linux/arch/x86/mm
Yinghai Lu c967da6a0b x86: Make sure free_init_pages() frees pages on page boundary
When CONFIG_NO_BOOTMEM=y, it could use memory more effiently, or
in a more compact fashion.

Example:

 Allocated new RAMDISK: 00ec2000 - 0248ce57
 Move RAMDISK from 000000002ea04000 - 000000002ffcee56 to 00ec2000 - 0248ce56

The new RAMDISK's end is not page aligned.
Last page could be shared with other users.

When free_init_pages are called for initrd or .init, the page
could be freed and we could corrupt other data.

code segment in free_init_pages():

 |        for (; addr < end; addr += PAGE_SIZE) {
 |                ClearPageReserved(virt_to_page(addr));
 |                init_page_count(virt_to_page(addr));
 |                memset((void *)(addr & ~(PAGE_SIZE-1)),
 |                        POISON_FREE_INITMEM, PAGE_SIZE);
 |                free_page(addr);
 |                totalram_pages++;
 |        }

last half page could be used as one whole free page.

So page align the boundaries.

-v2: make the original initramdisk to be aligned, according to
     Johannes, otherwise we have the chance to lose one page.
     we still need to keep initrd_end not aligned, otherwise it could
     confuse decompressor.
-v3: change to WARN_ON instead, suggested by Johannes.
-v4: use PAGE_ALIGN, suggested by Johannes.
     We may fix that macro name later to PAGE_ALIGN_UP, and PAGE_ALIGN_DOWN
     Add comments about assuming ramdisk start is aligned
     in relocate_initrd(), change to re get ramdisk_image instead of save it
     to make diff smaller. Add warning for wrong range, suggested by Johannes.
-v6: remove one WARN()
     We need to align beginning in free_init_pages()
     do not copy more than ramdisk_size, noticed by Johannes

Reported-by: Stanislaw Gruszka <sgruszka@redhat.com>
Tested-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1269830604-26214-3-git-send-email-yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-29 18:55:33 +02:00
..
kmemcheck kmemcheck: Test the full object in kmemcheck_is_obj_initialized() 2010-02-17 21:39:08 +02:00
dump_pagetables.c x86: remove (null) in /sys kernel_page_tables 2009-04-14 11:50:22 +02:00
extable.c x86, 64-bit: Move K8 B step iret fixup to fault entry asm 2009-10-12 18:29:46 +02:00
fault.c Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-05 15:33:27 -08:00
gup.c x86, doc: Fix minor spelling error in arch/x86/mm/gup.c 2010-02-02 16:00:44 -08:00
highmem_32.c Merge branch 'kvm-updates/2.6.32' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2009-09-14 17:43:43 -07:00
hugetlbpage.c x86: ignore VM_LOCKED when determining if hugetlb-backed page tables can be shared or not 2009-05-29 08:40:03 -07:00
init_32.c Merge branch 'x86-bootmem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-03-03 08:15:05 -08:00
init_64.c sparsemem: Put mem map for one node together. 2010-02-12 09:42:38 -08:00
init.c x86: Make sure free_init_pages() frees pages on page boundary 2010-03-29 18:55:33 +02:00
iomap_32.c x86, pat: Add PAT reserve free to io_mapping* APIs 2009-08-26 15:41:16 -07:00
ioremap.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-28 10:38:45 -08:00
k8topology_64.c x86: Move find_smp_config() earlier and avoid bootmem usage 2009-11-24 12:10:51 +01:00
kmmio.c hw-breakpoints, perf: Fix broken mmiotrace due to dr6 by reference change 2010-01-17 08:01:44 +01:00
Makefile x86: split NX setup into separate file to limit unstack-protected code 2009-09-21 13:56:58 -07:00
memtest.c x86: memtest: use pointers of equal type for comparison 2009-06-11 16:26:35 +02:00
mmap.c x86: Use helpers for rlimits 2010-01-27 15:17:31 -08:00
mmio-mod.c x86: Fix build warning in arch/x86/mm/mmio-mod.c 2009-12-14 08:55:43 +01:00
numa_32.c x86: Make 32bit support NO_BOOTMEM 2010-02-12 09:42:39 -08:00
numa_64.c Merge branch 'x86-bootmem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-03-03 08:15:05 -08:00
numa.c cpumask: convert node_to_cpumask_map[] to cpumask_var_t 2009-03-13 14:35:31 +01:00
pageattr-test.c x86: make sure the CPA test code's use of _PAGE_UNUSED1 is obvious 2008-09-05 17:09:57 +02:00
pageattr.c x86_64, cpa: Don't work hard in preserving kernel 2M mappings when using 4K already 2010-02-22 15:09:31 -08:00
pat.c vfs: Implement proper O_SYNC semantics 2009-12-10 15:02:50 +01:00
pf_in.c x86: fix mmiotrace 8-bit register decoding 2008-10-14 10:33:50 +02:00
pf_in.h x86 mmiotrace: move files into arch/x86/mm/. 2008-05-24 11:25:37 +02:00
pgtable_32.c x86/32: no need to use set_pte_present in set_pte_vaddr 2009-03-19 14:04:18 +01:00
pgtable.c x86, mm: Allow highmem user page tables to be disabled at boot time 2010-02-25 10:28:19 +01:00
physaddr.c x86: split __phys_addr out into separate file 2009-09-10 11:48:55 -07:00
physaddr.h x86: split __phys_addr out into separate file 2009-09-10 11:48:55 -07:00
setup_nx.c x86, mm: Report state of NX protections during boot 2009-11-16 13:44:59 -08:00
srat_32.c x86: Fix checking of SRAT when node 0 ram is not from 0 2009-12-16 16:43:37 -08:00
srat_64.c x86: Set hotpluggable nodes in nodes_possible_map 2010-01-23 06:21:57 +01:00
testmmiotrace.c testmmiotrace.c: Add and use pr_fmt(fmt) 2009-10-12 08:05:41 +02:00
tlb.c x86: Convert tlbstate_lock to raw_spinlock 2010-02-17 18:28:59 +01:00