ARM platforms: Demonstrate mem_protect from el3_runtime
Previously mem_protect used to be only supported from BL2. This is not
helpful in the case when ARM TF-A BL2 is not used. This patch demonstrates
mem_protect from el3_runtime firmware on ARM Platforms specifically
when RESET_TO_BL31 or RESET_TO_SP_MIN flag is set as BL2 may be absent
in these cases. The Non secure DRAM is dynamically mapped into EL3 mmap
tables temporarily and then the protected regions are then cleared. This
avoids the need to map the non secure DRAM permanently to BL31/sp_min.
The stack size is also increased, because DYNAMIC_XLAT_TABLES require
a bigger stack.
Change-Id: Ia44c594192ed5c5adc596c0cff2c7cc18c001fde
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/plat/arm/common/arm_nor_psci_mem_protect.c b/plat/arm/common/arm_nor_psci_mem_protect.c
index 3167a42..c01e4ed 100644
--- a/plat/arm/common/arm_nor_psci_mem_protect.c
+++ b/plat/arm/common/arm_nor_psci_mem_protect.c
@@ -12,10 +12,22 @@
#include <psci.h>
#include <utils.h>
+
+/*
+ * DRAM1 is used also to load the NS boot loader. For this reason we
+ * cannot clear the full DRAM1, because in that case we would clear
+ * the NS images (especially for RESET_TO_BL31 and RESET_TO_SPMIN cases).
+ * For this reason we reserve 64 MB for the NS images and protect the RAM
+ * until the end of DRAM1.
+ * We limit the size of DRAM2 to 1 GB to avoid big delays while booting
+ */
+#define DRAM1_NS_IMAGE_LIMIT (PLAT_ARM_NS_IMAGE_OFFSET + (32 << TWO_MB_SHIFT))
+#define DRAM1_PROTECTED_SIZE (ARM_NS_DRAM1_END+1u - DRAM1_NS_IMAGE_LIMIT)
+
static mem_region_t arm_ram_ranges[] = {
- {ARM_NS_DRAM1_BASE, ARM_NS_DRAM1_SIZE},
+ {DRAM1_NS_IMAGE_LIMIT, DRAM1_PROTECTED_SIZE},
#ifdef AARCH64
- {ARM_DRAM2_BASE, ARM_DRAM2_SIZE},
+ {ARM_DRAM2_BASE, 1u << ONE_GB_SHIFT},
#endif
};
@@ -29,7 +41,7 @@
int tmp;
tmp = *(int *) PLAT_ARM_MEM_PROT_ADDR;
- *enabled = (tmp == 1);
+ *enabled = (tmp == 1) ? 1 : 0;
return 0;
}
@@ -46,7 +58,7 @@
return -1;
}
- if (enable) {
+ if (enable != 0) {
/*
* If we want to write a value different than 0
* then we have to erase the full block because
@@ -71,15 +83,47 @@
* Function used for required psci operations performed when
* system boots
******************************************************************************/
-void arm_nor_psci_do_mem_protect(void)
+/*
+ * PLAT_MEM_PROTECT_VA_FRAME is a address specifically
+ * selected in a way that is not needed an additional
+ * translation table for memprotect. It happens because
+ * we use a chunk of size 2MB and it means that it can
+ * be mapped in a level 2 table and the level 2 table
+ * for 0xc0000000 is already used and the entry for
+ * 0xc0000000 is not used.
+ */
+#if defined(PLAT_XLAT_TABLES_DYNAMIC)
+void arm_nor_psci_do_dyn_mem_protect(void)
{
int enable;
arm_psci_read_mem_protect(&enable);
- if (!enable)
+ if (enable == 0)
return;
- INFO("PSCI: Overwritting non secure memory\n");
- clear_mem_regions(arm_ram_ranges, ARRAY_SIZE(arm_ram_ranges));
+
+ INFO("PSCI: Overwriting non secure memory\n");
+ clear_map_dyn_mem_regions(arm_ram_ranges,
+ ARRAY_SIZE(arm_ram_ranges),
+ PLAT_ARM_MEM_PROTEC_VA_FRAME,
+ 1 << TWO_MB_SHIFT);
+}
+#endif
+
+/*******************************************************************************
+ * Function used for required psci operations performed when
+ * system boots and dynamic memory is not used.
+ ******************************************************************************/
+void arm_nor_psci_do_static_mem_protect(void)
+{
+ int enable;
+
+ arm_psci_read_mem_protect(&enable);
+ if (enable == 0)
+ return;
+
+ INFO("PSCI: Overwriting non secure memory\n");
+ clear_mem_regions(arm_ram_ranges,
+ ARRAY_SIZE(arm_ram_ranges));
arm_nor_psci_write_mem_protect(0);
}