linux-kernel - Re: [PATCH] ARM: ioremap: Fix static vm area boundary checking.

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Date:	Thu, 15 May 2014 17:02:11 +0800
From:	Richard Lee <superlibj8301@...il.com>
To:	"Li.Xiubo@...escale.com" <Li.Xiubo@...escale.com>
Cc:	"linux@....linux.org.uk" <linux@....linux.org.uk>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"arnd@...db.de" <arnd@...db.de>,
	"robherring2@...il.com" <robherring2@...il.com>,
	"lauraa@...eaurora.org" <lauraa@...eaurora.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ARM: ioremap: Fix static vm area boundary checking.

 On Thu, May 15, 2014 at 4:55 PM, Li.Xiubo@...escale.com
<Li.Xiubo@...escale.com> wrote:
>> Subject: [PATCH] ARM: ioremap: Fix static vm area boundary checking.
>>
>> Static vm area boundary check:
>>
>>       paddr1 --->|       |
>>                  |       |
>>                  |-------| <-\--- svm->vm->addr(is page aligned)
>>       paddr2 --->|       |    |
>>                  |     --| <--|-- svm->vm->phys_addr
>>                  |       |    |
>>       paddr3 --->|       |    |
>>                  |       |    |
>>                  |-------| <--|-- next page boundary
>>                  |       |    |
>>       paddr4 --->|       |    | <----- svm->vm->size(including guard page)
>>                  |       |    |
>>                  |       |    |
>> max paddr_end -->|-------| <--|-- svm->vm's phys_addr_end
>>                  | ///// |    |
>>       paddr5 --->| guard |    |
>>                  | page  |    |
>>                  | ///// |    |
>>                   -------  <-/--- svm->vm->addr + svm->vm_size
>>
>> <1> If the paddr == paddr1, then continue;
>> <2> If the paddr == paddr2~paddr4 and paddr_end > phys_addr_end,
>>     then continue;
>> <3> if the paddr >= paddr5 then continue;
>>
>> Signed-off-by: Richard Lee <superlibj8301@...il.com>
>> ---
>>  arch/arm/mm/ioremap.c | 44 ++++++++++++++++++++++++++++++++++++++++++--
>>  1 file changed, 42 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
>> index be69333..2fa41f4 100644
>> --- a/arch/arm/mm/ioremap.c
>> +++ b/arch/arm/mm/ioremap.c
>> @@ -47,16 +47,56 @@ static struct static_vm *find_static_vm_paddr(phys_addr_t
>> paddr,
>>  {
>>       struct static_vm *svm;
>>       struct vm_struct *vm;
>> +     size_t offset;
>> +
>> +     /*
>> +      * Make sure the size the mapping size is page aligned.
>> +      */
>> +     size = PAGE_ALIGN((paddr & ~PAGE_SIZE) + size);
>> +     offset = paddr & ~PAGE_SIZE;
>>
>
> Shouldn't it be PAGE_MASK ?
>

Yes, it is. I'll fix it.

Thanks,

Best regards,
Richard Lee

>
>>       list_for_each_entry(svm, &static_vmlist, list) {
>> +             phys_addr_t paddr_end, phys_addr_end;
>> +             size_t vmoff;
>> +
>>               vm = &svm->vm;
>>               if (!(vm->flags & VM_ARM_STATIC_MAPPING))
>>                       continue;
>>               if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
>>                       continue;
>>
>> -             if (vm->phys_addr > paddr ||
>> -                     paddr + size - 1 > vm->phys_addr + vm->size - 1)
>> +             /* Static vm area boundary check:
>> +              *
>> +              *       paddr1 --->|       |
>> +              *                  |       |
>> +              *                  |-------| <-\--- svm->vm->addr(page aligned)
>> +              *       paddr2 --->|       |    |
>> +              *                  |     --| <--|-- svm->vm->phys_addr
>> +              *                  |       |    |
>> +              *       paddr3 --->|       |    |
>> +              *                  |       |    |
>> +              *                  |-------| <--|-- next page boundary
>> +              *                  |       |    |
>> +              *       paddr4 --->|       |    | <----- svm->vm->size,
>> +              *                  |       |    |         including guard page
>> +              *                  |       |    |
>> +              * max paddr_end -->|-------| <--|-- svm->vm's phys_addr_end
>> +              *                  | ///// |    |
>> +              *       paddr5 --->| guard |    |
>> +              *                  | page  |    |
>> +              *                  | ///// |    |
>> +              *                   -------  <-/-- svm->vm->addr + svm->vm_size
>> +              *
>> +              * <1> If paddr == paddr1, then continue;
>> +              * <2> If paddr == paddr2~paddr4 and paddr_end > phys_addr_end,
>> +              *     then continue;
>> +              * <3> if paddr >= paddr5 then continue;
>> +              */
>> +             vmoff = vm->phys_addr & ~PAGE_SIZE;
>
> And here.
>
> Thanks,
> BRs
> Xiubo
>
>> +             phys_addr_end = vm->phys_addr + vm->size - PAGE_SIZE - vmoff;
>> +             paddr_end = paddr + size - offset;
>> +             if (__phys_to_pfn(vm->phys_addr) > __phys_to_pfn(paddr) ||
>> +                     paddr_end - 1 > phys_addr_end - 1)
>>                       continue;
>>
>>               return svm;
>> --
>> 1.8.4
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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