add support for x0-x17 registers used by the SMC calls
In SMCCC v1.2 [1] arguments are passed in registers x1-x17. Results are returned in x0-x17.
This work is inspired from the following kernel commit:
arm64: smccc: Add support for SMCCCv1.2 extended input/output registers
[1]: https://documentation-service.arm.com/static/5f8edaeff86e16515cdbe4c6?token=
Signed-off-by: Abdellatif El Khlifi abdellatif.elkhlifi@arm.com Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org Reviewed-by: Jens Wiklander jens.wiklander@linaro.org Reviewed-by: Simon Glass sjg@chromium.org Cc: Tom Rini trini@konsulko.com
---
Changelog: ===============
v9:
* update the copyright string
v7:
* improve indentation of ARM_SMCCC_1_2_REGS_Xn_OFFS
v4:
* rename the commit title and improve description new commit title: the current
v3:
* port x0-x17 registers support from linux kernel as defined by SMCCCv1.2 commit title: arm64: smccc: add Xn registers support used by SMC calls
arch/arm/cpu/armv8/smccc-call.S | 57 ++++++++++++++++++++++++++++++++- arch/arm/lib/asm-offsets.c | 16 +++++++++ include/linux/arm-smccc.h | 45 ++++++++++++++++++++++++++ 3 files changed, 117 insertions(+), 1 deletion(-)
diff --git a/arch/arm/cpu/armv8/smccc-call.S b/arch/arm/cpu/armv8/smccc-call.S index dc92b28777..93f66d3366 100644 --- a/arch/arm/cpu/armv8/smccc-call.S +++ b/arch/arm/cpu/armv8/smccc-call.S @@ -1,7 +1,11 @@ /* SPDX-License-Identifier: GPL-2.0 */ /* * Copyright (c) 2015, Linaro Limited - */ + * Copyright 2022-2023 Arm Limited and/or its affiliates open-source-office@arm.com + * + * Authors: + * Abdellatif El Khlifi abdellatif.elkhlifi@arm.com +*/ #include <linux/linkage.h> #include <linux/arm-smccc.h> #include <generated/asm-offsets.h> @@ -45,3 +49,54 @@ ENDPROC(__arm_smccc_smc) ENTRY(__arm_smccc_hvc) SMCCC hvc ENDPROC(__arm_smccc_hvc) + +#ifdef CONFIG_ARM64 + + .macro SMCCC_1_2 instr + /* Save `res` and free a GPR that won't be clobbered */ + 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] + + \instr #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 + .endm + +/* + * 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) + SMCCC_1_2 smc +ENDPROC(arm_smccc_1_2_smc) + +#endif diff --git a/arch/arm/lib/asm-offsets.c b/arch/arm/lib/asm-offsets.c index 6de0ce9152..181a8ac4c2 100644 --- a/arch/arm/lib/asm-offsets.c +++ b/arch/arm/lib/asm-offsets.c @@ -9,6 +9,11 @@ * generate asm statements containing #defines, * compile this file to assembler, and then extract the * #defines from the assembly-language output. + * + * Copyright 2022-2023 Arm Limited and/or its affiliates open-source-office@arm.com + * + * Authors: + * Abdellatif El Khlifi abdellatif.elkhlifi@arm.com */
#include <common.h> @@ -90,6 +95,17 @@ int main(void) DEFINE(ARM_SMCCC_RES_X2_OFFS, offsetof(struct arm_smccc_res, a2)); DEFINE(ARM_SMCCC_QUIRK_ID_OFFS, offsetof(struct arm_smccc_quirk, id)); DEFINE(ARM_SMCCC_QUIRK_STATE_OFFS, offsetof(struct arm_smccc_quirk, state)); +#ifdef CONFIG_ARM64 + DEFINE(ARM_SMCCC_1_2_REGS_X0_OFFS, offsetof(struct arm_smccc_1_2_regs, a0)); + DEFINE(ARM_SMCCC_1_2_REGS_X2_OFFS, offsetof(struct arm_smccc_1_2_regs, a2)); + DEFINE(ARM_SMCCC_1_2_REGS_X4_OFFS, offsetof(struct arm_smccc_1_2_regs, a4)); + DEFINE(ARM_SMCCC_1_2_REGS_X6_OFFS, offsetof(struct arm_smccc_1_2_regs, a6)); + DEFINE(ARM_SMCCC_1_2_REGS_X8_OFFS, offsetof(struct arm_smccc_1_2_regs, a8)); + DEFINE(ARM_SMCCC_1_2_REGS_X10_OFFS, offsetof(struct arm_smccc_1_2_regs, a10)); + DEFINE(ARM_SMCCC_1_2_REGS_X12_OFFS, offsetof(struct arm_smccc_1_2_regs, a12)); + DEFINE(ARM_SMCCC_1_2_REGS_X14_OFFS, offsetof(struct arm_smccc_1_2_regs, a14)); + DEFINE(ARM_SMCCC_1_2_REGS_X16_OFFS, offsetof(struct arm_smccc_1_2_regs, a16)); +#endif #endif
return 0; diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index e1d09884a1..f44e9e8f93 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -1,6 +1,10 @@ /* SPDX-License-Identifier: GPL-2.0 */ /* * Copyright (c) 2015, Linaro Limited + * Copyright 2022-2023 Arm Limited and/or its affiliates open-source-office@arm.com + * + * Authors: + * Abdellatif El Khlifi abdellatif.elkhlifi@arm.com */ #ifndef __LINUX_ARM_SMCCC_H #define __LINUX_ARM_SMCCC_H @@ -70,6 +74,47 @@ struct arm_smccc_res { unsigned long a3; };
+#ifdef CONFIG_ARM64 +/** + * 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. + */ +asmlinkage void arm_smccc_1_2_smc(const struct arm_smccc_1_2_regs *args, + struct arm_smccc_1_2_regs *res); +#endif + /** * struct arm_smccc_quirk - Contains quirk information * @id: quirk identification