1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 #ifndef _PKEYS_POWERPC_H
4 #define _PKEYS_POWERPC_H
5 
6 #ifndef SYS_mprotect_key
7 # define SYS_mprotect_key	386
8 #endif
9 #ifndef SYS_pkey_alloc
10 # define SYS_pkey_alloc		384
11 # define SYS_pkey_free		385
12 #endif
13 #define REG_IP_IDX		PT_NIP
14 #define REG_TRAPNO		PT_TRAP
15 #define gregs			gp_regs
16 #define fpregs			fp_regs
17 #define si_pkey_offset		0x20
18 
19 #undef PKEY_DISABLE_ACCESS
20 #define PKEY_DISABLE_ACCESS	0x3  /* disable read and write */
21 
22 #undef PKEY_DISABLE_WRITE
23 #define PKEY_DISABLE_WRITE	0x2
24 
25 #define NR_PKEYS		32
26 #define NR_RESERVED_PKEYS_4K	27 /* pkey-0, pkey-1, exec-only-pkey
27 				      and 24 other keys that cannot be
28 				      represented in the PTE */
29 #define NR_RESERVED_PKEYS_64K_3KEYS	3 /* PowerNV and KVM: pkey-0,
30 					     pkey-1 and exec-only key */
31 #define NR_RESERVED_PKEYS_64K_4KEYS	4 /* PowerVM: pkey-0, pkey-1,
32 					     pkey-31 and exec-only key */
33 #define PKEY_BITS_PER_PKEY	2
34 #define HPAGE_SIZE		(1UL << 24)
35 #define PAGE_SIZE		sysconf(_SC_PAGESIZE)
36 
pkey_bit_position(int pkey)37 static inline u32 pkey_bit_position(int pkey)
38 {
39 	return (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
40 }
41 
__read_pkey_reg(void)42 static inline u64 __read_pkey_reg(void)
43 {
44 	u64 pkey_reg;
45 
46 	asm volatile("mfspr %0, 0xd" : "=r" (pkey_reg));
47 
48 	return pkey_reg;
49 }
50 
__write_pkey_reg(u64 pkey_reg)51 static inline void __write_pkey_reg(u64 pkey_reg)
52 {
53 	u64 amr = pkey_reg;
54 
55 	dprintf4("%s() changing %016llx to %016llx\n",
56 			 __func__, __read_pkey_reg(), pkey_reg);
57 
58 	asm volatile("isync; mtspr 0xd, %0; isync"
59 		     : : "r" ((unsigned long)(amr)) : "memory");
60 
61 	dprintf4("%s() pkey register after changing %016llx to %016llx\n",
62 			__func__, __read_pkey_reg(), pkey_reg);
63 }
64 
cpu_has_pkeys(void)65 static inline int cpu_has_pkeys(void)
66 {
67 	/* No simple way to determine this */
68 	return 1;
69 }
70 
arch_is_powervm()71 static inline bool arch_is_powervm()
72 {
73 	struct stat buf;
74 
75 	if ((stat("/sys/firmware/devicetree/base/ibm,partition-name", &buf) == 0) &&
76 	    (stat("/sys/firmware/devicetree/base/hmc-managed?", &buf) == 0) &&
77 	    (stat("/sys/firmware/devicetree/base/chosen/qemu,graphic-width", &buf) == -1) )
78 		return true;
79 
80 	return false;
81 }
82 
get_arch_reserved_keys(void)83 static inline int get_arch_reserved_keys(void)
84 {
85 	if (sysconf(_SC_PAGESIZE) == 4096)
86 		return NR_RESERVED_PKEYS_4K;
87 	else
88 		if (arch_is_powervm())
89 			return NR_RESERVED_PKEYS_64K_4KEYS;
90 		else
91 			return NR_RESERVED_PKEYS_64K_3KEYS;
92 }
93 
expect_fault_on_read_execonly_key(void * p1,int pkey)94 void expect_fault_on_read_execonly_key(void *p1, int pkey)
95 {
96 	/*
97 	 * powerpc does not allow userspace to change permissions of exec-only
98 	 * keys since those keys are not allocated by userspace. The signal
99 	 * handler wont be able to reset the permissions, which means the code
100 	 * will infinitely continue to segfault here.
101 	 */
102 	return;
103 }
104 
105 /* 4-byte instructions * 16384 = 64K page */
106 #define __page_o_noops() asm(".rept 16384 ; nop; .endr")
107 
malloc_pkey_with_mprotect_subpage(long size,int prot,u16 pkey)108 void *malloc_pkey_with_mprotect_subpage(long size, int prot, u16 pkey)
109 {
110 	void *ptr;
111 	int ret;
112 
113 	dprintf1("doing %s(size=%ld, prot=0x%x, pkey=%d)\n", __func__,
114 			size, prot, pkey);
115 	pkey_assert(pkey < NR_PKEYS);
116 	ptr = mmap(NULL, size, prot, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
117 	pkey_assert(ptr != (void *)-1);
118 
119 	ret = syscall(__NR_subpage_prot, ptr, size, NULL);
120 	if (ret) {
121 		perror("subpage_perm");
122 		return PTR_ERR_ENOTSUP;
123 	}
124 
125 	ret = mprotect_pkey((void *)ptr, PAGE_SIZE, prot, pkey);
126 	pkey_assert(!ret);
127 	record_pkey_malloc(ptr, size, prot);
128 
129 	dprintf1("%s() for pkey %d @ %p\n", __func__, pkey, ptr);
130 	return ptr;
131 }
132 
133 #endif /* _PKEYS_POWERPC_H */
134