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
 37static inline u32 pkey_bit_position(int pkey)
 38{
 39	return (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
 40}
 41
 42static 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
 51static 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
 65static inline int cpu_has_pkeys(void)
 66{
 67	/* No simple way to determine this */
 68	return 1;
 69}
 70
 71static 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
 83static 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
 94void 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
108void *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 */