Hi Jens,
> On 22 Feb 2023, at 16:32, Jens Wiklander <jens.wiklan...@linaro.org> wrote:
>
> SMCCC v1.2 [1] AArch64 allows x0-x17 to be used as both parameter
> registers and result registers for the SMC and HVC instructions.
>
> Arm Firmware Framework for Armv8-A specification makes use of x0-x7 as
> parameter and result registers.
>
> Let us add new interface to support this extended set of input/output
> registers.
>
> This is based on 3fdc0cb59d97 ("arm64: smccc: Add support for SMCCCv1.2
> extended input/output registers") by Sudeep Holla from the Linux kernel
>
> The SMCCC version reported to the VM is bumped to 1.2 in order to support
> handling FF-A messages.
>
> [1] https://developer.arm.com/documentation/den0028/c/?lang=en
>
> Reviewed-by: Luca Fancellu <luca.fance...@arm.com>
> Signed-off-by: Jens Wiklander <jens.wiklan...@linaro.org>
Reviewed-by: Bertrand Marquis <bertrand.marq...@arm.com>
Cheers
Bertrand
> ---
> xen/arch/arm/arm64/asm-offsets.c | 9 +++++++
> xen/arch/arm/arm64/smc.S | 42 ++++++++++++++++++++++++++++++++
> xen/arch/arm/include/asm/smccc.h | 40 ++++++++++++++++++++++++++++++
> xen/arch/arm/vsmc.c | 2 +-
> 4 files changed, 92 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/arm64/asm-offsets.c
> b/xen/arch/arm/arm64/asm-offsets.c
> index 7226cd9b2eb0..7adb67a1b81a 100644
> --- a/xen/arch/arm/arm64/asm-offsets.c
> +++ b/xen/arch/arm/arm64/asm-offsets.c
> @@ -57,6 +57,15 @@ void __dummy__(void)
> BLANK();
> OFFSET(SMCCC_RES_a0, struct arm_smccc_res, a0);
> OFFSET(SMCCC_RES_a2, struct arm_smccc_res, a2);
> + OFFSET(ARM_SMCCC_1_2_REGS_X0_OFFS, struct arm_smccc_1_2_regs, a0);
> + OFFSET(ARM_SMCCC_1_2_REGS_X2_OFFS, struct arm_smccc_1_2_regs, a2);
> + OFFSET(ARM_SMCCC_1_2_REGS_X4_OFFS, struct arm_smccc_1_2_regs, a4);
> + OFFSET(ARM_SMCCC_1_2_REGS_X6_OFFS, struct arm_smccc_1_2_regs, a6);
> + OFFSET(ARM_SMCCC_1_2_REGS_X8_OFFS, struct arm_smccc_1_2_regs, a8);
> + OFFSET(ARM_SMCCC_1_2_REGS_X10_OFFS, struct arm_smccc_1_2_regs, a10);
> + OFFSET(ARM_SMCCC_1_2_REGS_X12_OFFS, struct arm_smccc_1_2_regs, a12);
> + OFFSET(ARM_SMCCC_1_2_REGS_X14_OFFS, struct arm_smccc_1_2_regs, a14);
> + OFFSET(ARM_SMCCC_1_2_REGS_X16_OFFS, struct arm_smccc_1_2_regs, a16);
> }
>
> /*
> diff --git a/xen/arch/arm/arm64/smc.S b/xen/arch/arm/arm64/smc.S
> index 91bae62dd4d2..fc6b676e2ee3 100644
> --- a/xen/arch/arm/arm64/smc.S
> +++ b/xen/arch/arm/arm64/smc.S
> @@ -27,3 +27,45 @@ ENTRY(__arm_smccc_1_0_smc)
> stp x2, x3, [x4, #SMCCC_RES_a2]
> 1:
> ret
> +
> +/*
> + * void arm_smccc_1_2_smc(const struct arm_smccc_1_2_regs *args,
> + * struct arm_smccc_1_2_regs *res)
> + */
> +ENTRY(arm_smccc_1_2_smc)
> + /* Save `res` and free a GPR that won't be clobbered by SMC call */
> + stp x1, x19, [sp, #-16]!
