On 04/02/2013 05:28 AM, Frantisek Hrbata wrote:
>
> diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
> index d8e8eef..39607c6 100644
> --- a/arch/x86/include/asm/io.h
> +++ b/arch/x86/include/asm/io.h
> @@ -242,6 +242,10 @@ static inline void flush_write_buffers(void)
> #endif
> }
>
> +#define ARCH_HAS_VALID_PHYS_ADDR_RANGE
> +extern int valid_phys_addr_range(phys_addr_t addr, size_t count);
> +extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t count);
> +
> #endif /* __KERNEL__ */
>
> extern void native_io_delay(void);
> diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
> index 845df68..92ec31c 100644
> --- a/arch/x86/mm/mmap.c
> +++ b/arch/x86/mm/mmap.c
> @@ -31,6 +31,8 @@
> #include <linux/sched.h>
> #include <asm/elf.h>
>
> +#include "physaddr.h"
> +
> struct __read_mostly va_alignment va_align = {
> .flags = -1,
> };
> @@ -122,3 +124,14 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
> mm->unmap_area = arch_unmap_area_topdown;
> }
> }
> +
> +int valid_phys_addr_range(phys_addr_t addr, size_t count)
> +{
> + return addr + count <= __pa(high_memory);
> +}
> +
> +int valid_mmap_phys_addr_range(unsigned long pfn, size_t count)
> +{
> + resource_size_t addr = (pfn << PAGE_SHIFT) + count;
> + return phys_addr_valid(addr);
> +}
>
Good initiative, but I think the implementation is worong. I suspect we
should use the number of physical address bits supported rather than
high_memory, since it is common and legal to use /dev/mem to access I/O
resources that are beyond the last byte of RAM.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
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