From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp06.in.ibm.com (e28smtp06.in.ibm.com [122.248.162.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e28smtp06.in.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 5ECE92C0094 for ; Fri, 22 Feb 2013 03:48:08 +1100 (EST) Received: from /spool/local by e28smtp06.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 21 Feb 2013 22:15:05 +0530 Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id B4F50394004E for ; Thu, 21 Feb 2013 22:18:02 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay02.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r1LGm0WB21299398 for ; Thu, 21 Feb 2013 22:18:00 +0530 Received: from d28av02.in.ibm.com (loopback [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r1LGlvBY011344 for ; Fri, 22 Feb 2013 03:48:01 +1100 From: "Aneesh Kumar K.V" To: benh@kernel.crashing.org, paulus@samba.org Subject: [RFC PATCH -V2 17/21] powerpc/THP: Differentiate THP PMD entries from HUGETLB PMD entries Date: Thu, 21 Feb 2013 22:17:24 +0530 Message-Id: <1361465248-10867-18-git-send-email-aneesh.kumar@linux.vnet.ibm.com> In-Reply-To: <1361465248-10867-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1361465248-10867-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, "Aneesh Kumar K.V" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "Aneesh Kumar K.V" HUGETLB clear the top bit of PMD entries and use that to indicate a HUGETLB page directory. Since we store pfns in PMDs for THP, we would have the top bit cleared by default. Add the top bit mask for THP PMD entries and clear that when we are looking for pmd_pfn. Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/include/asm/pgtable.h | 15 ++++++++++++--- arch/powerpc/mm/pgtable.c | 5 ++++- arch/powerpc/mm/pgtable_64.c | 2 +- 3 files changed, 17 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h index ca1848a..5b8e93b 100644 --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h @@ -31,7 +31,7 @@ struct mm_struct; #define PMD_HUGE_EXEC 0x004 /* No execute on POWER4 and newer (we invert) */ #define PMD_HUGE_SPLITTING 0x008 #define PMD_HUGE_HASHPTE 0x010 -#define PMD_ISHUGE 0x020 +#define _PMD_ISHUGE 0x020 #define PMD_HUGE_DIRTY 0x080 /* C: page changed */ #define PMD_HUGE_ACCESSED 0x100 /* R: page referenced */ #define PMD_HUGE_RW 0x200 /* software: user write access allowed */ @@ -44,6 +44,14 @@ struct mm_struct; #define PMD_HUGE_RPN_SHIFT PTE_RPN_SHIFT #define HUGE_PAGE_SIZE (ASM_CONST(1) << 24) #define HUGE_PAGE_MASK (~(HUGE_PAGE_SIZE - 1)) +/* + * HugeTLB looks at the top bit of the Linux page table entries to + * decide whether it is a huge page directory or not. Mark HUGE + * PMD to differentiate + */ +#define PMD_HUGE_NOT_HUGETLB (ASM_CONST(1) << 63) +#define PMD_ISHUGE (_PMD_ISHUGE | PMD_HUGE_NOT_HUGETLB) +#define PMD_HUGE_PROTBITS (0xfff | PMD_HUGE_NOT_HUGETLB) #ifndef __ASSEMBLY__ extern void hpte_need_hugepage_flush(struct mm_struct *mm, unsigned long addr, @@ -61,7 +69,8 @@ static inline unsigned long pmd_pfn(pmd_t pmd) /* * Only called for huge page pmd */ - return pmd_val(pmd) >> PMD_HUGE_RPN_SHIFT; + unsigned long val = pmd_val(pmd) & ~PMD_HUGE_PROTBITS; + return val >> PMD_HUGE_RPN_SHIFT; } static inline int pmd_young(pmd_t pmd) @@ -95,7 +104,7 @@ static inline int pmd_trans_splitting(pmd_t pmd) static inline int pmd_trans_huge(pmd_t pmd) { - return pmd_val(pmd) & PMD_ISHUGE; + return ((pmd_val(pmd) & PMD_ISHUGE) == PMD_ISHUGE); } /* We will enable it in the last patch */ diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c index d117982..ef91331 100644 --- a/arch/powerpc/mm/pgtable.c +++ b/arch/powerpc/mm/pgtable.c @@ -528,7 +528,10 @@ static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot) pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot) { pmd_t pmd; - + /* + * We cannot support that many PFNs + */ + VM_BUG_ON(pfn & PMD_HUGE_NOT_HUGETLB); pmd_val(pmd) = pfn << PMD_HUGE_RPN_SHIFT; /* * pgtable_t is always 4K aligned, even in case where we use the diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index 3dc131d..5f22232 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -346,7 +346,7 @@ EXPORT_SYMBOL(__iounmap_at); struct page *pmd_page(pmd_t pmd) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE - if (pmd_val(pmd) & PMD_ISHUGE) + if ((pmd_val(pmd) & PMD_ISHUGE) == PMD_ISHUGE) return pfn_to_page(pmd_pfn(pmd)); #endif return virt_to_page(pmd_page_vaddr(pmd)); -- 1.7.10