Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755637AbaKSBov (ORCPT ); Tue, 18 Nov 2014 20:44:51 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:43635 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753919AbaKSBoq (ORCPT ); Tue, 18 Nov 2014 20:44:46 -0500 From: Yinghai Lu To: Kees Cook , Andrew Morton , Thomas Gleixner , "H. Peter Anvin" , Ingo Molnar Cc: Andy Lutomirski , Toshi Kani , Yasuaki Ishimatsu , David Vrabel , Wang Nan , linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH 3/4] x86, 64bit: remove highmap for not needed ranges Date: Tue, 18 Nov 2014 17:44:16 -0800 Message-Id: <1416361456-11060-3-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.8.4.5 In-Reply-To: <1416361456-11060-1-git-send-email-yinghai@kernel.org> References: <1416361456-11060-1-git-send-email-yinghai@kernel.org> X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org add cleanup_highmap_late to remove highmap for initmem, around rodata, and [_brk_end, all_end). Kernel Layout: [ 0.000000] .text: [0x01000000-0x0200df88] [ 0.000000] .rodata: [0x02200000-0x02a1dfff] [ 0.000000] .data: [0x02c00000-0x02e510ff] [ 0.000000] .init: [0x02e53000-0x03213fff] [ 0.000000] .bss: [0x03222000-0x0437cfff] [ 0.000000] .brk: [0x0437d000-0x043a2fff] Actually used brk: [ 0.270365] memblock_reserve: [0x0000000437d000-0x00000004383fff] flags 0x0 BRK Before patch: ---[ High Kernel Mapping ]--- ---[ High Kernel Mapping ]--- 0xffffffff80000000-0xffffffff81000000 16M pmd 0xffffffff81000000-0xffffffff82000000 16M ro PSE GLB x pmd 0xffffffff82000000-0xffffffff82011000 68K ro GLB x pte 0xffffffff82011000-0xffffffff82200000 1980K RW GLB x pte 0xffffffff82200000-0xffffffff82a00000 8M ro PSE GLB NX pmd 0xffffffff82a00000-0xffffffff82a1e000 120K ro GLB NX pte 0xffffffff82a1e000-0xffffffff82c00000 1928K RW GLB NX pte 0xffffffff82c00000-0xffffffff82e00000 2M RW PSE GLB NX pmd 0xffffffff82e00000-0xffffffff83000000 2M RW GLB NX pte 0xffffffff83000000-0xffffffff83200000 2M RW PSE GLB NX pmd 0xffffffff83200000-0xffffffff83400000 2M RW GLB NX pte 0xffffffff83400000-0xffffffff84400000 16M RW PSE GLB NX pmd 0xffffffff84400000-0xffffffffa0000000 444M pmd After patch: ---[ High Kernel Mapping ]--- 0xffffffff80000000-0xffffffff81000000 16M pmd 0xffffffff81000000-0xffffffff82000000 16M ro PSE GLB x pmd 0xffffffff82000000-0xffffffff82012000 72K ro GLB x pte 0xffffffff82012000-0xffffffff82200000 1976K pte 0xffffffff82200000-0xffffffff82a00000 8M ro PSE GLB NX pmd 0xffffffff82a00000-0xffffffff82a1e000 120K ro GLB NX pte 0xffffffff82a1e000-0xffffffff82c00000 1928K pte 0xffffffff82c00000-0xffffffff82e00000 2M RW PSE GLB NX pmd 0xffffffff82e00000-0xffffffff82e53000 332K RW GLB NX pte 0xffffffff82e53000-0xffffffff83000000 1716K pte 0xffffffff83000000-0xffffffff83200000 2M pmd 0xffffffff83200000-0xffffffff83214000 80K pte 0xffffffff83214000-0xffffffff83400000 1968K RW GLB NX pte 0xffffffff83400000-0xffffffff84200000 14M RW PSE GLB NX pmd 0xffffffff84200000-0xffffffff84384000 1552K RW GLB NX pte 0xffffffff84384000-0xffffffff84400000 496K pte 0xffffffff84400000-0xffffffffa0000000 444M pmd So remove some range before rodata with RW+x. -v4: adapt it to all_end change. Signed-off-by: Yinghai Lu --- arch/x86/mm/init_64.