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From: Anup Patel <anup@brainfault.org>
To: Atish Patra <atish.patra@wdc.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>,
	Anup Patel <anup.patel@wdc.com>,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Nick Kossifidis <mick@ics.forth.gr>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mike Rapoport <rppt@kernel.org>
Subject: Re: [PATCH 4/4] RISC-V: Fix maximum allowed phsyical memory for RV32
Date: Mon, 11 Jan 2021 09:34:07 +0530	[thread overview]
Message-ID: <CAAhSdy3Z1zxFdPr+dSvP6GH+1NtRw7o=JS7OnOmZnqb8LPbnRQ@mail.gmail.com> (raw)
In-Reply-To: <20210107092652.3438696-5-atish.patra@wdc.com>

On Thu, Jan 7, 2021 at 2:57 PM Atish Patra <atish.patra@wdc.com> wrote:
>
> Linux kernel can only map 1GB of address space for RV32 as the page offset
> is set to 0xC0000000. The current description in the Kconfig is confusing
> as it indicates that RV32 can support 2GB of physical memory. That is
> simply not true for current kernel. In future, a 2GB split support can be
> added to allow 2GB physical address space.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>

Just for information, Alex's also has a patch to simplify this. Refer,
"[RFC PATCH 05/12] riscv: Simplify MAXPHYSMEM config"

Looks good to me.

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

> ---
>  arch/riscv/Kconfig | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 81b76d44725d..e9e2c1f0a690 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -137,7 +137,7 @@ config PA_BITS
>
>  config PAGE_OFFSET
>         hex
> -       default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
> +       default 0xC0000000 if 32BIT && MAXPHYSMEM_1GB
>         default 0x80000000 if 64BIT && !MMU
>         default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
>         default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB
> @@ -247,10 +247,12 @@ config MODULE_SECTIONS
>
>  choice
>         prompt "Maximum Physical Memory"
> -       default MAXPHYSMEM_2GB if 32BIT
> +       default MAXPHYSMEM_1GB if 32BIT
>         default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
>         default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY
>
> +       config MAXPHYSMEM_1GB
> +               bool "1GiB"
>         config MAXPHYSMEM_2GB
>                 bool "2GiB"
>         config MAXPHYSMEM_128GB
> --
> 2.25.1
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

Regards,
Anup

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  reply	other threads:[~2021-01-11  4:04 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-07  9:26 [PATCH 0/4] Assorted fixes for RV32 Atish Patra
2021-01-07  9:26 ` [PATCH 1/4] RISC-V: Do not allocate memblock while iterating reserved memblocks Atish Patra
2021-01-08 16:25   ` Geert Uytterhoeven
2021-01-11  3:54   ` Anup Patel
2021-01-07  9:26 ` [PATCH 2/4] RISC-V: Set current memblock limit Atish Patra
2021-01-11  3:58   ` Anup Patel
2021-01-11 19:20     ` Atish Patra
2021-01-07  9:26 ` [PATCH 3/4] RISC-V: Fix L1_CACHE_BYTES for RV32 Atish Patra
2021-01-08 16:26   ` Geert Uytterhoeven
2021-01-11  4:00   ` Anup Patel
2021-01-14  5:09   ` Palmer Dabbelt
2021-01-14 18:33     ` Atish Patra
2021-01-14 19:46       ` Palmer Dabbelt
2021-01-14 21:11         ` Atish Patra
2021-01-14 21:24           ` Palmer Dabbelt
2021-01-15  7:59           ` Geert Uytterhoeven
2021-01-15 22:44             ` Palmer Dabbelt
2021-01-17 19:03               ` Geert Uytterhoeven
2021-01-20 10:59                 ` Geert Uytterhoeven
2021-01-16  1:39             ` Atish Patra
2021-01-17 18:55               ` Geert Uytterhoeven
2021-03-12 15:52       ` Geert Uytterhoeven
2021-01-07  9:26 ` [PATCH 4/4] RISC-V: Fix maximum allowed phsyical memory " Atish Patra
2021-01-11  4:04   ` Anup Patel [this message]
2021-01-11  4:05 ` [PATCH 0/4] Assorted fixes " Anup Patel
2021-01-14  5:09 ` Palmer Dabbelt
2021-01-14  5:12   ` Palmer Dabbelt

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