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Merge "Changes to support updated register usage in SMCCC v1.2" into integration

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Alexei Fedorov 2019-11-29 10:06:37 +00:00 • committed by TrustedFirmware Code Review
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26
docs/getting_started/rt-svc-writers-guide.rst
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@ -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