Re: [PATCH v3 1/3] riscv: Factorize xip and !xip kernel address conversion macros

Jisheng Zhang
2021-06-03T15:56:23Z

On Thu, 3 Jun 2021 17:51:25 +0200
Vitaly Wool <vitaly.wool@konsulko.com> wrote:

> On Thu, Jun 3, 2021, 14:57 Jisheng Zhang <jszhang3@mail.ustc.edu.cn> wrote:
> >
> > On Thu, 3 Jun 2021 20:27:48 +0800
> > Jisheng Zhang <jszhang3@mail.ustc.edu.cn> wrote:
> >
> > > On Thu, 3 Jun 2021 10:27:47 +0200
> > > Alexandre Ghiti <alex@ghiti.fr> wrote:
> > >
> > > > To simplify the kernel address conversion code, make the same definition of
> > > > kernel_mapping_pa_to_va and kernel_mapping_va_to_pa compatible for both xip
> > > > and !xip kernel by defining XIP_OFFSET to 0 in !xip kernel.
> > > >
> > > > Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
> > > > ---
> > > > arch/riscv/include/asm/page.h | 14 +++-----------
> > > > arch/riscv/include/asm/pgtable.h | 2 ++
> > > > 2 files changed, 5 insertions(+), 11 deletions(-)
> > > >
> > > > diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
> > > > index 6a7761c86ec2..6e004d8fda4d 100644
> > > > --- a/arch/riscv/include/asm/page.h
> > > > +++ b/arch/riscv/include/asm/page.h
> > > > @@ -93,9 +93,7 @@ extern unsigned long va_pa_offset;
> > > > #ifdef CONFIG_64BIT
> > > > extern unsigned long va_kernel_pa_offset;
> > > > #endif
> > > > -#ifdef CONFIG_XIP_KERNEL
> > > > extern unsigned long va_kernel_xip_pa_offset;
> > > > -#endif
> > > > extern unsigned long pfn_base;
> > > > #define ARCH_PFN_OFFSET (pfn_base)
> > > > #else
> > > > @@ -103,6 +101,7 @@ extern unsigned long pfn_base;
> > > > #ifdef CONFIG_64BIT
> > > > #define va_kernel_pa_offset 0
> > > > #endif
> > > > +#define va_kernel_xip_pa_offset 0
> > > > #define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT)
> > > > #endif /* CONFIG_MMU */
> > > >
> > > > @@ -110,29 +109,22 @@ extern unsigned long kernel_virt_addr;
> > > >
> > > > #ifdef CONFIG_64BIT
> > > > #define linear_mapping_pa_to_va(x) ((void *)((unsigned long)(x) + va_pa_offset))
> > > > -#ifdef CONFIG_XIP_KERNEL
> > > > #define kernel_mapping_pa_to_va(y) ({ \
> > > > unsigned long _y = y; \
> > > > (_y >= CONFIG_PHYS_RAM_BASE) ?
> > >
> > > This CONFIG_PHYS_RAM_BASE is only available for XIP, could result in a
> > > compiler error for !XIP?
> > >
> > > I'm also concerned with the unecessary overhead of kernel_mapping_pa_to_va()
> > > for !XIP case, there's a "if" condition branch, and extra symbol: va_kernel_xip_pa_offset
> >
> > Err, I just found this symobl always exists no matter XIP is enabled or not.
> > I will send out a patch for this clean up
>
> What cleanup?
>