linux-kernel - [PATCH 07/16] powerpc: mm: Support MAP_BELOW

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Message-Id: <20240827-patches-below_hint_mmap-v1-7-46ff2eb9022d@rivosinc.com>
Date: Tue, 27 Aug 2024 22:49:13 -0700
From: Charlie Jenkins <charlie@...osinc.com>
To: Arnd Bergmann <arnd@...db.de>, Paul Walmsley <paul.walmsley@...ive.com>, 
 Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
 Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>, 
 Christophe Leroy <christophe.leroy@...roup.eu>, 
 Naveen N Rao <naveen@...nel.org>, Muchun Song <muchun.song@...ux.dev>, 
 Andrew Morton <akpm@...ux-foundation.org>, 
 "Liam R. Howlett" <Liam.Howlett@...cle.com>, 
 Vlastimil Babka <vbabka@...e.cz>, 
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, 
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, 
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, 
 x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>, 
 Huacai Chen <chenhuacai@...nel.org>, WANG Xuerui <kernel@...0n.name>, 
 Russell King <linux@...linux.org.uk>, 
 Thomas Bogendoerfer <tsbogend@...ha.franken.de>, 
 "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>, 
 Helge Deller <deller@....de>, Alexander Gordeev <agordeev@...ux.ibm.com>, 
 Gerald Schaefer <gerald.schaefer@...ux.ibm.com>, 
 Heiko Carstens <hca@...ux.ibm.com>, Vasily Gorbik <gor@...ux.ibm.com>, 
 Christian Borntraeger <borntraeger@...ux.ibm.com>, 
 Sven Schnelle <svens@...ux.ibm.com>, 
 Yoshinori Sato <ysato@...rs.sourceforge.jp>, Rich Felker <dalias@...c.org>, 
 John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>, 
 "David S. Miller" <davem@...emloft.net>, 
 Andreas Larsson <andreas@...sler.com>, Shuah Khan <shuah@...nel.org>, 
 Alexandre Ghiti <alexghiti@...osinc.com>
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Palmer Dabbelt <palmer@...osinc.com>, linux-riscv@...ts.infradead.org, 
 linux-arm-kernel@...ts.infradead.org, linuxppc-dev@...ts.ozlabs.org, 
 linux-mm@...ck.org, loongarch@...ts.linux.dev, linux-mips@...r.kernel.org, 
 linux-parisc@...r.kernel.org, linux-s390@...r.kernel.org, 
 linux-sh@...r.kernel.org, sparclinux@...r.kernel.org, 
 linux-kselftest@...r.kernel.org, Charlie Jenkins <charlie@...osinc.com>
Subject: [PATCH 07/16] powerpc: mm: Support MAP_BELOW_HINT

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

Signed-off-by: Charlie Jenkins <charlie@...osinc.com>
---
 arch/powerpc/include/asm/task_size_64.h | 36 +++++++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/task_size_64.h b/arch/powerpc/include/asm/task_size_64.h
index 239b363841aa..a37a5a81365d 100644
--- a/arch/powerpc/include/asm/task_size_64.h
+++ b/arch/powerpc/include/asm/task_size_64.h
@@ -72,12 +72,36 @@
 #define STACK_TOP_MAX TASK_SIZE_USER64
 #define STACK_TOP (is_32bit_task() ? STACK_TOP_USER32 : STACK_TOP_USER64)

-#define arch_get_mmap_base(addr, len, base, flags) \
-	(((addr) > DEFAULT_MAP_WINDOW) ? (base) + TASK_SIZE - DEFAULT_MAP_WINDOW : (base))
+#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_end(addr, len, flags) \
-	(((addr) > DEFAULT_MAP_WINDOW) || \
-	 (((flags) & MAP_FIXED) && ((addr) + (len) > 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) ||					\
+				(((_flags) & MAP_FIXED) && ((_addr) + (_len) > DEFAULT_MAP_WINDOW))\
+				? TASK_SIZE : DEFAULT_MAP_WINDOW)				\
+	mmap_end;										\
+})

 #endif /* _ASM_POWERPC_TASK_SIZE_64_H */

-- 
2.45.0