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Changes to support updated register usage in SMCCC v1.2

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From AArch64 state, arguments are passed in registers W0-W7(X0-X7)
and results are returned in W0-W7(X0-X7) for SMC32(SMC64) calls.
From AArch32 state, arguments are passed in registers R0-R7 and
results are returned in registers R0-R7 for SMC32 calls.

Most of the functions and macros already existed to support using
upto 8 registers for passing/returning parameters/results. Added
few helper macros for SMC calls from AArch32 state.

Link to the specification:
https://developer.arm.com/docs/den0028/c

Change-Id: I87976b42454dc3fc45c8343e9640aa78210e9741
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
This commit is contained in:
Madhukar Pappireddy 2019-11-09 23:28:08 -06:00
parent d537ee795c
commit e34cc0cedc
4 changed files with 48 additions and 8 deletions
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4
docs/design/firmware-design.rst
View file

@ -978,8 +978,8 @@ manipulation; and with ``flags`` indicating the security state of the caller. Th
framework finally sets up the execution stack for the handler, and invokes the
services ``handle()`` function.
On return from the handler the result registers are populated in X0-X3 before
restoring the stack and CPU state and returning from the original SMC.
On return from the handler the result registers are populated in X0-X7 as needed
before restoring the stack and CPU state and returning from the original SMC.
Exception Handling Framework
----------------------------

26
docs/getting_started/rt-svc-writers-guide.rst
View file

@ -244,17 +244,35 @@ The handler is responsible for:
TF-A expects owning entities to follow this recommendation.
#. Returning the result to the caller. The `SMCCC`_ allows for up to 256 bits
of return value in SMC64 using X0-X3 and 128 bits in SMC32 using W0-W3. The
framework provides a family of macros to set the multi-register return
value and complete the handler:
#. Returning the result to the caller. Based on `SMCCC`_ spec, results are
returned in W0-W7(X0-X7) registers for SMC32(SMC64) calls from AArch64
state. Results are returned in R0-R7 registers for SMC32 calls from AArch32
state. The framework provides a family of macros to set the multi-register
return value and complete the handler:
.. code:: c
AArch64 state:
SMC_RET1(handle, x0);
SMC_RET2(handle, x0, x1);
SMC_RET3(handle, x0, x1, x2);
SMC_RET4(handle, x0, x1, x2, x3);
SMC_RET5(handle, x0, x1, x2, x3, x4);
SMC_RET6(handle, x0, x1, x2, x3, x4, x5);
SMC_RET7(handle, x0, x1, x2, x3, x4, x5, x6);
SMC_RET8(handle, x0, x1, x2, x3, x4, x5, x6, x7);
AArch32 state:
SMC_RET1(handle, r0);
SMC_RET2(handle, r0, r1);
SMC_RET3(handle, r0, r1, r2);
SMC_RET4(handle, r0, r1, r2, r3);
SMC_RET5(handle, r0, r1, r2, r3, r4);
SMC_RET6(handle, r0, r1, r2, r3, r4, r5);
SMC_RET7(handle, r0, r1, r2, r3, r4, r5, r6);
SMC_RET8(handle, r0, r1, r2, r3, r4, r5, r6, r7);
The ``cookie`` parameter to the handler is reserved for future use and can be
ignored. The ``handle`` is returned by the SMC handler - completion of the

18
include/arch/aarch32/smccc_helpers.h
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
* Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@ -130,6 +130,22 @@ CASSERT(SMC_CTX_SIZE == sizeof(smc_ctx_t), assert_smc_ctx_size_mismatch);
((smc_ctx_t *)(_h))->r3 = (_r3); \
SMC_RET3(_h, (_r0), (_r1), (_r2)); \
}
#define SMC_RET5(_h, _r0, _r1, _r2, _r3, _r4) { \
((smc_ctx_t *)(_h))->r4 = (_r4); \
SMC_RET4(_h, (_r0), (_r1), (_r2), (_r3)); \
}
#define SMC_RET6(_h, _r0, _r1, _r2, _r3, _r4, _r5) { \
((smc_ctx_t *)(_h))->r5 = (_r5); \
SMC_RET5(_h, (_r0), (_r1), (_r2), (_r3), (_r4)); \
}
#define SMC_RET7(_h, _r0, _r1, _r2, _r3, _r4, _r5, _r6) { \
((smc_ctx_t *)(_h))->r6 = (_r6); \
SMC_RET6(_h, (_r0), (_r1), (_r2), (_r3), (_r4), (_r5)); \
}
#define SMC_RET8(_h, _r0, _r1, _r2, _r3, _r4, _r5, _r6, _r7) { \
((smc_ctx_t *)(_h))->r7 = (_r7); \
SMC_RET7(_h, (_r0), (_r1), (_r2), (_r3), (_r4), (_r5), (_r6)); \
}
/*
* Helper macro to retrieve the SMC parameters from smc_ctx_t.

8
include/lib/smccc.h
View file

@ -20,7 +20,7 @@
SMCCC_VERSION_MINOR_SHIFT))
#define SMCCC_MAJOR_VERSION U(1)
#define SMCCC_MINOR_VERSION U(1)
#define SMCCC_MINOR_VERSION U(2)
/*******************************************************************************
* Bit definitions inside the function id as per the SMC calling convention
@ -83,6 +83,12 @@
#define SMC_UNK -1
#define SMC_PREEMPTED -2 /* Not defined by the SMCCC */
/* Return codes for Arm Architecture Service SMC calls */
#define SMC_ARCH_CALL_SUCCESS 0
#define SMC_ARCH_CALL_NOT_SUPPORTED -1
#define SMC_ARCH_CALL_NOT_REQUIRED -2
#define SMC_ARCH_CALL_INVAL_PARAM -3
/* Various flags passed to SMC handlers */
#define SMC_FROM_SECURE (U(0) << 0)
#define SMC_FROM_NON_SECURE (U(1) << 0)