s390: Allow vmalloc target buffers for copy_from_oldmem()

Currently copy_from_oldmem() is not able to copy to virtual memory.
When using kexec pre-allocated ELF header, copy_from_oldmem()
is used to copy the ELF notes information to vmalloc buffers.

So fix this and use the new function copy_from_realmem() that allows
copying also to vmalloc memory.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index c84f33d..7dd2172 100644 (file)
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -40,28 +40,26 @@ static inline void *load_real_addr(void *addr)
 }
 
 /*
- * Copy up to one page to vmalloc or real memory
+ * Copy real to virtual or real memory
  */
-static ssize_t copy_page_real(void *buf, void *src, size_t csize)
+static int copy_from_realmem(void *dest, void *src, size_t count)
 {
-       size_t size;
+       unsigned long size;
+       int rc;
 
-       if (is_vmalloc_addr(buf)) {
-               BUG_ON(csize >= PAGE_SIZE);
-               /* If buf is not page aligned, copy first part */
-               size = min(roundup(__pa(buf), PAGE_SIZE) - __pa(buf), csize);
-               if (size) {
-                       if (memcpy_real(load_real_addr(buf), src, size))
-                               return -EFAULT;
-                       buf += size;
-                       src += size;
-               }
-               /* Copy second part */
-               size = csize - size;
-               return (size) ? memcpy_real(load_real_addr(buf), src, size) : 0;
-       } else {
-               return memcpy_real(buf, src, csize);
-       }
+       if (!count)
+               return 0;
+       if (!is_vmalloc_or_module_addr(dest))
+               return memcpy_real(dest, src, count);
+       do {
+               size = min(count, PAGE_SIZE - (__pa(dest) & ~PAGE_MASK));
+               if (memcpy_real(load_real_addr(dest), src, size))
+                       return -EFAULT;
+               count -= size;
+               dest += size;
+               src += size;
+       } while (count);
+       return 0;
 }
 
 /*
@@ -114,7 +112,7 @@ static ssize_t copy_oldmem_page_kdump(char *buf, size_t csize,
                rc = copy_to_user_real((void __force __user *) buf,
                                       (void *) src, csize);
        else
-               rc = copy_page_real(buf, (void *) src, csize);
+               rc = copy_from_realmem(buf, (void *) src, csize);
        return (rc == 0) ? rc : csize;
 }
 
@@ -210,7 +208,7 @@ int copy_from_oldmem(void *dest, void *src, size_t count)
        if (OLDMEM_BASE) {
                if ((unsigned long) src < OLDMEM_SIZE) {
                        copied = min(count, OLDMEM_SIZE - (unsigned long) src);
-                       rc = memcpy_real(dest, src + OLDMEM_BASE, copied);
+                       rc = copy_from_realmem(dest, src + OLDMEM_BASE, copied);
                        if (rc)
                                return rc;
                }
@@ -223,7 +221,7 @@ int copy_from_oldmem(void *dest, void *src, size_t count)
                                return rc;
                }
        }
-       return memcpy_real(dest + copied, src + copied, count - copied);
+       return copy_from_realmem(dest + copied, src + copied, count - copied);
 }
 
 /*