[PATCH 06/16] arm64: mm: Support MAP_BELOW_HINT

[Charlie Jenkins]

Add support for MAP_BELOW_HINT to arch_get_mmap_base() and
arch_get_mmap_end().

Signed-off-by: Charlie Jenkins <charlie at rivosinc.com>
---
 arch/arm64/include/asm/processor.h | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index a67ca119bb91..39aabb1619f6 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -92,12 +92,36 @@
 #endif /* CONFIG_COMPAT */
 
 #ifndef CONFIG_ARM64_FORCE_52BIT
-#define arch_get_mmap_end(addr, len, flags) \
-		(((addr) > DEFAULT_MAP_WINDOW) ? TASK_SIZE : DEFAULT_MAP_WINDOW)
+#define arch_get_mmap_end(addr, len, flags)							\
+({												\
+	unsigned long mmap_end;									\
+	typeof(flags) _flags = (flags);								\
+	typeof(addr) _addr = (addr);								\
+	typeof(len) _len = (len);								\
+	if (_flags & MAP_BELOW_HINT && _addr != 0 && ((_addr + _len) > BIT(VA_BITS - 1)))	\
+		mmap_end = (_addr + _len);							\
+	else											\
+		mmap_end = ((_addr > DEFAULT_MAP_WINDOW) ? TASK_SIZE : DEFAULT_MAP_WINDOW);	\
+	mmap_end										\
+})
+
+#define arch_get_mmap_base(addr, len, base, flags)					\
+({											\
+	unsigned long mmap_base;							\
+	typeof(flags) _flags = (flags);							\
+	typeof(addr) _addr = (addr);							\
+	typeof(base) _base = (base);							\
+	typeof(len) _len = (len);							\
+	unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base);				\
+	if (_flags & MAP_BELOW_HINT && _addr != 0 && ((_addr + _len) > BIT(VA_BITS - 1)))\
+		mmap_base = (_addr + _len) - rnd_gap;					\
+	else										\
+		mmap_end = ((_addr > DEFAULT_MAP_WINDOW) ?				\
+				_base + TASK_SIZE - DEFAULT_MAP_WINDOW :		\
+				_base);							\
+	mmap_end									\
+})
 
-#define arch_get_mmap_base(addr, len, base, flags) ((addr > DEFAULT_MAP_WINDOW) ? \
-					base + TASK_SIZE - DEFAULT_MAP_WINDOW :\
-					base)
 #endif /* CONFIG_ARM64_FORCE_52BIT */
 
 extern phys_addr_t arm64_dma_phys_limit;

-- 
2.45.0