--- /dev/null
+/*
+ * Copyright (C) 2012 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#define pr_fmt(fmt) "persistent_ram: " fmt
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/memblock.h>
+#include <linux/rslib.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/pstore_ram.h>
+#include <asm/page.h>
+
+struct persistent_ram_buffer {
+ uint32_t sig;
+ atomic_t start;
+ atomic_t size;
+ uint8_t data[0];
+};
+
+#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
+
+static inline size_t buffer_size(struct persistent_ram_zone *prz)
+{
+ return atomic_read(&prz->buffer->size);
+}
+
+static inline size_t buffer_start(struct persistent_ram_zone *prz)
+{
+ return atomic_read(&prz->buffer->start);
+}
+
+/* increase and wrap the start pointer, returning the old value */
+static size_t buffer_start_add_atomic(struct persistent_ram_zone *prz, size_t a)
+{
+ int old;
+ int new;
+
+ do {
+ old = atomic_read(&prz->buffer->start);
+ new = old + a;
+ while (unlikely(new >= prz->buffer_size))
+ new -= prz->buffer_size;
+ } while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
+
+ return old;
+}
+
+/* increase the size counter until it hits the max size */
+static void buffer_size_add_atomic(struct persistent_ram_zone *prz, size_t a)
+{
+ size_t old;
+ size_t new;
+
+ if (atomic_read(&prz->buffer->size) == prz->buffer_size)
+ return;
+
+ do {
+ old = atomic_read(&prz->buffer->size);
+ new = old + a;
+ if (new > prz->buffer_size)
+ new = prz->buffer_size;
+ } while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
+}
+
+static DEFINE_RAW_SPINLOCK(buffer_lock);
+
+/* increase and wrap the start pointer, returning the old value */
+static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
+{
+ int old;
+ int new;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&buffer_lock, flags);
+
+ old = atomic_read(&prz->buffer->start);
+ new = old + a;
+ while (unlikely(new >= prz->buffer_size))
+ new -= prz->buffer_size;
+ atomic_set(&prz->buffer->start, new);
+
+ raw_spin_unlock_irqrestore(&buffer_lock, flags);
+
+ return old;
+}
+
+/* increase the size counter until it hits the max size */
+static void buffer_size_add_locked(struct persistent_ram_zone *prz, size_t a)
+{
+ size_t old;
+ size_t new;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&buffer_lock, flags);
+
+ old = atomic_read(&prz->buffer->size);
+ if (old == prz->buffer_size)
+ goto exit;
+
+ new = old + a;
+ if (new > prz->buffer_size)
+ new = prz->buffer_size;
+ atomic_set(&prz->buffer->size, new);
+
+exit:
+ raw_spin_unlock_irqrestore(&buffer_lock, flags);
+}
+
+static size_t (*buffer_start_add)(struct persistent_ram_zone *, size_t) = buffer_start_add_atomic;
+static void (*buffer_size_add)(struct persistent_ram_zone *, size_t) = buffer_size_add_atomic;
+
+static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
+ uint8_t *data, size_t len, uint8_t *ecc)
+{
+ int i;
+ uint16_t par[prz->ecc_info.ecc_size];
+
+ /* Initialize the parity buffer */
+ memset(par, 0, sizeof(par));
+ encode_rs8(prz->rs_decoder, data, len, par, 0);
+ for (i = 0; i < prz->ecc_info.ecc_size; i++)
+ ecc[i] = par[i];
+}
+
+static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
+ void *data, size_t len, uint8_t *ecc)
+{
+ int i;
+ uint16_t par[prz->ecc_info.ecc_size];
+
+ for (i = 0; i < prz->ecc_info.ecc_size; i++)
+ par[i] = ecc[i];
+ return decode_rs8(prz->rs_decoder, data, par, len,
+ NULL, 0, NULL, 0, NULL);
+}
+
+static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
+ unsigned int start, unsigned int count)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ uint8_t *buffer_end = buffer->data + prz->buffer_size;
+ uint8_t *block;
+ uint8_t *par;
+ int ecc_block_size = prz->ecc_info.block_size;
+ int ecc_size = prz->ecc_info.ecc_size;
+ int size = ecc_block_size;
+
+ if (!ecc_size)
+ return;
+
+ block = buffer->data + (start & ~(ecc_block_size - 1));
+ par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
+
+ do {
+ if (block + ecc_block_size > buffer_end)
+ size = buffer_end - block;
+ persistent_ram_encode_rs8(prz, block, size, par);
+ block += ecc_block_size;
+ par += ecc_size;
+ } while (block < buffer->data + start + count);
+}
+
