OpenZFS 4185 - add new cryptographic checksums to ZFS: SHA-512, Skein, Edon-R

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported by: Tony Hutter <hutter2@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/4185
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/45818ee

Porting Notes:
This code is ported on top of the Illumos Crypto Framework code:

    https://github.com/zfsonlinux/zfs/pull/4329/commits/b5e030c8dbb9cd393d313571dee4756fbba8c22d

The list of porting changes includes:

- Copied module/icp/include/sha2/sha2.h directly from illumos

- Removed from module/icp/algs/sha2/sha2.c:
	#pragma inline(SHA256Init, SHA384Init, SHA512Init)

- Added 'ctx' to lib/libzfs/libzfs_sendrecv.c:zio_checksum_SHA256() since
  it now takes in an extra parameter.

- Added CTASSERT() to assert.h from for module/zfs/edonr_zfs.c

- Added skein & edonr to libicp/Makefile.am

- Added sha512.S.  It was generated from sha512-x86_64.pl in Illumos.

- Updated ztest.c with new fletcher_4_*() args; used NULL for new CTX argument.

- In icp/algs/edonr/edonr_byteorder.h, Removed the #if defined(__linux) section
  to not #include the non-existant endian.h.

- In skein_test.c, renane NULL to 0 in "no test vector" array entries to get
  around a compiler warning.

- Fixup test files:
	- Rename <sys/varargs.h> -> <varargs.h>, <strings.h> -> <string.h>,
	- Remove <note.h> and define NOTE() as NOP.
	- Define u_longlong_t
	- Rename "#!/usr/bin/ksh" -> "#!/bin/ksh -p"
	- Rename NULL to 0 in "no test vector" array entries to get around a
	  compiler warning.
	- Remove "for isa in $($ISAINFO); do" stuff
	- Add/update Makefiles
	- Add some userspace headers like stdio.h/stdlib.h in places of
	  sys/types.h.

- EXPORT_SYMBOL *_Init/*_Update/*_Final... routines in ICP modules.

- Update scripts/zfs2zol-patch.sed

- include <sys/sha2.h> in sha2_impl.h

- Add sha2.h to include/sys/Makefile.am

- Add skein and edonr dirs to icp Makefile

- Add new checksums to zpool_get.cfg

- Move checksum switch block from zfs_secpolicy_setprop() to
  zfs_check_settable()

- Fix -Wuninitialized error in edonr_byteorder.h on PPC

- Fix stack frame size errors on ARM32
  	- Don't unroll loops in Skein on 32-bit to save stack space
  	- Add memory barriers in sha2.c on 32-bit to save stack space

- Add filetest_001_pos.ksh checksum sanity test

- Add option to write psudorandom data in file_write utility

module/zfs/dmu.c

@@ -1445,7 +1445,8 @@ dmu_sync_done(zio_t *zio, arc_buf_t *buf, void *varg)
 
 			ASSERT(BP_EQUAL(bp, bp_orig));
 			ASSERT(zio->io_prop.zp_compress != ZIO_COMPRESS_OFF);
-			ASSERT(zio_checksum_table[chksum].ci_dedup);
+			ASSERT(zio_checksum_table[chksum].ci_flags &
+			    ZCHECKSUM_FLAG_NOPWRITE);
 		}
 		dr->dt.dl.dr_overridden_by = *zio->io_bp;
 		dr->dt.dl.dr_override_state = DR_OVERRIDDEN;
@@ -1792,8 +1793,10 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp,
 		 * as well.  Otherwise, the metadata checksum defaults
 		 * to fletcher4.
 		 */
-		if (zio_checksum_table[checksum].ci_correctable < 1 ||
-		    zio_checksum_table[checksum].ci_eck)
+		if (!(zio_checksum_table[checksum].ci_flags &
+		    ZCHECKSUM_FLAG_METADATA) ||
+		    (zio_checksum_table[checksum].ci_flags &
+		    ZCHECKSUM_FLAG_EMBEDDED))
 			checksum = ZIO_CHECKSUM_FLETCHER_4;
 
 		if (os->os_redundant_metadata == ZFS_REDUNDANT_METADATA_ALL ||
@@ -1832,17 +1835,20 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp,
 		 */
 		if (dedup_checksum != ZIO_CHECKSUM_OFF) {
 			dedup = (wp & WP_DMU_SYNC) ? B_FALSE : B_TRUE;
-			if (!zio_checksum_table[checksum].ci_dedup)
+			if (!(zio_checksum_table[checksum].ci_flags &
+			    ZCHECKSUM_FLAG_DEDUP))
 				dedup_verify = B_TRUE;
 		}
 
 		/*
-		 * Enable nopwrite if we have a cryptographically secure
-		 * checksum that has no known collisions (i.e. SHA-256)
-		 * and compression is enabled.  We don't enable nopwrite if
-		 * dedup is enabled as the two features are mutually exclusive.
+		 * Enable nopwrite if we have secure enough checksum
+		 * algorithm (see comment in zio_nop_write) and
+		 * compression is enabled.  We don't enable nopwrite if
+		 * dedup is enabled as the two features are mutually
+		 * exclusive.
 		 */
-		nopwrite = (!dedup && zio_checksum_table[checksum].ci_dedup &&
+		nopwrite = (!dedup && (zio_checksum_table[checksum].ci_flags &
+		    ZCHECKSUM_FLAG_NOPWRITE) &&
 		    compress != ZIO_COMPRESS_OFF && zfs_nopwrite_enabled);
 	}