Re: [PATCH 02/12] RISC-V: MAXPHYSMEM_2GB doesn't depend on CMODEL_MEDLOW

Anup Patel
2021-11-20T03:57:41Z

On Fri, Nov 19, 2021 at 10:14 PM Palmer Dabbelt <palmer@rivosinc.com> wrote:
>
> From: Palmer Dabbelt <palmer@rivosinc.com>
>
> For non-relocatable kernels we need to be able to link the kernel at
> approximately PAGE_OFFSET, thus requiring medany (as medlow requires the
> code to be linked within 2GiB of 0). The inverse doesn't apply, though:
> since medany code can be linked anywhere it's fine to link it close to
> 0, so we can support the smaller memory config.
>
> Fixes: de5f4b8f634b ("RISC-V: Define MAXPHYSMEM_1GB only for RV32")
> Cc: stable@vger.kernel.org
> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

>
> ---
>
> I found this when going through the savedefconfig diffs for the K210
> defconfigs. I'm not entirely sure they're doing the right thing here
> (they should probably be setting CMODEL_LOW to take advantage of the
> better code generation), but I don't have any way to test those
> platforms so I don't want to change too much.
> ---
> arch/riscv/Kconfig | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 821252b65f89..61f64512dcde 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -280,7 +280,7 @@ choice
> depends on 32BIT
> bool "1GiB"
> config MAXPHYSMEM_2GB
> - depends on 64BIT && CMODEL_MEDLOW
> + depends on 64BIT
> bool "2GiB"
> config MAXPHYSMEM_128GB
> depends on 64BIT && CMODEL_MEDANY
> --
> 2.32.0
>