a10b9d93ec
Adapt the arm semihosting support code for RISCV. This implementation is based on the standard for RISC-V semihosting version 0.2 as documented in https://github.com/riscv/riscv-semihosting-spec/releases/tag/0.2 Signed-off-by: Keith Packard <keithp@keithp.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20210107170717.2098982-6-keithp@keithp.com> Message-Id: <20210108224256.2321-17-alex.bennee@linaro.org>
133 lines
3.8 KiB
C++
133 lines
3.8 KiB
C++
/*
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* RISC-V translation routines for the RISC-V privileged instructions.
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*
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* Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
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* Copyright (c) 2018 Peer Adelt, peer.adelt@hni.uni-paderborn.de
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* Bastian Koppelmann, kbastian@mail.uni-paderborn.de
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2 or later, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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static bool trans_ecall(DisasContext *ctx, arg_ecall *a)
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{
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/* always generates U-level ECALL, fixed in do_interrupt handler */
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generate_exception(ctx, RISCV_EXCP_U_ECALL);
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exit_tb(ctx); /* no chaining */
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ctx->base.is_jmp = DISAS_NORETURN;
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return true;
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}
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static bool trans_ebreak(DisasContext *ctx, arg_ebreak *a)
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{
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target_ulong ebreak_addr = ctx->base.pc_next;
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target_ulong pre_addr = ebreak_addr - 4;
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target_ulong post_addr = ebreak_addr + 4;
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uint32_t pre = 0;
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uint32_t ebreak = 0;
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uint32_t post = 0;
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/*
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* The RISC-V semihosting spec specifies the following
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* three-instruction sequence to flag a semihosting call:
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*
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* slli zero, zero, 0x1f 0x01f01013
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* ebreak 0x00100073
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* srai zero, zero, 0x7 0x40705013
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*
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* The two shift operations on the zero register are no-ops, used
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* here to signify a semihosting exception, rather than a breakpoint.
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*
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* Uncompressed instructions are required so that the sequence is easy
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* to validate.
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*
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* The three instructions are required to lie in the same page so
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* that no exception will be raised when fetching them.
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*/
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if ((pre_addr & TARGET_PAGE_MASK) == (post_addr & TARGET_PAGE_MASK)) {
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pre = opcode_at(&ctx->base, pre_addr);
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ebreak = opcode_at(&ctx->base, ebreak_addr);
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post = opcode_at(&ctx->base, post_addr);
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}
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if (pre == 0x01f01013 && ebreak == 0x00100073 && post == 0x40705013) {
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generate_exception(ctx, RISCV_EXCP_SEMIHOST);
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} else {
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generate_exception(ctx, RISCV_EXCP_BREAKPOINT);
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}
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exit_tb(ctx); /* no chaining */
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ctx->base.is_jmp = DISAS_NORETURN;
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return true;
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}
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static bool trans_uret(DisasContext *ctx, arg_uret *a)
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{
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return false;
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}
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static bool trans_sret(DisasContext *ctx, arg_sret *a)
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{
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#ifndef CONFIG_USER_ONLY
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tcg_gen_movi_tl(cpu_pc, ctx->base.pc_next);
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if (has_ext(ctx, RVS)) {
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gen_helper_sret(cpu_pc, cpu_env, cpu_pc);
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exit_tb(ctx); /* no chaining */
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ctx->base.is_jmp = DISAS_NORETURN;
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} else {
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return false;
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}
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return true;
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#else
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return false;
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#endif
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}
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static bool trans_mret(DisasContext *ctx, arg_mret *a)
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{
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#ifndef CONFIG_USER_ONLY
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tcg_gen_movi_tl(cpu_pc, ctx->base.pc_next);
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gen_helper_mret(cpu_pc, cpu_env, cpu_pc);
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exit_tb(ctx); /* no chaining */
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ctx->base.is_jmp = DISAS_NORETURN;
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return true;
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#else
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return false;
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#endif
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}
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static bool trans_wfi(DisasContext *ctx, arg_wfi *a)
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{
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#ifndef CONFIG_USER_ONLY
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tcg_gen_movi_tl(cpu_pc, ctx->pc_succ_insn);
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gen_helper_wfi(cpu_env);
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return true;
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#else
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return false;
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#endif
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}
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static bool trans_sfence_vma(DisasContext *ctx, arg_sfence_vma *a)
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{
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#ifndef CONFIG_USER_ONLY
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gen_helper_tlb_flush(cpu_env);
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return true;
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#endif
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return false;
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}
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static bool trans_sfence_vm(DisasContext *ctx, arg_sfence_vm *a)
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{
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return false;
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}
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