diff options
author | Yinghai Lu <yinghai@kernel.org> | 2010-03-29 02:42:55 (GMT) |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2010-03-29 16:55:33 (GMT) |
commit | c967da6a0ba837f762042e931d4afcf72045547c (patch) | |
tree | 3576d2f97e20f3d8d647ea7381f5f99d96220fa2 /arch/x86/mm/init.c | |
parent | 596b711ed6b5235f8545680ef38ace00f9898c32 (diff) | |
download | linux-fsl-qoriq-c967da6a0ba837f762042e931d4afcf72045547c.tar.xz |
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>
Diffstat (limited to 'arch/x86/mm/init.c')
-rw-r--r-- | arch/x86/mm/init.c | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index e71c5cb..452ee5b 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -331,11 +331,23 @@ int devmem_is_allowed(unsigned long pagenr) void free_init_pages(char *what, unsigned long begin, unsigned long end) { - unsigned long addr = begin; + unsigned long addr; + unsigned long begin_aligned, end_aligned; - if (addr >= end) + /* Make sure boundaries are page aligned */ + begin_aligned = PAGE_ALIGN(begin); + end_aligned = end & PAGE_MASK; + + if (WARN_ON(begin_aligned != begin || end_aligned != end)) { + begin = begin_aligned; + end = end_aligned; + } + + if (begin >= end) return; + addr = begin; + /* * If debugging page accesses then do not free this memory but * mark them not present - any buggy init-section access will @@ -343,7 +355,7 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end) */ #ifdef CONFIG_DEBUG_PAGEALLOC printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n", - begin, PAGE_ALIGN(end)); + begin, end); set_memory_np(begin, (end - begin) >> PAGE_SHIFT); #else /* @@ -358,8 +370,7 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end) 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); + memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE); free_page(addr); totalram_pages++; } @@ -376,6 +387,15 @@ void free_initmem(void) #ifdef CONFIG_BLK_DEV_INITRD void free_initrd_mem(unsigned long start, unsigned long end) { - free_init_pages("initrd memory", start, end); + /* + * end could be not aligned, and We can not align that, + * decompresser could be confused by aligned initrd_end + * We already reserve the end partial page before in + * - i386_start_kernel() + * - x86_64_start_kernel() + * - relocate_initrd() + * So here We can do PAGE_ALIGN() safely to get partial page to be freed + */ + free_init_pages("initrd memory", start, PAGE_ALIGN(end)); } #endif |