1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 #ifndef _PKEYS_POWERPC_H
4 #define _PKEYS_POWERPC_H
5
6 #ifndef SYS_pkey_alloc
7 # define SYS_pkey_alloc 384
8 # define SYS_pkey_free 385
9 #endif
10 #define REG_IP_IDX PT_NIP
11 #define MCONTEXT_IP(mc) mc.gp_regs[REG_IP_IDX]
12 #define MCONTEXT_TRAPNO(mc) mc.gp_regs[REG_TRAPNO]
13 #define REG_TRAPNO PT_TRAP
14 #define MCONTEXT_FPREGS
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