1 files changed, 100 insertions, 0 deletions
diff --git a/include/asm-i386/pda.h b/include/asm-i386/pda.h
new file mode 100644
index 000000000000..2ba2736aa109
--- /dev/null
+++ b/include/asm-i386/pda.h
@@ -0,0 +1,100 @@
+/*
+   Per-processor Data Areas
+   Jeremy Fitzhardinge <jeremy@goop.org> 2006
+   Based on asm-x86_64/pda.h by Andi Kleen.
+ */
+#ifndef _I386_PDA_H
+#define _I386_PDA_H
+
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+struct i386_pda
+{
+	struct i386_pda *_pda;		/* pointer to self */
+
+	int cpu_number;
+	struct task_struct *pcurrent;	/* current process */
+	struct pt_regs *irq_regs;
+};
+
+extern struct i386_pda *_cpu_pda[];
+
+#define cpu_pda(i)	(_cpu_pda[i])
+
+#define pda_offset(field) offsetof(struct i386_pda, field)
+
+extern void __bad_pda_field(void);
+
+/* This variable is never instantiated.  It is only used as a stand-in
+   for the real per-cpu PDA memory, so that gcc can understand what
+   memory operations the inline asms() below are performing.  This
+   eliminates the need to make the asms volatile or have memory
+   clobbers, so gcc can readily analyse them. */
+extern struct i386_pda _proxy_pda;
+
+#define pda_to_op(op,field,val)						\
+	do {								\
+		typedef typeof(_proxy_pda.field) T__;			\
+		if (0) { T__ tmp__; tmp__ = (val); }			\
+		switch (sizeof(_proxy_pda.field)) {			\
+		case 1:							\
+			asm(op "b %1,%%gs:%c2"				\
+			    : "+m" (_proxy_pda.field)			\
+			    :"ri" ((T__)val),				\
+			     "i"(pda_offset(field)));			\
+			break;						\
+		case 2:							\
+			asm(op "w %1,%%gs:%c2"				\
+			    : "+m" (_proxy_pda.field)			\
+			    :"ri" ((T__)val),				\
+			     "i"(pda_offset(field)));			\
+			break;						\
+		case 4:							\
+			asm(op "l %1,%%gs:%c2"				\
+			    : "+m" (_proxy_pda.field)			\
+			    :"ri" ((T__)val),				\
+			     "i"(pda_offset(field)));			\
+			break;						\
+		default: __bad_pda_field();				\
+		}							\
+	} while (0)
+
+#define pda_from_op(op,field)						\
+	({								\
+		typeof(_proxy_pda.field) ret__;				\
+		switch (sizeof(_proxy_pda.field)) {			\
+		case 1:							\
+			asm(op "b %%gs:%c1,%0"				\
+			    : "=r" (ret__)				\
+			    : "i" (pda_offset(field)),			\
+			      "m" (_proxy_pda.field));			\
+			break;						\
+		case 2:							\
+			asm(op "w %%gs:%c1,%0"				\
+			    : "=r" (ret__)				\
+			    : "i" (pda_offset(field)),			\
+			      "m" (_proxy_pda.field));			\
+			break;						\
+		case 4:							\
+			asm(op "l %%gs:%c1,%0"				\
+			    : "=r" (ret__)				\
+			    : "i" (pda_offset(field)),			\
+			      "m" (_proxy_pda.field));			\
+			break;						\
+		default: __bad_pda_field();				\
+		}							\
+		ret__; })
+
+/* Return a pointer to a pda field */
+#define pda_addr(field)							\
+	((typeof(_proxy_pda.field) *)((unsigned char *)read_pda(_pda) + \
+				      pda_offset(field)))
+
+#define read_pda(field) pda_from_op("mov",field)
+#define write_pda(field,val) pda_to_op("mov",field,val)
+#define add_pda(field,val) pda_to_op("add",field,val)
+#define sub_pda(field,val) pda_to_op("sub",field,val)
+#define or_pda(field,val) pda_to_op("or",field,val)
+
+#endif	/* _I386_PDA_H */