arm/arm64: smccc-1.1: Make return values unsigned long

Marc Zyngier · wildea01 · commit 1d8f574708a3 · 2018-08-29T11:42:20.000+01:00
An unfortunate consequence of having a strong typing for the input
values to the SMC call is that it also affects the type of the
return values, limiting r0 to 32 bits and r{1,2,3} to whatever
was passed as an input.

Let's turn everything into "unsigned long", which satisfies the
requirements of both architectures, and allows for the full
range of return values.

Reported-by: Julien Grall &lt;julien.grall@arm.com&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
@@ -199,31 +199,31 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1,
 
 #define __declare_arg_0(a0, res)					\
 	struct arm_smccc_res   *___res = res;				\
-	register u32           r0 asm("r0") = a0;			\
+	register unsigned long r0 asm("r0") = (u32)a0;			\
 	register unsigned long r1 asm("r1");				\
 	register unsigned long r2 asm("r2");				\
 	register unsigned long r3 asm("r3")
 
 #define __declare_arg_1(a0, a1, res)					\
 	struct arm_smccc_res   *___res = res;				\
-	register u32           r0 asm("r0") = a0;			\
-	register typeof(a1)    r1 asm("r1") = a1;			\
+	register unsigned long r0 asm("r0") = (u32)a0;			\
+	register unsigned long r1 asm("r1") = a1;			\
 	register unsigned long r2 asm("r2");				\
 	register unsigned long r3 asm("r3")
 
 #define __declare_arg_2(a0, a1, a2, res)				\
 	struct arm_smccc_res   *___res = res;				\
-	register u32           r0 asm("r0") = a0;			\
-	register typeof(a1)    r1 asm("r1") = a1;			\
-	register typeof(a2)    r2 asm("r2") = a2;			\
+	register unsigned long r0 asm("r0") = (u32)a0;			\
+	register unsigned long r1 asm("r1") = a1;			\
+	register unsigned long r2 asm("r2") = a2;			\
 	register unsigned long r3 asm("r3")
 
 #define __declare_arg_3(a0, a1, a2, a3, res)				\
 	struct arm_smccc_res   *___res = res;				\
-	register u32           r0 asm("r0") = a0;			\
-	register typeof(a1)    r1 asm("r1") = a1;			\
-	register typeof(a2)    r2 asm("r2") = a2;			\
-	register typeof(a3)    r3 asm("r3") = a3
+	register unsigned long r0 asm("r0") = (u32)a0;			\
+	register unsigned long r1 asm("r1") = a1;			\
+	register unsigned long r2 asm("r2") = a2;			\
+	register unsigned long r3 asm("r3") = a3
 
 #define __declare_arg_4(a0, a1, a2, a3, a4, res)			\
 	__declare_arg_3(a0, a1, a2, a3, res);				\
