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

[Xianting Tian]

在 2022/5/11 下午8:37, Xianting Tian 写道:
> 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 <jianghuaming.jhm@xxxxxxxxxxxxxxx>
> > > Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
> > > CC: Nick Kossifidis <mick@xxxxxxxxxxxx>
> > > Signed-off-by: Xianting Tian <xianting.tian@xxxxxxxxxxxxxxxxx>
> > > ---
> > >   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?

This is arm64 code, which doesn't add IORESOURCE_BUSY for no-map 
reserved memory,

arch/arm64/kernel/setup.c

        for_each_mem_region(region) {
                res = &standard_resources[i++];
                if (memblock_is_nomap(region)) {
                        res->name  = "reserved";
                        res->flags = IORESOURCE_MEM;
                        res->start = 
__pfn_to_phys(memblock_region_reserved_base_pfn(region));
                        res->end = 
__pfn_to_phys(memblock_region_reserved_end_pfn(region)) - 1;

> >