1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 #ifndef _PKEYS_X86_H
4 #define _PKEYS_X86_H
5
6 #ifdef __i386__
7
8 #ifndef SYS_mprotect_key
9 # define SYS_mprotect_key 380
10 #endif
11
12 #ifndef SYS_pkey_alloc
13 # define SYS_pkey_alloc 381
14 # define SYS_pkey_free 382
15 #endif
16
17 #define REG_IP_IDX REG_EIP
18 #define si_pkey_offset 0x14
19
20 #else
21
22 #ifndef SYS_mprotect_key
23 # define SYS_mprotect_key 329
24 #endif
25
26 #ifndef SYS_pkey_alloc
27 # define SYS_pkey_alloc 330
28 # define SYS_pkey_free 331
29 #endif
30
31 #define REG_IP_IDX REG_RIP
32 #define si_pkey_offset 0x20
33
34 #endif
35
36 #ifndef PKEY_DISABLE_ACCESS
37 # define PKEY_DISABLE_ACCESS 0x1
38 #endif
39
40 #ifndef PKEY_DISABLE_WRITE
41 # define PKEY_DISABLE_WRITE 0x2
42 #endif
43
44 #define NR_PKEYS 16
45 #define NR_RESERVED_PKEYS 2 /* pkey-0 and exec-only-pkey */
46 #define PKEY_BITS_PER_PKEY 2
47 #define HPAGE_SIZE (1UL<<21)
48 #define PAGE_SIZE 4096
49 #define MB (1<<20)
50
__page_o_noops(void)51 static inline void __page_o_noops(void)
52 {
53 /* 8-bytes of instruction * 512 bytes = 1 page */
54 asm(".rept 512 ; nopl 0x7eeeeeee(%eax) ; .endr");
55 }
56
__read_pkey_reg(void)57 static inline u64 __read_pkey_reg(void)
58 {
59 unsigned int eax, edx;
60 unsigned int ecx = 0;
61 unsigned pkey_reg;
62
63 asm volatile(".byte 0x0f,0x01,0xee\n\t"
64 : "=a" (eax), "=d" (edx)
65 : "c" (ecx));
66 pkey_reg = eax;
67 return pkey_reg;
68 }
69
__write_pkey_reg(u64 pkey_reg)70 static inline void __write_pkey_reg(u64 pkey_reg)
71 {
72 unsigned int eax = pkey_reg;
73 unsigned int ecx = 0;
74 unsigned int edx = 0;
75
76 dprintf4("%s() changing %016llx to %016llx\n", __func__,
77 __read_pkey_reg(), pkey_reg);
78 asm volatile(".byte 0x0f,0x01,0xef\n\t"
79 : : "a" (eax), "c" (ecx), "d" (edx));
80 assert(pkey_reg == __read_pkey_reg());
81 }
82
__cpuid(unsigned int * eax,unsigned int * ebx,unsigned int * ecx,unsigned int * edx)83 static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
84 unsigned int *ecx, unsigned int *edx)
85 {
86 /* ecx is often an input as well as an output. */
87 asm volatile(
88 "cpuid;"
89 : "=a" (*eax),
90 "=b" (*ebx),
91 "=c" (*ecx),
92 "=d" (*edx)
93 : "0" (*eax), "2" (*ecx));
94 }
95
96 /* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx) */
97 #define X86_FEATURE_PKU (1<<3) /* Protection Keys for Userspace */
98 #define X86_FEATURE_OSPKE (1<<4) /* OS Protection Keys Enable */
99
cpu_has_pkeys(void)100 static inline int cpu_has_pkeys(void)
101 {
102 unsigned int eax;
103 unsigned int ebx;
104 unsigned int ecx;
105 unsigned int edx;
106
107 eax = 0x7;
108 ecx = 0x0;
109 __cpuid(&eax, &ebx, &ecx, &edx);
110
111 if (!(ecx & X86_FEATURE_PKU)) {
112 dprintf2("cpu does not have PKU\n");
113 return 0;
114 }
115 if (!(ecx & X86_FEATURE_OSPKE)) {
116 dprintf2("cpu does not have OSPKE\n");
117 return 0;
118 }
119 return 1;
120 }
121
pkey_bit_position(int pkey)122 static inline u32 pkey_bit_position(int pkey)
123 {
124 return pkey * PKEY_BITS_PER_PKEY;
125 }
126
127 #define XSTATE_PKEY_BIT (9)
128 #define XSTATE_PKEY 0x200
129 #define XSTATE_BV_OFFSET 512
130
pkey_reg_xstate_offset(void)131 int pkey_reg_xstate_offset(void)
132 {
133 unsigned int eax;
134 unsigned int ebx;
135 unsigned int ecx;
136 unsigned int edx;
137 int xstate_offset;
138 int xstate_size;
139 unsigned long XSTATE_CPUID = 0xd;
140 int leaf;
141
142 /* assume that XSTATE_PKEY is set in XCR0 */
143 leaf = XSTATE_PKEY_BIT;
144 {
145 eax = XSTATE_CPUID;
146 ecx = leaf;
147 __cpuid(&eax, &ebx, &ecx, &edx);
148
149 if (leaf == XSTATE_PKEY_BIT) {
150 xstate_offset = ebx;
151 xstate_size = eax;
152 }
153 }
154
155 if (xstate_size == 0) {
156 printf("could not find size/offset of PKEY in xsave state\n");
157 return 0;
158 }
159
160 return xstate_offset;
161 }
162
get_arch_reserved_keys(void)163 static inline int get_arch_reserved_keys(void)
164 {
165 return NR_RESERVED_PKEYS;
166 }
167
expect_fault_on_read_execonly_key(void * p1,int pkey)168 void expect_fault_on_read_execonly_key(void *p1, int pkey)
169 {
170 int ptr_contents;
171
172 ptr_contents = read_ptr(p1);
173 dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
174 expected_pkey_fault(pkey);
175 }
176
malloc_pkey_with_mprotect_subpage(long size,int prot,u16 pkey)177 void *malloc_pkey_with_mprotect_subpage(long size, int prot, u16 pkey)
178 {
179 return PTR_ERR_ENOTSUP;
180 }
181
182 #endif /* _PKEYS_X86_H */
183
