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authorBarry Song <barry.song@analog.com>2009-12-07 10:05:58 +0000
committerMike Frysinger <vapier@gentoo.org>2010-03-09 00:30:46 -0500
commite18e7dd33454f277b9438af66d25984362278021 (patch)
tree3c809ab2ebf8ad6276570f7eab238bd45e7216e8 /arch/blackfin/kernel/setup.c
parentc9784ebb23be1e2ef23f537d6df04e0ea0206802 (diff)
downloadlinux-e18e7dd33454f277b9438af66d25984362278021.tar.bz2
Blackfin: fix MPU page permission masks overflow when dealing with async memory
Attempting to use the MPU while doing XIP out of parallel flash hooked up to the async memory bus would often result in random crashes as the MPU slowly corrupted memory. The fallout here is that the async banks gain MPU protection from user space too. So any accesses have to go through the mmap() interface rather than just using hardcoded pointers. Signed-off-by: Barry Song <barry.song@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch/blackfin/kernel/setup.c')
-rw-r--r--arch/blackfin/kernel/setup.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/setup.c b/arch/blackfin/kernel/setup.c
index 69cbc1a81201..8dc7ee1ef336 100644
--- a/arch/blackfin/kernel/setup.c
+++ b/arch/blackfin/kernel/setup.c
@@ -597,7 +597,12 @@ static __init void memory_setup(void)
}
#ifdef CONFIG_MPU
+#if defined(CONFIG_ROMFS_ON_MTD) && defined(CONFIG_MTD_ROM)
+ page_mask_nelts = (((_ramend + ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE -
+ ASYNC_BANK0_BASE) >> PAGE_SHIFT) + 31) / 32;
+#else
page_mask_nelts = ((_ramend >> PAGE_SHIFT) + 31) / 32;
+#endif
page_mask_order = get_order(3 * page_mask_nelts * sizeof(long));
#endif