Unverified Commit f862bbf4 authored by Samuel Holland's avatar Samuel Holland Committed by Palmer Dabbelt
Browse files

riscv: Allow NOMMU kernels to run in S-mode 



For ease of testing, it is convenient to run NOMMU kernels in supervisor
mode. The only required change is to offset the kernel load address,
since the beginning of RAM is usually reserved for M-mode firmware.

Signed-off-by: default avatarSamuel Holland <samuel.holland@sifive.com>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240227003630.3634533-5-samuel.holland@sifive.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 9c4319d6

arch/riscv/Kconfig

+10 −5
Original line number Diff line number Diff line
@@ -64,7 +64,7 @@ config RISCV 
	select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE

	select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU

	select BUILDTIME_TABLE_SORT if MMU

	select CLINT_TIMER if !MMU

	select CLINT_TIMER if RISCV_M_MODE

	select CLONE_BACKWARDS

	select COMMON_CLK

	select CPU_PM if CPU_IDLE || HIBERNATION || SUSPEND
@@ -220,8 +220,12 @@ config ARCH_MMAP_RND_COMPAT_BITS_MAX 


# set if we run in machine mode, cleared if we run in supervisor mode

config RISCV_M_MODE

	bool

	default !MMU

	bool "Build a kernel that runs in machine mode"

	depends on !MMU

	default y

	help

	  Select this option if you want to run the kernel in M-mode,

	  without the assistance of any other firmware.



# set if we are running in S-mode and can use SBI calls

config RISCV_SBI
@@ -238,8 +242,9 @@ config MMU 


config PAGE_OFFSET

	hex

	default 0xC0000000 if 32BIT && MMU

	default 0x80000000 if !MMU

	default 0x80000000 if !MMU && RISCV_M_MODE

	default 0x80200000 if !MMU

	default 0xc0000000 if 32BIT

	default 0xff60000000000000 if 64BIT



config KASAN_SHADOW_OFFSET