[PATCH v2 1/1] ARM: LPAE: Fix mapping in alloc_init_pte for unaligned addresses.

[R, Sricharan]

Hi,
On Fri, Aug 17, 2012 at 4:32 PM, R, Sricharan <r.sricharan at ti.com> wrote:
> Hi,
>
>> With LPAE, When either the start address or end address
>> or physical address to be mapped is unaligned,
>> alloc_init_section creates page granularity mappings.
>> alloc_init_section calls alloc_init_pte which populates
>> one pmd entry and sets up the ptes. But if the size is
>> greater than what can be mapped by one pmd entry,
>> then the rest remains unmapped.
>>
>> The issue becomes visible when LPAE is enabled, where we have
>> the 3 levels with seperate pgd and pmd's.
>> When a static mapping for 3MB is requested, only 2MB is mapped
>> and the remaining 1MB is unmapped. Fixing this here, by looping
>> in to map the entire unaligned address range.
>>
>> Boot tested on OMAP5 evm with both LPAE enabled/disabled
>> and verified that static mappings with unaligned addresses
>> are properly mapped.
>>
>> Signed-off-by: R Sricharan <r.sricharan at ti.com>
>> Reviewed-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
>> Cc: Catalin Marinas <catalin.marinas at arm.com>
>> ---
>> [V2] Moved the loop to alloc_init_pte as per Russell's
>>      feedback and changed the subject accordingly.
>>      Using PMD_XXX instead of SECTION_XXX to avoid
>>      different loop increments with/without LPAE.
>>
>>  arch/arm/mm/mmu.c |   22 ++++++++++++++++++----
>>  1 file changed, 18 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
>> index cf4528d..0ed8808 100644
>> --- a/arch/arm/mm/mmu.c
>> +++ b/arch/arm/mm/mmu.c
>> @@ -585,11 +585,25 @@ static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
>>                                   unsigned long end, unsigned long pfn,
>>                                   const struct mem_type *type)
>>  {
>> -       pte_t *pte = early_pte_alloc(pmd, addr, type->prot_l1);
>> +       unsigned long next;
>> +       pte_t *pte;
>> +       phys_addr_t phys;
>> +
>>         do {
>> -               set_pte_ext(pte, pfn_pte(pfn, __pgprot(type->prot_pte)), 0);
>> -               pfn++;
>> -       } while (pte++, addr += PAGE_SIZE, addr != end);
>> +               if ((end-addr) & PMD_MASK)
>> +                       next = (addr + PMD_SIZE) & PMD_MASK;
>> +               else
>> +                       next = end;
>> +
>> +               pte = early_pte_alloc(pmd, addr, type->prot_l1);
>> +               do {
>> +                       set_pte_ext(pte, pfn_pte(pfn,
>> +                                       __pgprot(type->prot_pte)), 0);
>> +                       pfn++;
>> +               } while (pte++, addr += PAGE_SIZE, addr != next);
>> +
>> +               phys += next - addr;
>> +       } while (pmd++, addr = next, addr != end);
>>  }
>>
>   ping..

  Ping again.
  The issue is reproducible in mainline with CMA + LPAE enabled.
  CMA tries to reserve/map 16 MB with 2 level table entries and
   crashes in alloc_init_pte.

  This patch fixes that. Just posted a V3 of the same patch.

         https://patchwork.kernel.org/patch/1472031/


Thanks,
 Sricharan