ARM: 9357/2: Reduce the number of #ifdef CONFIG_CPU_SW_DOMAIN_PAN

This is a clean-up patch aimed at reducing the number of checks on
CONFIG_CPU_SW_DOMAIN_PAN, together with some empty lines for better
clarity once the CONFIG_CPU_TTBR0_PAN is introduced.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Author: linusw

arch/arm/include/asm/uaccess-asm.h

@@ -39,8 +39,9 @@
 #endif
 	.endm
 
-	.macro	uaccess_disable, tmp, isb=1
 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
+
+	.macro	uaccess_disable, tmp, isb=1
 	/*
 	 * Whenever we re-enter userspace, the domains should always be
 	 * set appropriately.
@@ -50,11 +51,9 @@
 	.if	\isb
 	instr_sync
 	.endif
-#endif
 	.endm
 
 	.macro	uaccess_enable, tmp, isb=1
-#ifdef CONFIG_CPU_SW_DOMAIN_PAN
 	/*
 	 * Whenever we re-enter userspace, the domains should always be
 	 * set appropriately.
@@ -64,9 +63,18 @@
 	.if	\isb
 	instr_sync
 	.endif
-#endif
 	.endm
 
+#else
+
+	.macro	uaccess_disable, tmp, isb=1
+	.endm
+
+	.macro	uaccess_enable, tmp, isb=1
+	.endm
+
+#endif
+
 #if defined(CONFIG_CPU_SW_DOMAIN_PAN) || defined(CONFIG_CPU_USE_DOMAINS)
 #define DACR(x...)	x
 #else

arch/arm/include/asm/uaccess.h

@@ -24,29 +24,38 @@
  * perform such accesses (eg, via list poison values) which could then
  * be exploited for priviledge escalation.
  */
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+
 static __always_inline unsigned int uaccess_save_and_enable(void)
 {
-#ifdef CONFIG_CPU_SW_DOMAIN_PAN
 	unsigned int old_domain = get_domain();
 
 	/* Set the current domain access to permit user accesses */
 	set_domain((old_domain & ~domain_mask(DOMAIN_USER)) |
 		   domain_val(DOMAIN_USER, DOMAIN_CLIENT));
 
 	return old_domain;
-#else
-	return 0;
-#endif
 }
 
 static __always_inline void uaccess_restore(unsigned int flags)
 {
-#ifdef CONFIG_CPU_SW_DOMAIN_PAN
 	/* Restore the user access mask */
 	set_domain(flags);
-#endif
 }
 
+#else
+
+static inline unsigned int uaccess_save_and_enable(void)
+{
+	return 0;
+}
+
+static inline void uaccess_restore(unsigned int flags)
+{
+}
+
+#endif
+
 /*
  * These two are intentionally not defined anywhere - if the kernel
  * code generates any references to them, that's a bug.