u-boot/arch/riscv/Kconfig
Anup Patel d2db2a8fa4 riscv: Add kconfig option to run U-Boot in S-mode
This patch adds kconfig option RISCV_SMODE to run U-Boot in
S-mode. When this opition is enabled we use s<xyz> CSRs instead
of m<xyz> CSRs.

It is important to note that there is no equivalent S-mode CSR
for misa and mhartid CSRs so we expect M-mode runtime firmware
(BBL or equivalent) to emulate misa and mhartid CSR read.

In-future, we will have more patches to avoid accessing misa and
mhartid CSRs from S-mode.

Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
2018-12-05 14:13:53 +08:00

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menu "RISC-V architecture"
depends on RISCV
config SYS_ARCH
default "riscv"
choice
prompt "Target select"
optional
config TARGET_AX25_AE350
bool "Support ax25-ae350"
config TARGET_QEMU_VIRT
bool "Support QEMU Virt Board"
endchoice
# board-specific options below
source "board/AndesTech/ax25-ae350/Kconfig"
source "board/emulation/qemu-riscv/Kconfig"
# platform-specific options below
source "arch/riscv/cpu/ax25/Kconfig"
# architecture-specific options below
choice
prompt "Base ISA"
default ARCH_RV32I
config ARCH_RV32I
bool "RV32I"
select 32BIT
help
Choose this option to target the RV32I base integer instruction set.
config ARCH_RV64I
bool "RV64I"
select 64BIT
select PHYS_64BIT
help
Choose this option to target the RV64I base integer instruction set.
endchoice
config RISCV_ISA_C
bool "Emit compressed instructions"
default y
help
Adds "C" to the ISA subsets that the toolchain is allowed to emit
when building U-Boot, which results in compressed instructions in the
U-Boot binary.
config RISCV_ISA_A
def_bool y
config RISCV_SMODE
bool "Run in S-Mode"
help
Enable this option to build U-Boot for RISC-V S-Mode
config 32BIT
bool
config 64BIT
bool
endmenu