Thread (695 messages) 695 messages, 11 authors, 2021-05-13
STALE1844d REVIEWED: 3 (2M)

[PATCH 5.12 102/677] s390: fix detection of vector enhancements facility 1 vs. vector packed decimal facility

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-05-12 18:06:48
Also in: lkml

From: David Hildenbrand <redacted>

commit b208108638c4bd3215792415944467c36f5dfd97 upstream.

The PoP documents:
	134: The vector packed decimal facility is installed in the
	     z/Architecture architectural mode. When bit 134 is
	     one, bit 129 is also one.
	135: The vector enhancements facility 1 is installed in
	     the z/Architecture architectural mode. When bit 135
	     is one, bit 129 is also one.

Looks like we confuse the vector enhancements facility 1 ("EXT") with the
Vector packed decimal facility ("BCD"). Let's fix the facility checks.

Detected while working on QEMU/tcg z14 support and only unlocking
the vector enhancements facility 1, but not the vector packed decimal
facility.

Fixes: 2583b848cad0 ("s390: report new vector facilities")
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: David Hildenbrand <redacted>
Reviewed-by: Christian Borntraeger <redacted>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20210503121244.25232-1-david@redhat.com (local)
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/s390/kernel/setup.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -937,9 +937,9 @@ static int __init setup_hwcaps(void)
 	if (MACHINE_HAS_VX) {
 		elf_hwcap |= HWCAP_S390_VXRS;
 		if (test_facility(134))
-			elf_hwcap |= HWCAP_S390_VXRS_EXT;
-		if (test_facility(135))
 			elf_hwcap |= HWCAP_S390_VXRS_BCD;
+		if (test_facility(135))
+			elf_hwcap |= HWCAP_S390_VXRS_EXT;
 		if (test_facility(148))
 			elf_hwcap |= HWCAP_S390_VXRS_EXT2;
 		if (test_facility(152))

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