[coreboot-gerrit] New patch to review for coreboot: 32a3d97 ARMV7: add a function to disable MMU entries
Ronald G. Minnich (rminnich@gmail.com)
gerrit at coreboot.org
Tue Apr 30 19:13:58 CEST 2013
Ronald G. Minnich (rminnich at gmail.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3160
-gerrit
commit 32a3d97b1f0357e33977f65ce719fa0e27a8de83
Author: Ronald G. Minnich <rminnich at 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 at 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 1db86dc..df335a0 100644
--- a/src/arch/armv7/include/arch/cache.h
+++ b/src/arch/armv7/include/arch/cache.h
@@ -297,6 +297,8 @@ 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..9d61c56 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;
+
+ /* TODO: add helper to invalidate TLB by MVA */
+ tlb_invalidate_all();
+}
+
void mmu_config_range(unsigned long start_mb, unsigned long size_mb,
enum dcache_policy policy)
{
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