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

[Xianting Tian <xianting.tian@linux.alibaba.com>]

在 2022/6/2 下午1:57, Palmer Dabbelt 写道:
> On Sun, 29 May 2022 19:47:51 PDT (-0700), guoren@kernel.org wrote:
>> Hi Palmer,
>>
>> Please have a look at this patch which is a critical fixup. Our
>> current riscv implementation has broken the reserved memory.
>
> Putting "fix" somewhere in the subject is generally the best way to do 
> that, this one just looked like a feature and I stumbled into it when 
> going through stuff for this merge window.

Thanks for the advice.

Could you also keep an eye on this patch? 
https://lkml.org/lkml/2022/5/15/140 <https://lkml.org/lkml/2022/5/15/140>

>
> It's in for-next, which is still aimed at 5.19.
>
> Thanks!
>
>>
>> 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
>>>