1#ifndef X86_64_PDA_H
2#define X86_64_PDA_H
3
4#include <linux/stddef.h>
5#ifndef ASM_OFFSET_H
6#include <asm/offset.h>
7#endif
8#include <linux/cache.h>
9
10/* Per processor datastructure. %gs points to it while the kernel runs */
11/* To use a new field with the *_pda macros it needs to be added to tools/offset.c */
12struct x8664_pda {
13	unsigned long kernelstack;  /* TOS for current process */
14	unsigned long oldrsp; 	    /* user rsp for system call */
15	unsigned long irqrsp;	    /* Old rsp for interrupts. */
16	struct task_struct *pcurrent;	/* Current process */
17        int irqcount;		    /* Irq nesting counter. Starts with -1 */
18	int cpunumber;		    /* Logical CPU number */
19	unsigned long *pgd_quick;
20	unsigned long *pmd_quick;
21	unsigned long *pte_quick;
22	unsigned long pgtable_cache_sz;
23	char *irqstackptr;	/* top of irqstack */
24	unsigned long volatile *level4_pgt;
25} ____cacheline_aligned;
26
27#define PDA_STACKOFFSET (5*8)
28
29#define IRQSTACK_ORDER 2
30#define IRQSTACKSIZE (PAGE_SIZE << IRQSTACK_ORDER)
31
32extern struct x8664_pda cpu_pda[];
33
34/*
35 * There is no fast way to get the base address of the PDA, all the accesses
36 * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
37 */
38#define sizeof_field(type,field)  (sizeof(((type *)0)->field))
39#define typeof_field(type,field)  typeof(((type *)0)->field)
40#ifndef __STR
41#define __STR(x) #x
42#endif
43#define __STR2(x) __STR(x)
44
45extern void __bad_pda_field(void);
46
47#define pda_to_op(op,field,val) do { \
48       switch (sizeof_field(struct x8664_pda, field)) { 		\
49       case 2: asm volatile(op "w %0,%%gs:" __STR2(pda_ ## field) ::"r" (val):"memory"); break;	\
50       case 4: asm volatile(op "l %0,%%gs:" __STR2(pda_ ## field) ::"r" (val):"memory"); break;	\
51       case 8: asm volatile(op "q %0,%%gs:" __STR2(pda_ ## field) ::"r" (val):"memory"); break;	\
52       default: __bad_pda_field(); 					\
53       } \
54       } while (0)
55
56
57#define pda_from_op(op,field) ({ \
58       typedef typeof_field(struct x8664_pda, field) T__; T__ ret__; \
59       switch (sizeof_field(struct x8664_pda, field)) { 		\
60       case 2: asm volatile(op "w %%gs:" __STR2(pda_ ## field) ",%0":"=r" (ret__)::"memory"); break;	\
61       case 4: asm volatile(op "l %%gs:" __STR2(pda_ ## field) ",%0":"=r" (ret__)::"memory"); break;	\
62       case 8: asm volatile(op "q %%gs:" __STR2(pda_ ## field) ",%0":"=r" (ret__)::"memory"); break;	\
63       default: __bad_pda_field(); 					\
64       } \
65       ret__; })
66
67
68#define read_pda(field) pda_from_op("mov",field)
69#define write_pda(field,val) pda_to_op("mov",field,val)
70#define add_pda(field,val) pda_to_op("add",field,val)
71#define sub_pda(field,val) pda_to_op("sub",field,val)
72
73#endif
74