x86/idtentry: Provide IDTENTRY_DF

Provide a separate macro for #DF as this needs to emit paranoid only code
and has also a special ASM stub in 32bit.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135315.583415264@linutronix.de

arch/x86/include/asm/idtentry.h

@@ -132,6 +132,35 @@ static __always_inline void __##func(struct pt_regs *regs,		\
 #define DEFINE_IDTENTRY_RAW(func)					\
 __visible noinstr void func(struct pt_regs *regs)
 
+/**
+ * DECLARE_IDTENTRY_RAW_ERRORCODE - Declare functions for raw IDT entry points
+ *				    Error code pushed by hardware
+ * @vector:	Vector number (ignored for C)
+ * @func:	Function name of the entry point
+ *
+ * Maps to DECLARE_IDTENTRY_ERRORCODE()
+ */
+#define DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func)			\
+	DECLARE_IDTENTRY_ERRORCODE(vector, func)
+
+/**
+ * DEFINE_IDTENTRY_RAW_ERRORCODE - Emit code for raw IDT entry points
+ * @func:	Function name of the entry point
+ *
+ * @func is called from ASM entry code with interrupts disabled.
+ *
+ * The macro is written so it acts as function definition. Append the
+ * body with a pair of curly brackets.
+ *
+ * Contrary to DEFINE_IDTENTRY_ERRORCODE() this does not invoke the
+ * idtentry_enter/exit() helpers before and after the body invocation. This
+ * needs to be done in the body itself if applicable. Use if extra work
+ * is required before the enter/exit() helpers are invoked.
+ */
+#define DEFINE_IDTENTRY_RAW_ERRORCODE(func)				\
+__visible noinstr void func(struct pt_regs *regs, unsigned long error_code)
+
+
 #ifdef CONFIG_X86_64
 /**
  * DECLARE_IDTENTRY_IST - Declare functions for IST handling IDT entry points
@@ -165,10 +194,58 @@ __visible noinstr void func(struct pt_regs *regs)
 #define DEFINE_IDTENTRY_NOIST(func)					\
 	DEFINE_IDTENTRY_RAW(noist_##func)
 
+/**
+ * DECLARE_IDTENTRY_DF - Declare functions for double fault
+ * @vector:	Vector number (ignored for C)
+ * @func:	Function name of the entry point
+ *
+ * Maps to DECLARE_IDTENTRY_RAW_ERRORCODE
+ */
+#define DECLARE_IDTENTRY_DF(vector, func)				\
+	DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func)
+
+/**
+ * DEFINE_IDTENTRY_DF - Emit code for double fault
+ * @func:	Function name of the entry point
+ *
+ * Maps to DEFINE_IDTENTRY_RAW_ERRORCODE
+ */
+#define DEFINE_IDTENTRY_DF(func)					\
+	DEFINE_IDTENTRY_RAW_ERRORCODE(func)
+
 #else	/* CONFIG_X86_64 */
+
 /* Maps to a regular IDTENTRY on 32bit for now */
 # define DECLARE_IDTENTRY_IST		DECLARE_IDTENTRY
 # define DEFINE_IDTENTRY_IST		DEFINE_IDTENTRY
+
+/**
+ * DECLARE_IDTENTRY_DF - Declare functions for double fault 32bit variant
+ * @vector:	Vector number (ignored for C)
+ * @func:	Function name of the entry point
+ *
+ * Declares two functions:
+ * - The ASM entry point: asm_##func
+ * - The C handler called from the C shim
+ */
+#define DECLARE_IDTENTRY_DF(vector, func)				\
+	asmlinkage void asm_##func(void);				\
+	__visible void func(struct pt_regs *regs,			\
+			    unsigned long error_code,			\
+			    unsigned long address)
+
+/**
+ * DEFINE_IDTENTRY_DF - Emit code for double fault on 32bit
+ * @func:	Function name of the entry point
+ *
+ * This is called through the doublefault shim which already provides
+ * cr2 in the address argument.
+ */
+#define DEFINE_IDTENTRY_DF(func)					\
+__visible noinstr void func(struct pt_regs *regs,			\
+			    unsigned long error_code,			\
+			    unsigned long address)
+
 #endif	/* !CONFIG_X86_64 */
 
 /* C-Code mapping */
@@ -212,6 +289,9 @@ __visible noinstr void func(struct pt_regs *regs)
 #define DECLARE_IDTENTRY_RAW(vector, func)				\
 	DECLARE_IDTENTRY(vector, func)
 
+#define DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func)			\
+	DECLARE_IDTENTRY_ERRORCODE(vector, func)
+
 #ifdef CONFIG_X86_64
 # define DECLARE_IDTENTRY_MCE(vector, func)				\
 	idtentry_mce_db vector asm_##func func
@@ -219,12 +299,19 @@ __visible noinstr void func(struct pt_regs *regs)
 # define DECLARE_IDTENTRY_DEBUG(vector, func)				\
 	idtentry_mce_db vector asm_##func func
 
+# define DECLARE_IDTENTRY_DF(vector, func)				\
+	idtentry_df vector asm_##func func
+
 #else
 # define DECLARE_IDTENTRY_MCE(vector, func)				\
 	DECLARE_IDTENTRY(vector, func)
 
 # define DECLARE_IDTENTRY_DEBUG(vector, func)				\
 	DECLARE_IDTENTRY(vector, func)
+
+/* No ASM emitted for DF as this goes through a C shim */
+# define DECLARE_IDTENTRY_DF(vector, func)
+
 #endif
 
 /* No ASM code emitted for NMI */