From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id C75406B000D for ; Wed, 14 Mar 2018 14:11:31 -0400 (EDT) Received: by mail-pg0-f72.google.com with SMTP id s8so1747131pgf.16 for ; Wed, 14 Mar 2018 11:11:31 -0700 (PDT) Received: from g4t3426.houston.hpe.com (g4t3426.houston.hpe.com. [15.241.140.75]) by mx.google.com with ESMTPS id h1-v6si2338138pld.16.2018.03.14.11.11.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 14 Mar 2018 11:11:30 -0700 (PDT) From: Toshi Kani Subject: [PATCH v2 2/2] x86/mm: implement free pmd/pte page interfaces Date: Wed, 14 Mar 2018 12:01:55 -0600 Message-Id: <20180314180155.19492-3-toshi.kani@hpe.com> In-Reply-To: <20180314180155.19492-1-toshi.kani@hpe.com> References: <20180314180155.19492-1-toshi.kani@hpe.com> Sender: owner-linux-mm@kvack.org List-ID: To: mhocko@suse.com, akpm@linux-foundation.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, bp@suse.de, catalin.marinas@arm.com Cc: guohanjun@huawei.com, will.deacon@arm.com, wxf.wang@hisilicon.com, willy@infradead.org, cpandya@codeaurora.org, linux-mm@kvack.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Toshi Kani , stable@vger.kernel.org Implement pud_free_pmd_page() and pmd_free_pte_page() on x86, which clear a given pud/pmd entry and free up lower level page table(s). Address range associated with the pud/pmd entry must have been purged by INVLPG. fixes: e61ce6ade404e ("mm: change ioremap to set up huge I/O mappings") Signed-off-by: Toshi Kani Cc: Michal Hocko Cc: Andrew Morton Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Borislav Petkov Cc: Matthew Wilcox Cc: --- arch/x86/mm/pgtable.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 1eed7ed518e6..34cda7e0551b 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -712,7 +712,22 @@ int pmd_clear_huge(pmd_t *pmd) */ int pud_free_pmd_page(pud_t *pud) { - return pud_none(*pud); + pmd_t *pmd; + int i; + + if (pud_none(*pud)) + return 1; + + pmd = (pmd_t *)pud_page_vaddr(*pud); + + for (i = 0; i < PTRS_PER_PMD; i++) + if (!pmd_free_pte_page(&pmd[i])) + return 0; + + pud_clear(pud); + free_page((unsigned long)pmd); + + return 1; } /** @@ -724,6 +739,15 @@ int pud_free_pmd_page(pud_t *pud) */ int pmd_free_pte_page(pmd_t *pmd) { - return pmd_none(*pmd); + pte_t *pte; + + if (pmd_none(*pmd)) + return 1; + + pte = (pte_t *)pmd_page_vaddr(*pmd); + pmd_clear(pmd); + free_page((unsigned long)pte); + + return 1; } #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */