diff options
Diffstat (limited to 'kernel/power/tuxonice_checksum.c')
| -rw-r--r-- | kernel/power/tuxonice_checksum.c | 392 |
1 files changed, 392 insertions, 0 deletions
diff --git a/kernel/power/tuxonice_checksum.c b/kernel/power/tuxonice_checksum.c new file mode 100644 index 000000000..1c4e10c72 --- /dev/null +++ b/kernel/power/tuxonice_checksum.c @@ -0,0 +1,392 @@ +/* + * kernel/power/tuxonice_checksum.c + * + * Copyright (C) 2006-2015 Nigel Cunningham (nigel at nigelcunningham com au) + * + * This file is released under the GPLv2. + * + * This file contains data checksum routines for TuxOnIce, + * using cryptoapi. They are used to locate any modifications + * made to pageset 2 while we're saving it. + */ + +#include <linux/suspend.h> +#include <linux/highmem.h> +#include <linux/vmalloc.h> +#include <linux/crypto.h> +#include <linux/scatterlist.h> + +#include "tuxonice.h" +#include "tuxonice_modules.h" +#include "tuxonice_sysfs.h" +#include "tuxonice_io.h" +#include "tuxonice_pageflags.h" +#include "tuxonice_checksum.h" +#include "tuxonice_pagedir.h" +#include "tuxonice_alloc.h" +#include "tuxonice_ui.h" + +static struct toi_module_ops toi_checksum_ops; + +/* Constant at the mo, but I might allow tuning later */ +static char toi_checksum_name[32] = "md4"; +/* Bytes per checksum */ +#define CHECKSUM_SIZE (16) + +#define CHECKSUMS_PER_PAGE ((PAGE_SIZE - sizeof(void *)) / CHECKSUM_SIZE) + +struct cpu_context { + struct crypto_hash *transform; + struct hash_desc desc; + struct scatterlist sg[2]; + char *buf; +}; + +static DEFINE_PER_CPU(struct cpu_context, contexts); +static int pages_allocated; +static unsigned long page_list; + +static int toi_num_resaved; + +static unsigned long this_checksum, next_page; +static int checksum_count; + +static inline int checksum_pages_needed(void) +{ + return DIV_ROUND_UP(pagedir2.size, CHECKSUMS_PER_PAGE); +} + +/* ---- Local buffer management ---- */ + +/* + * toi_checksum_cleanup + * + * Frees memory allocated for our labours. + */ +static void toi_checksum_cleanup(int ending_cycle) +{ + int cpu; + + if (ending_cycle) { + for_each_online_cpu(cpu) { + struct cpu_context *this = &per_cpu(contexts, cpu); + if (this->transform) { + crypto_free_hash(this->transform); + this->transform = NULL; + this->desc.tfm = NULL; + } + + if (this->buf) { + toi_free_page(27, (unsigned long) this->buf); + this->buf = NULL; + } + } + } +} + +/* + * toi_crypto_initialise + * + * Prepare to do some work by allocating buffers and transforms. + * Returns: Int: Zero. Even if we can't set up checksum, we still + * seek to hibernate. + */ +static int toi_checksum_initialise(int starting_cycle) +{ + int cpu; + + if (!(starting_cycle & SYSFS_HIBERNATE) || !toi_checksum_ops.enabled) + return 0; + + if (!*toi_checksum_name) { + printk(KERN_INFO "TuxOnIce: No checksum algorithm name set.\n"); + return 1; + } + + for_each_online_cpu(cpu) { + struct cpu_context *this = &per_cpu(contexts, cpu); + struct page *page; + + this->transform = crypto_alloc_hash(toi_checksum_name, 0, 0); + if (IS_ERR(this->transform)) { + printk(KERN_INFO "TuxOnIce: Failed to initialise the " + "%s checksum algorithm: %ld.