> +
> + /* Ensure `args` won't be clobbered while loading regs in next step */
> + mov x19, x0
> +
> + /* Load the registers x0 - x17 from the struct arm_smccc_1_2_regs */
> + ldp x0, x1, [x19, #ARM_SMCCC_1_2_REGS_X0_OFFS]
> + ldp x2, x3, [x19, #ARM_SMCCC_1_2_REGS_X2_OFFS]
> + ldp x4, x5, [x19, #ARM_SMCCC_1_2_REGS_X4_OFFS]
> + ldp x6, x7, [x19, #ARM_SMCCC_1_2_REGS_X6_OFFS]
> + ldp x8, x9, [x19, #ARM_SMCCC_1_2_REGS_X8_OFFS]
> + ldp x10, x11, [x19, #ARM_SMCCC_1_2_REGS_X10_OFFS]
> + ldp x12, x13, [x19, #ARM_SMCCC_1_2_REGS_X12_OFFS]
> + ldp x14, x15, [x19, #ARM_SMCCC_1_2_REGS_X14_OFFS]
> + ldp x16, x17, [x19, #ARM_SMCCC_1_2_REGS_X16_OFFS]
> +
> + smc #0
> +
> + /* Load the `res` from the stack */
> + ldr x19, [sp]
> +
> + /* Store the registers x0 - x17 into the result structure */
> + stp x0, x1, [x19, #ARM_SMCCC_1_2_REGS_X0_OFFS]
> + stp x2, x3, [x19, #ARM_SMCCC_1_2_REGS_X2_OFFS]
> + stp x4, x5, [x19, #ARM_SMCCC_1_2_REGS_X4_OFFS]
> + stp x6, x7, [x19, #ARM_SMCCC_1_2_REGS_X6_OFFS]
> + stp x8, x9, [x19, #ARM_SMCCC_1_2_REGS_X8_OFFS]
> + stp x10, x11, [x19, #ARM_SMCCC_1_2_REGS_X10_OFFS]
> + stp x12, x13, [x19, #ARM_SMCCC_1_2_REGS_X12_OFFS]
> + stp x14, x15, [x19, #ARM_SMCCC_1_2_REGS_X14_OFFS]
> + stp x16, x17, [x19, #ARM_SMCCC_1_2_REGS_X16_OFFS]
> +
> + /* Restore original x19 */
> + ldp xzr, x19, [sp], #16
> + ret
> diff --git a/xen/arch/arm/include/asm/smccc.h
> b/xen/arch/arm/include/asm/smccc.h
> index b3dbeecc90ad..1adcd37443c7 100644
> --- a/xen/arch/arm/include/asm/smccc.h
> +++ b/xen/arch/arm/include/asm/smccc.h
> @@ -33,6 +33,7 @@
>
> #define ARM_SMCCC_VERSION_1_0 SMCCC_VERSION(1, 0)
> #define ARM_SMCCC_VERSION_1_1 SMCCC_VERSION(1, 1)
> +#define ARM_SMCCC_VERSION_1_2 SMCCC_VERSION(1, 2)
>
> /*
> * This file provides common defines for ARM SMC Calling Convention as
> @@ -265,6 +266,45 @@ void __arm_smccc_1_0_smc(register_t a0, register_t a1,
> register_t a2,
> else \
> arm_smccc_1_0_smc(__VA_ARGS__); \
> } while ( 0 )
> +
> +/*
> + * struct arm_smccc_1_2_regs - Arguments for or Results from SMC call
> + * @a0-a17 argument values from registers 0 to 17
> + */
> +struct arm_smccc_1_2_regs {
> + unsigned long a0;
> + unsigned long a1;
> + unsigned long a2;
> + unsigned long a3;
> + unsigned long a4;
> + unsigned long a5;
> + unsigned long a6;
> + unsigned long a7;
> + unsigned long a8;
> + unsigned long a9;
> + unsigned long a10;
> + unsigned long a11;
> + unsigned long a12;
> + unsigned long a13;
> + unsigned long a14;
> + unsigned long a15;
> + unsigned long a16;
> + unsigned long a17;
> +};
> +
> +/*
> + * arm_smccc_1_2_smc() - make SMC calls
> + * @args: arguments passed via struct arm_smccc_1_2_regs
> + * @res: result values via struct arm_smccc_1_2_regs
> + *
> + * This function is used to make SMC calls following SMC Calling Convention
> + * v1.2 or above. The content of the supplied param are copied from the
> + * structure to registers prior to the SMC instruction. The return values
> + * are updated with the content from registers on return from the SMC
> + * instruction.
> + */
> +void arm_smccc_1_2_smc(const struct arm_smccc_1_2_regs *args,
> + struct arm_smccc_1_2_regs *res);
> #endif /* CONFIG_ARM_64 */
>
> #endif /* __ASSEMBLY__ */
> diff --git a/xen/arch/arm/vsmc.c b/xen/arch/arm/vsmc.c
> index 7335276f3fa1..cd68fa80e98a 100644
> --- a/xen/arch/arm/vsmc.c
> +++ b/xen/arch/arm/vsmc.c
> @@ -85,7 +85,7 @@ static bool handle_arch(struct cpu_user_regs *regs)
> switch ( fid )
> {
> case ARM_SMCCC_VERSION_FID:
> - set_user_reg(regs, 0, ARM_SMCCC_VERSION_1_1);
> + set_user_reg(regs, 0, ARM_SMCCC_VERSION_1_2);
> return true;
>
> case ARM_SMCCC_ARCH_FEATURES_FID:
> --
> 2.34.1
>
