xlat v2: Split MMU setup and enable

At present, the function provided by the translation library to enable
MMU constructs appropriate values for translation library, and programs
them to the right registers. The construction of initial values,
however, is only required once as both the primary and secondaries
program the same values.

Additionally, the MMU-enabling function is written in C, which means
there's an active stack at the time of enabling MMU. On some systems,
like Arm DynamIQ, having active stack while enabling MMU during warm
boot might lead to coherency problems.

This patch addresses both the above problems by:

  - Splitting the MMU-enabling function into two: one that sets up
    values to be programmed into the registers, and another one that
    takes the pre-computed values and writes to the appropriate
    registers. With this, the primary effectively calls both functions
    to have the MMU enabled, but secondaries only need to call the
    latter.

  - Rewriting the function that enables MMU in assembly so that it
    doesn't use stack.

This patch fixes a bunch of MISRA issues on the way.

Change-Id: I0faca97263a970ffe765f0e731a1417e43fbfc45
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

3 files changed, 20 insertions, 5 deletions

diff --git a/include/lib/xlat_tables/xlat_mmu_helpers.h b/include/lib/xlat_tables/xlat_mmu_helpers.h
index 77953177..b6c53e26 100644
--- a/include/lib/xlat_tables/xlat_mmu_helpers.h
+++ b/include/lib/xlat_tables/xlat_mmu_helpers.h
@@ -48,10 +48,15 @@
 #ifdef AARCH32
 /* AArch32 specific translation table API */
 void enable_mmu_secure(unsigned int flags);
+
+void enable_mmu_direct(unsigned int flags);
 #else
 /* AArch64 specific translation table APIs */
 void enable_mmu_el1(unsigned int flags);
 void enable_mmu_el3(unsigned int flags);
+
+void enable_mmu_direct_el1(unsigned int flags);
+void enable_mmu_direct_el3(unsigned int flags);
 #endif /* AARCH32 */
 
 int xlat_arch_is_granule_size_supported(size_t size);
diff --git a/include/lib/xlat_tables/xlat_tables_v2.h b/include/lib/xlat_tables/xlat_tables_v2.h
index 98f00d71..4dc2c5ec 100644
--- a/include/lib/xlat_tables/xlat_tables_v2.h
+++ b/include/lib/xlat_tables/xlat_tables_v2.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -8,12 +8,12 @@
 #define __XLAT_TABLES_V2_H__
 
 #include <xlat_tables_defs.h>
+#include <xlat_tables_v2_helpers.h>
 
 #ifndef __ASSEMBLY__
 #include <stddef.h>
 #include <stdint.h>
 #include <xlat_mmu_helpers.h>
-#include <xlat_tables_v2_helpers.h>
 
 /*
  * Default granularity size for an mmap_region_t.
diff --git a/include/lib/xlat_tables/xlat_tables_v2_helpers.h b/include/lib/xlat_tables/xlat_tables_v2_helpers.h
index de1c2d4b..e1ea2b64 100644
--- a/include/lib/xlat_tables/xlat_tables_v2_helpers.h
+++ b/include/lib/xlat_tables/xlat_tables_v2_helpers.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -16,6 +16,13 @@
 #error "Do not include this header file directly. Include xlat_tables_v2.h instead."
 #endif
 
+/* Offsets into mmu_cfg_params array. All parameters are 32 bits wide. */
+#define MMU_CFG_MAIR0		0
+#define MMU_CFG_TCR		1
+#define MMU_CFG_TTBR0_LO	2
+#define MMU_CFG_TTBR0_HI	3
+#define MMU_CFG_PARAM_MAX	4
+
 #ifndef __ASSEMBLY__
 
 #include <cassert.h>
@@ -24,6 +31,9 @@
 #include <xlat_tables_arch.h>
 #include <xlat_tables_defs.h>
 
+/* Parameters of register values required when enabling MMU */
+extern uint32_t mmu_cfg_params[MMU_CFG_PARAM_MAX];
+
 /* Forward declaration */
 struct mmap_region;
 
@@ -162,6 +172,8 @@ struct xlat_ctx {
 		.initialized = 0,						\
 	}
 
+#endif /*__ASSEMBLY__*/
+
 #if AARCH64
 
 /*
@@ -187,6 +199,4 @@ struct xlat_ctx {
 
 #endif /* AARCH64 */
 
-#endif /*__ASSEMBLY__*/
-
 #endif /* __XLAT_TABLES_V2_HELPERS_H__ */