linux-kernel - [PATCH RT 4/7] arm*: disable NEON in kernel mode

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Date:   Wed,  4 Apr 2018 09:16:49 +0200
From:   Daniel Wagner <wagi@...om.org>
To:     linux-kernel@...r.kernel.org
Cc:     linux-rt-users <linux-rt-users@...r.kernel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Carsten Emde <C.Emde@...dl.org>,
        John Kacur <jkacur@...hat.com>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        Julia Cartwright <julia@...com>,
        Daniel Wagner <daniel.wagner@...mens.com>,
        tom.zanussi@...ux.intel.com,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        stable-rt@...r.kernel.org
Subject: [PATCH RT 4/7] arm*: disable NEON in kernel mode

From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>

NEON in kernel mode is used by the crypto algorithms and raid6 code.
While the raid6 code looks okay, the crypto algorithms do not: NEON
is enabled on first invocation and may allocate/free/map memory before
the NEON mode is disabled again.
This needs to be changed until it can be enabled.
On ARM NEON in kernel mode can be simply disabled. on ARM64 it needs to
stay on due to possible EFI callbacks so here I disable each algorithm.

Cc: stable-rt@...r.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 arch/arm/Kconfig          |  2 +-
 arch/arm64/crypto/Kconfig | 14 +++++++-------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 79c4603e9453..5e054a0c4b25 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -2119,7 +2119,7 @@ config NEON
 
 config KERNEL_MODE_NEON
 	bool "Support for NEON in kernel mode"
-	depends on NEON && AEABI
+	depends on NEON && AEABI && !PREEMPT_RT_BASE
 	help
 	  Say Y to include support for NEON in kernel mode.
 
diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index 2cf32e9887e1..cd71b3432720 100644
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -10,41 +10,41 @@ if ARM64_CRYPTO
 
 config CRYPTO_SHA1_ARM64_CE
 	tristate "SHA-1 digest algorithm (ARMv8 Crypto Extensions)"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_HASH
 
 config CRYPTO_SHA2_ARM64_CE
 	tristate "SHA-224/SHA-256 digest algorithm (ARMv8 Crypto Extensions)"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_HASH
 
 config CRYPTO_GHASH_ARM64_CE
 	tristate "GHASH (for GCM chaining mode) using ARMv8 Crypto Extensions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_HASH
 
 config CRYPTO_AES_ARM64_CE
 	tristate "AES core cipher using ARMv8 Crypto Extensions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_ALGAPI
 
 config CRYPTO_AES_ARM64_CE_CCM
 	tristate "AES in CCM mode using ARMv8 Crypto Extensions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_ALGAPI
 	select CRYPTO_AES_ARM64_CE
 	select CRYPTO_AEAD
 
 config CRYPTO_AES_ARM64_CE_BLK
 	tristate "AES in ECB/CBC/CTR/XTS modes using ARMv8 Crypto Extensions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_AES_ARM64_CE
 	select CRYPTO_ABLK_HELPER
 
 config CRYPTO_AES_ARM64_NEON_BLK
 	tristate "AES in ECB/CBC/CTR/XTS modes using NEON instructions"
-	depends on ARM64 && KERNEL_MODE_NEON
+	depends on ARM64 && KERNEL_MODE_NEON && !PREEMPT_RT_BASE
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_AES
 	select CRYPTO_ABLK_HELPER
-- 
2.14.3