new file mode 100644
@@ -0,0 +1,68 @@
+/* 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>
+
+/*
+ * 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;
+}
+
+#else /* CONFIG_X86_FRED */
+static __always_inline unsigned long fred_event_data(struct pt_regs *regs) { return 0; }
+#endif /* CONFIG_X86_FRED */
+#endif /* !__ASSEMBLY__ */
+
+#endif /* ASM_X86_FRED_H */