[v3,2/3] riscv: Kconfig: Allow RV32 to build with no MMU

Message ID 20230301002657.352637-3-Mr.Bossman075@gmail.com
State New
Headers
Series Add RISC-V 32 NOMMU support |

Commit Message

Jesse T March 1, 2023, 12:26 a.m. UTC
  From: Yimin Gu <ustcymgu@gmail.com>

Some RISC-V 32bit cores do not have an MMU, and the kernel should be
able to build for them. This patch enables the RV32 to be built with
no MMU support.

Signed-off-by: Yimin Gu <ustcymgu@gmail.com>
CC: Jesse Taube <Mr.Bossman075@gmail.com>
Tested-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>
---
V1->V2:
 - Fix typo in commit description
V2->V3:
 - No change
---
 arch/riscv/Kconfig | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
  

Comments

Damien Le Moal March 1, 2023, 1:22 a.m. UTC | #1
On 3/1/23 09:26, Jesse Taube wrote:
> From: Yimin Gu <ustcymgu@gmail.com>
> 
> Some RISC-V 32bit cores do not have an MMU, and the kernel should be
> able to build for them. This patch enables the RV32 to be built with
> no MMU support.
> 
> Signed-off-by: Yimin Gu <ustcymgu@gmail.com>
> CC: Jesse Taube <Mr.Bossman075@gmail.com>
> Tested-by: Waldemar Brodkorb <wbx@openadk.org>
> Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>

Looks OK.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
  

Patch

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index c5e42cc37604..d1f661425790 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -177,8 +177,8 @@  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
@@ -279,7 +279,6 @@  config ARCH_RV32I
 	select GENERIC_LIB_ASHRDI3
 	select GENERIC_LIB_LSHRDI3
 	select GENERIC_LIB_UCMPDI2
-	select MMU
 
 config ARCH_RV64I
 	bool "RV64I"