1 files changed, 115 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/legacy.h b/arch/x86/kernel/fpu/legacy.h
new file mode 100644
index 000000000000..17c26b164c63
--- /dev/null
+++ b/arch/x86/kernel/fpu/legacy.h
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __X86_KERNEL_FPU_LEGACY_H
+#define __X86_KERNEL_FPU_LEGACY_H
+
+#include <asm/fpu/types.h>
+
+extern unsigned int mxcsr_feature_mask;
+
+static inline void ldmxcsr(u32 mxcsr)
+{
+	asm volatile("ldmxcsr %0" :: "m" (mxcsr));
+}
+
+/*
+ * Returns 0 on success or the trap number when the operation raises an
+ * exception.
+ */
+#define user_insn(insn, output, input...)				\
+({									\
+	int err;							\
+									\
+	might_fault();							\
+									\
+	asm volatile(ASM_STAC "\n"					\
+		     "1: " #insn "\n"					\
+		     "2: " ASM_CLAC "\n"				\
+		     _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_FAULT_MCE_SAFE)	\
+		     : [err] "=a" (err), output				\
+		     : "0"(0), input);					\
+	err;								\
+})
+
+#define kernel_insn_err(insn, output, input...)				\
+({									\
+	int err;							\
+	asm volatile("1:" #insn "\n\t"					\
+		     "2:\n"						\
+		     ".section .fixup,\"ax\"\n"				\
+		     "3:  movl $-1,%[err]\n"				\
+		     "    jmp  2b\n"					\
+		     ".previous\n"					\
+		     _ASM_EXTABLE(1b, 3b)				\
+		     : [err] "=r" (err), output				\
+		     : "0"(0), input);					\
+	err;								\
+})
+
+#define kernel_insn(insn, output, input...)				\
+	asm volatile("1:" #insn "\n\t"					\
+		     "2:\n"						\
+		     _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_FPU_RESTORE)	\
+		     : output : input)
+
+static inline int fnsave_to_user_sigframe(struct fregs_state __user *fx)
+{
+	return user_insn(fnsave %[fx]; fwait,  [fx] "=m" (*fx), "m" (*fx));
+}
+
+static inline int fxsave_to_user_sigframe(struct fxregs_state __user *fx)
+{
+	if (IS_ENABLED(CONFIG_X86_32))
+		return user_insn(fxsave %[fx], [fx] "=m" (*fx), "m" (*fx));
+	else
+		return user_insn(fxsaveq %[fx], [fx] "=m" (*fx), "m" (*fx));
+
+}
+
+static inline void fxrstor(struct fxregs_state *fx)
+{
+	if (IS_ENABLED(CONFIG_X86_32))
+		kernel_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
+	else
+		kernel_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
+}
+
+static inline int fxrstor_safe(struct fxregs_state *fx)
+{
+	if (IS_ENABLED(CONFIG_X86_32))
+		return kernel_insn_err(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
+	else
+		return kernel_insn_err(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
+}
+
+static inline int fxrstor_from_user_sigframe(struct fxregs_state __user *fx)
+{
+	if (IS_ENABLED(CONFIG_X86_32))
+		return user_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
+	else
+		return user_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
+}
+
+static inline void frstor(struct fregs_state *fx)
+{
+	kernel_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
+}
+
+static inline int frstor_safe(struct fregs_state *fx)
+{
+	return kernel_insn_err(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
+}
+
+static inline int frstor_from_user_sigframe(struct fregs_state __user *fx)
+{
+	return user_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
+}
+
+static inline void fxsave(struct fxregs_state *fx)
+{
+	if (IS_ENABLED(CONFIG_X86_32))
+		asm volatile( "fxsave %[fx]" : [fx] "=m" (*fx));
+	else
+		asm volatile("fxsaveq %[fx]" : [fx] "=m" (*fx));
+}
+
+#endif