Re: [PATCH v2 02/11] mm: ioremap: fixup the physical address and page prot

Christophe Leroy
2022-08-22T06:31:05Z

Le 20/08/2022 à 02:31, Baoquan He a écrit :
> On some architectures, the physical address need be fixed up before
> doing mapping, e.g, parisc. And on architectures, e.g arc, the
> parameter 'prot' passed into ioremap_prot() need be adjusted too.
>
> In oder to convert them to take GENERIC_IOREMAP method, we need wrap
> the address fixing up code and page prot adjusting code into arch_ioremap()
> and pass the new address and 'prot' out for ioremap_prot() handling.

Is it really the best approach ? Wouldn't it be better to have helpers
to do that, those helpers being called by the ioremap_prot(), instead of
doing it inside the arch_ioremap() function ?

>
> This is a preparation patch, no functionality change.

Could this be squashed into previous patch ?

>
> Signed-off-by: Baoquan He <bhe@redhat.com>
> ---
> arch/arm64/include/asm/io.h | 3 ++-
> arch/arm64/mm/ioremap.c | 5 +++--
> include/asm-generic/io.h | 4 ++--
> mm/ioremap.c | 2 +-
> 4 files changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
> index dd7e1c2dc86c..6a5578ddbbf6 100644
> --- a/arch/arm64/include/asm/io.h
> +++ b/arch/arm64/include/asm/io.h
> @@ -139,7 +139,8 @@ extern void __memset_io(volatile void __iomem *, int, size_t);
> * I/O memory mapping functions.
> */
>
> -void __iomem *arch_ioremap(phys_addr_t phys_addr, size_t size, unsigned long prot);
> +void __iomem *
> +arch_ioremap(phys_addr_t *paddr, size_t size, unsigned long *prot_val);
> #define arch_ioremap arch_ioremap
>
> #define _PAGE_IOREMAP PROT_DEVICE_nGnRE
> diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
> index b0f4cea86f0e..ef75ffef4dbc 100644
> --- a/arch/arm64/mm/ioremap.c
> +++ b/arch/arm64/mm/ioremap.c
> @@ -3,9 +3,10 @@
> #include <linux/mm.h>
> #include <linux/io.h>
>
> -void __iomem *arch_ioremap(phys_addr_t phys_addr, size_t size, unsigned long prot)
> +void __iomem *
> +arch_ioremap(phys_addr_t *paddr, size_t size, unsigned long *prot_val)
> {
> - unsigned long last_addr, offset;
> + unsigned long last_addr, offset, phys_addr = *paddr;
>
> offset = phys_addr & (~PAGE_MASK);
> phys_addr -= offset;
> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
> index 7b6bfb62ef80..fb9bda2be8ed 100644
> --- a/include/asm-generic/io.h
> +++ b/include/asm-generic/io.h
> @@ -1059,8 +1059,8 @@ static inline void iounmap(volatile void __iomem *addr)
> */
> #ifndef arch_ioremap
> #define arch_ioremap arch_ioremap
> -static inline void __iomem *arch_ioremap(phys_addr_t phys_addr, size_t size,
> - unsigned long prot)
> +static inline void __iomem *arch_ioremap(phys_addr_t *paddr, size_t size,
> + unsigned long *prot_val)
> {
> return NULL;
> }
> diff --git a/mm/ioremap.c b/mm/ioremap.c
> index 99fde69becc7..7914b5cf5b78 100644
> --- a/mm/ioremap.c
> +++ b/mm/ioremap.c
> @@ -19,7 +19,7 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
> struct vm_struct *area;
> void __iomem *ioaddr;
>
> - ioaddr = arch_ioremap(phys_addr, size, prot);
> + ioaddr = arch_ioremap(&phys_addr, size, &prot);
> if (IS_ERR(ioaddr))
> return NULL;
> else if (ioaddr)