From mboxrd@z Thu Jan 1 00:00:00 1970 From: r.sricharan@ti.com (Sricharan R) Date: Fri, 15 Mar 2013 12:28:51 +0530 Subject: [PATCH v2 1/1] ARM: LPAE: Fix mapping in alloc_init_pte for unaligned addresses. In-Reply-To: <514230C5.4010502@codeaurora.org> References: <1344238885-13683-1-git-send-email-r.sricharan@ti.com> <514230C5.4010502@codeaurora.org> Message-ID: <5142C6AB.7030402@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Regards, Sricharan