1 files changed, 83 insertions, 0 deletions
diff --git a/include/asm-x86_64/pda.h b/include/asm-x86_64/pda.h
new file mode 100644
index 0000000..36b766c
--- /dev/null
+++ b/include/asm-x86_64/pda.h
@@ -0,0 +1,83 @@
+#ifndef X86_64_PDA_H
+#define X86_64_PDA_H
+
+#ifndef __ASSEMBLY__
+#include <linux/stddef.h>
+#include <linux/types.h>
+#include <linux/cache.h>
+
+/* Per processor datastructure. %gs points to it while the kernel runs */ 
+struct x8664_pda {
+	struct task_struct *pcurrent;	/* Current process */
+	unsigned long data_offset;	/* Per cpu data offset from linker address */
+	struct x8664_pda *me;	    /* Pointer to itself */  
+	unsigned long kernelstack;  /* top of kernel stack for current */ 
+	unsigned long oldrsp; 	    /* user rsp for system call */
+	unsigned long irqrsp;	    /* Old rsp for interrupts. */ 
+        int irqcount;		    /* Irq nesting counter. Starts with -1 */  	
+	int cpunumber;		    /* Logical CPU number */
+	char *irqstackptr;	/* top of irqstack */
+	unsigned int __softirq_pending;
+	unsigned int __nmi_count;	/* number of NMI on this CPUs */
+	struct mm_struct *active_mm;
+	int mmu_state;     
+	unsigned apic_timer_irqs;
+} ____cacheline_aligned;
+
+
+#define IRQSTACK_ORDER 2
+#define IRQSTACKSIZE (PAGE_SIZE << IRQSTACK_ORDER) 
+
+extern struct x8664_pda cpu_pda[];
+
+/* 
+ * There is no fast way to get the base address of the PDA, all the accesses
+ * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
+ */ 
+#define sizeof_field(type,field)  (sizeof(((type *)0)->field))
+#define typeof_field(type,field)  typeof(((type *)0)->field)
+
+extern void __bad_pda_field(void);
+
+#define pda_offset(field) offsetof(struct x8664_pda, field)
+
+#define pda_to_op(op,field,val) do { \
+       switch (sizeof_field(struct x8664_pda, field)) { 		\
+case 2: \
+asm volatile(op "w %0,%%gs:%P1"::"r" (val),"i"(pda_offset(field)):"memory"); break; \
+case 4: \
+asm volatile(op "l %0,%%gs:%P1"::"r" (val),"i"(pda_offset(field)):"memory"); break; \
+case 8: \
+asm volatile(op "q %0,%%gs:%P1"::"r" (val),"i"(pda_offset(field)):"memory"); break; \
+       default: __bad_pda_field(); 					\
+       } \
+       } while (0)
+
+/* 
+ * AK: PDA read accesses should be neither volatile nor have an memory clobber.
+ * Unfortunately removing them causes all hell to break lose currently.
+ */
+#define pda_from_op(op,field) ({ \
+       typedef typeof_field(struct x8664_pda, field) T__; T__ ret__; \
+       switch (sizeof_field(struct x8664_pda, field)) { 		\
+case 2: \
+asm volatile(op "w %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
+case 4: \
+asm volatile(op "l %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
+case 8: \
+asm volatile(op "q %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
+       default: __bad_pda_field(); 					\
+       } \
+       ret__; })
+
+
+#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)
+
+#endif
+
+#define PDA_STACKOFFSET (5*8)
+
+#endif