\n", + toi_checksum_name, (long) this->transform); + this->transform = NULL; + return 1; + } + + this->desc.tfm = this->transform; + this->desc.flags = 0; + + page = toi_alloc_page(27, GFP_KERNEL); + if (!page) + return 1; + this->buf = page_address(page); + sg_init_one(&this->sg[0], this->buf, PAGE_SIZE); + } + return 0; +} + +/* + * toi_checksum_print_debug_stats + * @buffer: Pointer to a buffer into which the debug info will be printed. + * @size: Size of the buffer. + * + * Print information to be recorded for debugging purposes into a buffer. + * Returns: Number of characters written to the buffer. + */ + +static int toi_checksum_print_debug_stats(char *buffer, int size) +{ + int len; + + if (!toi_checksum_ops.enabled) + return scnprintf(buffer, size, + "- Checksumming disabled.\n"); + + len = scnprintf(buffer, size, "- Checksum method is '%s'.\n", + toi_checksum_name); + len += scnprintf(buffer + len, size - len, + " %d pages resaved in atomic copy.\n", toi_num_resaved); + return len; +} + +static int toi_checksum_memory_needed(void) +{ + return toi_checksum_ops.enabled ? + checksum_pages_needed() << PAGE_SHIFT : 0; +} + +static int toi_checksum_storage_needed(void) +{ + if (toi_checksum_ops.enabled) + return strlen(toi_checksum_name) + sizeof(int) + 1; + else + return 0; +} + +/* + * toi_checksum_save_config_info + * @buffer: Pointer to a buffer of size PAGE_SIZE. + * + * Save informaton needed when reloading the image at resume time. + * Returns: Number of bytes used for saving our data. + */ +static int toi_checksum_save_config_info(char *buffer) +{ + int namelen = strlen(toi_checksum_name) + 1; + int total_len; + + *((unsigned int *) buffer) = namelen; + strncpy(buffer + sizeof(unsigned int), toi_checksum_name, namelen); + total_len = sizeof(unsigned int) + namelen; + return total_len; +} + +/* toi_checksum_load_config_info + * @buffer: Pointer to the start of the data. + * @size: Number of bytes that were saved. + * + * Description: Reload information needed for dechecksuming the image at + * resume time. + */ +static void toi_checksum_load_config_info(char *buffer, int size) +{ + int namelen; + + namelen = *((unsigned int *) (buffer)); + strncpy(toi_checksum_name, buffer + sizeof(unsigned int), + namelen); + return; +} + +/* + * Free Checksum Memory + */ + +void free_checksum_pages(void) +{ + while (pages_allocated) { + unsigned long next = *((unsigned long *) page_list); + ClearPageNosave(virt_to_page(page_list)); + toi_free_page(15, (unsigned long) page_list); + page_list = next; + pages_allocated--; + } +} + +/* + * Allocate Checksum Memory + */ + +int allocate_checksum_pages(void) +{ + int pages_needed = checksum_pages_needed(); + + if (!toi_checksum_ops.enabled) + return 0; + + while (pages_allocated < pages_needed) { + unsigned long *new_page = + (unsigned long *) toi_get_zeroed_page(15, TOI_ATOMIC_GFP); + if (!new_page) { + printk(KERN_ERR "Unable to allocate checksum pages.\n"); + return -ENOMEM; + } + SetPageNosave(virt_to_page(new_page)); + (*new_page) = page_list; + page_list = (unsigned long) new_page; + pages_allocated++; + } + + next_page = (unsigned long) page_list; + checksum_count = 0; + + return 0; +} + +char *tuxonice_get_next_checksum(void) +{ + if (!toi_checksum_ops.enabled) + return NULL; + + if (checksum_count % CHECKSUMS_PER_PAGE) + this_checksum += CHECKSUM_SIZE; + else { + this_checksum = next_page + sizeof(void *); + next_page = *((unsigned long *) next_page); + } + + checksum_count++; + return (char *) this_checksum; +} + +int tuxonice_calc_checksum(struct page *page, char *checksum_locn) +{ + char *pa; + int result, cpu = smp_processor_id(); + struct cpu_context *ctx = &per_cpu(contexts, cpu); + + if (!toi_checksum_ops.enabled) + return 0; + + pa = kmap(page); + memcpy(ctx->buf, pa, PAGE_SIZE); + kunmap(page); + result = crypto_hash_digest(&ctx->desc, ctx->sg, PAGE_SIZE, + checksum_locn); + if (result) + printk(KERN_ERR "TuxOnIce checksumming: crypto_hash_digest " + "returned %d.