Commit 5a360f3c9d for qemu.org
commit 5a360f3c9d068454d399a0f548e164298d496889
Author: Chao Liu <chao.liu.zevorn@gmail.com>
Date: Mon Sep 28 16:58:56 2026 -0300
target/riscv: add sdext Debug Mode helpers
RISC-V Debug Specification:
https://github.com/riscv/riscv-debug-spec/releases/tag/1.0
Add helpers to enter/leave Debug Mode and to update dpc/dcsr.
Model resume without a Debug Module by leaving Debug Mode at
cpu_exec_enter and continuing from dpc.
Signed-off-by: Chao Liu <chao.liu.zevorn@gmail.com>
Reviewed-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>
Tested-by: Tao Tang <tangtao1634@phytium.com.cn>
Signed-off-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20260928195902.2045235-3-daniel.barboza@oss.qualcomm.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 3b0d5e8aad..b0a0e5d51a 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -678,6 +678,9 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
char *riscv_isa_string(RISCVCPU *cpu);
int riscv_cpu_max_xlen(RISCVCPUClass *mcc);
bool riscv_cpu_option_set(RISCVCPU *cpu, const char *optname);
+void riscv_cpu_enter_debug_mode(CPURISCVState *env, target_ulong pc,
+ uint32_t cause);
+void riscv_cpu_leave_debug_mode(CPURISCVState *env);
#ifndef CONFIG_USER_ONLY
void riscv_cpu_do_interrupt(CPUState *cpu);
diff --git a/target/riscv/tcg/cpu_helper.c b/target/riscv/tcg/cpu_helper.c
index 58901bc3d8..a79efb2748 100644
--- a/target/riscv/tcg/cpu_helper.c
+++ b/target/riscv/tcg/cpu_helper.c
@@ -133,6 +133,91 @@ bool riscv_env_smode_dbltrp_enabled(CPURISCVState *env, bool virt)
#endif
}
+#ifndef CONFIG_USER_ONLY
+static bool riscv_sdext_enabled(CPURISCVState *env)
+{
+ return riscv_cpu_cfg(env)->ext_sdext;
+}
+#endif
+
+void riscv_cpu_enter_debug_mode(CPURISCVState *env, target_ulong pc,
+ uint32_t cause)
+{
+#ifndef CONFIG_USER_ONLY
+ if (!riscv_sdext_enabled(env)) {
+ return;
+ }
+
+ env->debug_mode = true;
+ env->dpc = pc & get_xepc_mask(env);
+ env->dcsr &= ~(DCSR_CAUSE_MASK | DCSR_PRV_MASK | DCSR_V);
+ env->dcsr |= (cause & 0x7) << DCSR_CAUSE_SHIFT;
+ env->dcsr |= env->priv & DCSR_PRV_MASK;
+ if (env->virt_enabled && riscv_has_ext(env, RVH)) {
+ env->dcsr |= DCSR_V;
+ }
+
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ if (env->elp) {
+ env->dcsr |= DCSR_PELP;
+ } else {
+ env->dcsr &= ~DCSR_PELP;
+ }
+ env->elp = false;
+ }
+#endif
+}
+
+void riscv_cpu_leave_debug_mode(CPURISCVState *env)
+{
+#ifndef CONFIG_USER_ONLY
+ uint32_t new_priv;
+ bool new_virt;
+
+ if (!riscv_sdext_enabled(env)) {
+ return;
+ }
+
+ new_priv = env->dcsr & DCSR_PRV_MASK;
+ new_virt = riscv_has_ext(env, RVH) && (env->dcsr & DCSR_V);
+
+ if (new_priv == PRV_M) {
+ new_virt = false;
+ }
+
+ if (new_priv == PRV_S && !riscv_has_ext(env, RVS)) {
+ new_priv = PRV_M;
+ new_virt = false;
+ } else if (new_priv == PRV_U && !riscv_has_ext(env, RVU)) {
+ new_priv = riscv_has_ext(env, RVS) ? PRV_S : PRV_M;
+ new_virt = false;
+ }
+
+ env->debug_mode = false;
+ riscv_cpu_set_mode(env, new_priv, new_virt);
+
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ env->elp = cpu_get_fcfien(env) && (env->dcsr & DCSR_PELP);
+ env->dcsr &= ~DCSR_PELP;
+ }
+
+ if (new_priv != PRV_M) {
+ env->mstatus = set_field(env->mstatus, MSTATUS_MPRV, 0);
+ }
+
+ if (env_archcpu(env)->cfg.ext_smdbltrp && new_priv != PRV_M) {
+ env->mstatus = set_field(env->mstatus, MSTATUS_MDT, 0);
+ }
+ if (env_archcpu(env)->cfg.ext_ssdbltrp && (new_priv == PRV_U || new_virt)) {
+ env->mstatus = set_field(env->mstatus, MSTATUS_SDT, 0);
+ if (new_virt && new_priv == PRV_U) {
+ env->vsstatus = set_field(env->vsstatus, MSTATUS_SDT, 0);
+ }
+ }
+#endif
+}
+
+
/*
* Returns the effective PMM field.
*
diff --git a/target/riscv/tcg/debug.c b/target/riscv/tcg/debug.c
index e4d719a1da..2537515f54 100644
--- a/target/riscv/tcg/debug.c
+++ b/target/riscv/tcg/debug.c
@@ -973,6 +973,11 @@ void riscv_cpu_debug_excp_handler(CPUState *cs)
RISCVCPU *cpu = RISCV_CPU(cs);
CPURISCVState *env = &cpu->env;
+ /* Triggers must not match or fire while in Debug Mode. */
+ if (env->debug_mode) {
+ return;
+ }
+
if (cs->watchpoint_hit) {
if (cs->watchpoint_hit->flags & BP_CPU) {
do_trigger_action(env, DBG_ACTION_BP);
diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index b68160af83..5729112201 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -269,6 +269,20 @@ static vaddr riscv_pointer_wrap(CPUState *cs, int mmu_idx,
}
return extract64(result, 0, 64 - pm_len);
}
+
+static void riscv_cpu_exec_enter(CPUState *cs)
+{
+ RISCVCPU *cpu = RISCV_CPU(cs);
+ CPURISCVState *env = &cpu->env;
+ target_ulong pc = env->dpc;
+
+ if (!cpu->cfg.ext_sdext || !env->debug_mode) {
+ return;
+ }
+
+ riscv_cpu_leave_debug_mode(env);
+ env->pc = pc;
+}
#endif
const TCGCPUOps riscv_tcg_ops = {
@@ -285,6 +299,7 @@ const TCGCPUOps riscv_tcg_ops = {
#ifndef CONFIG_USER_ONLY
.tlb_fill = riscv_cpu_tlb_fill,
.pointer_wrap = riscv_pointer_wrap,
+ .cpu_exec_enter = riscv_cpu_exec_enter,
.cpu_exec_interrupt = riscv_cpu_exec_interrupt,
.cpu_exec_halt = riscv_cpu_has_work,
.cpu_exec_reset = cpu_reset,