Commit 3fdc0cb5 authored by Sudeep Holla's avatar Sudeep Holla Committed by Will Deacon
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arm64: smccc: Add support for SMCCCv1.2 extended input/output registers 



SMCCC v1.2 allows x8-x17 to be used as parameter registers and x4—x17
to be used as result registers in SMC64/HVC64. Arm Firmware Framework
for Armv8-A specification makes use of x0-x7 as parameter and result
registers. There are other users like Hyper-V who intend to use beyond
x0-x7 as well.

Current SMCCC interface in the kernel just use x0-x7 as parameter and
x0-x3 as result registers as required by SMCCCv1.0. Let us add new
interface to support this extended set of input/output registers namely
x0-x17 as both parameter and result registers.

Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMichael Kelley <mikelley@microsoft.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Reviewed-by: default avatarMark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210518163618.43950-1-sudeep.holla@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 6efb943b

arch/arm64/kernel/asm-offsets.c

+9 −0
Original line number Diff line number Diff line
@@ -138,6 +138,15 @@ 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));

  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));

  BLANK();

  DEFINE(HIBERN_PBE_ORIG,	offsetof(struct pbe, orig_address));

  DEFINE(HIBERN_PBE_ADDR,	offsetof(struct pbe, address));

arch/arm64/kernel/smccc-call.S

+57 −0
Original line number Diff line number Diff line
@@ -43,3 +43,60 @@ SYM_FUNC_START(__arm_smccc_hvc) 
	SMCCC	hvc

SYM_FUNC_END(__arm_smccc_hvc)

EXPORT_SYMBOL(__arm_smccc_hvc)



	.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_hvc(const struct arm_smccc_1_2_regs *args,

 *			  struct arm_smccc_1_2_regs *res);

 */

SYM_FUNC_START(arm_smccc_1_2_hvc)

	SMCCC_1_2 hvc

SYM_FUNC_END(arm_smccc_1_2_hvc)

EXPORT_SYMBOL(arm_smccc_1_2_hvc)



/*

 * void arm_smccc_1_2_smc(const struct arm_smccc_1_2_regs *args,

 *			  struct arm_smccc_1_2_regs *res);

 */

SYM_FUNC_START(arm_smccc_1_2_smc)

	SMCCC_1_2 smc

SYM_FUNC_END(arm_smccc_1_2_smc)

EXPORT_SYMBOL(arm_smccc_1_2_smc)

include/linux/arm-smccc.h

+55 −0
Original line number Diff line number Diff line
@@ -227,6 +227,61 @@ struct arm_smccc_res { 
	unsigned long a3;

};



#ifdef CONFIG_ARM64

/**

 * struct arm_smccc_1_2_regs - Arguments for or Results from SMC/HVC 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_hvc() - make HVC 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 HVC 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 HVC instruction. The return values

 * are updated with the content from registers on return from the HVC

 * instruction.

 */

asmlinkage void arm_smccc_1_2_hvc(const struct arm_smccc_1_2_regs *args,

				  struct arm_smccc_1_2_regs *res);



/**

 * 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