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References: <20220518013428.1338983-1-xianting.tian@linux.alibaba.com>
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From:   Guo Ren <guoren@kernel.org>
Date:   Mon, 30 May 2022 10:47:51 +0800
Message-ID: <CAJF2gTRZCchLk9apNQagNmsNb3Pv+WfPTisrsWDDrQyVncUYeA@mail.gmail.com>
Subject: Re: [PATCH v3] RISC-V: Mark IORESOURCE_EXCLUSIVE for reserved mem
 instead of IORESOURCE_BUSY
To:     Palmer Dabbelt <palmer@dabbelt.com>
Cc:     Nick Kossifidis <mick@ics.forth.gr>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Anup Patel <anup@brainfault.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Mike Rapoport <rppt@kernel.org>,
        David Hildenbrand <david@redhat.com>, wangborong@cdjrlc.com,
        twd2 <twd2.me@gmail.com>, seanjc@google.com,
        Alex Ghiti <alex@ghiti.fr>, petr.pavlu@suse.com,
        Atish Patra <atishp@rivosinc.com>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        jianghuaming.jhm@alibaba-inc.com,
        =?UTF-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>,
        Xianting Tian <xianting.tian@linux.alibaba.com>
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Precedence: bulk

Hi Palmer,

Please have a look at this patch which is a critical fixup. Our
current riscv implementation has broken the reserved memory.

On Wed, May 18, 2022 at 9:34 AM Xianting Tian
<xianting.tian@linux.alibaba.com> wrote:
>
> Commit 00ab027a3b82 ("RISC-V: Add kernel image sections to the resource tree")
> marked IORESOURCE_BUSY for reserved memory, which 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.
>
> The code to reproduce the issue,
> dts:
>         mem0: memory@a0000000 {
>                 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@alibaba-inc.com>
> Reviewed-by: Guo Ren <guoren@kernel.org>
> Reviewed-by: Heiko Stuebner <heiko@sntech.de>
> Tested-by: Heiko Stuebner <heiko@sntech.de>
> Co-developed-by: Nick Kossifidis <mick@ics.forth.gr>
> Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
> ---
> Changes from v2:
> - Fix typo in commit message: casued -> caused
> - Remove Reviewed-by of Nick Kossifidis, who didn't give Reviewed-by actually
> - Add Co-developed-by of Nick
>
> Changes from v1:
> - Mark reserved memory as IORESOURCE_EXCLUSIVE, suggested by Nick
> ---
>  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;
> --
> 2.17.1
>


-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/