| /* |
| * 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) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/device.h> |
| #include <linux/err.h> |
| #include <linux/errno.h> |
| #include <linux/init.h> |
| #include <linux/io.h> |
| #include <linux/kernel.h> |
| #include <linux/list.h> |
| #include <linux/memblock.h> |
| #include <linux/pstore_ram.h> |
| #include <linux/rslib.h> |
| #include <linux/slab.h> |
| #include <linux/uaccess.h> |
| #include <linux/vmalloc.h> |
| #include <asm/page.h> |
| |
| /** |
| * struct persistent_ram_buffer - persistent circular RAM buffer |
| * |
| * @sig: |
| * signature to indicate header (PERSISTENT_RAM_SIG xor PRZ-type value) |
| * @start: |
| * offset into @data where the beginning of the stored bytes begin |
| * @size: |
| * number of valid bytes stored in @data |
| */ |
| 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(struct persistent_ram_zone *prz, size_t a) |
| { |
| int old; |
| int new; |
| unsigned long flags = 0; |
| |
| if (!(prz->flags & PRZ_FLAG_NO_LOCK)) |
| raw_spin_lock_irqsave(&prz->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); |
| |
| if (!(prz->flags & PRZ_FLAG_NO_LOCK)) |
| raw_spin_unlock_irqrestore(&prz->buffer_lock, flags); |
| |
| return old; |
| } |
| |
| /* increase the size counter until it hits the max size */ |
| static void buffer_size_add(struct persistent_ram_zone *prz, size_t a) |
| { |
| size_t old; |
| size_t new; |
| unsigned long flags = 0; |
| |
| if (!(prz->flags & PRZ_FLAG_NO_LOCK)) |
| raw_spin_lock_irqsave(&prz->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: |
| if (!(prz->flags & PRZ_FLAG_NO_LOCK)) |
| raw_spin_unlock_irqrestore(&prz->buffer_lock, flags); |
| } |
| |
| static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz, |
| uint8_t *data, size_t len, uint8_t *ecc) |
| { |
| int i; |
| |
| /* Initialize the parity buffer */ |
| memset(prz->ecc_info.par, 0, |
| prz->ecc_info.ecc_size * sizeof(prz->ecc_info.par[0])); |
| encode_rs8(prz->rs_decoder, data, len, prz->ecc_info.par, 0); |
| for (i = 0; i < prz->ecc_info.ecc_size; i++) |
| ecc[i] = prz->ecc_info.par[i]; |
| } |
| |
| static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz, |
| void *data, size_t len, uint8_t *ecc) |
| { |
| int i; |
| |
| for (i = 0; i < prz->ecc_info.ecc_size; i++) |
| prz->ecc_info.par[i] = ecc[i]; |
| return decode_rs8(prz->rs_decoder, data, prz->ecc_info.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; |
| } |
| |
| /* allocate workspace instead of using stack VLA */ |
| prz->ecc_info.par = kmalloc_array(prz->ecc_info.ecc_size, |
| sizeof(*prz->ecc_info.par), |
| GFP_KERNEL); |
| if (!prz->ecc_info.par) { |
| pr_err("cannot allocate ECC parity workspace\n"); |
| return -ENOMEM; |
| } |
| |
| 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_toio(buffer->data + start, s, count); |
| persistent_ram_update_ecc(prz, start, count); |
| } |
| |
| static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz, |
| const void __user *s, unsigned int start, unsigned int count) |
| { |
| struct persistent_ram_buffer *buffer = prz->buffer; |
| int ret = unlikely(__copy_from_user(buffer->data + start, s, count)) ? |
| -EFAULT : 0; |
| persistent_ram_update_ecc(prz, start, count); |
| return ret; |
| } |
| |
| 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_fromio(prz->old_log, &buffer->data[start], size - start); |
| memcpy_fromio(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; |
| } |
| |
| int notrace persistent_ram_write_user(struct persistent_ram_zone *prz, |
| const void __user *s, unsigned int count) |
| { |
| int rem, ret = 0, c = count; |
| size_t start; |
| |
| if (unlikely(!access_ok(VERIFY_READ, s, count))) |
| return -EFAULT; |
| 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)) { |
| ret = persistent_ram_update_user(prz, s, start, rem); |
| s += rem; |
| c -= rem; |
| start = 0; |
| } |
| if (likely(!ret)) |
| ret = persistent_ram_update_user(prz, s, start, c); |
| |
| persistent_ram_update_header_ecc(prz); |
| |
| return unlikely(ret) ? ret : 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); |
| |
| /* |
| * Since vmap() uses page granularity, we must add the offset |
| * into the page here, to get the byte granularity address |
| * into the mapping to represent the actual "start" location. |
| */ |
| return vaddr + offset_in_page(start); |
| } |
| |
| static void *persistent_ram_iomap(phys_addr_t start, size_t size, |
| unsigned int memtype, char *label) |
| { |
| void *va; |
| |
| if (!request_mem_region(start, size, label ?: "ramoops")) { |
| pr_err("request mem region (%s 0x%llx@0x%llx) failed\n", |
| label ?: "ramoops", |
| (unsigned long long)size, (unsigned long long)start); |
| return NULL; |
| } |
| |
| if (memtype) |
| va = ioremap(start, size); |
| else |
| va = ioremap_wc(start, size); |
| |
| /* |
| * Since request_mem_region() and ioremap() are byte-granularity |
| * there is no need handle anything special like we do when the |
| * vmap() case in persistent_ram_vmap() above. |
| */ |
| 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, |
| prz->label); |
| |
| 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; |
| 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; |
| bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD); |
| |
| ret = persistent_ram_init_ecc(prz, ecc_info); |
| if (ret) { |
| pr_warn("ECC failed %s\n", prz->label); |
| return ret; |
| } |
| |
| sig ^= PERSISTENT_RAM_SIG; |
| |
| if (prz->buffer->sig == sig) { |
| if (buffer_size(prz) == 0) { |
| pr_debug("found existing empty buffer\n"); |
| 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 = label; |
| |
| 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); |
| } |