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author | Chris Kay <chris.kay@arm.com> | 2021-03-09 13:34:35 +0000 |
---|---|---|
committer | Chris Kay <chris.kay@arm.com> | 2021-03-18 12:34:34 +0100 |
commit | 4e04478aace24232d9acb9ca7c71af8ae845811f (patch) | |
tree | 2ca0d8bc0865838798453bbf282b8e4a0d18c959 | |
parent | e3ff1766e3a657882a4f59d411c63880c7254d29 (diff) | |
download | trusted-firmware-a-4e04478aace24232d9acb9ca7c71af8ae845811f.tar.gz |
arch: Enable `FEAT_SB` for supported non-Armv8.5-A platforms
The speculation barrier feature (`FEAT_SB`) was introduced with and
made mandatory in the Armv8.5-A extension. It was retroactively made
optional in prior extensions, but the checks in our code-base do not
reflect that, assuming that it is only available in Armv8.5-A or later.
This change introduces the `ENABLE_FEAT_SB` definition, which derives
support for the `sb` instruction in the assembler from the feature
flags passed to it. Note that we assume that if this feature is enabled
then all the cores in the system support it - enabling speculation
barriers for only a subset of the cores is unsupported.
Signed-off-by: Chris Kay <chris.kay@arm.com>
Change-Id: I978ed38829385b221b10ba56d49b78f4756e20ea
-rw-r--r-- | Makefile | 9 | ||||
-rw-r--r-- | include/arch/aarch32/asm_macros.S | 6 | ||||
-rw-r--r-- | include/arch/aarch64/asm_macros.S | 6 |
3 files changed, 15 insertions, 6 deletions
@@ -245,6 +245,13 @@ endif # arch-features # Determine if FEAT_RNG is supported ENABLE_FEAT_RNG = $(if $(findstring rng,${arch-features}),1,0) +# Determine if FEAT_SB is supported +ENABLE_FEAT_SB = $(if $(findstring sb,${arch-features}),1,0) + +ifeq "8.5" "$(word 1, $(sort 8.5 $(ARM_ARCH_MAJOR).$(ARM_ARCH_MINOR)))" +ENABLE_FEAT_SB = 1 +endif + ifneq ($(findstring armclang,$(notdir $(CC))),) TF_CFLAGS_aarch32 = -target arm-arm-none-eabi $(march32-directive) TF_CFLAGS_aarch64 = -target aarch64-arm-none-eabi $(march64-directive) @@ -945,6 +952,7 @@ $(eval $(call assert_booleans,\ COT_DESC_IN_DTB \ USE_SP804_TIMER \ ENABLE_FEAT_RNG \ + ENABLE_FEAT_SB \ ))) $(eval $(call assert_numerics,\ @@ -1038,6 +1046,7 @@ $(eval $(call add_defines,\ COT_DESC_IN_DTB \ USE_SP804_TIMER \ ENABLE_FEAT_RNG \ + ENABLE_FEAT_SB \ ))) ifeq (${SANITIZE_UB},trap) diff --git a/include/arch/aarch32/asm_macros.S b/include/arch/aarch32/asm_macros.S index f75da0ce62..483f9fe056 100644 --- a/include/arch/aarch32/asm_macros.S +++ b/include/arch/aarch32/asm_macros.S @@ -107,12 +107,12 @@ #else /* - * Macro for mitigating against speculative execution beyond ERET. - * If possible use Speculation Barrier instruction defined in ARMv8.5 + * Macro for mitigating against speculative execution beyond ERET. Uses the + * speculation barrier instruction introduced by FEAT_SB, if it's enabled. */ .macro exception_return eret -#if ARM_ARCH_AT_LEAST(8, 5) +#if ENABLE_FEAT_SB sb #else dsb nsh diff --git a/include/arch/aarch64/asm_macros.S b/include/arch/aarch64/asm_macros.S index cbb9f0be8f..464c05be1a 100644 --- a/include/arch/aarch64/asm_macros.S +++ b/include/arch/aarch64/asm_macros.S @@ -219,12 +219,12 @@ .endm /* - * Macro for mitigating against speculative execution beyond ERET. - * If possible use Speculation Barrier instruction defined in ARMv8.5 + * Macro for mitigating against speculative execution beyond ERET. Uses the + * speculation barrier instruction introduced by FEAT_SB, if it's enabled. */ .macro exception_return eret -#if ARM_ARCH_AT_LEAST(8, 5) +#if ENABLE_FEAT_SB sb #else dsb nsh |