[U-Boot] [RFC PATCH 2/2] ARM: mmu: Set domain permissions to client access

[R Sricharan]

 The 'XN' execute never bit is set in the pagetables. This will
 prevent speculative prefetches to non executable regions. But the
 domain permissions are set as master in the DACR register.
 So the pagetable attribute for 'XN' is not effective. Change the
 permissions to client.

 This fixes lot of speculative prefetch aborts seen with CORTEX A15
 otherwise.

Signed-off-by: R Sricharan <r.sricharan at ti.com>
Cc: Vincent Stehle <v-stehle at ti.com>
Cc: Tom Rini <trini at ti.com>
---
 arch/arm/cpu/armv7/cache_v7.c                  |    3 ++
 arch/arm/cpu/armv7/omap-common/hwinit-common.c |   35 ++++++++++++++++++++++++
 arch/arm/include/asm/system.h                  |   14 ++++++++++
 arch/arm/lib/cache-cp15.c                      |    9 ++++++
 4 files changed, 61 insertions(+)

diff --git a/arch/arm/cpu/armv7/cache_v7.c b/arch/arm/cpu/armv7/cache_v7.c
index 5f6d039..8748c14 100644
--- a/arch/arm/cpu/armv7/cache_v7.c
+++ b/arch/arm/cpu/armv7/cache_v7.c
@@ -340,6 +340,9 @@ void mmu_page_table_flush(unsigned long start, unsigned long stop)
 {
 }
 
+void arm_init_domains(void)
+{
+}
 #endif /* #ifndef CONFIG_SYS_DCACHE_OFF */
 
 #ifndef CONFIG_SYS_ICACHE_OFF
diff --git a/arch/arm/cpu/armv7/omap-common/hwinit-common.c b/arch/arm/cpu/armv7/omap-common/hwinit-common.c
index 9ef10bd..4eaf75b 100644
--- a/arch/arm/cpu/armv7/omap-common/hwinit-common.c
+++ b/arch/arm/cpu/armv7/omap-common/hwinit-common.c
@@ -32,6 +32,12 @@
 #include <asm/arch/sys_proto.h>
 #include <asm/sizes.h>
 #include <asm/emif.h>
+#include <asm/cache.h>
+#include <asm/system.h>
+
+#define ARMV7_DCACHE_WRITEBACK  0xe
+#define	ARMV7_DOMAIN_CLIENT	1
+#define ARMV7_DOMAIN_MASK	(0x3 << 0)
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -258,4 +264,33 @@ void enable_caches(void)
 	/* Enable D-cache. I-cache is already enabled in start.S */
 	dcache_enable();
 }
+
+void dram_bank_mmu_setup(int bank)
+{
+	bd_t *bd = gd->bd;
+	int	i;
+
+	u32 start = bd->bi_dram[bank].start >> 20;
+	u32 size = bd->bi_dram[bank].size >> 20;
+	u32 end = start + size;
+
+	debug("%s: bank: %d\n", __func__, bank);
+	for (i = start; i < end; i++)
+		set_section_dcache(i, ARMV7_DCACHE_WRITEBACK);
+
+}
+
+void arm_init_domains(void)
+{
+	u32 reg;
+
+	reg = get_dacr();
+	/*
+	* Set DOMAIN to client access so that all permissions
+	* set in pagetables are validated by the mmu.
+	*/
+	reg &= ~ARMV7_DOMAIN_MASK;
+	reg |= ARMV7_DOMAIN_CLIENT;
+	set_dacr(reg);
+}
 #endif
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 78ca8e0..9cfbb17 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -75,6 +75,20 @@ static inline void set_cr(unsigned int val)
 	isb();
 }
 
+static inline unsigned int get_dacr(void)
+{
+	unsigned int val;
+	asm("mrc p15, 0, %0, c3, c0, 0	@ get DACR" : "=r" (val) : : "cc");
+	return val;
+}
+
+static inline void set_dacr(unsigned int val)
+{
+	asm volatile("mcr p15, 0, %0, c3, c0, 0	@ set DACR"
+	  : : "r" (val) : "cc");
+	isb();
+}
+
 /* options available for data cache on each page */
 enum dcache_option {
 	DCACHE_OFF = 0x12,
diff --git a/arch/arm/lib/cache-cp15.c b/arch/arm/lib/cache-cp15.c
index 843078e..2149677 100644
--- a/arch/arm/lib/cache-cp15.c
+++ b/arch/arm/lib/cache-cp15.c
@@ -36,6 +36,12 @@ void __arm_init_before_mmu(void)
 void arm_init_before_mmu(void)
 	__attribute__((weak, alias("__arm_init_before_mmu")));
 
+void __arm_init_domains(void)
+{
+}
+void arm_init_domains(void)
+	__attribute__((weak, alias("__arm_init_domains")));
+
 static void cp_delay (void)
 {
 	volatile int i;
@@ -120,6 +126,9 @@ static inline void mmu_setup(void)
 	/* Set the access control to all-supervisor */
 	asm volatile("mcr p15, 0, %0, c3, c0, 0"
 		     : : "r" (~0));
+
+	arm_init_domains();
+
 	/* and enable the mmu */
 	reg = get_cr();	/* get control reg. */
 	cp_delay();
-- 
1.7.9.5