1 files changed, 97 insertions, 0 deletions
diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h
new file mode 100644
index 000000000000..e86c7ba32435
--- /dev/null
+++ b/arch/x86/include/asm/fred.h
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Macros for Flexible Return and Event Delivery (FRED)
+ */
+
+#ifndef ASM_X86_FRED_H
+#define ASM_X86_FRED_H
+
+#include <linux/const.h>
+
+#include <asm/asm.h>
+#include <asm/trapnr.h>
+
+/*
+ * FRED event return instruction opcodes for ERET{S,U}; supported in
+ * binutils >= 2.41.
+ */
+#define ERETS			_ASM_BYTES(0xf2,0x0f,0x01,0xca)
+#define ERETU			_ASM_BYTES(0xf3,0x0f,0x01,0xca)
+
+/*
+ * RSP is aligned to a 64-byte boundary before used to push a new stack frame
+ */
+#define FRED_STACK_FRAME_RSP_MASK	_AT(unsigned long, (~0x3f))
+
+/*
+ * Used for the return address for call emulation during code patching,
+ * and measured in 64-byte cache lines.
+ */
+#define FRED_CONFIG_REDZONE_AMOUNT	1
+#define FRED_CONFIG_REDZONE		(_AT(unsigned long, FRED_CONFIG_REDZONE_AMOUNT) << 6)
+#define FRED_CONFIG_INT_STKLVL(l)	(_AT(unsigned long, l) << 9)
+#define FRED_CONFIG_ENTRYPOINT(p)	_AT(unsigned long, (p))
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_X86_FRED
+#include <linux/kernel.h>
+
+#include <asm/ptrace.h>
+
+struct fred_info {
+	/* Event data: CR2, DR6, ... */
+	unsigned long edata;
+	unsigned long resv;
+};
+
+/* Full format of the FRED stack frame */
+struct fred_frame {
+	struct pt_regs   regs;
+	struct fred_info info;
+};
+
+static __always_inline struct fred_info *fred_info(struct pt_regs *regs)
+{
+	return &container_of(regs, struct fred_frame, regs)->info;
+}
+
+static __always_inline unsigned long fred_event_data(struct pt_regs *regs)
+{
+	return fred_info(regs)->edata;
+}
+
+void asm_fred_entrypoint_user(void);
+void asm_fred_entrypoint_kernel(void);
+void asm_fred_entry_from_kvm(struct fred_ss);
+
+__visible void fred_entry_from_user(struct pt_regs *regs);
+__visible void fred_entry_from_kernel(struct pt_regs *regs);
+__visible void __fred_entry_from_kvm(struct pt_regs *regs);
+
+/* Can be called from noinstr code, thus __always_inline */
+static __always_inline void fred_entry_from_kvm(unsigned int type, unsigned int vector)
+{
+	struct fred_ss ss = {
+		.ss     =__KERNEL_DS,
+		.type   = type,
+		.vector = vector,
+		.nmi    = type == EVENT_TYPE_NMI,
+		.lm     = 1,
+	};
+
+	asm_fred_entry_from_kvm(ss);
+}
+
+void cpu_init_fred_exceptions(void);
+void fred_complete_exception_setup(void);
+
+#else /* CONFIG_X86_FRED */
+static __always_inline unsigned long fred_event_data(struct pt_regs *regs) { return 0; }
+static inline void cpu_init_fred_exceptions(void) { }
+static inline void fred_complete_exception_setup(void) { }
+static __always_inline void fred_entry_from_kvm(unsigned int type, unsigned int vector) { }
+#endif /* CONFIG_X86_FRED */
+#endif /* !__ASSEMBLY__ */
+
+#endif /* ASM_X86_FRED_H */