A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-07 12:25:00 -04:00
Code Issues Projects Releases Packages Wiki Activity

arm: mm: fix pte allocation with CONFIG_FORCE_PAGES feature

Browse source 
CONFIG_FORCE_PAGES introduces a debug option to mark free
pages as read only in order to trigger a fault if any code
attempts to write to a page on the buddy list.

In order to achieve this it splits all section mappings in
to PAGE_SIZE pages during boot. While doing this split, it
wrongly allocates a pte (of page size) for each pmd. Linux
however in armv7 short descriptor format, uses same second
level pte for 2 consecutive pmds offset by the actual second
level table size. Refer comments in kernel file
arch/arm/include/asm/pgtable-2level.h for details.

Fix this by allocating pte for a section mapped pmd while
providing required offset if pte already exists.

Change-Id: Iadbaa5e71e4b220208a7275bf039a2a413349e42
Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>
Signed-off-by: Qingqing Zhou <qqzhou@codeaurora.org>
This commit is contained in:
Shiraz Hashim 2014-05-21 09:35:08 +05:30 • committed by Gerrit - the friendly Code Review server
commit 848bfb6423
1 changed files with 18 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

19
arch/arm/mm/mmu.c
View file

@ -1617,8 +1617,25 @@ static noinline void __init split_pmd(pmd_t *pmd, unsigned long addr,
const struct mem_type *type)
{
pte_t *pte, *start_pte;
pmd_t *base_pmd;
start_pte = early_alloc(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE);
base_pmd = pmd_offset(
pud_offset(pgd_offset(&init_mm, addr), addr), addr);
if (pmd_none(*base_pmd) || pmd_bad(*base_pmd)) {
start_pte = early_alloc(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE);
#ifndef CONFIG_ARM_LPAE
/*
* Following is needed when new pte is allocated for pmd[1]
* cases, which may happen when base (start) address falls
* under pmd[1].
*/
if (addr & SECTION_SIZE)
start_pte += pte_index(addr);
#endif
} else {
start_pte = pte_offset_kernel(base_pmd, addr);
}
pte = start_pte;