pkey-x86.h

  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 */