linux-kernel - [PATCH 1/5] bus: arm-cci: use asm unreachable

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Date:   Wed, 21 Mar 2018 00:02:02 +0100
From:   Stefan Agner <stefan@...er.ch>
To:     linux@...linux.org.uk, ard.biesheuvel@...aro.org, arnd@...db.de
Cc:     nicolas.pitre@...aro.org, marc.zyngier@....com,
        behanw@...verseincode.com, keescook@...omium.org,
        Bernhard.Rosenkranzer@...aro.org, mka@...omium.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Stefan Agner <stefan@...er.ch>
Subject: [PATCH 1/5] bus: arm-cci: use asm unreachable

Mixing asm and C code is not recommended in a naked function by
gcc and leads to an error when using clang:
  drivers/bus/arm-cci.c:2107:2: error: non-ASM statement in naked
  function is not supported
        unreachable();
        ^

Instead of using the unreachable() macro use the assember variant
ASM_UNREACHABLE.  This will no longer emit __builtin_unreachable(),
but since the function is naked and its return type is void it seems
not to have aversive effects.

Signed-off-by: Stefan Agner <stefan@...er.ch>
---
 drivers/bus/arm-cci.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index 5426c04fe24b..ee9da86fec47 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -2084,6 +2084,7 @@ asmlinkage void __naked cci_enable_port_for_self(void)
 
 "	mov	r0, #0 \n"
 "	bx	lr \n"
+	ASM_UNREACHABLE
 
 "	.align	2 \n"
 "5:	.word	cpu_port - . \n"
@@ -2103,8 +2104,6 @@ asmlinkage void __naked cci_enable_port_for_self(void)
 	[sizeof_struct_cpu_port] "i" (sizeof(struct cpu_port)),
 	[sizeof_struct_ace_port] "i" (sizeof(struct cci_ace_port)),
 	[offsetof_port_phys] "i" (offsetof(struct cci_ace_port, phys)) );
-
-	unreachable();
 }
 
 /**
-- 
2.16.2