Blame SOURCES/0001-os-detect-PMULL-support-before-enabling-accelerated-.patch

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From 3721c7fe276dbbc93e584359f87913e58f96626e Mon Sep 17 00:00:00 2001
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From: Sitsofe Wheeler <sitsofe@yahoo.com>
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Date: Mon, 6 Dec 2021 20:02:53 +0000
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Subject: [PATCH] os: detect PMULL support before enabling accelerated crc32c
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 on ARM
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Issue #1239 shows a crash on a FUJITSU/A64FX ARM platform at the
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following line:
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crc/crc32c-arm64.c:
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 64                 t1 = (uint64_t)vmull_p64(crc1, k2);
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On armv8 PMULL crypto instructions like vmull_p64 are defined as
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optional (see
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https://github.com/google/crc32c/pull/6#issuecomment-328713398 and
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https://github.com/dotnet/runtime/issues/35143#issuecomment-617263508 ).
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Avoid the crash by gating use of the hardware accelerated ARM crc32c
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path behind runtime detection of PMULL.
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Fixes: https://github.com/axboe/fio/issues/1239
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Signed-off-by: Sitsofe Wheeler <sitsofe@yahoo.com>
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Tested-by: Yi Zhang <yi.zhang@redhat.com>
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Signed-off-by: Pavel Reichl <preichl@redhat.com>
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---
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 os/os-linux.h | 6 +++++-
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 1 file changed, 5 insertions(+), 1 deletion(-)
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diff --git a/os/os-linux.h b/os/os-linux.h
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index 808f1d02..3001140c 100644
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--- a/os/os-linux.h
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+++ b/os/os-linux.h
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@@ -20,6 +20,9 @@
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 #ifdef ARCH_HAVE_CRC_CRYPTO
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 #include <sys/auxv.h>
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+#ifndef HWCAP_PMULL
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+#define HWCAP_PMULL             (1 << 4)
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+#endif /* HWCAP_PMULL */
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 #ifndef HWCAP_CRC32
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 #define HWCAP_CRC32             (1 << 7)
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 #endif /* HWCAP_CRC32 */
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@@ -405,7 +408,8 @@ static inline bool os_cpu_has(cpu_features feature)
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 #ifdef ARCH_HAVE_CRC_CRYPTO
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 	case CPU_ARM64_CRC32C:
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 		hwcap = getauxval(AT_HWCAP);
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-		have_feature = (hwcap & HWCAP_CRC32) != 0;
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+		have_feature = (hwcap & (HWCAP_PMULL | HWCAP_CRC32)) ==
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+			       (HWCAP_PMULL | HWCAP_CRC32);
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 		break;
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 #endif
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 	default:
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-- 
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2.38.1
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