diff options
author | Dimitris Papastamos <dimitris.papastamos@arm.com> | 2017-11-30 14:53:53 +0000 |
---|---|---|
committer | Igal Liberman <igall@marvell.com> | 2018-01-22 14:52:15 +0200 |
commit | 59dc3f05d1dcbb3cedc7a0550fe7247b952a6505 (patch) | |
tree | ec2c0f7775e7fca16d37dd933e7e7325fe9c5e8a | |
parent | 6d269a9b6c8ddb2d19d1087ec9ec20901af78278 (diff) |
Workaround for CVE-2017-5715 on Cortex A57 and A72
Invalidate the Branch Target Buffer (BTB) on entry to EL3 by disabling
and enabling the MMU. To achieve this without performing any branch
instruction, a per-cpu vbar is installed which executes the workaround
and then branches off to the corresponding vector entry in the main
vector table. A side effect of this change is that the main vbar is
configured before any reset handling. This is to allow the per-cpu
reset function to override the vbar setting.
This workaround is enabled by default on the affected CPUs.
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
Change-Id: I10920c4980ebebf9be83d48186c5f98f9eed6534
[Resolve conflicts]
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-on: http://vgitil04.il.marvell.com:8080/48848
Reviewed-by: Igal Liberman <igall@marvell.com>
Tested-by: iSoC Platform CI <ykjenk@marvell.com>
-rw-r--r-- | bl31/aarch64/runtime_exceptions.S | 20 | ||||
-rw-r--r-- | bl31/bl31.mk | 4 | ||||
-rw-r--r-- | docs/cpu-specific-build-macros.rst | 10 | ||||
-rw-r--r-- | include/common/aarch64/el3_common_macros.S | 20 | ||||
-rw-r--r-- | lib/cpus/aarch64/cortex_a57.S | 5 | ||||
-rw-r--r-- | lib/cpus/aarch64/cortex_a72.S | 6 | ||||
-rw-r--r-- | lib/cpus/aarch64/workaround_cve_2017_5715_mmu.S | 114 | ||||
-rw-r--r-- | lib/cpus/cpu-ops.mk | 5 |
8 files changed, 174 insertions, 10 deletions
diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S index 45b0213d..994239ed 100644 --- a/bl31/aarch64/runtime_exceptions.S +++ b/bl31/aarch64/runtime_exceptions.S @@ -14,6 +14,26 @@ .globl runtime_exceptions + .globl sync_exception_sp_el0 + .globl irq_sp_el0 + .globl fiq_sp_el0 + .globl serror_sp_el0 + + .globl sync_exception_sp_elx + .globl irq_sp_elx + .globl fiq_sp_elx + .globl serror_sp_elx + + .globl sync_exception_aarch64 + .globl irq_aarch64 + .globl fiq_aarch64 + .globl serror_aarch64 + + .globl sync_exception_aarch32 + .globl irq_aarch32 + .globl fiq_aarch32 + .globl serror_aarch32 + /* --------------------------------------------------------------------- * This macro handles Synchronous exceptions. * Only SMC exceptions are supported. diff --git a/bl31/bl31.mk b/bl31/bl31.mk index 0c9e3939..59cfae18 100644 --- a/bl31/bl31.mk +++ b/bl31/bl31.mk @@ -21,6 +21,10 @@ ifeq (${ENABLE_PMF}, 1) BL31_SOURCES += lib/pmf/pmf_main.c endif +ifeq (${WORKAROUND_CVE_2017_5715},1) +BL31_SOURCES += lib/cpus/aarch64/workaround_cve_2017_5715_mmu.S +endif + BL31_LINKERFILE := bl31/bl31.ld.S # Flag used to indicate if Crash reporting via console should be included diff --git a/docs/cpu-specific-build-macros.rst b/docs/cpu-specific-build-macros.rst index ce564a2d..b8fe13d0 100644 --- a/docs/cpu-specific-build-macros.rst +++ b/docs/cpu-specific-build-macros.rst @@ -11,6 +11,15 @@ This document describes the various build options present in the CPU specific operations framework to enable errata workarounds and to enable optimizations for a specific CPU on a platform. +Security Vulnerability Workarounds +---------------------------------- + +ARM Trusted Firmware exports a series of build flags which control which +security vulnerability workarounds should be applied at runtime. + +- ``WORKAROUND_CVE_2017_5715``: Enables the security workaround for + `CVE-2017-5715`_. Defaults to 1. + CPU Errata Workarounds ---------------------- @@ -121,6 +130,7 @@ architecture that can be enabled by the platform as desired. *Copyright (c) 2014-2016, ARM Limited and Contributors. All rights reserved.