From mboxrd@z Thu Jan 1 00:00:00 1970 From: lauraa@codeaurora.org (Laura Abbott) Date: Fri, 15 Mar 2013 07:50:27 -0700 Subject: [PATCH v2 1/1] ARM: LPAE: Fix mapping in alloc_init_pte for unaligned addresses. In-Reply-To: <5142C6AB.7030402@ti.com> References: <1344238885-13683-1-git-send-email-r.sricharan@ti.com> <514230C5.4010502@codeaurora.org> <5142C6AB.7030402@ti.com> Message-ID: <51433533.3090408@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Laura > Regards, > Sricharan > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation