@@ -31,8 +31,8 @@
* - inform the user about the firmware's notion of memory layout
* via /sys/firmware/memmap
*
- * - the hibernation code uses it to generate a kernel-independent MD5
- * fingerprint of the physical memory layout of a system.
+ * - the hibernation code uses it to generate a kernel-independent CRC32
+ * checksum of the physical memory layout of a system.
*
* - 'e820_table_kexec': a slightly modified (by the kernel) firmware version
* passed to us by the bootloader - the major difference between
@@ -13,8 +13,8 @@
#include <linux/kdebug.h>
#include <linux/cpu.h>
#include <linux/pgtable.h>
-
-#include <crypto/hash.h>
+#include <linux/types.h>
+#include <linux/crc32.h>
#include <asm/e820/api.h>
#include <asm/init.h>
@@ -54,95 +54,33 @@ int pfn_is_nosave(unsigned long pfn)
return pfn >= nosave_begin_pfn && pfn < nosave_end_pfn;
}
-
-#define MD5_DIGEST_SIZE 16
-
struct restore_data_record {
unsigned long jump_address;
unsigned long jump_address_phys;
unsigned long cr3;
unsigned long magic;
- u8 e820_digest[MD5_DIGEST_SIZE];
+ unsigned long e820_checksum;
};
-#if IS_BUILTIN(CONFIG_CRYPTO_MD5)
/**
- * get_e820_md5 - calculate md5 according to given e820 table
+ * compute_e820_crc32 - calculate crc32 of a given e820 table
*
* @table: the e820 table to be calculated
- * @buf: the md5 result to be stored to
+ *
+ * Return: the resulting checksum
*/
-static int get_e820_md5(struct e820_table *table, void *buf)
+static inline u32 compute_e820_crc32(struct e820_table *table)
{
- struct crypto_shash *tfm;
- struct shash_desc *desc;
- int size;
- int ret = 0;
-
- tfm = crypto_alloc_shash("md5", 0, 0);
- if (IS_ERR(tfm))
- return -ENOMEM;
-
- desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
- GFP_KERNEL);
- if (!desc) {
- ret = -ENOMEM;
- goto free_tfm;
- }
-
- desc->tfm = tfm;
-
- size = offsetof(struct e820_table, entries) +
+ int size = offsetof(struct e820_table, entries) +
sizeof(struct e820_entry) * table->nr_entries;
- if (crypto_shash_digest(desc, (u8 *)table, size, buf))
- ret = -EINVAL;
-
- kfree_sensitive(desc);
-
-free_tfm:
- crypto_free_shash(tfm);
- return ret;
-}
-
-static int hibernation_e820_save(void *buf)
-{
- return get_e820_md5(e820_table_firmware, buf);
-}
-
-static bool hibernation_e820_mismatch(void *buf)
-{
- int ret;
- u8 result[MD5_DIGEST_SIZE];
-
- memset(result, 0, MD5_DIGEST_SIZE);
- /* If there is no digest in suspend kernel, let it go. */
- if (!memcmp(result, buf, MD5_DIGEST_SIZE))
- return false;
-
- ret = get_e820_md5(e820_table_firmware, result);
- if (ret)
- return true;
-
- return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false;
-}
-#else
-static int hibernation_e820_save(void *buf)
-{
- return 0;
-}
-
-static bool hibernation_e820_mismatch(void *buf)
-{
- /* If md5 is not builtin for restore kernel, let it go. */
- return false;
+ return ~crc32_le(~0, (unsigned char const *)table, size);
}
-#endif
#ifdef CONFIG_X86_64
-#define RESTORE_MAGIC 0x23456789ABCDEF01UL
+#define RESTORE_MAGIC 0x23456789ABCDEF02UL
#else
-#define RESTORE_MAGIC 0x12345678UL
+#define RESTORE_MAGIC 0x12345679UL
#endif
/**
@@ -179,7 +117,8 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size)
*/
rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK;
- return hibernation_e820_save(rdr->e820_digest);
+ rdr->e820_checksum = compute_e820_crc32(e820_table_firmware);
+ return 0;
}
/**
@@ -200,7 +139,7 @@ int arch_hibernation_header_restore(void *addr)
jump_address_phys = rdr->jump_address_phys;
restore_cr3 = rdr->cr3;
- if (hibernation_e820_mismatch(rdr->e820_digest)) {
+ if (rdr->e820_checksum != compute_e820_crc32(e820_table_firmware)) {
pr_crit("Hibernate inconsistent memory map detected!\n");
return -ENODEV;
}