* +.. _CVE-2017-5715: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=2017-5715 .. _Cortex-A53 MPCore Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm048406/index.html .. _Cortex-A57 MPCore Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm049219/cortex_a57_mpcore_software_developers_errata_notice.pdf .. _Firmware Design guide: firmware-design.rst diff --git a/include/common/aarch64/el3_common_macros.S b/include/common/aarch64/el3_common_macros.S index 34fdaee9..58bd3dd7 100644 --- a/include/common/aarch64/el3_common_macros.S +++ b/include/common/aarch64/el3_common_macros.S @@ -13,7 +13,7 @@ /* * Helper macro to initialise EL3 registers we care about. */ - .macro el3_arch_init_common _exception_vectors + .macro el3_arch_init_common /* --------------------------------------------------------------------- * SCTLR_EL3 has already been initialised - read current value before * modifying. @@ -50,14 +50,6 @@ #endif /* IMAGE_BL31 */ /* --------------------------------------------------------------------- - * Set the exception vectors. - * --------------------------------------------------------------------- - */ - adr x0, \_exception_vectors - msr vbar_el3, x0 - isb - - /* --------------------------------------------------------------------- * Initialise SCR_EL3, setting all fields rather than relying on hw. * All fields are architecturally UNKNOWN on reset. The following fields * do not change during the TF lifetime. The remaining fields are set to @@ -238,6 +230,14 @@ .endif /* _warm_boot_mailbox */ /* --------------------------------------------------------------------- + * Set the exception vectors. + * --------------------------------------------------------------------- + */ + adr x0, \_exception_vectors + msr vbar_el3, x0 + isb + + /* --------------------------------------------------------------------- * It is a cold boot. * Perform any processor specific actions upon reset e.g. cache, TLB * invalidations etc. @@ -245,7 +245,7 @@ */ bl reset_handler - el3_arch_init_common \_exception_vectors + el3_arch_init_common .if \_secondary_cold_boot /* ------------------------------------------------------------- diff --git a/lib/cpus/aarch64/cortex_a57.S b/lib/cpus/aarch64/cortex_a57.S index 9e8480a3..4932605a 100644 --- a/lib/cpus/aarch64/cortex_a57.S +++ b/lib/cpus/aarch64/cortex_a57.S @@ -354,6 +354,11 @@ func cortex_a57_reset_func bl errata_a57_833471_wa #endif +#if IMAGE_BL31 && WORKAROUND_CVE_2017_5715 + adr x0, workaround_mmu_runtime_exceptions + msr vbar_el3, x0 +#endif + /* --------------------------------------------- * Enable the SMP bit. * --------------------------------------------- diff --git a/lib/cpus/aarch64/cortex_a72.S b/lib/cpus/aarch64/cortex_a72.S index 0307627c..dfc8e553 100644 --- a/lib/cpus/aarch64/cortex_a72.S +++ b/lib/cpus/aarch64/cortex_a72.S @@ -78,6 +78,12 @@ endfunc cortex_a72_disable_ext_debug * ------------------------------------------------- */ func cortex_a72_reset_func + +#if IMAGE_BL31 && WORKAROUND_CVE_2017_5715 + adr x0, workaround_mmu_runtime_exceptions + msr vbar_el3, x0 +#endif + /* --------------------------------------------- * As a bare minimum enable the SMP bit. * --------------------------------------------- diff --git a/lib/cpus/aarch64/workaround_cve_2017_5715_mmu.S b/lib/cpus/aarch64/workaround_cve_2017_5715_mmu.S new file mode 100644 index 00000000..f4781484 --- /dev/null +++ b/lib/cpus/aarch64/workaround_cve_2017_5715_mmu.S @@ -0,0 +1,114 @@ +/* + * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <arch.h> +#include <asm_macros.S> +#include <context.h> + + .globl workaround_mmu_runtime_exceptions + +vector_base workaround_mmu_runtime_exceptions + + .macro apply_workaround + stp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0] + mrs x0, sctlr_el3 + /* Disable MMU */ + bic