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