From 6d7f0b0a746b06a903ec8e14fe14cd0605fb210f Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Sat, 16 Jun 2018 04:52:35 +0200
Subject: simd: encapsulate fpu amortization into nice functions

---
 src/crypto/simd.h | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 src/crypto/simd.h

(limited to 'src/crypto/simd.h')

diff --git a/src/crypto/simd.h b/src/crypto/simd.h
new file mode 100644
index 0000000..21e3c55
--- /dev/null
+++ b/src/crypto/simd.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#ifndef _WG_SIMD_H
+#define _WG_SIMD_H
+
+#if defined(CONFIG_X86_64)
+#include <linux/version.h>
+#include <asm/fpu/api.h>
+#include <asm/simd.h>
+#elif IS_ENABLED(CONFIG_KERNEL_MODE_NEON)
+#include <asm/neon.h>
+#include <asm/simd.h>
+#endif
+
+static inline bool simd_get(void)
+{
+	bool have_simd = false;
+#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) && !defined(CONFIG_PREEMPT_RT_BASE)
+	have_simd = irq_fpu_usable();
+	if (have_simd)
+		kernel_fpu_begin();
+#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
+	if (have_simd)
+		kernel_neon_begin();
+#endif
+	return have_simd;
+}
+
+static inline void simd_put(bool was_on)
+{
+#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) && !defined(CONFIG_PREEMPT_RT_BASE)
+	if (was_on)
+		kernel_fpu_end();
+#elif IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && !defined(CONFIG_PREEMPT_RT_BASE)
+	if (was_on)
+		kernel_neon_end();
+#endif
+}
+
+static inline bool simd_relax(bool was_on)
+{
+	if (was_on && need_resched()) {
+		simd_put(true);
+		return simd_get();
+	}
+	return was_on;
+}
+
+#endif /* _WG_SIMD_H */
-- 
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