linux-kernel - [PATCH 3/3] riscv: mm: Do not restrict mmap address based on hint

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Message-Id: <20240826-riscv_mmap-v1-3-cd8962afe47f@rivosinc.com>
Date: Mon, 26 Aug 2024 09:36:47 -0700
From: Charlie Jenkins <charlie@...osinc.com>
To: Jonathan Corbet <corbet@....net>, 
 Paul Walmsley <paul.walmsley@...ive.com>, 
 Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
 Shuah Khan <shuah@...nel.org>, Yangyu Chen <cyy@...self.name>, 
 Levi Zim <rsworktech@...look.com>, Alexandre Ghiti <alexghiti@...osinc.com>
Cc: linux-doc@...r.kernel.org, linux-riscv@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, Palmer Dabbelt <palmer@...osinc.com>, 
 linux-kselftest@...r.kernel.org, Charlie Jenkins <charlie@...osinc.com>
Subject: [PATCH 3/3] riscv: mm: Do not restrict mmap address based on hint

The hint address should not forcefully restrict the addresses returned
by mmap as this causes mmap to report ENOMEM when there is memory still
available.

Signed-off-by: Charlie Jenkins <charlie@...osinc.com>
Fixes: b5b4287accd7 ("riscv: mm: Use hint address in mmap if available")
Fixes: add2cc6b6515 ("RISC-V: mm: Restrict address space for sv39,sv48,sv57")
Closes: https://lore.kernel.org/linux-kernel/ZbxTNjQPFKBatMq+@ghost/T/#mccb1890466bf5a488c9ce7441e57e42271895765
---
 arch/riscv/include/asm/processor.h | 26 ++------------------------
 1 file changed, 2 insertions(+), 24 deletions(-)

diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 8702b8721a27..efa1b3519b23 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -14,36 +14,14 @@
 
 #include <asm/ptrace.h>
 
-/*
- * addr is a hint to the maximum userspace address that mmap should provide, so
- * this macro needs to return the largest address space available so that
- * mmap_end < addr, being mmap_end the top of that address space.
- * See Documentation/arch/riscv/vm-layout.rst for more details.
- */
 #define arch_get_mmap_end(addr, len, flags)			\
 ({								\
-	unsigned long mmap_end;					\
-	typeof(addr) _addr = (addr);				\
-	if ((_addr) == 0 || is_compat_task() ||			\
-	    ((_addr + len) > BIT(VA_BITS - 1)))			\
-		mmap_end = STACK_TOP_MAX;			\
-	else							\
-		mmap_end = (_addr + len);			\
-	mmap_end;						\
+	STACK_TOP_MAX;						\
 })
 
 #define arch_get_mmap_base(addr, base)				\
 ({								\
-	unsigned long mmap_base;				\
-	typeof(addr) _addr = (addr);				\
-	typeof(base) _base = (base);				\
-	unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base);	\
-	if ((_addr) == 0 || is_compat_task() || 		\
-	    ((_addr + len) > BIT(VA_BITS - 1)))			\
-		mmap_base = (_base);				\
-	else							\
-		mmap_base = (_addr + len) - rnd_gap;		\
-	mmap_base;						\
+	base;							\
 })
 
 #ifdef CONFIG_64BIT

-- 
2.45.0