Ronald G. Minnich (rminnich@gmail.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3160
-gerrit
commit 5c0855abead284f3ef4d3d0e6505f8bff7795cab Author: Ronald G. Minnich rminnich@gmail.com Date: Tue Apr 30 10:11:30 2013 -0700
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 --- src/arch/armv7/include/arch/cache.h | 2 ++ src/arch/armv7/lib/mmu.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+)
diff --git a/src/arch/armv7/include/arch/cache.h b/src/arch/armv7/include/arch/cache.h index 028cf18..d5c3a5b 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 224b566..d7a0203 100644 --- a/src/arch/armv7/lib/mmu.c +++ b/src/arch/armv7/lib/mmu.c @@ -39,6 +39,20 @@
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) {