x1, x0, #SCTLR_M_BIT + msr sctlr_el3, x1 + isb + /* Restore MMU config */ + msr sctlr_el3, x0 + isb + ldp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0] + .endm + + /* --------------------------------------------------------------------- + * Current EL with SP_EL0 : 0x0 - 0x200 + * --------------------------------------------------------------------- + */ +vector_entry workaround_mmu_sync_exception_sp_el0 + b sync_exception_sp_el0 + check_vector_size workaround_mmu_sync_exception_sp_el0 + +vector_entry workaround_mmu_irq_sp_el0 + b irq_sp_el0 + check_vector_size workaround_mmu_irq_sp_el0 + +vector_entry workaround_mmu_fiq_sp_el0 + b fiq_sp_el0 + check_vector_size workaround_mmu_fiq_sp_el0 + +vector_entry workaround_mmu_serror_sp_el0 + b serror_sp_el0 + check_vector_size workaround_mmu_serror_sp_el0 + + /* --------------------------------------------------------------------- + * Current EL with SP_ELx: 0x200 - 0x400 + * --------------------------------------------------------------------- + */ +vector_entry workaround_mmu_sync_exception_sp_elx + b sync_exception_sp_elx + check_vector_size workaround_mmu_sync_exception_sp_elx + +vector_entry workaround_mmu_irq_sp_elx + b irq_sp_elx + check_vector_size workaround_mmu_irq_sp_elx + +vector_entry workaround_mmu_fiq_sp_elx + b fiq_sp_elx + check_vector_size workaround_mmu_fiq_sp_elx + +vector_entry workaround_mmu_serror_sp_elx + b serror_sp_elx + check_vector_size workaround_mmu_serror_sp_elx + + /* --------------------------------------------------------------------- + * Lower EL using AArch64 : 0x400 - 0x600 + * --------------------------------------------------------------------- + */ +vector_entry workaround_mmu_sync_exception_aarch64 + apply_workaround + b sync_exception_aarch64 + check_vector_size workaround_mmu_sync_exception_aarch64 + +vector_entry workaround_mmu_irq_aarch64 + apply_workaround + b irq_aarch64 + check_vector_size workaround_mmu_irq_aarch64 + +vector_entry workaround_mmu_fiq_aarch64 + apply_workaround + b fiq_aarch64 + check_vector_size workaround_mmu_fiq_aarch64 + +vector_entry workaround_mmu_serror_aarch64 + apply_workaround + b serror_aarch64 + check_vector_size workaround_mmu_serror_aarch64 + + /* --------------------------------------------------------------------- + * Lower EL using AArch32 : 0x600 - 0x800 + * --------------------------------------------------------------------- + */ +vector_entry workaround_mmu_sync_exception_aarch32 + apply_workaround + b sync_exception_aarch32 + check_vector_size workaround_mmu_sync_exception_aarch32 + +vector_entry workaround_mmu_irq_aarch32 + apply_workaround + b irq_aarch32 + check_vector_size workaround_mmu_irq_aarch32 + +vector_entry workaround_mmu_fiq_aarch32 + apply_workaround + b fiq_aarch32 + check_vector_size workaround_mmu_fiq_aarch32 + +vector_entry workaround_mmu_serror_aarch32 + apply_workaround + b serror_aarch32 + check_vector_size workaround_mmu_serror_aarch32 diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk index ad329719..54444189 100644 --- a/lib/cpus/cpu-ops.mk +++ b/lib/cpus/cpu-ops.mk @@ -16,6 +16,8 @@ A53_DISABLE_NON_TEMPORAL_HINT ?=1 # It is enabled by default. A57_DISABLE_NON_TEMPORAL_HINT ?=1 +WORKAROUND_CVE_2017_5715 ?=1 + # Process SKIP_A57_L1_FLUSH_PWR_DWN flag $(eval $(call assert_boolean,SKIP_A57_L1_FLUSH_PWR_DWN)) $(eval $(call add_define,SKIP_A57_L1_FLUSH_PWR_DWN)) @@ -28,6 +30,9 @@ $(eval $(call add_define,A53_DISABLE_NON_TEMPORAL_HINT)) $(eval $(call assert_boolean,A57_DISABLE_NON_TEMPORAL_HINT)) $(eval $(call add_define,A57_DISABLE_NON_TEMPORAL_HINT)) +# Process WORKAROUND_CVE_2017_5715 flag +$(eval $(call assert_boolean,WORKAROUND_CVE_2017_5715)) +$(eval $(call add_define,WORKAROUND_CVE_2017_5715)) # CPU Errata Build flags. # These should be enabled by the platform if the erratum workaround needs to be |