powerpc/mm: Remove unneeded #ifdef CONFIG_PPC_MEM_KEYS

In fault.c, #ifdef CONFIG_PPC_MEM_KEYS is not needed because all
functions are always defined, and arch_vma_access_permitted()
always returns true when CONFIG_PPC_MEM_KEYS is not defined so
access_pkey_error() will return false so bad_access_pkey()
will never be called.

Include linux/pkeys.h to get a definition of vma_pkeys() for
bad_access_pkey().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8038392f38d81f2ad169347efac29146f553b238.1615819955.git.christophe.leroy@csgroup.eu

arch/powerpc/mm/fault.c

@@ -33,6 +33,7 @@
 #include <linux/hugetlb.h>
 #include <linux/uaccess.h>
 #include <linux/kfence.h>
+#include <linux/pkeys.h>
 
 #include <asm/firmware.h>
 #include <asm/interrupt.h>
@@ -88,7 +89,6 @@ static noinline int bad_area(struct pt_regs *regs, unsigned long address)
 	return __bad_area(regs, address, SEGV_MAPERR);
 }
 
-#ifdef CONFIG_PPC_MEM_KEYS
 static noinline int bad_access_pkey(struct pt_regs *regs, unsigned long address,
 				    struct vm_area_struct *vma)
 {
@@ -128,7 +128,6 @@ static noinline int bad_access_pkey(struct pt_regs *regs, unsigned long address,
 
 	return 0;
 }
-#endif
 
 static noinline int bad_access(struct pt_regs *regs, unsigned long address)
 {
@@ -235,7 +234,6 @@ static bool bad_kernel_fault(struct pt_regs *regs, unsigned long error_code,
 	return false;
 }
 
-#ifdef CONFIG_PPC_MEM_KEYS
 static bool access_pkey_error(bool is_write, bool is_exec, bool is_pkey,
 			      struct vm_area_struct *vma)
 {
@@ -249,7 +247,6 @@ static bool access_pkey_error(bool is_write, bool is_exec, bool is_pkey,
 
 	return false;
 }
-#endif
 
 static bool access_error(bool is_write, bool is_exec, struct vm_area_struct *vma)
 {
@@ -497,11 +494,9 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
 			return bad_area(regs, address);
 	}
 
-#ifdef CONFIG_PPC_MEM_KEYS
 	if (unlikely(access_pkey_error(is_write, is_exec,
 				       (error_code & DSISR_KEYFAULT), vma)))
 		return bad_access_pkey(regs, address, vma);
-#endif /* CONFIG_PPC_MEM_KEYS */
 
 	if (unlikely(access_error(is_write, is_exec, vma)))
 		return bad_access(regs, address);