Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __ASM_POINTER_AUTH_H
3#define __ASM_POINTER_AUTH_H
4
5#include <linux/bitops.h>
6#include <linux/random.h>
7
8#include <asm/cpufeature.h>
9#include <asm/memory.h>
10#include <asm/sysreg.h>
11
12#ifdef CONFIG_ARM64_PTR_AUTH
13/*
14 * Each key is a 128-bit quantity which is split across a pair of 64-bit
15 * registers (Lo and Hi).
16 */
17struct ptrauth_key {
18 unsigned long lo, hi;
19};
20
21/*
22 * We give each process its own keys, which are shared by all threads. The keys
23 * are inherited upon fork(), and reinitialised upon exec*().
24 */
25struct ptrauth_keys {
26 struct ptrauth_key apia;
27 struct ptrauth_key apib;
28 struct ptrauth_key apda;
29 struct ptrauth_key apdb;
30 struct ptrauth_key apga;
31};
32
33static inline void ptrauth_keys_init(struct ptrauth_keys *keys)
34{
35 if (system_supports_address_auth()) {
36 get_random_bytes(&keys->apia, sizeof(keys->apia));
37 get_random_bytes(&keys->apib, sizeof(keys->apib));
38 get_random_bytes(&keys->apda, sizeof(keys->apda));
39 get_random_bytes(&keys->apdb, sizeof(keys->apdb));
40 }
41
42 if (system_supports_generic_auth())
43 get_random_bytes(&keys->apga, sizeof(keys->apga));
44}
45
46#define __ptrauth_key_install(k, v) \
47do { \
48 struct ptrauth_key __pki_v = (v); \
49 write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \
50 write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \
51} while (0)
52
53static inline void ptrauth_keys_switch(struct ptrauth_keys *keys)
54{
55 if (system_supports_address_auth()) {
56 __ptrauth_key_install(APIA, keys->apia);
57 __ptrauth_key_install(APIB, keys->apib);
58 __ptrauth_key_install(APDA, keys->apda);
59 __ptrauth_key_install(APDB, keys->apdb);
60 }
61
62 if (system_supports_generic_auth())
63 __ptrauth_key_install(APGA, keys->apga);
64}
65
66extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg);
67
68/*
69 * The EL0 pointer bits used by a pointer authentication code.
70 * This is dependent on TBI0 being enabled, or bits 63:56 would also apply.
71 */
72#define ptrauth_user_pac_mask() GENMASK(54, vabits_user)
73
74/* Only valid for EL0 TTBR0 instruction pointers */
75static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
76{
77 return ptr & ~ptrauth_user_pac_mask();
78}
79
80#define ptrauth_thread_init_user(tsk) \
81do { \
82 struct task_struct *__ptiu_tsk = (tsk); \
83 ptrauth_keys_init(&__ptiu_tsk->thread.keys_user); \
84 ptrauth_keys_switch(&__ptiu_tsk->thread.keys_user); \
85} while (0)
86
87#define ptrauth_thread_switch(tsk) \
88 ptrauth_keys_switch(&(tsk)->thread.keys_user)
89
90#else /* CONFIG_ARM64_PTR_AUTH */
91#define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL)
92#define ptrauth_strip_insn_pac(lr) (lr)
93#define ptrauth_thread_init_user(tsk)
94#define ptrauth_thread_switch(tsk)
95#endif /* CONFIG_ARM64_PTR_AUTH */
96
97#endif /* __ASM_POINTER_AUTH_H */