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https://github.com/ARM-software/arm-trusted-firmware.git
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2ae197acd6
Enable the trng on the platform, which can be used by other features. `rng-seed` has been removed and enabled `FEAT_RNG_TRAP` to trap to EL3 when accessing system registers RNDR and RNDRRS Change-Id: Ibde39115f285e67d31b14863c75beaf37493deca Signed-off-by: Leo Yan <leo.yan@arm.com> Signed-off-by: Icen Zeyada <Icen.Zeyada2@arm.com>
41 lines
895 B
C
41 lines
895 B
C
/*
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* Copyright (c) 2025, ARM Limited and Contributors. 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 <assert.h>
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#include <bl31/sync_handle.h>
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#include <context.h>
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#include <plat/common/plat_trng.h>
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#define XZR_REG_NUM 31
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int plat_handle_rng_trap(uint64_t esr_el3, cpu_context_t *ctx)
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{
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uint64_t entropy;
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/* extract the target register number from the exception syndrome */
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unsigned int rt = get_sysreg_iss_rt(esr_el3);
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/* ignore XZR accesses and writes to the register */
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assert(rt != XZR_REG_NUM && !is_sysreg_iss_write(esr_el3));
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if (!plat_get_entropy(&entropy)) {
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ERROR("Failed to get entropy\n");
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panic();
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}
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/* Emulate RNDR and RNDRRS */
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gp_regs_t *gpregs = get_gpregs_ctx(ctx);
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write_ctx_reg(gpregs, rt, entropy);
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/*
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* We successfully handled the trap, continue with the next
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* instruction.
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*/
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return TRAP_RET_CONTINUE;
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}
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