+static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+
+ if (!prz->ecc_info.ecc_size)
+ return;
+
+ persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
+ prz->par_header);
+}
+
+static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ uint8_t *block;
+ uint8_t *par;
+
+ if (!prz->ecc_info.ecc_size)
+ return;
+
+ block = buffer->data;
+ par = prz->par_buffer;
+ while (block < buffer->data + buffer_size(prz)) {
+ int numerr;
+ int size = prz->ecc_info.block_size;
+ if (block + size > buffer->data + prz->buffer_size)
+ size = buffer->data + prz->buffer_size - block;
+ numerr = persistent_ram_decode_rs8(prz, block, size, par);
+ if (numerr > 0) {
+ pr_devel("error in block %p, %d\n", block, numerr);
+ prz->corrected_bytes += numerr;
+ } else if (numerr < 0) {
+ pr_devel("uncorrectable error in block %p\n", block);
+ prz->bad_blocks++;
+ }
+ block += prz->ecc_info.block_size;
+ par += prz->ecc_info.ecc_size;
+ }
+}
+
+static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
+ struct persistent_ram_ecc_info *ecc_info)
+{
+ int numerr;
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ int ecc_blocks;
+ size_t ecc_total;
+
+ if (!ecc_info || !ecc_info->ecc_size)
+ return 0;
+
+ prz->ecc_info.block_size = ecc_info->block_size ?: 128;
+ prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
+ prz->ecc_info.symsize = ecc_info->symsize ?: 8;
+ prz->ecc_info.poly = ecc_info->poly ?: 0x11d;
+
+ ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
+ prz->ecc_info.block_size +
+ prz->ecc_info.ecc_size);
+ ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
+ if (ecc_total >= prz->buffer_size) {
+ pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
+ __func__, prz->ecc_info.ecc_size,
+ ecc_total, prz->buffer_size);
+ return -EINVAL;
+ }
+
+ prz->buffer_size -= ecc_total;
+ prz->par_buffer = buffer->data + prz->buffer_size;
+ prz->par_header = prz->par_buffer +
+ ecc_blocks * prz->ecc_info.ecc_size;
+
+ /*
+ * first consecutive root is 0
+ * primitive element to generate roots = 1
+ */
+ prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
+ 0, 1, prz->ecc_info.ecc_size);
+ if (prz->rs_decoder == NULL) {
+ pr_info("init_rs failed\n");
+ return -EINVAL;
+ }
+
+ prz->corrected_bytes = 0;
+ prz->bad_blocks = 0;
+
+ numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
+ prz->par_header);
+ if (numerr > 0) {
+ pr_info("error in header, %d\n", numerr);
+ prz->corrected_bytes += numerr;
+ } else if (numerr < 0) {
+ pr_info("uncorrectable error in header\n");
+ prz->bad_blocks++;
+ }
+
+ return 0;
+}
+
+ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
+ char *str, size_t len)
+{
+ ssize_t ret;
+
+ if (!prz->ecc_info.ecc_size)
+ return 0;
+
+ if (prz->corrected_bytes || prz->bad_blocks)
+ ret = snprintf(str, len, ""
+ "\n%d Corrected bytes, %d unrecoverable blocks\n",
+ prz->corrected_bytes, prz->bad_blocks);
+ else
+ ret = snprintf(str, len, "\nNo errors detected\n");
+
+ return ret;
+}
+
+static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
+ const void *s, unsigned int start, unsigned int count)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ memcpy(buffer->data + start, s, count);
+ persistent_ram_update_ecc(prz, start, count);
+}
+
+void persistent_ram_save_old(struct persistent_ram_zone *prz)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ size_t size = buffer_size(prz);
+ size_t start = buffer_start(prz);
+
+ if (!size)
+ return;
+
+ if (!prz->old_log) {
+ persistent_ram_ecc_old(prz);
+ prz->old_log = kmalloc(size, GFP_KERNEL);
+ }
+ if (!prz->old_log) {
+ pr_err("failed to allocate buffer\n");
+ return;
+ }
+
+ prz->old_log_size = size;
+ memcpy(prz->old_log, &buffer->data[start], size - start);
+ memcpy(prz->old_log + size - start, &buffer->data[0], start);
+}
+
+int notrace persistent_ram_write(struct persistent_ram_zone *prz,
+ const void *s, unsigned int count)
+{
+ int rem;
+ int c = count;
+ size_t start;
+
+ if (unlikely(c > prz->buffer_size)) {
+ s += c - prz->buffer_size;
+ c = prz->buffer_size;
+ }
+
+ buffer_size_add(prz, c);
+
+ start = buffer_start_add(prz, c);
+
+ rem = prz->buffer_size - start;
+ if (unlikely(rem < c)) {
+ persistent_ram_update(prz, s, start, rem);
+ s += rem;
