svn commit: r365459 - in head/sys: arm64/include sys

[Mitchell Horne]

Author: mhorne
Date: Tue Sep  8 15:08:20 2020
New Revision: 365459
URL: https://svnweb.freebsd.org/changeset/base/365459

Log:
  arm64: fix incorrect HWCAP definitions
  
  FreeBSD exports CPU features as bits in the AT_HWCAP and AT_HWCAP2
  vectors via elf_aux_info(3). This interface is similar to getauxval(3)
  on Linux, and for simplicity to consumers we try to maintain an
  identical set of feature flags on arm64.
  
  The first batch of AT_HWCAP flags were added in r350166, corresponding
  to definitions that already existed in Linux. Unfortunately, one flag
  was missed, and a portion of the values are shifted one bit to the right
  as a result.
  
  Add the missing definition for HWCAP_ASIMDHP, and adjust the affected
  values to match their Linux counterparts.
  
  Although this is an ABI-breaking change, there is no plan to provide
  compat code for old binaries. An audit of our ports tree and other
  software via Debian code search indicates that there are not yet any
  consumers of this interface for FreeBSD/arm64.
  
  Bump __FreeBSD_version to be on the safe side, in case compat code needs
  to be added in the future.
  
  Reviewed by:	emaste, manu
  MFC after:	2 weeks
  Sponsored by:	The FreeBSD Foundation
  Differential Revision:	https://reviews.freebsd.org/D26329

Modified:
  head/sys/arm64/include/elf.h
  head/sys/sys/param.h

Modified: head/sys/arm64/include/elf.h
==============================================================================
--- head/sys/arm64/include/elf.h	Tue Sep  8 15:01:49 2020	(r365458)
+++ head/sys/arm64/include/elf.h	Tue Sep  8 15:08:20 2020	(r365459)
@@ -102,25 +102,29 @@ __ElfType(Auxinfo);
 #define	HWCAP_CRC32		0x00000080
 #define	HWCAP_ATOMICS		0x00000100
 #define	HWCAP_FPHP		0x00000200
-/* XXX: The following bits don't match the Linux definitions */
-#define	HWCAP_CPUID		0x00000400
-#define	HWCAP_ASIMDRDM		0x00000800
-#define	HWCAP_JSCVT		0x00001000
-#define	HWCAP_FCMA		0x00002000
-#define	HWCAP_LRCPC		0x00004000
-#define	HWCAP_DCPOP		0x00008000
-#define	HWCAP_SHA3		0x00010000
-#define	HWCAP_SM3		0x00020000
-#define	HWCAP_SM4		0x00040000
-#define	HWCAP_ASIMDDP		0x00080000
-#define	HWCAP_SHA512		0x00100000
-#define	HWCAP_SVE		0x00200000
-#define	HWCAP_ASIMDFHM		0x00400000
-#define	HWCAP_DIT		0x00800000
-#define	HWCAP_USCAT		0x01000000
-#define	HWCAP_ILRCPC		0x02000000
-#define	HWCAP_FLAGM		0x04000000
-/* XXX: end of incorrect definitions */
+#define	HWCAP_ASIMDHP		0x00000400
+/*
+ * XXX: The following bits (from CPUID to FLAGM) were originally incorrect,
+ * but later changed to match the Linux definitions. No compatibility code is
+ * provided, as the fix was expected to result in near-zero fallout.
+ */
+#define	HWCAP_CPUID		0x00000800
+#define	HWCAP_ASIMDRDM		0x00001000
+#define	HWCAP_JSCVT		0x00002000
+#define	HWCAP_FCMA		0x00004000
+#define	HWCAP_LRCPC		0x00008000
+#define	HWCAP_DCPOP		0x00010000
+#define	HWCAP_SHA3		0x00020000
+#define	HWCAP_SM3		0x00040000
+#define	HWCAP_SM4		0x00080000
+#define	HWCAP_ASIMDDP		0x00100000
+#define	HWCAP_SHA512		0x00200000
+#define	HWCAP_SVE		0x00400000
+#define	HWCAP_ASIMDFHM		0x00800000
+#define	HWCAP_DIT		0x01000000
+#define	HWCAP_USCAT		0x02000000
+#define	HWCAP_ILRCPC		0x04000000
+#define	HWCAP_FLAGM		0x08000000
 #define	HWCAP_SSBS		0x10000000
 #define	HWCAP_SB		0x20000000
 #define	HWCAP_PACA		0x40000000

Modified: head/sys/sys/param.h
==============================================================================
--- head/sys/sys/param.h	Tue Sep  8 15:01:49 2020	(r365458)
+++ head/sys/sys/param.h	Tue Sep  8 15:08:20 2020	(r365459)
@@ -60,7 +60,7 @@
  *		in the range 5 to 9.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1300113	/* Master, propagated to newvers */
+#define __FreeBSD_version 1300114	/* Master, propagated to newvers */
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,