[PATCH 2/3] arm64: Use level-2 for largest block mappings when FEAT_HAFDBS is present

[Ying-Chun Liu (PaulLiu)]

From: Marc Zyngier <maz at kernel.org>

In order to make invalidation by VA more efficient, set the largest
block mapping to 2MB, mapping it onto level-2. This has no material
impact on u-boot's runtime performance, and allows a huge speedup
when cleaning the cache.

Signed-off-by: Marc Zyngier <maz at kernel.org>
[ Paul: pick from the Android tree. Rebase to the upstream ]
Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu at linaro.org>
Cc: Tom Rini <trini at konsulko.com>
Link: https://android.googlesource.com/platform/external/u-boot/+/417a73581a72ff6d6ee4b0938117b8a23e32f7e8
---
 arch/arm/cpu/armv8/cache_v8.c      | 14 ++++++++++----
 arch/arm/include/asm/global_data.h |  1 +
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/arm/cpu/armv8/cache_v8.c b/arch/arm/cpu/armv8/cache_v8.c
index 4760064ee1..4c6a1b1d6c 100644
--- a/arch/arm/cpu/armv8/cache_v8.c
+++ b/arch/arm/cpu/armv8/cache_v8.c
@@ -314,7 +314,7 @@ static void map_range(u64 virt, u64 phys, u64 size, int level,
 	for (i = idx; size; i++) {
 		u64 next_size, *next_table;
 
-		if (level >= 1 &&
+		if (level >= gd->arch.first_block_level &&
 		    size >= map_size && !(virt & (map_size - 1))) {
 			if (level == 3)
 				table[i] = phys | attrs | PTE_TYPE_PAGE;
@@ -353,6 +353,9 @@ static void add_map(struct mm_region *map)
 	if (va_bits < 39)
 		level = 1;
 
+	if (!gd->arch.first_block_level)
+		gd->arch.first_block_level = 1;
+
 	if (gd->arch.has_hafdbs)
 		attrs |= PTE_DBM | PTE_RDONLY;
 
@@ -369,7 +372,7 @@ static void count_range(u64 virt, u64 size, int level, int *cntp)
 	for (i = idx; size; i++) {
 		u64 next_size;
 
-		if (level >= 1 &&
+		if (level >= gd->arch.first_block_level &&
 		    size >= map_size && !(virt & (map_size - 1))) {
 			virt += map_size;
 			size -= map_size;
@@ -410,10 +413,13 @@ __weak u64 get_page_table_size(void)
 	u64 size, mmfr1;
 
 	asm volatile("mrs %0, id_aa64mmfr1_el1" : "=r" (mmfr1));
-	if ((mmfr1 & 0xf) == 2)
+	if ((mmfr1 & 0xf) == 2) {
 		gd->arch.has_hafdbs = true;
-	else
+		gd->arch.first_block_level = 2;
+	} else {
 		gd->arch.has_hafdbs = false;
+		gd->arch.first_block_level = 1;
+	}
 
 	/* Account for all page tables we would need to cover our memory map */
 	size = one_pt * count_ranges();
diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h
index eda99b5b41..9d94cbe665 100644
--- a/arch/arm/include/asm/global_data.h
+++ b/arch/arm/include/asm/global_data.h
@@ -52,6 +52,7 @@ struct arch_global_data {
 #if defined(CONFIG_ARM64)
 	unsigned long tlb_fillptr;
 	unsigned long tlb_emerg;
+	unsigned int first_block_level;
 	bool has_hafdbs;
 #endif
 #endif
-- 
2.39.2