[U-Boot] [PATCH 08/30] riscv: add Kconfig entries for the code model

[Lukas Auer]

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 at aisec.fraunhofer.de>
---

 arch/riscv/Kconfig  | 19 +++++++++++++++++++
 arch/riscv/Makefile |  7 +++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index e15329c35e..ce07fb4b55 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 6fb292d0b4..da6e50bd14 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -13,8 +13,11 @@ riscv-mabi-$(CONFIG_ARCH_RV32I)	:= ilp32
 
 arch-y := -march=$(riscv-march-y) -mabi=$(riscv-mabi-y)
 
-PLATFORM_CPPFLAGS	+= $(arch-y)
-CFLAGS_EFI		+= $(arch-y)
+cmodel-$(CONFIG_CMODEL_MEDLOW)	:= -mcmodel=medlow
+cmodel-$(CONFIG_CMODEL_MEDANY)	:= -mcmodel=medany
+
+PLATFORM_CPPFLAGS	+= $(arch-y) $(cmodel-y)
+CFLAGS_EFI		+= $(arch-y) $(cmodel-y)
 
 head-y := arch/riscv/cpu/start.o
 
-- 
2.17.2