[PATCH] ARM: Handle non-pmd-aligned end of first memblock.

From: yun.hsiang
Date: Fri Mar 18 2016 - 05:49:47 EST


From: Yun Hsiang <yun.hsiang@xxxxxxxxxxxx>

In paging_init(), if the end address of first memblock
is non-PMD-aligned,we need to create a next-level page table
for mapping the non-PMD-sized area.
The memory of this next-level page table will be allocated
from address of memblock.limit with a top-down order.
sanity_check_meminfo() will find the address of
first non-pmd-aligned page in memblock.memory,
round down the address, and set it to memblock.current_limit.

There is a risk if arm_memblock_init()execute before
sanity_check_meminfo(). arm_memblock_init() parse the device tree
and modified memblock if there are no-map node in device tree.
It might produce a new non-PMD-aligned block. While creating mapping
to this new non-PMD-aligned block, the page table will be allocated
from the memblock.limit which is still unmapped.

Signed-off-by: Yun Hsiang <yun.hsiang@xxxxxxxxxxxx>
---
arch/arm/kernel/setup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 7d0cba6f..940e4bd 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -1036,11 +1036,11 @@ void __init setup_arch(char **cmdline_p)
#endif
setup_dma_zone(mdesc);
efi_init();
- sanity_check_meminfo();
arm_memblock_init(mdesc);

early_ioremap_reset();

+ sanity_check_meminfo();
paging_init(mdesc);
request_standard_resources(mdesc);

--
1.9.1