On Sat, Jan 26, 2013 at 12:31:58AM +0000, Christoffer Dall wrote:
> When using LPAE the call to alloc_init_pte is passed then end address
> for the entire 1st level page table region, and the code unluckily ends
> up going over the bounds of the single allocated PTE, which is sad.
>
> This caused LPAE boot on omap5 to crash.
>
> There may be some hidden mystery in the boot code that I'm unaware of
> or it may be assumed that all mappings are always mappable as sections
> on LPAE and therefore omap5 just does something bad, in which case this
> patch isn't the right fix, but I'd be happy to be told the reason.
>
> Cc: Tony Lindgren <tony@xxxxxxxxxxx>
> Cc: Jeremy C. Andrus <jeremya@xxxxxxxxxxxxxxx>
> Signed-off-by: Christoffer Dall <chris@xxxxxxxxxxxx>
> ---
> arch/arm/mm/mmu.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index ce328c7..1cecc99 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -603,11 +603,13 @@ static void __init alloc_init_section(pud_t *pud, unsigned long addr,
>
> flush_pmd_entry(p);
> } else {
> - /*
> - * No need to loop; pte's aren't interested in the
> - * individual L1 entries.
> - */
> - alloc_init_pte(pmd, addr, end, __phys_to_pfn(phys), type);
> + unsigned long next;
> +
> + do {
> + next = pmd_addr_end(addr, end);
> + alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys), type);
> + phys += next - addr;
> + } while (pmd++, addr = next, addr != end);
I now noticed your patch (I'm a bit behind with the list). It looks to
me like it should work since next == end with the classic MMU, so we
only go through the loop once.
--
Catalin
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