From mboxrd@z Thu Jan 1 00:00:00 1970 From: r.sricharan@ti.com (Sricharan R) Date: Fri, 15 Mar 2013 20:30:52 +0530 Subject: [PATCH v2 1/1] ARM: LPAE: Fix mapping in alloc_init_pte for unaligned addresses. In-Reply-To: <51433533.3090408@codeaurora.org> References: <1344238885-13683-1-git-send-email-r.sricharan@ti.com> <514230C5.4010502@codeaurora.org> <5142C6AB.7030402@ti.com> <51433533.3090408@codeaurora.org> Message-ID: <514337A4.8060706@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 15 March 2013 08:20 PM, Laura Abbott wrote: > On 3/14/2013 11:58 PM, Sricharan R wrote: >> Hi, >> On Friday 15 March 2013 01:49 AM, Laura Abbott wrote: >>> On 3/13/2013 10:14 PM, Catalin Marinas wrote: >>>> (sorry for if you got this message twice, gmail's new reply method >>>> decided to send html) >>>> >>>> On 18 September 2012 12:52, R, Sricharan wrote: >>>>> Hi, >>>>> On Fri, Aug 17, 2012 at 4:32 PM, R, Sricharan 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 >>>>>>> Reviewed-by: Santosh Shilimkar >>>>>>> Cc: Catalin Marinas >>>>>>> --- >>>>>>> [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/ >>>> >>>> I thought there was another patch where the looping was in an >>>> alloc_init_pmd() function, or there are just two different threads. I >>>> acked the other but not this one as I don't think looping over pmd >>>> inside the alloc_init_pte() function is the right thing. >>>> >>> >>> I submitted a patch last week for what I think is the same issue ("arm: mm: Populate initial page tables across sections") but I don't think I ever saw any feedback on the patch. Do we have three patches floating around fixing the same issue? >>> >>> Laura >>> >> your patch is looking like the intial version that i posted. So after some reviews, >> finally ended up with the below patch [1]. Can you please check if your issue gets >> fixed with this. >> >> [1] http://permalink.gmane.org/gmane.linux.ports.arm.kernel/216880 >> > > The patch does fix the problem for me as well. You are welcome to add > > Tested-by Laura Abbott > Thanks for testing and will add . Regards, Sricharan