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

[Xianting Tian]

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?

>