RISC-V has two code models, medium low (medlow) and medium any (medany). Medlow limits addressable memory to a single 2 GiB range between the absolute addresses -2 GiB and +2 GiB. Medany limits addressable memory to any single 2 GiB address range. By default, medlow is selected on 32-bit systems and medany on 64-bit systems. This matches the configuration in Linux.
The -mcmodel compiler flag is selected according to the Kconfig configuration.
Signed-off-by: Lukas Auer lukas.auer@aisec.fraunhofer.de ---
Changes in v2: - Change ISA string construction, as suggested by Bin Meng
arch/riscv/Kconfig | 19 +++++++++++++++++++ arch/riscv/Makefile | 9 ++++++++- 2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 0de77a75d7..371921b412 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -38,6 +38,25 @@ config ARCH_RV64I
endchoice
+choice + prompt "Code Model" + default CMODEL_MEDLOW if 32BIT + default CMODEL_MEDANY if 64BIT + +config CMODEL_MEDLOW + bool "medium low code model" + help + U-Boot and its statically defined symbols must lie within a single 2 GiB + address range and must lie between absolute addresses -2 GiB and +2 GiB. + +config CMODEL_MEDANY + bool "medium any code model" + help + U-Boot and its statically defined symbols must be within any single 2 GiB + address range. + +endchoice + config RISCV_ISA_C bool "Emit compressed instructions" default y diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 55d7c6550e..0b80eb8d86 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -17,8 +17,15 @@ endif ifeq ($(CONFIG_RISCV_ISA_C),y) ARCH_C = c endif +ifeq ($(CONFIG_CMODEL_MEDLOW),y) + CMODEL = medlow +endif +ifeq ($(CONFIG_CMODEL_MEDANY),y) + CMODEL = medany +endif
-ARCH_FLAGS = -march=$(ARCH_BASE)$(ARCH_A)$(ARCH_C) -mabi=$(ABI) +ARCH_FLAGS = -march=$(ARCH_BASE)$(ARCH_A)$(ARCH_C) -mabi=$(ABI) \ + -mcmodel=$(CMODEL)
PLATFORM_CPPFLAGS += $(ARCH_FLAGS) CFLAGS_EFI += $(ARCH_FLAGS)