[External] Re: [PATCH] RISC-V: ACPI: fix early_ioremap to early_memremap

[yunhui cui]

Hi Alex,

On Mon, Oct 14, 2024 at 8:12 PM Alexandre Ghiti <alex at ghiti.fr> wrote:
>
> Hi Yunhui,
>
> On 14/10/2024 11:47, Yunhui Cui wrote:
> > When SVPBMT is enabled, __acpi_map_table() will directly access the
> > data in DDR through the IO attribute, rather than through hardware
> > cache consistency, resulting in incorrect data in the obtained ACPI
> > table.
> >
> > The log: ACPI: [ACPI:0x18] Invalid zero length.
> >
> > We do not assume whether the bootloader flushes or not. We should
> > access in a cacheable way instead of maintaining cache consistency
> > by software.
> >
> > Signed-off-by: Yunhui Cui <cuiyunhui at bytedance.com>
> > ---
> >   arch/riscv/kernel/acpi.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/kernel/acpi.c b/arch/riscv/kernel/acpi.c
> > index 6e0d333f57e5..3177c9af8764 100644
> > --- a/arch/riscv/kernel/acpi.c
> > +++ b/arch/riscv/kernel/acpi.c
> > @@ -210,7 +210,7 @@ void __init __iomem *__acpi_map_table(unsigned long phys, unsigned long size)
> >       if (!size)
> >               return NULL;
> >
> > -     return early_ioremap(phys, size);
> > +     return early_memremap(phys, size);
> >   }
> >
> >   void __init __acpi_unmap_table(void __iomem *map, unsigned long size)
>
>
> It makes sense to me since with this, we don't have to care about how
> the firmware mapped the table. And it mimics all other architectures
> (arm64, loongarch and x86).
>
> Here is the corresponding fixes tag:
>
> Fixes: 3b426d4b5b14 ("RISC-V: ACPI : Fix for usage of pointers in
> different address space")
>
> With the corresponding fix in __acpi_unmap_table() as pointed by Sunil,
> you can add:
>
> Reviewed-by: Alexandre Ghiti <alexghiti at rivosinc.com>
>
> And regarding the sparse error, I don't see any other architecture
> casting to __iomem, so maybe that's not necessary anymore?

OK. I will make the changes in v2. Regarding the sparse error, I will
use another patch specifically to solve it. Is that okay?

>
> Thanks,
>
> Alex
>
>

Thanks,
Yunhui