I'd like to put the code into asm/io.h, and make it static.
> +#ifdef CONFIG_STRICT_DEVMEM
> +/*
> + * devmem_is_allowed() checks to see if /dev/mem access to a certain
> + * address is valid. The argument is a physical page number.
> + * We mimic x86 here by disallowing access to system RAM as well as
> + * device-exclusive MMIO regions. This effectively disable read()/write()
> + * on /dev/mem.
> + */
> +static int devmem_is_allowed(unsigned long pfn)
> +{
> + if (iomem_is_exclusive(pfn << PAGE_SHIFT))
> + return 0;
> + if (!page_is_ram(pfn))
> + return 1;
> + return 0;
> +}
> +#endif /* CONFIG_STRICT_DEVMEM */
Thanks,
Acked-by: Xuetao Guan <g...@mprc.pku.edu.cn>
----- Chen Gang <gang.chen.5...@gmail.com> 写道：
> unicore32 supports STRICT_DEVMEM, so it needs devmem_is_allowed(), like
> some of other architectures have done (e.g. arm, powerpc, x86 ...).
>
> The related error with allmodconfig:
>
> CC drivers/char/mem.o
> drivers/char/mem.c: In function ‘range_is_allowed’:
> drivers/char/mem.c:69: error: implicit declaration of function
> ‘devmem_is_allowed’
> make[2]: *** [drivers/char/mem.o] Error 1
> make[1]: *** [drivers/char] Error 2
> make: *** [drivers] Error 2
>
>
> Signed-off-by: Chen Gang <gang.chen.5...@gmail.com>
> ---
> arch/unicore32/include/asm/page.h | 4 ++++
> arch/unicore32/mm/init.c | 18 ++++++++++++++++++
> 2 files changed, 22 insertions(+)
>
> diff --git a/arch/unicore32/include/asm/page.h
> b/arch/unicore32/include/asm/page.h
> index 594b322..231cb89 100644
> --- a/arch/unicore32/include/asm/page.h
> +++ b/arch/unicore32/include/asm/page.h
> @@ -68,6 +68,10 @@ typedef struct page *pgtable_t;
>
> extern int pfn_valid(unsigned long);
>
> +#ifdef CONFIG_STRICT_DEVMEM
> +extern int devmem_is_allowed(unsigned long pfn);
> +#endif /* CONFIG_STRICT_DEVMEM */
> +
> #include <asm/memory.h>
>
> #endif /* !__ASSEMBLY__ */
> diff --git a/arch/unicore32/mm/init.c b/arch/unicore32/mm/init.c
> index be2bde9..3bc3a59 100644
> --- a/arch/unicore32/mm/init.c
> +++ b/arch/unicore32/mm/init.c
> @@ -449,3 +449,21 @@ static int __init keepinitrd_setup(char *__unused)
>
> __setup("keepinitrd", keepinitrd_setup);
> #endif
> +
> +#ifdef CONFIG_STRICT_DEVMEM
> +/*
> + * devmem_is_allowed() checks to see if /dev/mem access to a certain
> + * address is valid. The argument is a physical page number.
> + * We mimic x86 here by disallowing access to system RAM as well as
> + * device-exclusive MMIO regions. This effectively disable read()/write()
> + * on /dev/mem.
> + */
> +int devmem_is_allowed(unsigned long pfn)
> +{
> + if (iomem_is_exclusive(pfn << PAGE_SHIFT))
> + return 0;
> + if (!page_is_ram(pfn))
> + return 1;
> + return 0;
> +}
> +#endif /* CONFIG_STRICT_DEVMEM */
> --
> 1.7.9.5
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