1 files changed, 95 insertions, 16 deletions
diff --git a/mm/nommu.c b/mm/nommu.c
index baa79abdaf03..617e7ba8022f 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -42,18 +42,11 @@
 #include <asm/mmu_context.h>
 #include "internal.h"
 
-void *high_memory;
-EXPORT_SYMBOL(high_memory);
-struct page *mem_map;
-unsigned long max_mapnr;
-EXPORT_SYMBOL(max_mapnr);
 unsigned long highest_memmap_pfn;
-int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
 int heap_stack_gap = 0;
 
 atomic_long_t mmap_pages_allocated;
 
-EXPORT_SYMBOL(mem_map);
 
 /* list of mapped, potentially shareable regions */
 static struct kmem_cache *vm_region_jar;
@@ -392,6 +385,19 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
 	return mm->brk = brk;
 }
 
+static int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
+
+static const struct ctl_table nommu_table[] = {
+	{
+		.procname	= "nr_trim_pages",
+		.data		= &sysctl_nr_trim_pages,
+		.maxlen		= sizeof(sysctl_nr_trim_pages),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+};
+
 /*
  * initialise the percpu counter for VM and region record slabs
  */
@@ -402,6 +408,7 @@ void __init mmap_init(void)
 	ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
 	VM_BUG_ON(ret);
 	vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT);
+	register_sysctl_init("vm", nommu_table);
 }
 
 /*
@@ -1191,7 +1198,7 @@ share:
 	setup_vma_to_mm(vma, current->mm);
 	current->mm->map_count++;
 	/* add the VMA to the tree */
-	vma_iter_store(&vmi, vma);
+	vma_iter_store_new(&vmi, vma);
 
 	/* we flush the region from the icache only when the first executable
 	 * mapping of it is made  */
@@ -1356,7 +1363,7 @@ static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
 
 	setup_vma_to_mm(vma, mm);
 	setup_vma_to_mm(new, mm);
-	vma_iter_store(vmi, new);
+	vma_iter_store_new(vmi, new);
 	mm->map_count++;
 	return 0;
 
@@ -1613,13 +1620,6 @@ int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
 }
 EXPORT_SYMBOL(remap_vmalloc_range);
 
-vm_fault_t filemap_fsnotify_fault(struct vm_fault *vmf)
-{
-	BUG();
-	return 0;
-}
-EXPORT_SYMBOL_GPL(filemap_fsnotify_fault);
-
 vm_fault_t filemap_fault(struct vm_fault *vmf)
 {
 	BUG();
@@ -1708,6 +1708,85 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
 }
 EXPORT_SYMBOL_GPL(access_process_vm);
 
+#ifdef CONFIG_BPF_SYSCALL
+/*
+ * Copy a string from another process's address space as given in mm.
+ * If there is any error return -EFAULT.
+ */
+static int __copy_remote_vm_str(struct mm_struct *mm, unsigned long addr,
+				void *buf, int len)
+{
+	unsigned long addr_end;
+	struct vm_area_struct *vma;
+	int ret = -EFAULT;
+
+	*(char *)buf = '\0';
+
+	if (mmap_read_lock_killable(mm))
+		return ret;
+
+	/* the access must start within one of the target process's mappings */
+	vma = find_vma(mm, addr);
+	if (!vma)
+		goto out;
+
+	if (check_add_overflow(addr, len, &addr_end))
+		goto out;
+
+	/* don't overrun this mapping */
+	if (addr_end > vma->vm_end)
+		len = vma->vm_end - addr;
+
+	/* only read mappings where it is permitted */
+	if (vma->vm_flags & VM_MAYREAD) {
+		ret = strscpy(buf, (char *)addr, len);
+		if (ret < 0)
+			ret = len - 1;
+	}
+
+out:
+	mmap_read_unlock(mm);
+	return ret;
+}
+
+/**
+ * copy_remote_vm_str - copy a string from another process's address space.
+ * @tsk:	the task of the target address space
+ * @addr:	start address to read from
+ * @buf:	destination buffer
+ * @len:	number of bytes to copy
+ * @gup_flags:	flags modifying lookup behaviour (unused)
+ *
+ * The caller must hold a reference on @mm.
+ *
+ * Return: number of bytes copied from @addr (source) to @buf (destination);
+ * not including the trailing NUL. Always guaranteed to leave NUL-terminated
+ * buffer. On any error, return -EFAULT.
+ */
+int copy_remote_vm_str(struct task_struct *tsk, unsigned long addr,
+		       void *buf, int len, unsigned int gup_flags)
+{
+	struct mm_struct *mm;
+	int ret;
+
+	if (unlikely(len == 0))
+		return 0;
+
+	mm = get_task_mm(tsk);
+	if (!mm) {
+		*(char *)buf = '\0';
+		return -EFAULT;
+	}
+
+	ret = __copy_remote_vm_str(mm, addr, buf, len);
+
+	mmput(mm);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(copy_remote_vm_str);
+#endif /* CONFIG_BPF_SYSCALL */
+
 /**
  * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
  * @inode: The inode to check