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609 lines
15 KiB
609 lines
15 KiB
// 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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|
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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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/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_ratelimited("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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#define MEM_TYPE_WCOMBINE 0 |
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#define MEM_TYPE_NONCACHED 1 |
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#define MEM_TYPE_NORMAL 2 |
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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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switch (memtype) { |
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case MEM_TYPE_NORMAL: |
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prot = PAGE_KERNEL; |
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break; |
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case MEM_TYPE_NONCACHED: |
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prot = pgprot_noncached(PAGE_KERNEL); |
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break; |
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case MEM_TYPE_WCOMBINE: |
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prot = pgprot_writecombine(PAGE_KERNEL); |
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break; |
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default: |
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pr_err("invalid mem_type=%d\n", memtype); |
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return NULL; |
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} |
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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; |
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} |
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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("found existing invalid buffer, size %zu, start %zu\n", |
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buffer_size(prz), buffer_start(prz)); |
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zap = true; |
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} else { |
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pr_debug("found existing buffer, 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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} |
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} else { |
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pr_debug("no valid data in buffer (sig = 0x%08x)\n", |
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prz->buffer->sig); |
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prz->buffer->sig = sig; |
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zap = true; |
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} |
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/* Reset missing, invalid, or single-use memory area. */ |
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if (zap) |
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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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/* We must vunmap() at page-granularity. */ |
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vunmap(prz->vaddr - offset_in_page(prz->paddr)); |
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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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if (prz->rs_decoder) { |
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free_rs(prz->rs_decoder); |
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prz->rs_decoder = NULL; |
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} |
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kfree(prz->ecc_info.par); |
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prz->ecc_info.par = NULL; |
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|
|
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); |
|
}
|
|
|