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Date: Fri, 16 May 2014 07:17:37 +0000
From: "Li.Xiubo@...escale.com" <Li.Xiubo@...escale.com>
To: Richard Lee <superlibj8301@...il.com>,
Nicolas Pitre <nicolas.pitre@...aro.org>
CC: Russell King - ARM Linux <linux@....linux.org.uk>,
"iamjoonsoo.kim@....com" <iamjoonsoo.kim@....com>,
"santosh.shilimkar@...com" <santosh.shilimkar@...com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
Arnd Bergmann <arnd@...db.de>,
"robherring2@...il.com" <robherring2@...il.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"lauraa@...eaurora.org" <lauraa@...eaurora.org>
Subject: RE: [PATCHv2] ARM: ioremap: Fix static vm area boundary checking.
> Subject: Re: [PATCHv2] ARM: ioremap: Fix static vm area boundary checking.
>
> On Fri, May 16, 2014 at 1:28 AM, Nicolas Pitre <nicolas.pitre@...aro.org>
> wrote:
> > On Thu, 15 May 2014, Richard Lee wrote:
> >
> >> 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>
> >
> > instead of doing this repeatedly, why not simply ensure the recorded
> > static vm information is already page aligned in the first place?
> >
>
> Sorry, I'm not very sure what vm information you meant here.
>
> And the 'svm->vm->addr' and 'svm->vm->size' are all page aligned
> already, but we cannot make sure that the 'paddr' and
> 'svm->vm->phys_addr' are page aligned.
>
The paddr and svm->vm->phys_addr are all already pfn aligned here.
What we should fix about is the boundary of them.
Thanks,
BRs
Xiubo
>
> Thanks,
>
> BRs
> Richard Lee
>
> >
> >
> >> ---
> >>
> >>
> >> Change in V2:
> >> - PAGE_SIZE --> PAGE_MASK
> >> - remove the 'size' page size align operation.
> >>
> >>
> >>
> >>
> >>
> >>
> >> arch/arm/mm/ioremap.c | 40 ++++++++++++++++++++++++++++++++++++++--
> >> 1 file changed, 38 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
> >> index be69333..f235ab7 100644
> >> --- a/arch/arm/mm/ioremap.c
> >> +++ b/arch/arm/mm/ioremap.c
> >> @@ -47,16 +47,52 @@ static struct static_vm
> *find_static_vm_paddr(phys_addr_t paddr,
> >> {
> >> struct static_vm *svm;
> >> struct vm_struct *vm;
> >> + size_t offset;
> >> +
> >> + offset = paddr & ~PAGE_MASK;
> >>
> >> 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_MASK;
> >> + 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
> >>
--
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