From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f71.google.com (mail-it0-f71.google.com [209.85.214.71]) by kanga.kvack.org (Postfix) with ESMTP id AD7926B0253 for ; Tue, 12 Jul 2016 01:02:02 -0400 (EDT) Received: by mail-it0-f71.google.com with SMTP id g8so14984084itb.2 for ; Mon, 11 Jul 2016 22:02:02 -0700 (PDT) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com. [119.145.14.65]) by mx.google.com with ESMTPS id z136si1025437itc.1.2016.07.11.22.02.00 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 11 Jul 2016 22:02:01 -0700 (PDT) From: zhongjiang Subject: [PATCH 2/2] kexec: add a pmd huge entry condition during the page table Date: Tue, 12 Jul 2016 12:56:43 +0800 Message-ID: <1468299403-27954-2-git-send-email-zhongjiang@huawei.com> In-Reply-To: <1468299403-27954-1-git-send-email-zhongjiang@huawei.com> References: <1468299403-27954-1-git-send-email-zhongjiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: ebiederm@xmission.com, dyoung@redhat.com, horms@verge.net.au, vgoyal@redhat.com, yinghai@kernel.org, akpm@linux-foundation.org Cc: kexec@lists.infradead.org, linux-mm@kvack.org From: zhong jiang when image is loaded into kernel, we need set up page table for it. and all valid pfn also set up new mapping. it will tend to establish a pmd page table in the form of a large page if pud_present is true. relocate_kernel points to code segment can locate in the pmd huge entry in init_transtion_pgtable. therefore, we need to take the situation into account. Signed-off-by: zhong jiang --- arch/x86/kernel/machine_kexec_64.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index 5a294e4..c33e344 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -34,6 +35,17 @@ static struct kexec_file_ops *kexec_file_loaders[] = { }; #endif +static void split_pmd(pmd_t *pmd, pte_t *pte) +{ + unsigned long pfn = pmd_pfn(*pmd); + int i = 0; + + do { + set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC)); + pfn++; + } while (pte++, i++, i < PTRS_PER_PTE); +} + static void free_transition_pgtable(struct kimage *image) { free_page((unsigned long)image->arch.pud); @@ -68,15 +80,19 @@ static int init_transition_pgtable(struct kimage *image, pgd_t *pgd) set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); } pmd = pmd_offset(pud, vaddr); - if (!pmd_present(*pmd)) { + if (!pmd_present(*pmd) || pmd_huge(*pmd)) { pte = (pte_t *)get_zeroed_page(GFP_KERNEL); if (!pte) goto err; image->arch.pte = pte; - set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); + if (pmd_huge(*pmd)) + split_pmd(pmd, pte); + else + set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); } pte = pte_offset_kernel(pmd, vaddr); set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC)); + return 0; err: free_transition_pgtable(image); -- 1.8.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org