From patchwork series 421241

https://patchwork.ozlabs.org//project/linuxppc-dev/list/?series=421241

arch/arm/mm/mmap.c

@@ -71,6 +71,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	info.length = len;
 	info.low_limit = mm->mmap_base;
 	info.high_limit = TASK_SIZE;
+	if (flags & MAP_BELOW_HINT)
+		info.high_limit = MIN(info.high_limit, addr + len);
 	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
 	info.align_offset = pgoff << PAGE_SHIFT;
 	return vm_unmapped_area(&info);
@@ -122,6 +124,12 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	info.length = len;
 	info.low_limit = FIRST_USER_ADDRESS;
 	info.high_limit = mm->mmap_base;
+	if (flags & MAP_BELOW_HINT)
+		/*
+		 * Subtract (STACK_TOP - mm->mmap_base) to get random
+		 * offset defined in mmap_base() in mm/util.c
+		 */
+		info.high_limit = MIN(info.high_limit, (addr + len) - (STACK_TOP - mm->mmap_base));
 	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
 	info.align_offset = pgoff << PAGE_SHIFT;
 	addr = vm_unmapped_area(&info);
@@ -137,6 +145,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 		info.flags = 0;
 		info.low_limit = mm->mmap_base;
 		info.high_limit = TASK_SIZE;
+		if (flags & MAP_BELOW_HINT)
+			info.high_limit = MIN(info.high_limit, addr + len);
 		addr = vm_unmapped_area(&info);
 	}
 

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, base) ((addr > DEFAULT_MAP_WINDOW) ? \
-					base + TASK_SIZE - DEFAULT_MAP_WINDOW :\
-					base)
 #endif /* CONFIG_ARM64_FORCE_52BIT */
 
 extern phys_addr_t arm64_dma_phys_limit;

arch/loongarch/mm/mmap.c

@@ -70,6 +70,13 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 		info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 		info.low_limit = PAGE_SIZE;
 		info.high_limit = mm->mmap_base;
+		if (flags & MAP_BELOW_HINT)
+			/*
+			 * Subtract (STACK_TOP - mm->mmap_base) to get random
+			 * offset defined in mmap_base() in mm/util.c
+			 */
+			info.high_limit = MIN(mm->mmap_base,
+					      (addr + len) - (STACK_TOP - mm->mmap_base))
 		addr = vm_unmapped_area(&info);
 
 		if (!(addr & ~PAGE_MASK))
@@ -84,7 +91,11 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 	}
 
 	info.low_limit = mm->mmap_base;
+
 	info.high_limit = TASK_SIZE;
+	if (flags & MAP_BELOW_HINT)
+		info.high_limit = MIN(info.high_limit, addr + len);
+
 	return vm_unmapped_area(&info);
 }
 

arch/mips/mm/mmap.c

@@ -79,6 +79,13 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 		info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 		info.low_limit = PAGE_SIZE;
 		info.high_limit = mm->mmap_base;
+		if (flags & MAP_BELOW_HINT)
+			/*
+			 * Subtract (STACK_TOP - mm->mmap_base) to get random
+			 * offset defined in mmap_base() in mm/util.c
+			 */
+			info.high_limit = MIN(info.high_limit,
+					      (addr + len) - (STACK_TOP - mm->mmap_base));
 		addr = vm_unmapped_area(&info);
 
 		if (!(addr & ~PAGE_MASK))
@@ -94,6 +101,8 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 
 	info.low_limit = mm->mmap_base;
 	info.high_limit = TASK_SIZE;
+	if (flags & MAP_BELOW_HINT)
+		info.high_limit = MIN(info.high_limit, addr + len);
 	return vm_unmapped_area(&info);
 }
 

arch/parisc/include/uapi/asm/mman.h

@@ -26,6 +26,7 @@
 #define MAP_HUGETLB	0x80000		/* create a huge page mapping */
 #define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED which doesn't unmap underlying mapping */
 #define MAP_UNINITIALIZED 0		/* uninitialized anonymous mmap */
+#define MAP_BELOW_HINT  0x200000	/* give out address that is below (inclusive) hint address */
 
 #define MS_SYNC		1		/* synchronous memory sync */
 #define MS_ASYNC	2		/* sync memory asynchronously */

arch/parisc/kernel/sys_parisc.c

@@ -148,6 +148,13 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 		info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 		info.low_limit = PAGE_SIZE;
 		info.high_limit = mm->mmap_base;
+		if (flags & MAP_BELOW_HINT)
+			/*
+			 * Subtract (STACK_TOP - mm->mmap_base) to get random
+			 * offset defined in mmap_base() in mm/util.c
+			 */
+			info.high_limit = MIN(info.high_limit,
+					      (addr + len) - (STACK_TOP - mm->mmap_base));
 		addr = vm_unmapped_area(&info);
 		if (!(addr & ~PAGE_MASK))
 			return addr;
@@ -163,6 +170,8 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 
 	info.low_limit = mm->mmap_base;
 	info.high_limit = mmap_upper_limit(NULL);
+	if (flags & MAP_BELOW_HINT)
+		info.high_limit = MIN(info.high_limit, addr + len);
 	return vm_unmapped_area(&info);
 }
 

