tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2
3#ifndef _PKEYS_X86_H
4#define _PKEYS_X86_H
5
6#ifdef __i386__
7
8#define REG_IP_IDX REG_EIP
9#define si_pkey_offset 0x14
10
11#else
12
13#define REG_IP_IDX REG_RIP
14#define si_pkey_offset 0x20
15
16#endif
17
18#define MCONTEXT_IP(mc) mc.gregs[REG_IP_IDX]
19#define MCONTEXT_TRAPNO(mc) mc.gregs[REG_TRAPNO]
20#define MCONTEXT_FPREGS
21
22#ifndef PKEY_DISABLE_ACCESS
23# define PKEY_DISABLE_ACCESS 0x1
24#endif
25
26#ifndef PKEY_DISABLE_WRITE
27# define PKEY_DISABLE_WRITE 0x2
28#endif
29
30#define NR_PKEYS 16
31#define NR_RESERVED_PKEYS 2 /* pkey-0 and exec-only-pkey */
32#define PKEY_BITS_PER_PKEY 2
33#define HPAGE_SIZE (1UL<<21)
34#define PAGE_SIZE 4096
35#define MB (1<<20)
36
37#define PKEY_REG_ALLOW_NONE 0x55555555
38
39static inline void __page_o_noops(void)
40{
41 /* 8-bytes of instruction * 512 bytes = 1 page */
42 asm(".rept 512 ; nopl 0x7eeeeeee(%eax) ; .endr");
43}
44
45static inline u64 __read_pkey_reg(void)
46{
47 unsigned int eax, edx;
48 unsigned int ecx = 0;
49 unsigned pkey_reg;
50
51 asm volatile(".byte 0x0f,0x01,0xee\n\t"
52 : "=a" (eax), "=d" (edx)
53 : "c" (ecx));
54 pkey_reg = eax;
55 return pkey_reg;
56}
57
58static inline void __write_pkey_reg(u64 pkey_reg)
59{
60 unsigned int eax = pkey_reg;
61 unsigned int ecx = 0;
62 unsigned int edx = 0;
63
64 dprintf4("%s() changing %016llx to %016llx\n", __func__,
65 __read_pkey_reg(), pkey_reg);
66 asm volatile(".byte 0x0f,0x01,0xef\n\t"
67 : : "a" (eax), "c" (ecx), "d" (edx));
68 assert(pkey_reg == __read_pkey_reg());
69}
70
71/* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx) */
72#define X86_FEATURE_PKU (1<<3) /* Protection Keys for Userspace */
73#define X86_FEATURE_OSPKE (1<<4) /* OS Protection Keys Enable */
74
75static inline int cpu_has_pkeys(void)
76{
77 unsigned int eax;
78 unsigned int ebx;
79 unsigned int ecx;
80 unsigned int edx;
81
82 __cpuid_count(0x7, 0x0, eax, ebx, ecx, edx);
83
84 if (!(ecx & X86_FEATURE_PKU)) {
85 dprintf2("cpu does not have PKU\n");
86 return 0;
87 }
88 if (!(ecx & X86_FEATURE_OSPKE)) {
89 dprintf2("cpu does not have OSPKE\n");
90 return 0;
91 }
92 return 1;
93}
94
95static inline int cpu_max_xsave_size(void)
96{
97 unsigned long XSTATE_CPUID = 0xd;
98 unsigned int eax;
99 unsigned int ebx;
100 unsigned int ecx;
101 unsigned int edx;
102
103 __cpuid_count(XSTATE_CPUID, 0, eax, ebx, ecx, edx);
104 return ecx;
105}
106
107static inline u32 pkey_bit_position(int pkey)
108{
109 return pkey * PKEY_BITS_PER_PKEY;
110}
111
112#define XSTATE_PKEY_BIT (9)
113#define XSTATE_PKEY 0x200
114#define XSTATE_BV_OFFSET 512
115
116static inline int pkey_reg_xstate_offset(void)
117{
118 unsigned int eax;
119 unsigned int ebx;
120 unsigned int ecx;
121 unsigned int edx;
122 int xstate_offset;
123 int xstate_size = 0;
124 unsigned long XSTATE_CPUID = 0xd;
125 int leaf;
126
127 /* assume that XSTATE_PKEY is set in XCR0 */
128 leaf = XSTATE_PKEY_BIT;
129 {
130 __cpuid_count(XSTATE_CPUID, leaf, eax, ebx, ecx, edx);
131
132 if (leaf == XSTATE_PKEY_BIT) {
133 xstate_offset = ebx;
134 xstate_size = eax;
135 }
136 }
137
138 if (xstate_size == 0) {
139 printf("could not find size/offset of PKEY in xsave state\n");
140 return 0;
141 }
142
143 return xstate_offset;
144}
145
146static inline int get_arch_reserved_keys(void)
147{
148 return NR_RESERVED_PKEYS;
149}
150
151static inline void expect_fault_on_read_execonly_key(void *p1, int pkey)
152{
153 int ptr_contents;
154
155 ptr_contents = read_ptr(p1);
156 dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
157 expected_pkey_fault(pkey);
158}
159
160static inline void *malloc_pkey_with_mprotect_subpage(long size, int prot, u16 pkey)
161{
162 return PTR_ERR_ENOTSUP;
163}
164
165#endif /* _PKEYS_X86_H */