[RFC PATCH v4 2/6] arm64: Add level-hinted TLB invalidation helper

[Zhenyu Ye]

From: Marc Zyngier <maz@xxxxxxxxxx>

Add a level-hinted TLB invalidation helper that only gets used if
ARMv8.4-TTL gets detected.

Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Zhenyu Ye <yezhenyu2@xxxxxxxxxx>
---
 arch/arm64/include/asm/tlbflush.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index bc3949064725..a3f70778a325 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -10,6 +10,7 @@
 
 #ifndef __ASSEMBLY__
 
+#include <linux/bitfield.h>
 #include <linux/mm_types.h>
 #include <linux/sched.h>
 #include <asm/cputype.h>
@@ -59,6 +60,35 @@
 		__ta;						\
 	})
 
+#define TLBI_TTL_MASK	GENMASK_ULL(47, 44)
+
+#define __tlbi_level(op, addr, level)					\
+	do {								\
+		u64 arg = addr;						\
+									\
+		if (cpus_have_const_cap(ARM64_HAS_ARMv8_4_TTL) &&	\
+		    level) {						\
+			u64 ttl = level;				\
+									\
+			switch (PAGE_SIZE) {				\
+			case SZ_4K:					\
+				ttl |= 1 << 2;				\
+				break;					\
+			case SZ_16K:					\
+				ttl |= 2 << 2;				\
+				break;					\
+			case SZ_64K:					\
+				ttl |= 3 << 2;				\
+				break;					\
+			}						\
+									\
+			arg &= ~TLBI_TTL_MASK;				\
+			arg |= FIELD_PREP(TLBI_TTL_MASK, ttl);		\
+		}							\
+									\
+		__tlbi(op,  arg);					\
+	} while(0)
+
 /*
  *	TLB Invalidation
  *	================
-- 
2.19.1