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, base) \
-	(((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 */

arch/riscv/include/asm/processor.h

@@ -14,38 +14,6 @@
 
 #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;						\
-})
-
-#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;						\
-})
-
 #ifdef CONFIG_64BIT
 #define DEFAULT_MAP_WINDOW	(UL(1) << (MMAP_VA_BITS - 1))
 #define STACK_TOP_MAX		TASK_SIZE_64

arch/s390/mm/mmap.c

@@ -105,6 +105,8 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	info.length = len;
 	info.low_limit = mm->mmap_base;
 	info.high_limit = TASK_SIZE;
+	if (flags & MAP_BELOW_HINT)
+		info.high_limit = MIN(info.high_limit, addr + len);
 	info.align_mask = get_align_mask(filp, flags);
 	info.align_offset = pgoff << PAGE_SHIFT;
 	addr = vm_unmapped_area(&info);
@@ -143,6 +145,12 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, unsigned long ad
 	info.length = len;
 	info.low_limit = PAGE_SIZE;
 	info.high_limit = mm->mmap_base;
+	if (flags & MAP_BELOW_HINT)
+		/*
+		 * Subtract (STACK_TOP - mm->mmap_base) to get random
+		 * offset defined in mmap_base() in mm/util.c
+		 */
+		info.high_limit = MIN(info.high_limit, addr + len) - (STACK_TOP - mm->mmap_base);
 	info.align_mask = get_align_mask(filp, flags);
 	info.align_offset = pgoff << PAGE_SHIFT;
 	addr = vm_unmapped_area(&info);
@@ -158,6 +166,8 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, unsigned long ad
 		info.flags = 0;
 		info.low_limit = TASK_UNMAPPED_BASE;
 		info.high_limit = TASK_SIZE;
+		if (flags & MAP_BELOW_HINT)
+			info.high_limit = MIN(TASK_SIZE, addr + len);
 		addr = vm_unmapped_area(&info);
 		if (offset_in_page(addr))
 			return addr;

arch/sh/mm/mmap.c

@@ -91,6 +91,8 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	info.length = len;
 	info.low_limit = TASK_UNMAPPED_BASE;
 	info.high_limit = TASK_SIZE;
+	if (flags & MAP_BELOW_HINT)
+		info.high_limit = MIN(info.high_limit, addr + len);
 	info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
 	info.align_offset = pgoff << PAGE_SHIFT;
 	return vm_unmapped_area(&info);
@@ -141,6 +143,12 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	info.length = len;
 	info.low_limit = PAGE_SIZE;
 	info.high_limit = mm->mmap_base;
+	if (flags & MAP_BELOW_HINT)
+		/*
+		 * Subtract (STACK_TOP - mm->mmap_base) to get random
+		 * offset defined in mmap_base() in mm/util.c
+		 */
+		info.high_limit = MIN(info.high_limit, (addr + len) - (STACK_TOP - mm->mmap_base));
 	info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
 	info.align_offset = pgoff << PAGE_SHIFT;
 	addr = vm_unmapped_area(&info);
@@ -156,6 +164,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 		info.flags = 0;
 		info.low_limit = TASK_UNMAPPED_BASE;
 		info.high_limit = TASK_SIZE;
+		if (flags & MAP_BELOW_HINT)
+			info.high_limit = MIN(info.high_limit, addr + len);
 		addr = vm_unmapped_area(&info);
 	}
 

arch/sparc/kernel/sys_sparc_64.c

@@ -129,6 +129,8 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
 	info.length = len;
 	info.low_limit = TASK_UNMAPPED_BASE;
 	info.high_limit = min(task_size, VA_EXCLUDE_START);
+	if (flags & MAP_BELOW_HINT)
+		info.high_limit = MIN(info.high_limit, addr + len);
 	info.align_mask = do_color_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
 	info.align_offset = pgoff << PAGE_SHIFT;
 	addr = vm_unmapped_area(&info);
@@ -137,6 +139,8 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
 		VM_BUG_ON(addr != -ENOMEM);
 		info.low_limit = VA_EXCLUDE_END;
 		info.high_limit = task_size;
+		if (flags & MAP_BELOW_HINT)
+			info.high_limit = MIN(info.high_limit, addr + len);
 		addr = vm_unmapped_area(&info);
 	}
 
@@ -192,6 +196,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	info.length = len;
 	info.low_limit = PAGE_SIZE;
 	info.high_limit = mm->mmap_base;
+	if (flags & MAP_BELOW_HINT)
+		info.high_limit = MIN(info.high_limit, addr + len);
 	info.align_mask = do_color_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
 	info.align_offset = pgoff << PAGE_SHIFT;
 	addr = vm_unmapped_area(&info);
@@ -207,6 +213,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 		info.flags = 0;
 		info.low_limit = TASK_UNMAPPED_BASE;
 		info.high_limit = STACK_TOP32;
+		if (flags & MAP_BELOW_HINT)
+			info.high_limit = MIN(info.high_limit, addr + len);
 		addr = vm_unmapped_area(&info);
 	}