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Re: [Xen-devel] [PATCH 1/6] xen/arm: smccc-1.1: Make return values unsigned long
Hi Julien, Marc
On 24.08.18 19:58, Julien Grall wrote:
From: Marc Zyngier <marc.zyngier@xxxxxxx>
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.
Maybe it better to use register_t then? By definition register_t has the
same size as a CPU register and SMC uses CPU registers to pass
parameters/return values.
Reported-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
---
xen/include/asm-arm/smccc.h | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/xen/include/asm-arm/smccc.h b/xen/include/asm-arm/smccc.h
index 74c13f8419..a31d67a1de 100644
--- a/xen/include/asm-arm/smccc.h
+++ b/xen/include/asm-arm/smccc.h
@@ -119,35 +119,35 @@ struct arm_smccc_res {
#define __declare_arg_0(a0, res) \
struct arm_smccc_res *___res = res; \
- register uin32_t r0 asm("r0") = a0; \
+ register unsigned long r0 asm("r0") = (uint32_t)a0;\
Do you really want to silently drop upper 32 bits of the argument?
I know, that SMCCC states that function id is a 32-bit value,
but I don't think that it is a good place to enforce this
behavior.
I think it is better to allow user to shoot in his leg in this case.
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 uint32_t r0 asm("r0") = a0; \
- register typeof(a1) r1 asm("r1") = a1; \
+ register unsigned long r0 asm("r0") = (uint32_t)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") = (uint32_t)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") = (uint32_t)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); \
- register typeof(a4) r4 asm("r4") = a4
+ register unsigned long r4 asm("r4") = a4
#define __declare_arg_5(a0, a1, a2, a3, a4, a5, res) \
__declare_arg_4(a0, a1, a2, a3, a4, res); \
--
Volodymyr Babchuk
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