1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_SPECIAL_INSNS_H
3#define _ASM_X86_SPECIAL_INSNS_H
4
5
6#ifdef __KERNEL__
7
8#include <asm/nops.h>
9
10/*
11 * Volatile isn't enough to prevent the compiler from reordering the
12 * read/write functions for the control registers and messing everything up.
13 * A memory clobber would solve the problem, but would prevent reordering of
14 * all loads stores around it, which can hurt performance. Solution is to
15 * use a variable and mimic reads and writes to it to enforce serialization
16 */
17extern unsigned long __force_order;
18
19static inline unsigned long native_read_cr0(void)
20{
21 unsigned long val;
22 asm volatile("mov %%cr0,%0\n\t" : "=r" (val), "=m" (__force_order));
23 return val;
24}
25
26static inline void native_write_cr0(unsigned long val)
27{
28 asm volatile("mov %0,%%cr0": : "r" (val), "m" (__force_order));
29}
30
31static inline unsigned long native_read_cr2(void)
32{
33 unsigned long val;
34 asm volatile("mov %%cr2,%0\n\t" : "=r" (val), "=m" (__force_order));
35 return val;
36}
37
38static inline void native_write_cr2(unsigned long val)
39{
40 asm volatile("mov %0,%%cr2": : "r" (val), "m" (__force_order));
41}
42
43static inline unsigned long __native_read_cr3(void)
44{
45 unsigned long val;
46 asm volatile("mov %%cr3,%0\n\t" : "=r" (val), "=m" (__force_order));
47 return val;
48}
49
50static inline void native_write_cr3(unsigned long val)
51{
52 asm volatile("mov %0,%%cr3": : "r" (val), "m" (__force_order));
53}
54
55static inline unsigned long native_read_cr4(void)
56{
57 unsigned long val;
58#ifdef CONFIG_X86_32
59 /*
60 * This could fault if CR4 does not exist. Non-existent CR4
61 * is functionally equivalent to CR4 == 0. Keep it simple and pretend
62 * that CR4 == 0 on CPUs that don't have CR4.
63 */
64 asm volatile("1: mov %%cr4, %0\n"
65 "2:\n"
66 _ASM_EXTABLE(1b, 2b)
67 : "=r" (val), "=m" (__force_order) : "0" (0));
68#else
69 /* CR4 always exists on x86_64. */
70 asm volatile("mov %%cr4,%0\n\t" : "=r" (val), "=m" (__force_order));
71#endif
72 return val;
73}
74
75static inline void native_write_cr4(unsigned long val)
76{
77 asm volatile("mov %0,%%cr4": : "r" (val), "m" (__force_order));
78}
79
80#ifdef CONFIG_X86_64
81static inline unsigned long native_read_cr8(void)
82{
83 unsigned long cr8;
84 asm volatile("movq %%cr8,%0" : "=r" (cr8));
85 return cr8;
86}
87
88static inline void native_write_cr8(unsigned long val)
89{
90 asm volatile("movq %0,%%cr8" :: "r" (val) : "memory");
91}
92#endif
93
94#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
95static inline u32 __read_pkru(void)
96{
97 u32 ecx = 0;
98 u32 edx, pkru;
99
100 /*
101 * "rdpkru" instruction. Places PKRU contents in to EAX,
102 * clears EDX and requires that ecx=0.
103 */
104 asm volatile(".byte 0x0f,0x01,0xee\n\t"
105 : "=a" (pkru), "=d" (edx)
106 : "c" (ecx));
107 return pkru;
108}
109
110static inline void __write_pkru(u32 pkru)
111{
112 u32 ecx = 0, edx = 0;
113
114 /*
115 * "wrpkru" instruction. Loads contents in EAX to PKRU,
116 * requires that ecx = edx = 0.
117 */
118 asm volatile(".byte 0x0f,0x01,0xef\n\t"
119 : : "a" (pkru), "c"(ecx), "d"(edx));
120}
121#else
122static inline u32 __read_pkru(void)
123{
124 return 0;
125}
126
127static inline void __write_pkru(u32 pkru)
128{
129}
130#endif
131
132static inline void native_wbinvd(void)
133{
134 asm volatile("wbinvd": : :"memory");
135}
136
137extern asmlinkage void native_load_gs_index(unsigned);
138
139static inline unsigned long __read_cr4(void)
140{
141 return native_read_cr4();
142}
143
144#ifdef CONFIG_PARAVIRT_XXL
145#include <asm/paravirt.h>
146#else
147
148static inline unsigned long read_cr0(void)
149{
150 return native_read_cr0();
151}
152
153static inline void write_cr0(unsigned long x)
154{
155 native_write_cr0(x);
156}
157
158static inline unsigned long read_cr2(void)
159{
160 return native_read_cr2();
161}
162
163static inline void write_cr2(unsigned long x)
164{
165 native_write_cr2(x);
166}
167
168/*
169 * Careful! CR3 contains more than just an address. You probably want
170 * read_cr3_pa() instead.
171 */
172static inline unsigned long __read_cr3(void)
173{
174 return __native_read_cr3();
175}
176
177static inline void write_cr3(unsigned long x)
178{
179 native_write_cr3(x);
180}
181
182static inline void __write_cr4(unsigned long x)
183{
184 native_write_cr4(x);
185}
186
187static inline void wbinvd(void)
188{
189 native_wbinvd();
190}
191
192#ifdef CONFIG_X86_64
193
194static inline unsigned long read_cr8(void)
195{
196 return native_read_cr8();
197}
198
199static inline void write_cr8(unsigned long x)
200{
201 native_write_cr8(x);
202}
203
204static inline void load_gs_index(unsigned selector)
205{
206 native_load_gs_index(selector);
207}
208
209#endif
210
211#endif /* CONFIG_PARAVIRT_XXL */
212
213static inline void clflush(volatile void *__p)
214{
215 asm volatile("clflush %0" : "+m" (*(volatile char __force *)__p));
216}
217
218static inline void clflushopt(volatile void *__p)
219{
220 alternative_io(".byte " __stringify(NOP_DS_PREFIX) "; clflush %P0",
221 ".byte 0x66; clflush %P0",
222 X86_FEATURE_CLFLUSHOPT,
223 "+m" (*(volatile char __force *)__p));
224}
225
226static inline void clwb(volatile void *__p)
227{
228 volatile struct { char x[64]; } *p = __p;
229
230 asm volatile(ALTERNATIVE_2(
231 ".byte " __stringify(NOP_DS_PREFIX) "; clflush (%[pax])",
232 ".byte 0x66; clflush (%[pax])", /* clflushopt (%%rax) */
233 X86_FEATURE_CLFLUSHOPT,
234 ".byte 0x66, 0x0f, 0xae, 0x30", /* clwb (%%rax) */
235 X86_FEATURE_CLWB)
236 : [p] "+m" (*p)
237 : [pax] "a" (p));
238}
239
240#define nop() asm volatile ("nop")
241
242
243#endif /* __KERNEL__ */
244
245#endif /* _ASM_X86_SPECIAL_INSNS_H */
246