RAM_SIG;
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if (prz->buffer->sig == sig) {
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if (buffer_size(prz) > prz->buffer_size ||
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buffer_start(prz) > buffer_size(prz))
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pr_info("persistent_ram: found existing invalid buffer,"
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" size %zu, start %zu\n",
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buffer_size(prz), buffer_start(prz));
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else {
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pr_debug("persistent_ram: found existing buffer,"
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" size %zu, start %zu\n",
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buffer_size(prz), buffer_start(prz));
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persistent_ram_save_old(prz);
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return 0;
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}
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} else {
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pr_debug("persistent_ram: no valid data in buffer"
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" (sig = 0x%08x)\n", prz->buffer->sig);
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}
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prz->buffer->sig = sig;
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persistent_ram_zap(prz);
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return 0;
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}
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void persistent_ram_free(struct persistent_ram_zone *prz)
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{
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if (!prz)
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return;
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if (prz->vaddr) {
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if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
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vunmap(prz->vaddr);
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} else {
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iounmap(prz->vaddr);
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release_mem_region(prz->paddr, prz->size);
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}
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prz->vaddr = NULL;
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}
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persistent_ram_free_old(prz);
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kfree(prz);
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}
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struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
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u32 sig, struct persistent_ram_ecc_info *ecc_info)
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{
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struct persistent_ram_zone *prz;
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int ret = -ENOMEM;
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prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
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if (!prz) {
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pr_err("persistent_ram: failed to allocate persistent ram zone\n");
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goto err;
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}
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ret = persistent_ram_buffer_map(start, size, prz);
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if (ret)
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goto err;
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ret = persistent_ram_post_init(prz, sig, ecc_info);
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if (ret)
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goto err;
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return prz;
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err:
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persistent_ram_free(prz);
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return ERR_PTR(ret);
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}
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