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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_POINTER_AUTH_H
#define __ASM_POINTER_AUTH_H
#include <linux/bitops.h>
#include <linux/prctl.h>
#include <linux/random.h>
#include <asm/cpufeature.h>
#include <asm/memory.h>
#include <asm/sysreg.h>
/*
* The EL0/EL1 pointer bits used by a pointer authentication code.
* This is dependent on TBI0/TBI1 being enabled, or bits 63:56 would also apply.
*/
#define ptrauth_user_pac_mask() GENMASK_ULL(54, vabits_actual)
#define ptrauth_kernel_pac_mask() GENMASK_ULL(63, vabits_actual)
#define PR_PAC_ENABLED_KEYS_MASK \
(PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY | PR_PAC_APDBKEY)
#ifdef CONFIG_ARM64_PTR_AUTH
/*
* Each key is a 128-bit quantity which is split across a pair of 64-bit
* registers (Lo and Hi).
*/
struct ptrauth_key {
unsigned long lo, hi;
};
/*
* We give each process its own keys, which are shared by all threads. The keys
* are inherited upon fork(), and reinitialised upon exec*().
*/
struct ptrauth_keys_user {
struct ptrauth_key apia;
struct ptrauth_key apib;
struct ptrauth_key apda;
struct ptrauth_key apdb;
struct ptrauth_key apga;
};
#define __ptrauth_key_install_nosync(k, v) \
do { \
struct ptrauth_key __pki_v = (v); \
write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \
write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \
} while (0)
#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
struct ptrauth_keys_kernel {
struct ptrauth_key apia;
};
static __always_inline void ptrauth_keys_init_kernel(struct ptrauth_keys_kernel *keys)
{
if (system_supports_address_auth())
get_random_bytes(&keys->apia, sizeof(keys->apia));
}
static __always_inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel *keys)
{
if (!system_supports_address_auth())
return;
__ptrauth_key_install_nosync(APIA, keys->apia);
isb();
}
#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */
static inline void ptrauth_keys_install_user(struct ptrauth_keys_user *keys)
{
if (system_supports_address_auth()) {
__ptrauth_key_install_nosync(APIB, keys->apib);
__ptrauth_key_install_nosync(APDA, keys->apda);
__ptrauth_key_install_nosync(APDB, keys->apdb);
}
if (system_supports_generic_auth())
__ptrauth_key_install_nosync(APGA, keys->apga);
}
static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys)
{
if (system_supports_address_auth()) {
get_random_bytes(&keys->apia, sizeof(keys->apia));
get_random_bytes(&keys->apib, sizeof(keys->apib));
get_random_bytes(&keys->apda, sizeof(keys->apda));
get_random_bytes(&keys->apdb, sizeof(keys->apdb));
}
if (system_supports_generic_auth())
get_random_bytes(&keys->apga, sizeof(keys->apga));
ptrauth_keys_install_user(keys);
}
extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg);
extern int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
unsigned long enabled);
extern int ptrauth_get_enabled_keys(struct task_struct *tsk);
static __always_inline void ptrauth_enable(void)
{
if (!system_supports_address_auth())
return;
sysreg_clear_set(sctlr_el1, 0, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB |
SCTLR_ELx_ENDA | SCTLR_ELx_ENDB));
isb();
}
#define ptrauth_suspend_exit() \
ptrauth_keys_install_user(¤t->thread.keys_user)
#define ptrauth_thread_init_user() \
do { \
ptrauth_keys_init_user(¤t->thread.keys_user); \
\
/* enable all keys */ \
if (system_supports_address_auth()) \
ptrauth_set_enabled_keys(current, \
PR_PAC_ENABLED_KEYS_MASK, \
PR_PAC_ENABLED_KEYS_MASK); \
} while (0)
#define ptrauth_thread_switch_user(tsk) \
ptrauth_keys_install_user(&(tsk)->thread.keys_user)
#else /* CONFIG_ARM64_PTR_AUTH */
#define ptrauth_enable()
#define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL)
#define ptrauth_set_enabled_keys(tsk, keys, enabled) (-EINVAL)
#define ptrauth_get_enabled_keys(tsk) (-EINVAL)
#define ptrauth_suspend_exit()
#define ptrauth_thread_init_user()
#define ptrauth_thread_switch_user(tsk)
#endif /* CONFIG_ARM64_PTR_AUTH */
#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
#define ptrauth_thread_init_kernel(tsk) \
ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel)
#define ptrauth_thread_switch_kernel(tsk) \
ptrauth_keys_switch_kernel(&(tsk)->thread.keys_kernel)
#else
#define ptrauth_thread_init_kernel(tsk)
#define ptrauth_thread_switch_kernel(tsk)
#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */
#endif /* __ASM_POINTER_AUTH_H */
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