It's currently only used in the EFI code, which is safe AFAICT.
Warn if anyone tries to use it on the normal kernel pgd.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
arch/x86/mm/pageattr.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 6a8026918bf6..e9b9c5cedbb8 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1996,6 +1996,9 @@ out:
void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address,
unsigned numpages)
{
+ /* Unmapping kernel entries from init_mm's pgd is not allowed. */
+ WARN_ON(root == init_mm.pgd);
+
unmap_pgd_range(root, address, address + (numpages << PAGE_SHIFT));
}
--
2.5.5
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