diff options
| author | Ronald G. Minnich <rminnich@gmail.com> | 2013-04-30 10:11:30 -0700 |
|---|---|---|
| committer | David Hendricks <dhendrix@chromium.org> | 2013-05-01 20:12:48 +0200 |
| commit | c0466d46b7ea511f102eb6e57da59d95bf4ef95f (patch) | |
| tree | 8cdaee13e73d96c9fc3cc21c94020d1fcdfda125 | |
| parent | 043b823a736d101da46a120cfa883c5c48e3ab81 (diff) | |
ARMV7: add a function to disable MMU entries
It is useful to be able to lock out certain address ranges,
NULL being the most important example.
void mmu_disable_range(unsigned long start_mb, unsigned long size_mb)
will allow us to lock out selected virtual addresses on MiB boundaries.
As in other ARM mmu functions, the addresses and quantities are in units
of MiB.
Change-Id: If516ce955ee2d12c5a409f25acbb5a4b424f699b
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: http://review.coreboot.org/3160
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>
| -rw-r--r-- | src/arch/armv7/include/arch/cache.h | 2 | ||||
| -rw-r--r-- | src/arch/armv7/lib/mmu.c | 13 |
2 files changed, 15 insertions, 0 deletions
diff --git a/src/arch/armv7/include/arch/cache.h b/src/arch/armv7/include/arch/cache.h index 028cf1808d..d5c3a5b241 100644 --- a/src/arch/armv7/include/arch/cache.h +++ b/src/arch/armv7/include/arch/cache.h @@ -303,6 +303,8 @@ enum dcache_policy { DCACHE_WRITETHROUGH, }; +/* disable the mmu for a range. Primarily useful to lock out address 0. */ +void mmu_disable_range(unsigned long start_mb, unsigned long size_mb); /* mmu range configuration (set dcache policy) */ void mmu_config_range(unsigned long start_mb, unsigned long size_mb, enum dcache_policy policy); diff --git a/src/arch/armv7/lib/mmu.c b/src/arch/armv7/lib/mmu.c index 224b566a50..82c735818e 100644 --- a/src/arch/armv7/lib/mmu.c +++ b/src/arch/armv7/lib/mmu.c @@ -39,6 +39,19 @@ static uintptr_t ttb_addr; +void mmu_disable_range(unsigned long start_mb, unsigned long size_mb) +{ + unsigned int i; + uint32_t *ttb_entry = (uint32_t *)ttb_addr; + printk(BIOS_DEBUG, "Disabling: 0x%08lx:0x%08lx\n", + start_mb << 20, ((start_mb + size_mb) << 20) - 1); + + for (i = start_mb; i < start_mb + size_mb; i++) { + ttb_entry[i] = 0; + tlbimvaa(i); + } +} + void mmu_config_range(unsigned long start_mb, unsigned long size_mb, enum dcache_policy policy) { |