From ed108b56051de5da8024568a06781ce287e86c78 Mon Sep 17 00:00:00 2001 From: Alexei Fedorov Date: Fri, 13 Sep 2019 14:11:59 +0100 Subject: Refactor ARMv8.3 Pointer Authentication support code This patch provides the following features and makes modifications listed below: - Individual APIAKey key generation for each CPU. - New key generation on every BL31 warm boot and TSP CPU On event. - Per-CPU storage of APIAKey added in percpu_data[] of cpu_data structure. - `plat_init_apiakey()` function replaced with `plat_init_apkey()` which returns 128-bit value and uses Generic timer physical counter value to increase the randomness of the generated key. The new function can be used for generation of all ARMv8.3-PAuth keys - ARMv8.3-PAuth specific code placed in `lib\extensions\pauth`. - New `pauth_init_enable_el1()` and `pauth_init_enable_el3()` functions generate, program and enable APIAKey_EL1 for EL1 and EL3 respectively; pauth_disable_el1()` and `pauth_disable_el3()` functions disable PAuth for EL1 and EL3 respectively; `pauth_load_bl31_apiakey()` loads saved per-CPU APIAKey_EL1 from cpu-data structure. - Combined `save_gp_pauth_registers()` function replaces calls to `save_gp_registers()` and `pauth_context_save()`; `restore_gp_pauth_registers()` replaces `pauth_context_restore()` and `restore_gp_registers()` calls. - `restore_gp_registers_eret()` function removed with corresponding code placed in `el3_exit()`. - Fixed the issue when `pauth_t pauth_ctx` structure allocated space for 12 uint64_t PAuth registers instead of 10 by removal of macro CTX_PACGAKEY_END from `include/lib/el3_runtime/aarch64/context.h` and assigning its value to CTX_PAUTH_REGS_END. - Use of MODE_SP_ELX and MODE_SP_EL0 macro definitions in `msr spsel` instruction instead of hard-coded values. - Changes in documentation related to ARMv8.3-PAuth and ARMv8.5-BTI. Change-Id: Id18b81cc46f52a783a7e6a09b9f149b6ce803211 Signed-off-by: Alexei Fedorov --- plat/arm/common/aarch64/arm_pauth.c | 28 +++++++++++++--------------- plat/arm/common/arm_common.mk | 3 ++- 2 files changed, 15 insertions(+), 16 deletions(-) (limited to 'plat/arm') diff --git a/plat/arm/common/aarch64/arm_pauth.c b/plat/arm/common/aarch64/arm_pauth.c index a685c319..7cea8a0c 100644 --- a/plat/arm/common/aarch64/arm_pauth.c +++ b/plat/arm/common/aarch64/arm_pauth.c @@ -4,27 +4,25 @@ * SPDX-License-Identifier: BSD-3-Clause */ +#include #include #include /* - * Instruction pointer authentication key A. The low 64-bit are at [0], and the - * high bits at [1]. + * This is only a toy implementation to generate a seemingly random + * 128-bit key from sp, x30 and cntpct_el0 values. + * A production system must re-implement this function to generate + * keys from a reliable randomness source. */ -uint64_t plat_apiakey[2]; - -/* - * This is only a toy implementation to generate a seemingly random 128-bit key - * from sp and x30 values. A production system must re-implement this function - * to generate keys from a reliable randomness source. - */ -uint64_t *plat_init_apiakey(void) +uint128_t plat_init_apkey(void) { - uintptr_t return_addr = (uintptr_t)__builtin_return_address(0U); - uintptr_t frame_addr = (uintptr_t)__builtin_frame_address(0U); + uint64_t return_addr = (uint64_t)__builtin_return_address(0U); + uint64_t frame_addr = (uint64_t)__builtin_frame_address(0U); + uint64_t cntpct = read_cntpct_el0(); - plat_apiakey[0] = (return_addr << 13) ^ frame_addr; - plat_apiakey[1] = (frame_addr << 15) ^ return_addr; + /* Generate 128-bit key */ + uint64_t key_lo = (return_addr << 13) ^ frame_addr ^ cntpct; + uint64_t key_hi = (frame_addr << 15) ^ return_addr ^ cntpct; - return plat_apiakey; + return ((uint128_t)(key_hi) << 64) | key_lo; } diff --git a/plat/arm/common/arm_common.mk b/plat/arm/common/arm_common.mk index 10b6e512..a4a29bf7 100644 --- a/plat/arm/common/arm_common.mk +++ b/plat/arm/common/arm_common.mk @@ -234,7 +234,8 @@ endif # Pointer Authentication sources ifeq (${ENABLE_PAUTH}, 1) -PLAT_BL_COMMON_SOURCES += plat/arm/common/aarch64/arm_pauth.c +PLAT_BL_COMMON_SOURCES += plat/arm/common/aarch64/arm_pauth.c \ + lib/extensions/pauth/pauth_helpers.S endif # SPM uses libfdt in Arm platforms -- cgit v1.2.3