lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <mhng-c5a71036-061e-4704-bcdf-2b23cab36908@palmer-ri-x1c9a>
Date:   Thu, 06 Jul 2023 10:05:54 -0700 (PDT)
From:   Palmer Dabbelt <palmer@...belt.com>
To:     alexghiti@...osinc.com
CC:     Paul Walmsley <paul.walmsley@...ive.com>, aou@...s.berkeley.edu,
        suagrfillet@...il.com, linux-riscv@...ts.infradead.org,
        linux-kernel@...r.kernel.org, alexghiti@...osinc.com
Subject:     Re: [PATCH] riscv: Start of DRAM should at least be aligned on PMD size for the direct mapping

On Tue, 04 Jul 2023 05:18:37 PDT (-0700), alexghiti@...osinc.com wrote:
> So that we do not end up mapping the whole linear mapping using 4K
> pages, which is slow at boot time, and also very likely at runtime.
>
> So make sure we align the start of DRAM on a PMD boundary.
>
> Signed-off-by: Alexandre Ghiti <alexghiti@...osinc.com>
> ---
>  arch/riscv/mm/init.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 4fa420faa780..4a43ec275c6d 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -214,8 +214,13 @@ static void __init setup_bootmem(void)
>  	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
>
>  	phys_ram_end = memblock_end_of_DRAM();
> +
> +	/*
> +	 * Make sure we align the start of the memory on a PMD boundary so that
> +	 * at worst, we map the linear mapping with PMD mappings.
> +	 */
>  	if (!IS_ENABLED(CONFIG_XIP_KERNEL))
> -		phys_ram_base = memblock_start_of_DRAM();
> +		phys_ram_base = memblock_start_of_DRAM() & PMD_MASK;

This rounds down, which IIUC will result in mappings outside what 
memblock detected as the start af DRAM.  I'd expect that to cause bad 
behavior somewhere.

Shouldn't we be rounding up?

>
>  	/*
>  	 * In 64-bit, any use of __va/__pa before this point is wrong as we

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