+ c -= rem;
+ start = 0;
+ }
+ persistent_ram_update(prz, s, start, c);
+
+ persistent_ram_update_header_ecc(prz);
+
+ return count;
+}
+
+size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
+{
+ return prz->old_log_size;
+}
+
+void *persistent_ram_old(struct persistent_ram_zone *prz)
+{
+ return prz->old_log;
+}
+
+void persistent_ram_free_old(struct persistent_ram_zone *prz)
+{
+ kfree(prz->old_log);
+ prz->old_log = NULL;
+ prz->old_log_size = 0;
+}
+
+void persistent_ram_zap(struct persistent_ram_zone *prz)
+{
+ atomic_set(&prz->buffer->start, 0);
+ atomic_set(&prz->buffer->size, 0);
+ persistent_ram_update_header_ecc(prz);
+}
+
+static void *persistent_ram_vmap(phys_addr_t start, size_t size,
+ unsigned int memtype)
+{
+ struct page **pages;
+ phys_addr_t page_start;
+ unsigned int page_count;
+ pgprot_t prot;
+ unsigned int i;
+ void *vaddr;
+
+ page_start = start - offset_in_page(start);
+ page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
+
+ if (memtype)
+ prot = pgprot_noncached(PAGE_KERNEL);
+ else
+ prot = pgprot_writecombine(PAGE_KERNEL);
+
+ pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
+ if (!pages) {
+ pr_err("%s: Failed to allocate array for %u pages\n",
+ __func__, page_count);
+ return NULL;
+ }
+
+ for (i = 0; i < page_count; i++) {
+ phys_addr_t addr = page_start + i * PAGE_SIZE;
+ pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
+ }
+ vaddr = vmap(pages, page_count, VM_MAP, prot);
+ kfree(pages);
+
+ return vaddr;
+}
+
+static void *persistent_ram_iomap(phys_addr_t start, size_t size,
+ unsigned int memtype)
+{
+ void *va;
+
+ if (!request_mem_region(start, size, "persistent_ram")) {
+ pr_err("request mem region (0x%llx@0x%llx) failed\n",
+ (unsigned long long)size, (unsigned long long)start);
+ return NULL;
+ }
+
+ buffer_start_add = buffer_start_add_locked;
+ buffer_size_add = buffer_size_add_locked;
+
+ if (memtype)
+ va = ioremap(start, size);
+ else
+ va = ioremap_wc(start, size);
+
+ return va;
+}
+
+static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
+ struct persistent_ram_zone *prz, int memtype)
+{
+ prz->paddr = start;
+ prz->size = size;
+
+ if (pfn_valid(start >> PAGE_SHIFT))
+ prz->vaddr = persistent_ram_vmap(start, size, memtype);
+ else
+ prz->vaddr = persistent_ram_iomap(start, size, memtype);
+
+ if (!prz->vaddr) {
+ pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
+ (unsigned long long)size, (unsigned long long)start);
+ return -ENOMEM;
+ }
+
+ prz->buffer = prz->vaddr + offset_in_page(start);
+ prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
+
+ return 0;
+}
+
+static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
+ struct persistent_ram_ecc_info *ecc_info)
+{
+ int ret;
+
+ ret = persistent_ram_init_ecc(prz, ecc_info);
+ if (ret)
+ return ret;
+
+ sig ^= PERSISTENT_RAM_SIG;
+
+ if (prz->buffer->sig == sig) {
+ if (buffer_size(prz) > prz->buffer_size ||
+ buffer_start(prz) > buffer_size(prz))
+ pr_info("found existing invalid buffer, size %zu, start %zu\n",
+ buffer_size(prz), buffer_start(prz));
+ else {
+ pr_debug("found existing buffer, size %zu, start %zu\n",
+ buffer_size(prz), buffer_start(prz));
+ persistent_ram_save_old(prz);
+ return 0;
+ }
+ } else {
+ pr_debug("no valid data in buffer (sig = 0x%08x)\n",
+ prz->buffer->sig);
+ }
+
+ prz->buffer->sig = sig;
+ persistent_ram_zap(prz);
+
+ return 0;
+}
+
+void persistent_ram_free(struct persistent_ram_zone *prz)
+{
+ if (!prz)
+ return;
+
+ if (prz->vaddr) {
+ if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
+ vunmap(prz->vaddr);
+ } else {
+ iounmap(prz->vaddr);
+ release_mem_region(prz->paddr, prz->size);
+ }
+ prz->vaddr = NULL;
+ }
+ persistent_ram_free_old(prz);
+ kfree(prz);
+}
+
+struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
+ u32 sig, struct persistent_ram_ecc_info *ecc_info,
+ unsigned int memtype)
+{
+ 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;
+ }
+
+ ret = persistent_ram_buffer_map(start, size, prz, memtype);
+ if (ret)
+ goto err;
+
+ ret = persistent_ram_post_init(prz, sig, ecc_info);
+ if (ret)
+ goto err;
+
+ return prz;
+err:
+ persistent_ram_free(prz);
+ return ERR_PTR(ret);
+}
Code Review / kvmfornfv.git / blobdiff