[PATCH V6 42/49] x86/entry: Add a C macro to define the function body for IST in .entry.text with an error code

[Lai Jiangshan]

From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>

Add DEFINE_IDTENTRY_IST_ENTRY_ERRORCODE() macro to define C code to
implement the ASM code which calls paranoid_entry(), modify orig_ax,
cfunc(), paranoid_exit() in series for IST exceptions with an error code.

Not functional difference intended.

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/idtentry.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index b65cb61aafdc..46b2ef021992 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -351,6 +351,22 @@ __visible __entry_text void ist_##func(struct pt_regs *regs)		\
 	ist_paranoid_exit(cr3, gsbase);					\
 }
 
+/**
+ * DEFINE_IDTENTRY_IST_ENTRY_ERRORCODE - Emit __entry_text code for IST
+ *					 entry points with an error code
+ * @func:	Function name of the entry point
+ */
+#define DEFINE_IDTENTRY_IST_ENTRY_ERRORCODE(func)			\
+__visible __entry_text void ist_##func(struct pt_regs *regs)		\
+{									\
+	unsigned long cr3, gsbase, error_code = regs->orig_ax;		\
+									\
+	ist_paranoid_entry(&cr3, &gsbase);				\
+	regs->orig_ax = -1;	/* no syscall to restart */		\
+	func(regs, error_code);						\
+	ist_paranoid_exit(cr3, gsbase);					\
+}
+
 /**
  * DEFINE_IDTENTRY_IST - Emit code for IST entry points
  * @func:	Function name of the entry point
-- 
2.19.1.6.gb485710b