diff mbox series

[v6,08/10] arm/arm64: Provide a wrapper for SMCCC 1.1 calls

Message ID 20191011125930.40834-9-steven.price@arm.com
State New, archived
Headers show
Series arm64: Stolen time support | expand

Commit Message

Steven Price Oct. 11, 2019, 12:59 p.m. UTC
SMCCC 1.1 calls may use either HVC or SMC depending on the PSCI
conduit. Rather than coding this in every call site provide a macro
which uses the correct instruction. The macro also handles the case
where no PSCI conduit is configured returning a not supported error
in res, along with returning the conduit used for the call.

This allow us to remove some duplicated code and will be useful later
when adding paravirtualized time hypervisor calls.

Signed-off-by: Steven Price <steven.price@arm.com>
Acked-by: Will Deacon <will@kernel.org>
---
 include/linux/arm-smccc.h | 44 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

Comments

Marc Zyngier Oct. 21, 2019, 11:42 a.m. UTC | #1
On 2019-10-11 13:59, Steven Price wrote:
> SMCCC 1.1 calls may use either HVC or SMC depending on the PSCI
> conduit. Rather than coding this in every call site provide a macro
> which uses the correct instruction. The macro also handles the case
> where no PSCI conduit is configured returning a not supported error
> in res, along with returning the conduit used for the call.
>
> This allow us to remove some duplicated code and will be useful later
> when adding paravirtualized time hypervisor calls.
>
> Signed-off-by: Steven Price <steven.price@arm.com>
> Acked-by: Will Deacon <will@kernel.org>
> ---
>  include/linux/arm-smccc.h | 44 
> +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
>
> diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
> index 5daf0e2adf47..fd84a9bfb455 100644
> --- a/include/linux/arm-smccc.h
> +++ b/include/linux/arm-smccc.h
> @@ -303,6 +303,50 @@ asmlinkage void __arm_smccc_hvc(unsigned long
> a0, unsigned long a1,
>  #define SMCCC_RET_NOT_SUPPORTED			-1
>  #define SMCCC_RET_NOT_REQUIRED			-2
>
> +/* Like arm_smccc_1_1* but always returns SMCCC_RET_NOT_SUPPORTED.
> + * Used when the PSCI conduit is not defined. The empty asm 
> statement
> + * avoids compiler warnings about unused variables.

nit: comment style.

> + */
> +#define __fail_smccc_1_1(...)						\
> +	do {								\
> +		__declare_args(__count_args(__VA_ARGS__), __VA_ARGS__);	\
> +		asm ("" __constraints(__count_args(__VA_ARGS__)));	\
> +		if (___res)						\
> +			___res->a0 = SMCCC_RET_NOT_SUPPORTED;		\
> +	} while (0)
> +
> +/*
> + * arm_smccc_1_1_invoke() - make an SMCCC v1.1 compliant call
> + *
> + * This is a variadic macro taking one to eight source arguments, 
> and
> + * an optional return structure.
> + *
> + * @a0-a7: arguments passed in registers 0 to 7
> + * @res: result values from registers 0 to 3
> + *
> + * This macro will make either an HVC call or an SMC call depending 
> on the
> + * current PSCI conduit. If no valid conduit is available then -1
> + * (SMCCC_RET_NOT_SUPPORTED) is returned in @res.a0 (if supplied).
> + *
> + * The return value also provides the conduit that was used.
> + */
> +#define arm_smccc_1_1_invoke(...) ({					\
> +		int method = psci_ops.conduit;				\
> +		switch (method) {					\
> +		case PSCI_CONDUIT_HVC:					\
> +			arm_smccc_1_1_hvc(__VA_ARGS__);			\
> +			break;						\
> +		case PSCI_CONDUIT_SMC:					\
> +			arm_smccc_1_1_smc(__VA_ARGS__);			\
> +			break;						\
> +		default:						\
> +			__fail_smccc_1_1(__VA_ARGS__);			\
> +			method = PSCI_CONDUIT_NONE;			\
> +			break;						\
> +		}							\
> +		method;							\
> +	})
> +
>  /* Paravirtualised time calls (defined by ARM DEN0057A) */
>  #define ARM_SMCCC_HV_PV_TIME_FEATURES				\
>  	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\

All this should most probably go on top of the SMCCC conduit cleanup 
that
has already been already queued in the arm64 tree (see 
arm64/for-next/smccc-conduit-cleanup).

