powerpc: Fix virt_addr_valid() check

hulk inclusion
category: bugfix
bugzilla: 186017 https://gitee.com/openeuler/kernel/issues/I4DDEL



--------------------------------

When run ethtool eth0, the BUG occurred,

  usercopy: Kernel memory exposure attempt detected from SLUB object not in SLUB page?! (offset 0, size 1048)!
  kernel BUG at mm/usercopy.c:99
  ...
  usercopy_abort+0x64/0xa0 (unreliable)
  __check_heap_object+0x168/0x190
  __check_object_size+0x1a0/0x200
  dev_ethtool+0x2494/0x2b20
  dev_ioctl+0x5d0/0x770
  sock_do_ioctl+0xf0/0x1d0
  sock_ioctl+0x3ec/0x5a0
  __se_sys_ioctl+0xf0/0x160
  system_call_exception+0xfc/0x1f0
  system_call_common+0xf8/0x200

The code shows below,

  data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));
  copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN))

The data is alloced by vmalloc(), virt_addr_valid(ptr) will return true
on PowerPC64, which leads to the panic.

As commit 4dd7554a ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va
and __pa addresses") does, make sure the virt addr above PAGE_OFFSET in
the virt_addr_valid().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Yuanzheng Song <songyuanzheng@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>