[PATCH v2 22/37] powerpc: Fail ioremap() instead of silently ignoring flags when PAGE_USER is set

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Calling ioremap() with _PAGE_USER (or _PAGE_PRIVILEDGE unset)
is wrong. Loudly fail the call to ioremap() instead of blindly
clearing the flags.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/mm/ioremap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/ioremap.c b/arch/powerpc/mm/ioremap.c
index d5159f205380..7823c38f09de 100644
--- a/arch/powerpc/mm/ioremap.c
+++ b/arch/powerpc/mm/ioremap.c
@@ -51,7 +51,8 @@ void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long flags)
 		pte = pte_mkdirty(pte);
 
 	/* we don't want to let _PAGE_USER leak out */
-	pte = pte_mkprivileged(pte);
+	if (WARN_ON(pte_user(pte)))
+		return NULL;
 
 	if (iowa_is_active())
 		return iowa_ioremap(addr, size, pte_pgprot(pte), caller);
-- 
2.41.0