Thanks,

         M.
Steven Price Oct. 21, 2019, 1:43 p.m. UTC | #2
On 21/10/2019 12:42, Marc Zyngier wrote:
> On 2019-10-11 13:59, Steven Price wrote:
[...]
> All this should most probably go on top of the SMCCC conduit cleanup that
> has already been already queued in the arm64 tree (see
> arm64/for-next/smccc-conduit-cleanup).

Good point, I'll rebase. Are you happy for the entire series to be based
on top of that? i.e. based on commit e6ea46511b1a ("firmware: arm_sdei:
use common SMCCC_CONDUIT_*")

Thanks,

Steve
Marc Zyngier Oct. 21, 2019, 2:05 p.m. UTC | #3
On 2019-10-21 14:43, Steven Price wrote:
> On 21/10/2019 12:42, Marc Zyngier wrote:
>> On 2019-10-11 13:59, Steven Price wrote:
> [...]
>> All this should most probably go on top of the SMCCC conduit cleanup 
>> that
>> has already been already queued in the arm64 tree (see
>> arm64/for-next/smccc-conduit-cleanup).
>
> Good point, I'll rebase. Are you happy for the entire series to be 
> based
> on top of that? i.e. based on commit e6ea46511b1a ("firmware: 
> arm_sdei:
> use common SMCCC_CONDUIT_*")

Absolutely. I'll sync with Will and Catalin to get a stable branch that
includes these commits.

Thanks,

         M.
diff mbox series

Patch

diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 5daf0e2adf47..fd84a9bfb455 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -303,6 +303,50 @@  asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1,
 #define SMCCC_RET_NOT_SUPPORTED			-1
 #define SMCCC_RET_NOT_REQUIRED			-2
 
+/* Like arm_smccc_1_1* but always returns SMCCC_RET_NOT_SUPPORTED.
+ * Used when the PSCI conduit is not defined. The empty asm statement
+ * avoids compiler warnings about unused variables.
+ */
+#define __fail_smccc_1_1(...)						\
+	do {								\
+		__declare_args(__count_args(__VA_ARGS__), __VA_ARGS__);	\
+		asm ("" __constraints(__count_args(__VA_ARGS__)));	\
+		if (___res)						\
+			___res->a0 = SMCCC_RET_NOT_SUPPORTED;		\
+	} while (0)
+
+/*
+ * arm_smccc_1_1_invoke() - make an SMCCC v1.1 compliant call
+ *
+ * This is a variadic macro taking one to eight source arguments, and
+ * an optional return structure.
+ *
+ * @a0-a7: arguments passed in registers 0 to 7
+ * @res: result values from registers 0 to 3
+ *
+ * This macro will make either an HVC call or an SMC call depending on the
+ * current PSCI conduit. If no valid conduit is available then -1
+ * (SMCCC_RET_NOT_SUPPORTED) is returned in @res.a0 (if supplied).
+ *
+ * The return value also provides the conduit that was used.
+ */
+#define arm_smccc_1_1_invoke(...) ({					\
+		int method = psci_ops.conduit;				\
+		switch (method) {					\
+		case PSCI_CONDUIT_HVC:					\
+			arm_smccc_1_1_hvc(__VA_ARGS__);			\
+			break;						\
+		case PSCI_CONDUIT_SMC:					\
+			arm_smccc_1_1_smc(__VA_ARGS__);			\
+			break;						\
+		default:						\
+			__fail_smccc_1_1(__VA_ARGS__);			\
+			method = PSCI_CONDUIT_NONE;			\
+			break;						\
+		}							\
+		method;							\
+	})
+
 /* Paravirtualised time calls (defined by ARM DEN0057A) */
 #define ARM_SMCCC_HV_PV_TIME_FEATURES				\
 	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\