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) Index: linux-2.6/arch/x86/mm/init_64.c =================================================================== --- linux-2.6.orig/arch/x86/mm/init_64.c +++ linux-2.6/arch/x86/mm/init_64.c @@ -1101,6 +1101,61 @@ void __init mem_init(void) } #ifdef CONFIG_DEBUG_RODATA +static void remove_highmap_2m(unsigned long addr) +{ + pgd_t *pgd = pgd_offset_k(addr); + pud_t *pud = (pud_t *)pgd_page_vaddr(*pgd) + pud_index(addr); + pmd_t *pmd = (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr); + + set_pmd(pmd, __pmd(0)); +} + +static void remove_highmap_2m_partial(unsigned long addr, unsigned long end) +{ + int i; + pgd_t *pgd = pgd_offset_k(addr); + pud_t *pud = (pud_t *)pgd_page_vaddr(*pgd) + pud_index(addr); + pmd_t *pmd = (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr); + pte_t *pte = (pte_t *)pmd_page_vaddr(*pmd) + pte_index(addr); + + for (i = pte_index(addr); i < pte_index(end - 1) + 1; i++, pte++) + set_pte(pte, __pte(0)); +} + +static void cleanup_highmap_late(unsigned long start, unsigned long end) +{ + unsigned long addr; + unsigned long start_2m_aligned = roundup(start, PMD_SIZE); + unsigned long end_2m_aligned = rounddown(end, PMD_SIZE); + + start = PFN_ALIGN(start); + end &= PAGE_MASK; + + if (start >= end) + return; + + if (start < start_2m_aligned) { + unsigned long tmp = min(start_2m_aligned, end); + + set_memory_4k(start, (tmp - start) >> PAGE_SHIFT); + remove_highmap_2m_partial(start, tmp); + } + + for (addr = start_2m_aligned; addr < end_2m_aligned; addr += PMD_SIZE) + remove_highmap_2m(addr); + + if (start <= end_2m_aligned && end_2m_aligned < end) { + set_memory_4k(end_2m_aligned, + (end - end_2m_aligned) >> PAGE_SHIFT); + remove_highmap_2m_partial(end_2m_aligned, end); + } + + subtract_range(pfn_highmapped, NR_RANGE, + __pa_symbol(start) >> PAGE_SHIFT, + __pa_symbol(end) >> PAGE_SHIFT); + nr_pfn_highmapped = clean_sort_range(pfn_highmapped, NR_RANGE); +} + const int rodata_test_data = 0xC3; EXPORT_SYMBOL_GPL(rodata_test_data); @@ -1149,6 +1204,7 @@ void mark_rodata_ro(void) unsigned long end = (unsigned long) &__end_rodata_hpage_align; unsigned long text_end = PFN_ALIGN(&__stop___ex_table); unsigned long rodata_end = PFN_ALIGN(&__end_rodata); + unsigned long data_start = PFN_ALIGN(&_sdata); unsigned long all_end; printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", @@ -1172,6 +1228,12 @@ void mark_rodata_ro(void) all_end = roundup(_brk_end, PMD_SIZE); set_memory_nx(rodata_start, (all_end - rodata_start) >> PAGE_SHIFT); + cleanup_highmap_late(text_end, rodata_start); + cleanup_highmap_late(rodata_end, data_start); + cleanup_highmap_late(PFN_ALIGN(_brk_end), all_end); + cleanup_highmap_late((unsigned long)(&__init_begin), + (unsigned long)(&__init_end)); + rodata_test(); #ifdef CONFIG_CPA_DEBUG -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/