From 7a49918c35b389166943f48d88a8ff9b2a78e9e4 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Fri, 28 Sep 2018 16:06:49 +0200
Subject: simd: refactor simd availability handling

---
 src/compat/compat.h                  | 18 ++++++++++++++++++
 src/compat/simd/include/linux/simd.h | 22 ++++++----------------
 2 files changed, 24 insertions(+), 16 deletions(-)

(limited to 'src/compat')

diff --git a/src/compat/compat.h b/src/compat/compat.h
index 2e67edb..8c679a1 100644
--- a/src/compat/compat.h
+++ b/src/compat/compat.h
@@ -737,6 +737,24 @@ static inline void crypto_xor_cpy(u8 *dst, const u8 *src1, const u8 *src2,
 #define read_cpuid_part() read_cpuid_part_number()
 #endif
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 13, 0) || (!defined(CONFIG_X86_64) && !defined(CONFIG_ARM64) && !defined(CONFIG_ARM))
+#if defined(CONFIG_X86_64)
+#include <asm/fpu/api.h>
+#endif
+static __must_check inline bool may_use_simd(void)
+{
+#if defined(CONFIG_X86_64)
+	return irq_fpu_usable();
+#elif defined(CONFIG_ARM64) && defined(CONFIG_KERNEL_MODE_NEON)
+	return true;
+#elif defined(CONFIG_ARM) && defined(CONFIG_KERNEL_MODE_NEON)
+	return !in_nmi() && !in_irq() && !in_serving_softirq();
+#else
+	return false;
+#endif
+}
+#endif
+
 /* https://lkml.kernel.org/r/20170624021727.17835-1-Jason@zx2c4.com */
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 #include <linux/ip.h>
diff --git a/src/compat/simd/include/linux/simd.h b/src/compat/simd/include/linux/simd.h
index 8fd077b..f45aa1f 100644
--- a/src/compat/simd/include/linux/simd.h
+++ b/src/compat/simd/include/linux/simd.h
@@ -11,7 +11,7 @@
 #include <linux/version.h>
 #include <asm/fpu/api.h>
 #include <asm/simd.h>
-#elif IS_ENABLED(CONFIG_KERNEL_MODE_NEON)
+#elif defined(CONFIG_KERNEL_MODE_NEON)
 #include <asm/neon.h>
 #include <asm/simd.h>
 #endif
@@ -24,25 +24,15 @@ typedef enum {
 
 static inline void simd_get(simd_context_t *ctx)
 {
-	bool have_simd = false;
-#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) && !defined(CONFIG_PREEMPT_RT_BASE)
-	have_simd = irq_fpu_usable();
-#elif IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && !defined(CONFIG_PREEMPT_RT_BASE)
-#if defined(CONFIG_ARM64)
-	have_simd = true; /* ARM64 supports NEON in any context. */
-#elif defined(CONFIG_ARM)
-	have_simd = may_use_simd(); /* ARM doesn't support NEON in interrupt context. */
-#endif
-#endif
-	*ctx = have_simd ? HAVE_FULL_SIMD : HAVE_NO_SIMD;
+	*ctx = !IS_ENABLED(CONFIG_PREEMPT_RT_BASE) && may_use_simd() ? HAVE_FULL_SIMD : HAVE_NO_SIMD;
 }
 
 static inline void simd_put(simd_context_t *ctx)
 {
-#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) && !defined(CONFIG_PREEMPT_RT_BASE)
+#if defined(CONFIG_X86_64)
 	if (*ctx & HAVE_SIMD_IN_USE)
 		kernel_fpu_end();
-#elif IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && !defined(CONFIG_PREEMPT_RT_BASE)
+#elif defined(CONFIG_KERNEL_MODE_NEON)
 	if (*ctx & HAVE_SIMD_IN_USE)
 		kernel_neon_end();
 #endif
@@ -67,9 +57,9 @@ static __must_check inline bool simd_use(simd_context_t *ctx)
 		return false;
 	if (*ctx & HAVE_SIMD_IN_USE)
 		return true;
-#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) && !defined(CONFIG_PREEMPT_RT_BASE)
+#if defined(CONFIG_X86_64)
 	kernel_fpu_begin();
-#elif IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && !defined(CONFIG_PREEMPT_RT_BASE)
+#elif defined(CONFIG_KERNEL_MODE_NEON)
 	kernel_neon_begin();
 #endif
 	*ctx |= HAVE_SIMD_IN_USE;
-- 
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