Merge patch series "Add RISC-V 32 NOMMU support"

Jesse Taube <mr.bossman075@gmail.com> says:

This patch-set aims to add NOMMU support to RV32.
Many people want to build simple emulators or HDL
models of RISC-V this patch makes it possible to
run linux on them.

Yimin Gu is the original author of this set.
Submitted here:
https://lists.buildroot.org/pipermail/buildroot/2022-November/656134.html

Though Jesse T rewrote the Dconf.

* b4-shazam-merge:
  riscv: configs: Add nommu PHONY defconfig for RV32
  riscv: Kconfig: Allow RV32 to build with no MMU

Link: https://lore.kernel.org/r/20230301002657.352637-1-Mr.Bossman075@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Author: palmer-dabbelt

arch/riscv/Kconfig

@@ -178,8 +178,8 @@ config MMU
 
 config PAGE_OFFSET
 	hex
-	default 0xC0000000 if 32BIT
-	default 0x80000000 if 64BIT && !MMU
+	default 0xC0000000 if 32BIT && MMU
+	default 0x80000000 if !MMU
 	default 0xff60000000000000 if 64BIT
 
 config KASAN_SHADOW_OFFSET
@@ -280,7 +280,6 @@ config ARCH_RV32I
 	select GENERIC_LIB_ASHRDI3
 	select GENERIC_LIB_LSHRDI3
 	select GENERIC_LIB_UCMPDI2
-	select MMU
 
 config ARCH_RV64I
 	bool "RV64I"

arch/riscv/Makefile

@@ -174,3 +174,7 @@ rv64_randconfig:
 PHONY += rv32_defconfig
 rv32_defconfig:
 	$(Q)$(MAKE) -f $(srctree)/Makefile defconfig 32-bit.config
+
+PHONY += rv32_nommu_virt_defconfig
+rv32_nommu_virt_defconfig:
+	$(Q)$(MAKE) -f $(srctree)/Makefile nommu_virt_defconfig 32-bit.config