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