smcc_helpers.h

/*
 * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of ARM nor the names of its contributors may be used
 * to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __SMCC_HELPERS_H__
#define __SMCC_HELPERS_H__

/*******************************************************************************
 * Bit definitions inside the function id as per the SMC calling convention
 ******************************************************************************/
#define FUNCID_TYPE_SHIFT		31
#define FUNCID_CC_SHIFT			30
#define FUNCID_OEN_SHIFT		24
#define FUNCID_NUM_SHIFT		0

#define FUNCID_TYPE_MASK		0x1
#define FUNCID_CC_MASK			0x1
#define FUNCID_OEN_MASK			0x3f
#define FUNCID_NUM_MASK			0xffff

#define FUNCID_TYPE_WIDTH		1
#define FUNCID_CC_WIDTH			1
#define FUNCID_OEN_WIDTH		6
#define FUNCID_NUM_WIDTH		16

#define GET_SMC_CC(id)			((id >> FUNCID_CC_SHIFT) & \
					 FUNCID_CC_MASK)
#define GET_SMC_TYPE(id)		((id >> FUNCID_TYPE_SHIFT) & \
					 FUNCID_TYPE_MASK)

#define SMC_64				1
#define SMC_32				0
#define SMC_UNK				0xffffffff
#define SMC_TYPE_FAST			1
#define SMC_TYPE_STD			0
#define SMC_PREEMPTED		0xfffffffe
/*******************************************************************************
 * Owning entity number definitions inside the function id as per the SMC
 * calling convention
 ******************************************************************************/
#define OEN_ARM_START			0
#define OEN_ARM_END			0
#define OEN_CPU_START			1
#define OEN_CPU_END			1
#define OEN_SIP_START			2
#define OEN_SIP_END			2
#define OEN_OEM_START			3
#define OEN_OEM_END			3
#define OEN_STD_START			4	/* Standard Calls */
#define OEN_STD_END			4
#define OEN_TAP_START			48	/* Trusted Applications */
#define OEN_TAP_END			49
#define OEN_TOS_START			50	/* Trusted OS */
#define OEN_TOS_END			63
#define OEN_LIMIT			64

#ifndef __ASSEMBLY__

#include <cassert.h>
#include <context.h>
#include <stdint.h>

/* Various flags passed to SMC handlers */
#define SMC_FROM_SECURE		(0 << 0)
#define SMC_FROM_NON_SECURE	(1 << 0)

#define is_caller_non_secure(_f)	(!!(_f & SMC_FROM_NON_SECURE))
#define is_caller_secure(_f)		(!(is_caller_non_secure(_f)))

/* Convenience macros to return from SMC handler */
#define SMC_RET0(_h)	{ \
	return (uint64_t) (_h);		\
}
#define SMC_RET1(_h, _x0)	{ \
	write_ctx_reg(get_gpregs_ctx(_h), CTX_GPREG_X0, (_x0)); \
	SMC_RET0(_h);						\
}
#define SMC_RET2(_h, _x0, _x1)	{ \
	write_ctx_reg(get_gpregs_ctx(_h), CTX_GPREG_X1, (_x1)); \
	SMC_RET1(_h, (_x0)); \
}
#define SMC_RET3(_h, _x0, _x1, _x2)	{ \
	write_ctx_reg(get_gpregs_ctx(_h), CTX_GPREG_X2, (_x2)); \
	SMC_RET2(_h, (_x0), (_x1)); \
}
#define SMC_RET4(_h, _x0, _x1, _x2, _x3)	{ \
	write_ctx_reg(get_gpregs_ctx(_h), CTX_GPREG_X3, (_x3)); \
	SMC_RET3(_h, (_x0), (_x1), (_x2)); \
}

/*
 * Convenience macros to access general purpose registers using handle provided
 * to SMC handler. These takes the offset values defined in context.h
 */
#define SMC_GET_GP(_h, _g) \
	read_ctx_reg(get_gpregs_ctx(_h), (_g));
#define SMC_SET_GP(_h, _g, _v) \
	write_ctx_reg(get_gpregs_ctx(_h), (_g), (_v));

/*
 * Convenience macros to access EL3 context registers using handle provided to
 * SMC handler. These takes the offset values defined in context.h
 */
#define SMC_GET_EL3(_h, _e) \
	read_ctx_reg(get_el3state_ctx(_h), (_e));
#define SMC_SET_EL3(_h, _e, _v) \
	write_ctx_reg(get_el3state_ctx(_h), (_e), (_v));

/* The macro below is used to identify a Standard Service SMC call */
#define is_std_svc_call(_fid)		((((_fid) >> FUNCID_OEN_SHIFT) & \
					   FUNCID_OEN_MASK) == OEN_STD_START)

/* The macro below is used to identify a valid Fast SMC call */
#define is_valid_fast_smc(_fid)		((!(((_fid) >> 16) & 0xff)) && \
					   (GET_SMC_TYPE(_fid) == SMC_TYPE_FAST))

/*
 * Macro to define UUID for services. Apart from defining and initializing a
 * uuid_t structure, this macro verifies that the first word of the defined UUID
 * does not equal SMC_UNK. This is to ensure that the caller won't mistake the
 * returned UUID in x0 for an invalid SMC error return
 */
#define DEFINE_SVC_UUID(_name, _tl, _tm, _th, _cl, _ch, \
		_n0, _n1, _n2, _n3, _n4, _n5) \
	CASSERT(_tl != SMC_UNK, invalid_svc_uuid);\
	static const uuid_t _name = { \
		_tl, _tm, _th, _cl, _ch, \
		{ _n0, _n1, _n2, _n3, _n4, _n5 } \
	}

/* Return a UUID in the SMC return registers */
#define SMC_UUID_RET(_h, _uuid) \
	SMC_RET4(handle, ((const uint32_t *) &(_uuid))[0], \
			 ((const uint32_t *) &(_uuid))[1], \
			 ((const uint32_t *) &(_uuid))[2], \
			 ((const uint32_t *) &(_uuid))[3])

#endif /*__ASSEMBLY__*/
#endif /* __SMCC_HELPERS_H__ */