powerpc/nohash: Replace pte_user() by pte_read()

pte_user() is now only used in pte_access_permitted() to check
access on vmas. User flag is cleared to make a page unreadable.

So rename it pte_read() and remove pte_user() which isn't used
anymore.

For the time being it checks _PAGE_USER but in the near futur
all plateforms will be converted to _PAGE_READ so lets support
both for now.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/72cbb5be595e9ef884140def73815ed0b0b37010.1695659959.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/nohash/32/pte-8xx.h

@@ -112,13 +112,6 @@ static inline pte_t pte_mkwrite_novma(pte_t pte)
 
 #define pte_mkwrite_novma pte_mkwrite_novma
 
-static inline bool pte_user(pte_t pte)
-{
-	return !(pte_val(pte) & _PAGE_SH);
-}
-
-#define pte_user pte_user
-
 static inline pte_t pte_mkhuge(pte_t pte)
 {
 	return __pte(pte_val(pte) | _PAGE_SPS | _PAGE_HUGE);

arch/powerpc/include/asm/nohash/pgtable.h

@@ -159,9 +159,6 @@ static inline int pte_write(pte_t pte)
 	return pte_val(pte) & _PAGE_WRITE;
 }
 #endif
-#ifndef pte_read
-static inline int pte_read(pte_t pte)		{ return 1; }
-#endif
 static inline int pte_dirty(pte_t pte)		{ return pte_val(pte) & _PAGE_DIRTY; }
 static inline int pte_special(pte_t pte)	{ return pte_val(pte) & _PAGE_SPECIAL; }
 static inline int pte_none(pte_t pte)		{ return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
@@ -189,10 +186,14 @@ static inline int pte_young(pte_t pte)
  * and PTE_64BIT, PAGE_KERNEL_X contains _PAGE_BAP_SR which is also in
  * _PAGE_USER.  Need to explicitly match _PAGE_BAP_UR bit in that case too.
  */
-#ifndef pte_user
-static inline bool pte_user(pte_t pte)
+#ifndef pte_read
+static inline bool pte_read(pte_t pte)
 {
+#ifdef _PAGE_READ
+	return (pte_val(pte) & _PAGE_READ) == _PAGE_READ;
+#else
 	return (pte_val(pte) & _PAGE_USER) == _PAGE_USER;
+#endif
 }
 #endif
 
@@ -207,7 +208,7 @@ static inline bool pte_access_permitted(pte_t pte, bool write)
 	 * A read-only access is controlled by _PAGE_USER bit.
 	 * We have _PAGE_READ set for WRITE and EXECUTE
 	 */
-	if (!pte_present(pte) || !pte_user(pte) || !pte_read(pte))
+	if (!pte_present(pte) || !pte_read(pte))
 		return false;
 
 	if (write && !pte_write(pte))

arch/powerpc/mm/ioremap.c

@@ -50,10 +50,6 @@ void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long flags)
 	if (pte_write(pte))
 		pte = pte_mkdirty(pte);
 
-	/* we don't want to let _PAGE_USER leak out */
-	if (WARN_ON(pte_user(pte)))
-		return NULL;
-
 	if (iowa_is_active())
 		return iowa_ioremap(addr, size, pte_pgprot(pte), caller);
 	return __ioremap_caller(addr, size, pte_pgprot(pte), caller);