[PATCH 6/12] early-clobber-tss

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Use an early clobber on addr to avoid the extra rorl instruction at the
end of _set_tssldt_desc.

Also, get some C type checking on the descriptor struct here.

Signed-off-by: Zachary Amsden <zach@xxxxxxxxxx>
Index: linux-2.6.13/include/asm-i386/desc.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/desc.h	2005-08-08 15:41:11.000000000 -0700
+++ linux-2.6.13/include/asm-i386/desc.h	2005-08-08 15:47:01.000000000 -0700
@@ -51,17 +51,21 @@
 extern struct desc_struct default_ldt[];
 extern void set_intr_gate(unsigned int irq, void * addr);
 
-#define _set_tssldt_desc(n,addr,limit,type) \
-asm volatile ("movw %w3,0(%2)\n\t" \
-	"movw %w1,2(%2)\n\t" \
-	"rorl $16,%1\n\t" \
-	"movb %b1,4(%2)\n\t" \
-	"movb %4,5(%2)\n\t" \
-	"movb $0,6(%2)\n\t" \
-	"movb %h1,7(%2)\n\t" \
-	"rorl $16,%1" \
-	: "=m"(*(n)) : "q" (addr), "r"(n), "ir"(limit), "i"(type))
-
+#define _set_tssldt_desc(desc,addr,limit,type) \
+do { \
+	unsigned long __tmp; \
+	typecheck(struct desc_struct *, desc); \
+	asm volatile ("movw %w4,0(%3)\n\t" \
+		      "movw %w2,2(%3)\n\t" \
+		      "rorl $16,%2\n\t" \
+		      "movb %b2,4(%3)\n\t" \
+		      "movb %5,5(%3)\n\t" \
+		      "movb $0,6(%3)\n\t" \
+		      "movb %h2,7(%3)\n\t" \
+		      : "=m"(*(desc)), "=&q" (__tmp) \
+		      : "1" (addr), "r"(desc), "ir"(limit), "i"(type)); \
+} while (0)
+  
 static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void *addr)
 {
 	_set_tssldt_desc(&per_cpu(cpu_gdt_table, cpu)[entry], (int)addr,

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