x86: unify and correct the GDT_ENTRY() macro

H. Peter Anvin · H. Peter Anvin · commit f910d134442f · 2008-07-17T14:31:42.000-07:00
Impact: None (cleanup only)

Merge the GDT_ENTRY() macro between arch/x86/boot/pm.c and
arch/x86/kernel/acpi/sleep.c and put the new one in
&lt;asm-x86/segment.h&gt;.

While we're at it, correct the bitmasks for the limit and flags.  The
new version relies on using ULL constants in order to cause type
promotion rather than explicit casts; this avoids having to include
&lt;linux/types.h&gt; in &lt;asm-x86/segments.h&gt;.

Signed-off-by: H. Peter Anvin &lt;hpa@zytor.com&gt;
diff --git a/arch/x86/boot/pm.c b/arch/x86/boot/pm.c
@@ -98,12 +98,6 @@ static void reset_coprocessor(void)
 /*
  * Set up the GDT
  */
-#define GDT_ENTRY(flags, base, limit)		\
-	(((u64)(base & 0xff000000) << 32) |	\
-	 ((u64)flags << 40) |			\
-	 ((u64)(limit & 0x00ff0000) << 32) |	\
-	 ((u64)(base & 0x00ffffff) << 16) |	\
-	 ((u64)(limit & 0x0000ffff)))
 
 struct gdt_ptr {
 	u16 len;
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
@@ -9,6 +9,7 @@
 #include <linux/bootmem.h>
 #include <linux/dmi.h>
 #include <linux/cpumask.h>
+#include <asm/segment.h>
 
 #include "realmode/wakeup.h"
 #include "sleep.h"
@@ -23,15 +24,6 @@ static unsigned long acpi_realmode;
 static char temp_stack[10240];
 #endif
 
-/* XXX: this macro should move to asm-x86/segment.h and be shared with the
-   boot code... */
-#define GDT_ENTRY(flags, base, limit)		\
-	(((u64)(base & 0xff000000) << 32) |	\
-	 ((u64)flags << 40) |			\
-	 ((u64)(limit & 0x00ff0000) << 32) |	\
-	 ((u64)(base & 0x00ffffff) << 16) |	\
-	 ((u64)(limit & 0x0000ffff)))
-
 /**
  * acpi_save_state_mem - save kernel state
  *
diff --git a/include/asm-x86/segment.h b/include/asm-x86/segment.h
@@ -1,6 +1,15 @@
 #ifndef _ASM_X86_SEGMENT_H_
 #define _ASM_X86_SEGMENT_H_
 
+/* Constructor for a conventional segment GDT (or LDT) entry */
+/* This is a macro so it can be used in initializers */
+#define GDT_ENTRY(flags, base, limit)			\
+	((((base)  & 0xff000000ULL) << (56-24)) |	\
+	 (((flags) & 0x0000f0ffULL) << 40) |		\
+	 (((limit) & 0x000f0000ULL) << (48-16)) |	\
+	 (((base)  & 0x00ffffffULL) << 16) |		\
+	 (((limit) & 0x0000ffffULL)))
+
 /* Simple and small GDT entries for booting only */
 
 #define GDT_ENTRY_BOOT_CS	2
