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-rw-r--r--arch/loongarch/mm/mmap.c147
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 000000000..fbe1a4856
--- /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)));
+}