1 files changed, 147 insertions, 0 deletions
diff --git a/arch/loongarch/mm/mmap.c b/arch/loongarch/mm/mmap.c
new file mode 100644
index 000000000000..fbe1a4856fc4
--- /dev/null
+++ b/arch/loongarch/mm/mmap.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <linux/export.h>
+#include <linux/io.h>
+#include <linux/memblock.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+
+unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */
+EXPORT_SYMBOL(shm_align_mask);
+
+#define COLOUR_ALIGN(addr, pgoff)				\
+	((((addr) + shm_align_mask) & ~shm_align_mask) +	\
+	 (((pgoff) << PAGE_SHIFT) & shm_align_mask))
+
+enum mmap_allocation_direction {UP, DOWN};
+
+static unsigned long arch_get_unmapped_area_common(struct file *filp,
+	unsigned long addr0, unsigned long len, unsigned long pgoff,
+	unsigned long flags, enum mmap_allocation_direction dir)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	unsigned long addr = addr0;
+	int do_color_align;
+	struct vm_unmapped_area_info info;
+
+	if (unlikely(len > TASK_SIZE))
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED) {
+		/* Even MAP_FIXED mappings must reside within TASK_SIZE */
+		if (TASK_SIZE - len < addr)
+			return -EINVAL;
+
+		/*
+		 * We do not accept a shared mapping if it would violate
+		 * cache aliasing constraints.
+		 */
+		if ((flags & MAP_SHARED) &&
+		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
+			return -EINVAL;
+		return addr;
+	}
+
+	do_color_align = 0;
+	if (filp || (flags & MAP_SHARED))
+		do_color_align = 1;
+
+	/* requesting a specific address */
+	if (addr) {
+		if (do_color_align)
+			addr = COLOUR_ALIGN(addr, pgoff);
+		else
+			addr = PAGE_ALIGN(addr);
+
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr &&
+		    (!vma || addr + len <= vm_start_gap(vma)))
+			return addr;
+	}
+
+	info.length = len;
+	info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
+	info.align_offset = pgoff << PAGE_SHIFT;
+
+	if (dir == DOWN) {
+		info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+		info.low_limit = PAGE_SIZE;
+		info.high_limit = mm->mmap_base;
+		addr = vm_unmapped_area(&info);
+
+		if (!(addr & ~PAGE_MASK))
+			return addr;
+
+		/*
+		 * A failed mmap() very likely causes application failure,
+		 * so fall back to the bottom-up function here. This scenario
+		 * can happen with large stack limits and large mmap()
+		 * allocations.
+		 */
+	}
+
+	info.flags = 0;
+	info.low_limit = mm->mmap_base;
+	info.high_limit = TASK_SIZE;
+	return vm_unmapped_area(&info);
+}
+
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
+	unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+	return arch_get_unmapped_area_common(filp,
+			addr0, len, pgoff, flags, UP);
+}
+
+/*
+ * There is no need to export this but sched.h declares the function as
+ * extern so making it static here results in an error.
+ */
+unsigned long arch_get_unmapped_area_topdown(struct file *filp,
+	unsigned long addr0, unsigned long len, unsigned long pgoff,
+	unsigned long flags)
+{
+	return arch_get_unmapped_area_common(filp,
+			addr0, len, pgoff, flags, DOWN);
+}
+
+int __virt_addr_valid(volatile void *kaddr)
+{
+	unsigned long vaddr = (unsigned long)kaddr;
+
+	if ((vaddr < PAGE_OFFSET) || (vaddr >= vm_map_base))
+		return 0;
+
+	return pfn_valid(PFN_DOWN(PHYSADDR(kaddr)));
+}
+EXPORT_SYMBOL_GPL(__virt_addr_valid);
+
+/*
+ * You really shouldn't be using read() or write() on /dev/mem.  This might go
+ * away in the future.
+ */
+int valid_phys_addr_range(phys_addr_t addr, size_t size)
+{
+	/*
+	 * Check whether addr is covered by a memory region without the
+	 * MEMBLOCK_NOMAP attribute, and whether that region covers the
+	 * entire range. In theory, this could lead to false negatives
+	 * if the range is covered by distinct but adjacent memory regions
+	 * that only differ in other attributes. However, few of such
+	 * attributes have been defined, and it is debatable whether it
+	 * follows that /dev/mem read() calls should be able traverse
+	 * such boundaries.
+	 */
+	return memblock_is_region_memory(addr, size) && memblock_is_map_memory(addr);
+}
+
+/*
+ * Do not allow /dev/mem mappings beyond the supported physical range.
+ */
+int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
+{
+	return !(((pfn << PAGE_SHIFT) + size) & ~(GENMASK_ULL(cpu_pabits, 0)));
+}