31 lines
803 B
C
31 lines
803 B
C
/*
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* Copyright (c) 2019, Arm Limited. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <cdefs.h>
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#include <stdint.h>
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/*
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* Instruction pointer authentication key A. The low 64-bit are at [0], and the
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* high bits at [1].
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*/
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uint64_t plat_apiakey[2];
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/*
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* This is only a toy implementation to generate a seemingly random 128-bit key
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* from sp and x30 values. A production system must re-implement this function
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* to generate keys from a reliable randomness source.
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*/
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uint64_t *plat_init_apiakey(void)
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{
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uintptr_t return_addr = (uintptr_t)__builtin_return_address(0U);
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uintptr_t frame_addr = (uintptr_t)__builtin_frame_address(0U);
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plat_apiakey[0] = (return_addr << 13) ^ frame_addr;
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plat_apiakey[1] = (frame_addr << 15) ^ return_addr;
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return plat_apiakey;
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}
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