Re: [PATCH v3] RISC-V: Mark IORESOURCE_EXCLUSIVE for reserved mem instead of IORESOURCE_BUSY

[Guo Ren]

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@xxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx>
> Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
> Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>
> Tested-by: Heiko Stuebner <heiko@xxxxxxxxx>
> Co-developed-by: Nick Kossifidis <mick@xxxxxxxxxxxx>
> Signed-off-by: Xianting Tian <xianting.tian@xxxxxxxxxxxxxxxxx>
> ---
> 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/