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ff84778104
don't bother trying to do bulk access_ok() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
596 lines
15 KiB
C
596 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2012 Google, Inc.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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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/init.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/memblock.h>
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#include <linux/pstore_ram.h>
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#include <linux/rslib.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/vmalloc.h>
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#include <asm/page.h>
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/**
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* 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
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*/
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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[];
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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 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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unsigned long flags = 0;
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if (!(prz->flags & PRZ_FLAG_NO_LOCK))
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raw_spin_lock_irqsave(&prz->buffer_lock, flags);
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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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atomic_set(&prz->buffer->start, new);
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if (!(prz->flags & PRZ_FLAG_NO_LOCK))
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raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
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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 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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unsigned long flags = 0;
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if (!(prz->flags & PRZ_FLAG_NO_LOCK))
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raw_spin_lock_irqsave(&prz->buffer_lock, flags);
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old = atomic_read(&prz->buffer->size);
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if (old == prz->buffer_size)
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goto exit;
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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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atomic_set(&prz->buffer->size, new);
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exit:
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if (!(prz->flags & PRZ_FLAG_NO_LOCK))
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raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
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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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/* Initialize the parity buffer */
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memset(prz->ecc_info.par, 0,
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prz->ecc_info.ecc_size * sizeof(prz->ecc_info.par[0]));
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encode_rs8(prz->rs_decoder, data, len, prz->ecc_info.par, 0);
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for (i = 0; i < prz->ecc_info.ecc_size; i++)
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ecc[i] = prz->ecc_info.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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for (i = 0; i < prz->ecc_info.ecc_size; i++)
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prz->ecc_info.par[i] = ecc[i];
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return decode_rs8(prz->rs_decoder, data, prz->ecc_info.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("error in block %p, %d\n", block, numerr);
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prz->corrected_bytes += numerr;
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} else if (numerr < 0) {
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pr_devel("uncorrectable error in block %p\n", 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("init_rs failed\n");
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return -EINVAL;
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}
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/* allocate workspace instead of using stack VLA */
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prz->ecc_info.par = kmalloc_array(prz->ecc_info.ecc_size,
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sizeof(*prz->ecc_info.par),
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GFP_KERNEL);
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if (!prz->ecc_info.par) {
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pr_err("cannot allocate ECC parity workspace\n");
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return -ENOMEM;
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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("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("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_toio(buffer->data + start, s, count);
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persistent_ram_update_ecc(prz, start, count);
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}
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static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,
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const void __user *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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int ret = unlikely(copy_from_user(buffer->data + start, s, count)) ?
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-EFAULT : 0;
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persistent_ram_update_ecc(prz, start, count);
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return ret;
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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("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_fromio(prz->old_log, &buffer->data[start], size - start);
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memcpy_fromio(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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int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,
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const void __user *s, unsigned int count)
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{
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int rem, ret = 0, 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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ret = persistent_ram_update_user(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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if (likely(!ret))
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ret = persistent_ram_update_user(prz, s, start, c);
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persistent_ram_update_header_ecc(prz);
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return unlikely(ret) ? ret : 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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unsigned int memtype)
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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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if (memtype)
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prot = pgprot_noncached(PAGE_KERNEL);
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else
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prot = pgprot_writecombine(PAGE_KERNEL);
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pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
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if (!pages) {
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pr_err("%s: Failed to allocate array for %u pages\n",
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__func__, 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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/*
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* Since vmap() uses page granularity, we must add the offset
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* into the page here, to get the byte granularity address
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* into the mapping to represent the actual "start" location.
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*/
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return vaddr + offset_in_page(start);
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}
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static void *persistent_ram_iomap(phys_addr_t start, size_t size,
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unsigned int memtype, char *label)
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{
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void *va;
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if (!request_mem_region(start, size, label ?: "ramoops")) {
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pr_err("request mem region (%s 0x%llx@0x%llx) failed\n",
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label ?: "ramoops",
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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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if (memtype)
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va = ioremap(start, size);
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else
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va = ioremap_wc(start, size);
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/*
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* Since request_mem_region() and ioremap() are byte-granularity
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* there is no need handle anything special like we do when the
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* vmap() case in persistent_ram_vmap() above.
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*/
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return va;
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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, int memtype)
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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, memtype);
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else
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prz->vaddr = persistent_ram_iomap(start, size, memtype,
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prz->label);
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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;
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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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bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD);
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ret = persistent_ram_init_ecc(prz, ecc_info);
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if (ret) {
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pr_warn("ECC failed %s\n", prz->label);
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return ret;
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}
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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) == 0) {
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pr_debug("found existing empty buffer\n");
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return 0;
|
|
}
|
|
|
|
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));
|
|
zap = true;
|
|
} else {
|
|
pr_debug("found existing buffer, size %zu, start %zu\n",
|
|
buffer_size(prz), buffer_start(prz));
|
|
persistent_ram_save_old(prz);
|
|
}
|
|
} else {
|
|
pr_debug("no valid data in buffer (sig = 0x%08x)\n",
|
|
prz->buffer->sig);
|
|
prz->buffer->sig = sig;
|
|
zap = true;
|
|
}
|
|
|
|
/* Reset missing, invalid, or single-use memory area. */
|
|
if (zap)
|
|
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)) {
|
|
/* We must vunmap() at page-granularity. */
|
|
vunmap(prz->vaddr - offset_in_page(prz->paddr));
|
|
} else {
|
|
iounmap(prz->vaddr);
|
|
release_mem_region(prz->paddr, prz->size);
|
|
}
|
|
prz->vaddr = NULL;
|
|
}
|
|
if (prz->rs_decoder) {
|
|
free_rs(prz->rs_decoder);
|
|
prz->rs_decoder = NULL;
|
|
}
|
|
kfree(prz->ecc_info.par);
|
|
prz->ecc_info.par = NULL;
|
|
|
|
persistent_ram_free_old(prz);
|
|
kfree(prz->label);
|
|
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, char *label)
|
|
{
|
|
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. */
|
|
raw_spin_lock_init(&prz->buffer_lock);
|
|
prz->flags = flags;
|
|
prz->label = kstrdup(label, GFP_KERNEL);
|
|
|
|
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;
|
|
|
|
pr_debug("attached %s 0x%zx@0x%llx: %zu header, %zu data, %zu ecc (%d/%d)\n",
|
|
prz->label, prz->size, (unsigned long long)prz->paddr,
|
|
sizeof(*prz->buffer), prz->buffer_size,
|
|
prz->size - sizeof(*prz->buffer) - prz->buffer_size,
|
|
prz->ecc_info.ecc_size, prz->ecc_info.block_size);
|
|
|
|
return prz;
|
|
err:
|
|
persistent_ram_free(prz);
|
|
return ERR_PTR(ret);
|
|
}
|