linux/arch/arm64/include/asm/asm_pointer_auth.h
Kristina Martsenko 33e4523498 arm64: initialize and switch ptrauth kernel keys
Set up keys to use pointer authentication within the kernel. The kernel
will be compiled with APIAKey instructions, the other keys are currently
unused. Each task is given its own APIAKey, which is initialized during
fork. The key is changed during context switch and on kernel entry from
EL0.

The keys for idle threads need to be set before calling any C functions,
because it is not possible to enter and exit a function with different
keys.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
[Amit: Modified secondary cores key structure, comments]
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-03-18 09:50:20 +00:00

64 lines
1.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_ASM_POINTER_AUTH_H
#define __ASM_ASM_POINTER_AUTH_H
#include <asm/alternative.h>
#include <asm/asm-offsets.h>
#include <asm/cpufeature.h>
#include <asm/sysreg.h>
#ifdef CONFIG_ARM64_PTR_AUTH
/*
* thread.keys_user.ap* as offset exceeds the #imm offset range
* so use the base value of ldp as thread.keys_user and offset as
* thread.keys_user.ap*.
*/
.macro ptrauth_keys_install_user tsk, tmp1, tmp2, tmp3
mov \tmp1, #THREAD_KEYS_USER
add \tmp1, \tsk, \tmp1
alternative_if_not ARM64_HAS_ADDRESS_AUTH
b .Laddr_auth_skip_\@
alternative_else_nop_endif
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APIA]
msr_s SYS_APIAKEYLO_EL1, \tmp2
msr_s SYS_APIAKEYHI_EL1, \tmp3
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APIB]
msr_s SYS_APIBKEYLO_EL1, \tmp2
msr_s SYS_APIBKEYHI_EL1, \tmp3
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APDA]
msr_s SYS_APDAKEYLO_EL1, \tmp2
msr_s SYS_APDAKEYHI_EL1, \tmp3
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APDB]
msr_s SYS_APDBKEYLO_EL1, \tmp2
msr_s SYS_APDBKEYHI_EL1, \tmp3
.Laddr_auth_skip_\@:
alternative_if ARM64_HAS_GENERIC_AUTH
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APGA]
msr_s SYS_APGAKEYLO_EL1, \tmp2
msr_s SYS_APGAKEYHI_EL1, \tmp3
alternative_else_nop_endif
.endm
.macro ptrauth_keys_install_kernel tsk, tmp1, tmp2, tmp3
alternative_if ARM64_HAS_ADDRESS_AUTH
mov \tmp1, #THREAD_KEYS_KERNEL
add \tmp1, \tsk, \tmp1
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_KERNEL_KEY_APIA]
msr_s SYS_APIAKEYLO_EL1, \tmp2
msr_s SYS_APIAKEYHI_EL1, \tmp3
isb
alternative_else_nop_endif
.endm
#else /* CONFIG_ARM64_PTR_AUTH */
.macro ptrauth_keys_install_user tsk, tmp1, tmp2, tmp3
.endm
.macro ptrauth_keys_install_kernel tsk, tmp1, tmp2, tmp3
.endm
#endif /* CONFIG_ARM64_PTR_AUTH */
#endif /* __ASM_ASM_POINTER_AUTH_H */