[PATCH v6] arm/arm64: add arm-smccc

[Lorenzo Pieralisi]

On Wed, Dec 09, 2015 at 02:24:55PM +0100, Jens Wiklander wrote:
> Adds helpers to do SMC and HVC based on ARM SMC Calling Convention.
> CONFIG_HAVE_ARM_SMCCC is enabled for architectures that may support the
> SMC or HVC instruction. It's the responsibility of the caller to know if
> the SMC instruction is supported by the platform.
> 
> This patch doesn't provide an implementation of the declared functions.
> Later patches will bring in implementations and set
> CONFIG_HAVE_ARM_SMCCC for ARM and ARM64 respectively.
> 
> Signed-off-by: Jens Wiklander <jens.wiklander at linaro.org>
> ---
> 
> v6:
> * Move HAVE_ARM_SMCCC from init/Kconfig
> 
>  arch/Kconfig              |  3 ++
>  include/linux/arm-smccc.h | 98 +++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 101 insertions(+)
>  create mode 100644 include/linux/arm-smccc.h
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 4e949e5..ce3c0b0 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -564,4 +564,7 @@ config OLD_SIGACTION
>  config COMPAT_OLD_SIGACTION
>  	bool
>  
> +config HAVE_ARM_SMCCC
> +	bool

It is ok by me to move it there, probably we do not want it at the end of
the "ABI hall of shame" list :)

Or drivers/firmware/Kconfig ?

Strictly speaking, since PSCI uses this by default, you should also
enforce an ARM_PSCI_FW dependency on HAVE_ARM_SMCCC.

>  source "kernel/gcov/Kconfig"
> diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
> new file mode 100644
> index 0000000..dea68a9
> --- /dev/null
> +++ b/include/linux/arm-smccc.h
> @@ -0,0 +1,98 @@
> +/*
> + * Copyright (c) 2015, Linaro Limited
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +#ifndef __LINUX_ARM_SMCCC_H
> +#define __LINUX_ARM_SMCCC_H
> +
> +#include <linux/types.h>
> +#include <linux/linkage.h>

Nit: alphabetical order please.

> +
> +/*
> + * This file provides common defines for ARM SMC Calling Convention as
> + * specified in
> + * http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html
> + */
> +
> +#define ARM_SMCCC_SMC_32		(0 << 30)
> +#define ARM_SMCCC_SMC_64		(1 << 30)
> +#define ARM_SMCCC_FAST_CALL		(1 << 31)
> +#define ARM_SMCCC_STD_CALL		(0 << 31)
> +
> +#define ARM_SMCCC_OWNER_MASK		0x3F
> +#define ARM_SMCCC_OWNER_SHIFT		24
> +
> +#define ARM_SMCCC_FUNC_MASK		0xFFFF
> +
> +#define ARM_SMCCC_IS_FAST_CALL(smc_val)	((smc_val) & ARM_SMCCC_FAST_CALL)
> +#define ARM_SMCCC_IS_64(smc_val)	((smc_val) & ARM_SMCCC_SMC_64)
> +#define ARM_SMCCC_FUNC_NUM(smc_val)	((smc_val) & ARM_SMCCC_FUNC_MASK)
> +#define ARM_SMCCC_OWNER_NUM(smc_val) \
> +	(((smc_val) >> ARM_SMCCC_OWNER_SHIFT) & ARM_SMCCC_OWNER_MASK)
> +
> +#define ARM_SMCCC_CALL_VAL(type, calling_convention, owner, func_num) \
> +	((type) | (calling_convention) | \

Nit: if you use a shift macro for some fields it would be clearer if you use
for all of them (I am referring to type/calling_convention here), it can
be changed later.

Other than that:

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>

> +	(((owner) & ARM_SMCCC_OWNER_MASK) << ARM_SMCCC_OWNER_SHIFT) | \
> +	((func_num) & ARM_SMCCC_FUNC_MASK))
> +
> +#define ARM_SMCCC_OWNER_ARCH		0
> +#define ARM_SMCCC_OWNER_CPU		1
> +#define ARM_SMCCC_OWNER_SIP		2
> +#define ARM_SMCCC_OWNER_OEM		3
> +#define ARM_SMCCC_OWNER_STANDARD	4
> +#define ARM_SMCCC_OWNER_TRUSTED_APP	48
> +#define ARM_SMCCC_OWNER_TRUSTED_APP_END	49
> +#define ARM_SMCCC_OWNER_TRUSTED_OS	50
> +#define ARM_SMCCC_OWNER_TRUSTED_OS_END	63
> +
> +/**
> + * struct arm_smccc_res - Result from SMC/HVC call
> + * @a0-a3 result values from registers 0 to 3
> + */
> +struct arm_smccc_res {
> +	unsigned long a0;
> +	unsigned long a1;
> +	unsigned long a2;
> +	unsigned long a3;
> +};
> +
> +/**
> + * arm_smccc_smc() - make SMC calls
> + * @a0-a7: arguments passed in registers 0 to 7
> + * @res: result values from registers 0 to 3
> + *
> + * This function is used to make SMC calls following SMC Calling Convention.
> + * The content of the supplied param are copied to registers 0 to 7 prior
> + * to the SMC instruction. The return values are updated with the content
> + * from register 0 to 3 on return from the SMC instruction.
> + */
> +asmlinkage void arm_smccc_smc(unsigned long a0, unsigned long a1,
> +			unsigned long a2, unsigned long a3, unsigned long a4,
> +			unsigned long a5, unsigned long a6, unsigned long a7,
> +			struct arm_smccc_res *res);
> +
> +/**
> + * arm_smccc_hvc() - make HVC calls
> + * @a0-a7: arguments passed in registers 0 to 7
> + * @res: result values from registers 0 to 3
> + *
> + * This function is used to make HVC calls following SMC Calling
> + * Convention.  The content of the supplied param are copied to registers 0
> + * to 7 prior to the HVC instruction. The return values are updated with
> + * the content from register 0 to 3 on return from the HVC instruction.
> + */
> +asmlinkage void arm_smccc_hvc(unsigned long a0, unsigned long a1,
> +			unsigned long a2, unsigned long a3, unsigned long a4,
> +			unsigned long a5, unsigned long a6, unsigned long a7,
> +			struct arm_smccc_res *res);
> +
> +#endif /*__LINUX_ARM_SMCCC_H*/
> -- 
> 1.9.1
>