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

[Xianting Tian]

在 2022/6/2 下午1:57, Palmer Dabbelt 写道:
> On Sun, 29 May 2022 19:47:51 PDT (-0700), guoren@xxxxxxxxxx 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@xxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx>
> > > Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
> > > Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>
> > > Tested-by: Heiko Stuebner <heiko@xxxxxxxxx>
> > > Co-developed-by: Nick Kossifidis <mick@xxxxxxxxxxxx>
> > > Signed-off-by: Xianting Tian <xianting.tian@xxxxxxxxxxxxxxxxx>
> > > ---
> > > 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