tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#ifndef X86_64_PDA_H
2#define X86_64_PDA_H
3
4#ifndef __ASSEMBLY__
5#include <linux/stddef.h>
6#include <linux/types.h>
7#include <linux/cache.h>
8#include <asm/page.h>
9
10/* Per processor datastructure. %gs points to it while the kernel runs */
11struct x8664_pda {
12 struct task_struct *pcurrent; /* 0 Current process */
13 unsigned long data_offset; /* 8 Per cpu data offset from linker
14 address */
15 unsigned long kernelstack; /* 16 top of kernel stack for current */
16 unsigned long oldrsp; /* 24 user rsp for system call */
17 int irqcount; /* 32 Irq nesting counter. Starts -1 */
18 unsigned int cpunumber; /* 36 Logical CPU number */
19#ifdef CONFIG_CC_STACKPROTECTOR
20 unsigned long stack_canary; /* 40 stack canary value */
21 /* gcc-ABI: this canary MUST be at
22 offset 40!!! */
23#endif
24 char *irqstackptr;
25 unsigned int __softirq_pending;
26 unsigned int __nmi_count; /* number of NMI on this CPUs */
27 short mmu_state;
28 short isidle;
29 struct mm_struct *active_mm;
30 unsigned apic_timer_irqs;
31 unsigned irq0_irqs;
32 unsigned irq_resched_count;
33 unsigned irq_call_count;
34 unsigned irq_tlb_count;
35 unsigned irq_thermal_count;
36 unsigned irq_threshold_count;
37 unsigned irq_spurious_count;
38} ____cacheline_aligned_in_smp;
39
40extern struct x8664_pda *_cpu_pda[];
41extern struct x8664_pda boot_cpu_pda[];
42extern void pda_init(int);
43
44#define cpu_pda(i) (_cpu_pda[i])
45
46/*
47 * There is no fast way to get the base address of the PDA, all the accesses
48 * have to mention %fs/%gs. So it needs to be done this Torvaldian way.
49 */
50extern void __bad_pda_field(void) __attribute__((noreturn));
51
52/*
53 * proxy_pda doesn't actually exist, but tell gcc it is accessed for
54 * all PDA accesses so it gets read/write dependencies right.
55 */
56extern struct x8664_pda _proxy_pda;
57
58#define pda_offset(field) offsetof(struct x8664_pda, field)
59
60#define pda_to_op(op, field, val) \
61do { \
62 typedef typeof(_proxy_pda.field) T__; \
63 if (0) { T__ tmp__; tmp__ = (val); } /* type checking */ \
64 switch (sizeof(_proxy_pda.field)) { \
65 case 2: \
66 asm(op "w %1,%%gs:%c2" : \
67 "+m" (_proxy_pda.field) : \
68 "ri" ((T__)val), \
69 "i"(pda_offset(field))); \
70 break; \
71 case 4: \
72 asm(op "l %1,%%gs:%c2" : \
73 "+m" (_proxy_pda.field) : \
74 "ri" ((T__)val), \
75 "i" (pda_offset(field))); \
76 break; \
77 case 8: \
78 asm(op "q %1,%%gs:%c2": \
79 "+m" (_proxy_pda.field) : \
80 "ri" ((T__)val), \
81 "i"(pda_offset(field))); \
82 break; \
83 default: \
84 __bad_pda_field(); \
85 } \
86} while (0)
87
88#define pda_from_op(op, field) \
89({ \
90 typeof(_proxy_pda.field) ret__; \
91 switch (sizeof(_proxy_pda.field)) { \
92 case 2: \
93 asm(op "w %%gs:%c1,%0" : \
94 "=r" (ret__) : \
95 "i" (pda_offset(field)), \
96 "m" (_proxy_pda.field)); \
97 break; \
98 case 4: \
99 asm(op "l %%gs:%c1,%0": \
100 "=r" (ret__): \
101 "i" (pda_offset(field)), \
102 "m" (_proxy_pda.field)); \
103 break; \
104 case 8: \
105 asm(op "q %%gs:%c1,%0": \
106 "=r" (ret__) : \
107 "i" (pda_offset(field)), \
108 "m" (_proxy_pda.field)); \
109 break; \
110 default: \
111 __bad_pda_field(); \
112 } \
113 ret__; \
114})
115
116#define read_pda(field) pda_from_op("mov", field)
117#define write_pda(field, val) pda_to_op("mov", field, val)
118#define add_pda(field, val) pda_to_op("add", field, val)
119#define sub_pda(field, val) pda_to_op("sub", field, val)
120#define or_pda(field, val) pda_to_op("or", field, val)
121
122/* This is not atomic against other CPUs -- CPU preemption needs to be off */
123#define test_and_clear_bit_pda(bit, field) \
124({ \
125 int old__; \
126 asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0" \
127 : "=r" (old__), "+m" (_proxy_pda.field) \
128 : "dIr" (bit), "i" (pda_offset(field)) : "memory");\
129 old__; \
130})
131
132#endif
133
134#define PDA_STACKOFFSET (5*8)
135
136#endif