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

Heiko Stübner
2022-05-12T12:32:00Z

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@sntech.de>

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

Heiko

> 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: Nick Kossifidis <mick@ics.forth.gr>
> Signed-off-by: Xianting Tian <xianting.tian@linux.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;