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