Re: [PATCH] x86: add phys addr validity check for /dev/mem mmap

[Simon Jeons]

Hi H.Peter,
On 04/03/2013 02:48 AM, H. Peter Anvin wrote:
> 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);
> > +}

Why we consider boot_cpu_data.x86_phys_bits instead of e820 map here?

> 	-hpa

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