\n", result); + return result; +} +/* + * Calculate checksums + */ + +void check_checksums(void) +{ + int index = 0, cpu = smp_processor_id(); + char current_checksum[CHECKSUM_SIZE]; + struct cpu_context *ctx = &per_cpu(contexts, cpu); + unsigned long pfn; + + if (!toi_checksum_ops.enabled) { + toi_message(TOI_IO, TOI_VERBOSE, 0, "Checksumming disabled."); + return; + } + + next_page = (unsigned long) page_list; + + toi_num_resaved = 0; + this_checksum = 0; + + toi_trace_index++; + + toi_message(TOI_IO, TOI_VERBOSE, 0, "Verifying checksums."); + memory_bm_position_reset(pageset2_map); + for (pfn = memory_bm_next_pfn(pageset2_map, 0); pfn != BM_END_OF_MAP; + pfn = memory_bm_next_pfn(pageset2_map, 0)) { + int ret, resave_needed = false; + char *pa; + struct page *page = pfn_to_page(pfn); + + if (index < checksum_count) { + if (index % CHECKSUMS_PER_PAGE) { + this_checksum += CHECKSUM_SIZE; + } else { + this_checksum = next_page + sizeof(void *); + next_page = *((unsigned long *) next_page); + } + + /* Done when IRQs disabled so must be atomic */ + pa = kmap_atomic(page); + memcpy(ctx->buf, pa, PAGE_SIZE); + kunmap_atomic(pa); + ret = crypto_hash_digest(&ctx->desc, ctx->sg, PAGE_SIZE, + current_checksum); + + if (ret) { + printk(KERN_INFO "Digest failed. Returned %d.\n", ret); + return; + } + + resave_needed = memcmp(current_checksum, (char *) this_checksum, + CHECKSUM_SIZE); + } else { + resave_needed = true; + } + + if (resave_needed) { + TOI_TRACE_DEBUG(pfn, "_Resaving %d", resave_needed); + SetPageResave(pfn_to_page(pfn)); + toi_num_resaved++; + if (test_action_state(TOI_ABORT_ON_RESAVE_NEEDED)) + set_abort_result(TOI_RESAVE_NEEDED); + } + + index++; + } + toi_message(TOI_IO, TOI_VERBOSE, 0, "Checksum verification complete."); +} + +static struct toi_sysfs_data sysfs_params[] = { + SYSFS_INT("enabled", SYSFS_RW, &toi_checksum_ops.enabled, 0, 1, 0, + NULL), + SYSFS_BIT("abort_if_resave_needed", SYSFS_RW, &toi_bkd.toi_action, + TOI_ABORT_ON_RESAVE_NEEDED, 0) +}; + +/* + * Ops structure. + */ +static struct toi_module_ops toi_checksum_ops = { + .type = MISC_MODULE, + .name = "checksumming", + .directory = "checksum", + .module = THIS_MODULE, + .initialise = toi_checksum_initialise, + .cleanup = toi_checksum_cleanup, + .print_debug_info = toi_checksum_print_debug_stats, + .save_config_info = toi_checksum_save_config_info, + .load_config_info = toi_checksum_load_config_info, + .memory_needed = toi_checksum_memory_needed, + .storage_needed = toi_checksum_storage_needed, + + .sysfs_data = sysfs_params, + .num_sysfs_entries = sizeof(sysfs_params) / + sizeof(struct toi_sysfs_data), +}; + +/* ---- Registration ---- */ +int toi_checksum_init(void) +{ + int result = toi_register_module(&toi_checksum_ops); + return result; +} + +void toi_checksum_exit(void) +{ + toi_unregister_module(&toi_checksum_ops); +} |