Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
  fs/proc/vmcore.c        | 28 +++++++---------------------
  include/linux/uaccess.h |  1 +
  lib/usercopy.c          | 15 +++++++++++++++
  3 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 509f851..f67fd77 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c

@@ -238,22 +238,8 @@ copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
  	return copy_oldmem_page(pfn, buf, csize, offset, userbuf);
  }
  
-/*
- * Copy to either kernel or user space
- */
-static int copy_to(void *target, void *src, size_t size, int userbuf)
-{
-	if (userbuf) {
-		if (copy_to_user((char __user *) target, src, size))
-			return -EFAULT;
-	} else {
-		memcpy(target, src, size);
-	}
-	return 0;
-}
-
  #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
-static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
+static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, bool userbuf)

  {
  	struct vmcoredd_node *dump;
  	u64 offset = 0;

@@ -266,7 +252,7 @@ static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
  		if (start < offset + dump->size) {
  			tsz = min(offset + (u64)dump->size - start, (u64)size);
  			buf = dump->buf + start - offset;
-			if (copy_to(dst, buf, tsz, userbuf)) {
+			if (copy_to_user_or_kernel(dst, buf, tsz, userbuf)) {
  				ret = -EFAULT;
  				goto out_unlock;
  			}

@@ -330,7 +316,7 @@ static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst,
   * returned otherwise number of bytes read are returned.
   */
  static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
-			     int userbuf)
+			     bool userbuf)
  {
  	ssize_t acc = 0, tmp;
  	size_t tsz;

@@ -347,7 +333,7 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
  	/* Read ELF core header */
  	if (*fpos < elfcorebuf_sz) {
  		tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
-		if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
+		if (copy_to_user_or_kernel(buffer, elfcorebuf + *fpos, tsz, userbuf))
  			return -EFAULT;
  		buflen -= tsz;
  		*fpos += tsz;

@@ -395,7 +381,7 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
  		/* Read remaining elf notes */
  		tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
  		kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
-		if (copy_to(buffer, kaddr, tsz, userbuf))
+		if (copy_to_user_or_kernel(buffer, kaddr, tsz, userbuf))
  			return -EFAULT;
  
  		buflen -= tsz;

@@ -435,7 +421,7 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
  static ssize_t read_vmcore(struct file *file, char __user *buffer,
  			   size_t buflen, loff_t *fpos)
  {
-	return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
+	return __read_vmcore((__force char *) buffer, buflen, fpos, true);
  }
  
  /*

@@ -461,7 +447,7 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
  	if (!PageUptodate(page)) {
  		offset = (loff_t) index << PAGE_SHIFT;
  		buf = __va((page_to_pfn(page) << PAGE_SHIFT));
-		rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
+		rc = __read_vmcore(buf, PAGE_SIZE, &offset, false);
  		if (rc < 0) {
  			unlock_page(page);
  			put_page(page);

diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index ac03940..a25e682e 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h

@@ -283,6 +283,7 @@ __copy_from_user_inatomic_nocache(void *to, const void __user *from,
  #endif		/* ARCH_HAS_NOCACHE_UACCESS */
  
  extern __must_check int check_zeroed_user(const void __user *from, size_t size);
+extern __must_check int copy_to_user_or_kernel(void *target, void *src, size_t size, bool userbuf);

  
  /**
   * copy_struct_from_user: copy a struct from userspace

diff --git a/lib/usercopy.c b/lib/usercopy.c
index 7413dd3..7431b1b 100644
--- a/lib/usercopy.c
+++ b/lib/usercopy.c

@@ -90,3 +90,18 @@ int check_zeroed_user(const void __user *from, size_t size)
  	return -EFAULT;
  }
  EXPORT_SYMBOL(check_zeroed_user);
+
+/*
+ * Copy to either user or kernel space
+ */
+int copy_to_user_or_kernel(void *target, void *src, size_t size, bool userbuf)
+{
+	if (userbuf) {
+		if (copy_to_user((char __user *) target, src, size))
+			return -EFAULT;
+	} else {
+		memcpy(target, src, size);
+	}
+	return 0;
+}
+EXPORT_SYMBOL(copy_to_user_or_kernel);