Re: [PATCH v1 1/2] riscv: Kconfig: Allow RV32 to build with no MMU

[Jesse Taube]

On 1/20/23 02:59, Conor Dooley wrote:
> Hello!
>
> Since you'll have to re-submit, making sure that allowing !MMU on rv32
> doesn't break the build due to canaan k210 drivers being enabled despite
> relying on 64-bit divisions, I've got some nits for you.
Not sure what driver needs 64bit, but sense !MMU was only selected by 
64BIT. This should work.
diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
index 69774bb362d6..b9835b8ede86 100644
--- a/arch/riscv/Kconfig.socs
+++ b/arch/riscv/Kconfig.socs
@@ -43,7 +43,7 @@ config SOC_VIRT

 config SOC_CANAAN
        bool "Canaan Kendryte K210 SoC"
-       depends on !MMU
+       depends on !MMU && 64BIT
        select CLINT_TIMER if RISCV_M_MODE
        select SERIAL_SIFIVE if TTY
        select SERIAL_SIFIVE_CONSOLE if TTY

> On Thu, Jan 19, 2023 at 12:26:41AM -0500, Jesse Taube wrote:
> > From: Yimin Gu <ustcymgu@xxxxxxxxx>
> >
> > Some RISC-V 32bit ores do not have an MMU, and the kernel should be
>
>   s/ores/cores
OH thanks sorry for the spelling mistakes.

Thanks,
Jesse Taube
> > able to build for them. This patch enables the RV32 to be built with
> > no MMU support.
> >
> > Signed-off-by: Yimin Gu <ustcymgu@xxxxxxxxx>
> > CC: Jesse Taube <Mr.Bossman075@xxxxxxxxx>
> > Tested-By: Waldemar Brodkorb <wbx@xxxxxxxxxxx>
>
> And the automation complains that this tag is not "Tested-by:"
>
> Thanks,
> Conor.
>
> > Signed-off-by: Jesse Taube <Mr.Bossman075@xxxxxxxxx>
> > ---
> >   arch/riscv/Kconfig | 5 ++---
> >   1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > index 59d18881f35b..49759dbe6a8f 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -163,8 +163,8 @@ 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
> > @@ -262,7 +262,6 @@ config ARCH_RV32I
> >   	select GENERIC_LIB_ASHRDI3
> >   	select GENERIC_LIB_LSHRDI3
> >   	select GENERIC_LIB_UCMPDI2
> > -	select MMU
> >   
> >   config ARCH_RV64I
> >   	bool "RV64I"
> > --
> > 2.39.0