linux-kernel - Re: [PATCH v2] RISC-V: Mark IORESOURCE_EXCLUSIVE for reserved mem instead of IORESOURCE

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Date:   Thu, 12 May 2022 14:31:07 +0200
From:   Heiko Stübner <heiko@...ech.de>
To:     mick@....forth.gr, paul.walmsley@...ive.com, palmer@...belt.com,
        aou@...s.berkeley.edu, anup@...infault.org,
        akpm@...ux-foundation.org, wangkefeng.wang@...wei.com,
        rppt@...nel.org, david@...hat.com, wangborong@...rlc.com,
        twd2.me@...il.com, seanjc@...gle.com, alex@...ti.fr,
        petr.pavlu@...e.com, atishp@...osinc.com,
        linux-riscv@...ts.infradead.org
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        jianghuaming.jhm@...baba-inc.com, guoren@...nel.org,
        Xianting Tian <xianting.tian@...ux.alibaba.com>,
        Xianting Tian <xianting.tian@...ux.alibaba.com>
Subject: Re: [PATCH v2] RISC-V: Mark IORESOURCE_EXCLUSIVE for reserved mem instead of IORESOURCE_BUSY

Am Donnerstag, 12. Mai 2022, 08:09:10 CEST schrieb Xianting Tian:
> Commit 00ab027a3b82 ("RISC-V: Add kernel image sections to the resource tree")
> marked IORESOURCE_BUSY for reserved memory, which casued resource map

typo "caused" resource map

> failed in subsequent operations of related driver, so remove the
> IORESOURCE_BUSY flag. In order to prohibit userland mapping reserved
> memory, mark IORESOURCE_EXCLUSIVE for it.

Looking at the comment for IORESOURCE_EXCLUSIVE
(/* Userland may not map this resource */)

this also looks like the way better match for "no-map" :-) .

Reviewed-by: Heiko Stuebner <heiko@...ech.de>

Also on qemu + d1-nezha board
Tested-by: Heiko Stuebner <heiko@...ech.de>


Heiko

> The code to reproduce the issue,
> dts:
>         mem0: memory@...00000 {
>                 reg = <0x0 0xa0000000 0 0x1000000>;
>                 no-map;
>         };
> 
>         &test {
>                 status = "okay";
>                 memory-region = <&mem0>;
>         };
> 
> code:
>         np = of_parse_phandle(pdev->dev.of_node, "memory-region", 0);
>         ret = of_address_to_resource(np, 0, &r);
>         base = devm_ioremap_resource(&pdev->dev, &r);
>         // base = -EBUSY
> 
> Fixes: 00ab027a3b82 ("RISC-V: Add kernel image sections to the resource tree")
> Reported-by: Huaming Jiang <jianghuaming.jhm@...baba-inc.com>
> Reviewed-by: Guo Ren <guoren@...nel.org>
> Reviewed-by: Nick Kossifidis <mick@....forth.gr>
> Signed-off-by: Xianting Tian <xianting.tian@...ux.alibaba.com>
> ---
>  arch/riscv/kernel/setup.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 834eb652a7b9..e0a00739bd13 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -189,7 +189,7 @@ static void __init init_resources(void)
>  		res = &mem_res[res_idx--];
>  
>  		res->name = "Reserved";
> -		res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> +		res->flags = IORESOURCE_MEM | IORESOURCE_EXCLUSIVE;
>  		res->start = __pfn_to_phys(memblock_region_reserved_base_pfn(region));
>  		res->end = __pfn_to_phys(memblock_region_reserved_end_pfn(region)) - 1;
>  
> @@ -214,7 +214,7 @@ static void __init init_resources(void)
>  
>  		if (unlikely(memblock_is_nomap(region))) {
>  			res->name = "Reserved";
> -			res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> +			res->flags = IORESOURCE_MEM | IORESOURCE_EXCLUSIVE;
>  		} else {
>  			res->name = "System RAM";
>  			res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
>