[PATCH 3/4] ARM: Reduce the number of #ifdef CONFIG_CPU_SW_DOMAIN_PAN

[Linus Walleij]

From: Catalin Marinas <catalin.marinas at arm.com>

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 at arm.com>
Reviewed-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
 arch/arm/include/asm/uaccess-asm.h | 16 ++++++++++++----
 arch/arm/include/asm/uaccess.h     | 21 +++++++++++++++------
 arch/arm/lib/csumpartialcopyuser.S |  6 +++++-
 3 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/arch/arm/include/asm/uaccess-asm.h b/arch/arm/include/asm/uaccess-asm.h
index 65da32e1f1c1..ea42ba25920f 100644
--- a/arch/arm/include/asm/uaccess-asm.h
+++ b/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
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 9556d04387f7..9b9234d1bb6a 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -24,9 +24,10 @@
  * perform such accesses (eg, via list poison values) which could then
  * be exploited for priviledge escalation.
  */
+#if defined(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 */
@@ -34,19 +35,27 @@ static __always_inline unsigned int uaccess_save_and_enable(void)
 		   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.
diff --git a/arch/arm/lib/csumpartialcopyuser.S b/arch/arm/lib/csumpartialcopyuser.S
index 6928781e6bee..04d8d9d741c7 100644
--- a/arch/arm/lib/csumpartialcopyuser.S
+++ b/arch/arm/lib/csumpartialcopyuser.S
@@ -13,7 +13,8 @@
 
 		.text
 
-#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+#if defined(CONFIG_CPU_SW_DOMAIN_PAN)
+
 		.macro	save_regs
 		mrc	p15, 0, ip, c3, c0, 0
 		stmfd	sp!, {r1, r2, r4 - r8, ip, lr}
@@ -25,7 +26,9 @@
 		mcr	p15, 0, ip, c3, c0, 0
 		ret	lr
 		.endm
+
 #else
+
 		.macro	save_regs
 		stmfd	sp!, {r1, r2, r4 - r8, lr}
 		.endm
@@ -33,6 +36,7 @@
 		.macro	load_regs
 		ldmfd	sp!, {r1, r2, r4 - r8, pc}
 		.endm
+
 #endif
 
 		.macro	load1b,	reg1

-- 
2.34.1