1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 #ifndef _PKEYS_POWERPC_H
4 #define _PKEYS_POWERPC_H
5
6 #include <sys/stat.h>
7
8 #ifndef SYS_pkey_alloc
9 # define SYS_pkey_alloc 384
10 # define SYS_pkey_free 385
11 #endif
12 #define REG_IP_IDX PT_NIP
13 #define MCONTEXT_IP(mc) mc.gp_regs[REG_IP_IDX]
14 #define MCONTEXT_TRAPNO(mc) mc.gp_regs[REG_TRAPNO]
15 #define REG_TRAPNO PT_TRAP
16 #define MCONTEXT_FPREGS
17 #define gregs gp_regs
18 #define fpregs fp_regs
19 #define si_pkey_offset 0x20
20
21 #undef PKEY_DISABLE_ACCESS
22 #define PKEY_DISABLE_ACCESS 0x3 /* disable read and write */
23
24 #undef PKEY_DISABLE_WRITE
25 #define PKEY_DISABLE_WRITE 0x2
26
27 #define NR_PKEYS 32
28 #define NR_RESERVED_PKEYS_4K 27 /* pkey-0, pkey-1, exec-only-pkey
29 and 24 other keys that cannot be
30 represented in the PTE */
31 #define NR_RESERVED_PKEYS_64K_3KEYS 3 /* PowerNV and KVM: pkey-0,
32 pkey-1 and exec-only key */
33 #define NR_RESERVED_PKEYS_64K_4KEYS 4 /* PowerVM: pkey-0, pkey-1,
34 pkey-31 and exec-only key */
35 #define PKEY_BITS_PER_PKEY 2
36 #define HPAGE_SIZE (1UL << 24)
37 #define PAGE_SIZE sysconf(_SC_PAGESIZE)
38
pkey_bit_position(int pkey)39 static inline u32 pkey_bit_position(int pkey)
40 {
41 return (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
42 }
43
__read_pkey_reg(void)44 static inline u64 __read_pkey_reg(void)
45 {
46 u64 pkey_reg;
47
48 asm volatile("mfspr %0, 0xd" : "=r" (pkey_reg));
49
50 return pkey_reg;
51 }
52
__write_pkey_reg(u64 pkey_reg)53 static inline void __write_pkey_reg(u64 pkey_reg)
54 {
55 u64 amr = pkey_reg;
56
57 dprintf4("%s() changing %016llx to %016llx\n",
58 __func__, __read_pkey_reg(), pkey_reg);
59
60 asm volatile("isync; mtspr 0xd, %0; isync"
61 : : "r" ((unsigned long)(amr)) : "memory");
62
63 dprintf4("%s() pkey register after changing %016llx to %016llx\n",
64 __func__, __read_pkey_reg(), pkey_reg);
65 }
66
cpu_has_pkeys(void)67 static inline int cpu_has_pkeys(void)
68 {
69 /* No simple way to determine this */
70 return 1;
71 }
72
arch_is_powervm()73 static inline bool arch_is_powervm()
74 {
75 struct stat buf;
76
77 if ((stat("/sys/firmware/devicetree/base/ibm,partition-name", &buf) == 0) &&
78 (stat("/sys/firmware/devicetree/base/hmc-managed?", &buf) == 0) &&
79 (stat("/sys/firmware/devicetree/base/chosen/qemu,graphic-width", &buf) == -1) )
80 return true;
81
82 return false;
83 }
84
get_arch_reserved_keys(void)85 static inline int get_arch_reserved_keys(void)
86 {
87 if (sysconf(_SC_PAGESIZE) == 4096)
88 return NR_RESERVED_PKEYS_4K;
89 else
90 if (arch_is_powervm())
91 return NR_RESERVED_PKEYS_64K_4KEYS;
92 else
93 return NR_RESERVED_PKEYS_64K_3KEYS;
94 }
95
expect_fault_on_read_execonly_key(void * p1,int pkey)96 static inline void expect_fault_on_read_execonly_key(void *p1, int pkey)
97 {
98 /*
99 * powerpc does not allow userspace to change permissions of exec-only
100 * keys since those keys are not allocated by userspace. The signal
101 * handler wont be able to reset the permissions, which means the code
102 * will infinitely continue to segfault here.
103 */
104 return;
105 }
106
107 #define REPEAT_8(s) s s s s s s s s
108 #define REPEAT_64(s) REPEAT_8(s) REPEAT_8(s) REPEAT_8(s) REPEAT_8(s) \
109 REPEAT_8(s) REPEAT_8(s) REPEAT_8(s) REPEAT_8(s)
110 #define REPEAT_512(s) REPEAT_64(s) REPEAT_64(s) REPEAT_64(s) REPEAT_64(s) \
111 REPEAT_64(s) REPEAT_64(s) REPEAT_64(s) REPEAT_64(s)
112 #define REPEAT_4096(s) REPEAT_512(s) REPEAT_512(s) REPEAT_512(s) REPEAT_512(s) \
113 REPEAT_512(s) REPEAT_512(s) REPEAT_512(s) REPEAT_512(s)
114 #define REPEAT_16384(s) REPEAT_4096(s) REPEAT_4096(s) \
115 REPEAT_4096(s) REPEAT_4096(s)
116
117 /* 4-byte instructions * 16384 = 64K page */
118 #define __page_o_noops() asm(REPEAT_16384("nop\n"))
119
malloc_pkey_with_mprotect_subpage(long size,int prot,u16 pkey)120 static inline void *malloc_pkey_with_mprotect_subpage(long size, int prot, u16 pkey)
121 {
122 void *ptr;
123 int ret;
124
125 dprintf1("doing %s(size=%ld, prot=0x%x, pkey=%d)\n", __func__,
126 size, prot, pkey);
127 pkey_assert(pkey < NR_PKEYS);
128 ptr = mmap(NULL, size, prot, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
129 pkey_assert(ptr != (void *)-1);
130
131 ret = syscall(__NR_subpage_prot, ptr, size, NULL);
132 if (ret) {
133 perror("subpage_perm");
134 return PTR_ERR_ENOTSUP;
135 }
136
137 ret = mprotect_pkey((void *)ptr, PAGE_SIZE, prot, pkey);
138 pkey_assert(!ret);
139 record_pkey_malloc(ptr, size, prot);
140
141 dprintf1("%s() for pkey %d @ %p\n", __func__, pkey, ptr);
142 return ptr;
143 }
144
145 #endif /* _PKEYS_POWERPC_H */
146