Re: [RFC PATCH 3/8] mm/ioremap: Define generic_ioremap_prot() and generic_iounmap()

From: Alexander Gordeev
Date: Sun Oct 16 2022 - 04:15:47 EST


On Wed, Oct 12, 2022 at 12:09:39PM +0200, Christophe Leroy wrote:
> Define a generic version of ioremap_prot() and iounmap() that
> architectures can call after they have performed the necessary
> alteration to parameters and/or necessary verifications.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>

[...]

> diff --git a/mm/ioremap.c b/mm/ioremap.c
> index 8652426282cc..9f34a8f90b58 100644
> --- a/mm/ioremap.c
> +++ b/mm/ioremap.c
> @@ -11,8 +11,8 @@
> #include <linux/io.h>
> #include <linux/export.h>
>
> -void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
> - unsigned long prot)
> +void __iomem *generic_ioremap_prot(phys_addr_t phys_addr, size_t size,
> + pgprot_t prot)
> {
> unsigned long offset, vaddr;
> phys_addr_t last_addr;
> @@ -28,7 +28,7 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
> phys_addr -= offset;
> size = PAGE_ALIGN(size + offset);
>
> - if (!ioremap_allowed(phys_addr, size, prot))
> + if (!ioremap_allowed(phys_addr, size, pgprot_val(prot)))
> return NULL;

It seems to me ioremap_allowed() is not needed anymore.
Whatever is checked here would move to architecture-
specific implementation.

> area = get_vm_area_caller(size, VM_IOREMAP,
> @@ -38,17 +38,24 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
> vaddr = (unsigned long)area->addr;
> area->phys_addr = phys_addr;
>
> - if (ioremap_page_range(vaddr, vaddr + size, phys_addr,
> - __pgprot(prot))) {
> + if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
> free_vm_area(area);
> return NULL;
> }
>
> return (void __iomem *)(vaddr + offset);
> }
> +
> +#ifndef ioremap_prot

I guess, this is also needed:

#define ioremap_prot ioremap_prot

> +void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
> + unsigned long prot)
> +{
> + return generic_ioremap_prot(phys_addr, size, __pgprot(prot));
> +}
> EXPORT_SYMBOL(ioremap_prot);
> +#endif
>
> -void iounmap(volatile void __iomem *addr)
> +void generic_iounmap(volatile void __iomem *addr)
> {
> void *vaddr = (void *)((unsigned long)addr & PAGE_MASK);
>
> @@ -58,4 +65,11 @@ void iounmap(volatile void __iomem *addr)
> if (is_vmalloc_addr(vaddr))
> vunmap(vaddr);
> }
> +
> +#ifndef iounmap

Same here.

> +void iounmap(volatile void __iomem *addr)
> +{
> + generic_iounmap(addr);
> +}
> EXPORT_SYMBOL(iounmap);
> +#endif