From patchwork Fri Apr 14 13:11:26 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 750848 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3w4J3f06Xvz9s8C for ; Fri, 14 Apr 2017 23:12:30 +1000 (AEST) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3w4J3d5zFHzDqGr for ; Fri, 14 Apr 2017 23:12:29 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3w4J2W5GdrzDq7c for ; Fri, 14 Apr 2017 23:11:30 +1000 (AEST) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 3w4J2960J2z9ttwD; Fri, 14 Apr 2017 15:11:13 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id AdglDMyUuAxR; Fri, 14 Apr 2017 15:11:13 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 3w4J295TvDz9ttwC; Fri, 14 Apr 2017 15:11:13 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 005E48B7D6; Fri, 14 Apr 2017 15:11:26 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id JhfmVho76QBo; Fri, 14 Apr 2017 15:11:26 +0200 (CEST) Received: from PO15451.localdomain (po15451.idsi0.si.c-s.fr [172.25.231.16]) by messagerie.si.c-s.fr (Postfix) with ESMTP id D15488B767; Fri, 14 Apr 2017 15:11:26 +0200 (CEST) Received: by localhost.localdomain (Postfix, from userid 0) id AA07A67422; Fri, 14 Apr 2017 15:11:26 +0200 (CEST) From: Christophe Leroy Subject: [PATCH] powerpc/32: Fix protection of kernel RAM after freeing unused memory To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Scott Wood Message-Id: <20170414131126.AA07A67422@localhost.localdomain> Date: Fri, 14 Apr 2017 15:11:26 +0200 (CEST) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" As seen below, allthough the init sections have been freed, the associated memory area is still marked as executable in the page tables. This patch fixes that. [ 5.860093] Freeing unused kernel memory: 592K (c0570000 - c0604000) ---[ Start of kernel VM ]--- 0xc0000000-0xc0497fff 4704K rw X present dirty accessed shared 0xc0498000-0xc056ffff 864K rw present dirty accessed shared 0xc0570000-0xc059ffff 192K rw X present dirty accessed shared 0xc05a0000-0xc7ffffff 125312K rw present dirty accessed shared ---[ vmalloc() Area ]--- Signed-off-by: Christophe Leroy --- arch/powerpc/mm/mem.c | 3 +++ arch/powerpc/mm/mmu_decl.h | 1 + arch/powerpc/mm/pgtable_32.c | 20 ++++++++++++++++++++ 3 files changed, 24 insertions(+) diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 9ee536ec0739..e95931c4e6cf 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -401,6 +401,9 @@ void free_initmem(void) { ppc_md.progress = ppc_printk_progress; free_initmem_default(POISON_FREE_INITMEM); +#ifdef CONFIG_PPC32 + remap_init_ram(); +#endif } #ifdef CONFIG_BLK_DEV_INITRD diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h index f988db655e5b..d39d92600839 100644 --- a/arch/powerpc/mm/mmu_decl.h +++ b/arch/powerpc/mm/mmu_decl.h @@ -95,6 +95,7 @@ extern void _tlbia(void); extern void mapin_ram(void); extern int map_page(unsigned long va, phys_addr_t pa, int flags); +void remap_init_ram(void); extern void setbat(int index, unsigned long virt, phys_addr_t phys, unsigned int size, pgprot_t prot); diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c index a65c0b4c0669..d506bd61b629 100644 --- a/arch/powerpc/mm/pgtable_32.c +++ b/arch/powerpc/mm/pgtable_32.c @@ -323,6 +323,26 @@ get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp) return(retval); } +void remap_init_ram(void) +{ + unsigned long start = (unsigned long)_sinittext & PAGE_MASK; + unsigned long end = (unsigned long)_einittext; + unsigned long va; + + for (va = start; va < end; va += PAGE_SIZE) { + pte_t *kpte; + pmd_t *kpmd; + pte_t pte = pfn_pte(__pa(va) >> PAGE_SHIFT, PAGE_KERNEL); + + if (!get_pteptr(&init_mm, va, &kpte, &kpmd)) + continue; + __set_pte_at(&init_mm, va, kpte, pte, 0); + wmb(); + pte_unmap(kpte); + } + flush_tlb_kernel_range(start, end); +} + #ifdef CONFIG_DEBUG_PAGEALLOC static int __change_page_attr(struct page *page, pgprot_t prot)