From mboxrd@z Thu Jan 1 00:00:00 1970 From: lauraa@codeaurora.org (Laura Abbott) Date: Thu, 14 Mar 2013 13:19:17 -0700 Subject: [PATCH v2 1/1] ARM: LPAE: Fix mapping in alloc_init_pte for unaligned addresses. In-Reply-To: References: <1344238885-13683-1-git-send-email-r.sricharan@ti.com> Message-ID: <514230C5.4010502@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation