142 lines
4.9 KiB
Diff
142 lines
4.9 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
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Date: Fri, 29 Sep 2017 17:08:16 +0300
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Subject: [PATCH] mm/sparsemem: Allocate mem_section at runtime for
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CONFIG_SPARSEMEM_EXTREME=y
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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Size of the mem_section[] array depends on the size of the physical address space.
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In preparation for boot-time switching between paging modes on x86-64
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we need to make the allocation of mem_section[] dynamic, because otherwise
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we waste a lot of RAM: with CONFIG_NODE_SHIFT=10, mem_section[] size is 32kB
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for 4-level paging and 2MB for 5-level paging mode.
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The patch allocates the array on the first call to sparse_memory_present_with_active_regions().
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Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
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Cc: Andrew Morton <akpm@linux-foundation.org>
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Cc: Andy Lutomirski <luto@amacapital.net>
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Cc: Borislav Petkov <bp@suse.de>
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Cc: Cyrill Gorcunov <gorcunov@openvz.org>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Cc: linux-mm@kvack.org
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Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@linux.intel.com
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 83e3c48729d9ebb7af5a31a504f3fd6aff0348c4)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit c70f71e01a0ae5d884abae0424618abe90b82011)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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include/linux/mmzone.h | 6 +++++-
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mm/page_alloc.c | 10 ++++++++++
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mm/sparse.c | 17 +++++++++++------
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3 files changed, 26 insertions(+), 7 deletions(-)
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diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
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index fc14b8b3f6ce..9c6c001a8c6c 100644
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--- a/include/linux/mmzone.h
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+++ b/include/linux/mmzone.h
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@@ -1137,13 +1137,17 @@ struct mem_section {
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#define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)
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#ifdef CONFIG_SPARSEMEM_EXTREME
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-extern struct mem_section *mem_section[NR_SECTION_ROOTS];
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+extern struct mem_section **mem_section;
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#else
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extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
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#endif
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static inline struct mem_section *__nr_to_section(unsigned long nr)
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{
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+#ifdef CONFIG_SPARSEMEM_EXTREME
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+ if (!mem_section)
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+ return NULL;
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+#endif
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if (!mem_section[SECTION_NR_TO_ROOT(nr)])
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return NULL;
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return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
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diff --git a/mm/page_alloc.c b/mm/page_alloc.c
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index 1423da8dd16f..66eb23ab658d 100644
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--- a/mm/page_alloc.c
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+++ b/mm/page_alloc.c
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@@ -5707,6 +5707,16 @@ void __init sparse_memory_present_with_active_regions(int nid)
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unsigned long start_pfn, end_pfn;
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int i, this_nid;
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+#ifdef CONFIG_SPARSEMEM_EXTREME
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+ if (!mem_section) {
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+ unsigned long size, align;
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+
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+ size = sizeof(struct mem_section) * NR_SECTION_ROOTS;
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+ align = 1 << (INTERNODE_CACHE_SHIFT);
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+ mem_section = memblock_virt_alloc(size, align);
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+ }
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+#endif
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+
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for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
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memory_present(this_nid, start_pfn, end_pfn);
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}
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diff --git a/mm/sparse.c b/mm/sparse.c
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index cdce7a7bb3f3..308a0789d1bb 100644
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--- a/mm/sparse.c
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+++ b/mm/sparse.c
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@@ -22,8 +22,7 @@
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* 1) mem_section - memory sections, mem_map's for valid memory
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*/
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#ifdef CONFIG_SPARSEMEM_EXTREME
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-struct mem_section *mem_section[NR_SECTION_ROOTS]
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- ____cacheline_internodealigned_in_smp;
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+struct mem_section **mem_section;
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#else
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struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
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____cacheline_internodealigned_in_smp;
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@@ -104,7 +103,7 @@ static inline int sparse_index_init(unsigned long section_nr, int nid)
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int __section_nr(struct mem_section* ms)
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{
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unsigned long root_nr;
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- struct mem_section* root;
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+ struct mem_section *root = NULL;
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for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
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root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
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@@ -115,7 +114,7 @@ int __section_nr(struct mem_section* ms)
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break;
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}
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- VM_BUG_ON(root_nr == NR_SECTION_ROOTS);
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+ VM_BUG_ON(!root);
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return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
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}
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@@ -333,11 +332,17 @@ sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
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static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
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{
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unsigned long usemap_snr, pgdat_snr;
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- static unsigned long old_usemap_snr = NR_MEM_SECTIONS;
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- static unsigned long old_pgdat_snr = NR_MEM_SECTIONS;
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+ static unsigned long old_usemap_snr;
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+ static unsigned long old_pgdat_snr;
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struct pglist_data *pgdat = NODE_DATA(nid);
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int usemap_nid;
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+ /* First call */
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+ if (!old_usemap_snr) {
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+ old_usemap_snr = NR_MEM_SECTIONS;
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+ old_pgdat_snr = NR_MEM_SECTIONS;
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+ }
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+
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usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
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pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
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if (usemap_snr == pgdat_snr)
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--
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2.14.2
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