2022-05-11 15:03:27

by David Hildenbrand

Subject: Re: [PATCH] RISC-V: Remove IORESOURCE_BUSY flag for no-map reserved memory

On 11.05.22 13:24, Xianting Tian wrote:
> Commit 00ab027a3b82 ("RISC-V: Add kernel image sections to the resource tree")
> added IORESOURCE_BUSY flag for no-map reserved memory, this casued
> devm_ioremap_resource() failed for the no-map reserved memory in subsequent
> operations of related driver, so remove the IORESOURCE_BUSY flag.
>
> 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 <[email protected]>
> Reviewed-by: Guo Ren <[email protected]>
> CC: Nick Kossifidis <[email protected]>
> Signed-off-by: Xianting Tian <[email protected]>
> ---
> arch/riscv/kernel/setup.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 834eb652a7b9..71f2966b1474 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -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;
> } else {
> res->name = "System RAM";
> res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;

I assume the "Reserved" part is essentially unused by the kernel correct?

--
Thanks,

David / dhildenb

2022-05-12 19:05:32

by Xianting Tian

Subject: Re: [PATCH] RISC-V: Remove IORESOURCE_BUSY flag for no-map reserved memory

在 2022/5/11 下午8:27, David Hildenbrand 写道:
> On 11.05.22 13:24, Xianting Tian wrote:
>> Commit 00ab027a3b82 ("RISC-V: Add kernel image sections to the resource tree")
>> added IORESOURCE_BUSY flag for no-map reserved memory, this casued
>> devm_ioremap_resource() failed for the no-map reserved memory in subsequent
>> operations of related driver, so remove the IORESOURCE_BUSY flag.
>>
>> 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 <[email protected]>
>> Reviewed-by: Guo Ren <[email protected]>
>> CC: Nick Kossifidis <[email protected]>
>> Signed-off-by: Xianting Tian <[email protected]>
>> ---
>> arch/riscv/kernel/setup.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
>> index 834eb652a7b9..71f2966b1474 100644
>> --- a/arch/riscv/kernel/setup.c
>> +++ b/arch/riscv/kernel/setup.c
>> @@ -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;
>> } else {
>> res->name = "System RAM";
>> res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> I assume the "Reserved" part is essentially unused by the kernel correct?

I think we may use it, actually we found the issue in our product after
merged kdump functionality.

Actually, the code didn't add IORESOURCE_BUSY for no-map reserved memory
before 00ab027a3b82 merged,  so it is a typo for commit 00ab027a3b82 to
add IORESOURCE_BUSY?

>