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Fix double trap #2163

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Merged
merged 2 commits into from
Nov 30, 2025
Merged

Fix double trap #2163

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47c1a95
csr: move menvcfg in front of mstatus
chihminchao Nov 26, 2025
6d6cc2c
csr: fix double trap state access
chihminchao Nov 26, 2025
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36 changes: 19 additions & 17 deletions riscv/csr_init.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -224,6 +224,25 @@ void state_t::csr_init(processor_t* const proc, reg_t max_isa)
} else {
add_hypervisor_csr(CSR_HIDELEG, hideleg);
}

const reg_t menvcfg_mask = (proc->extension_enabled(EXT_ZICBOM) ? MENVCFG_CBCFE | MENVCFG_CBIE : 0) |
(proc->extension_enabled(EXT_ZICBOZ) ? MENVCFG_CBZE : 0) |
(proc->extension_enabled(EXT_SMNPM) ? MENVCFG_PMM : 0) |
(proc->extension_enabled(EXT_SVADU) ? MENVCFG_ADUE: 0) |
(proc->extension_enabled(EXT_SVPBMT) ? MENVCFG_PBMTE : 0) |
(proc->extension_enabled(EXT_SSTC) ? MENVCFG_STCE : 0) |
(proc->extension_enabled(EXT_ZICFILP) ? MENVCFG_LPE : 0) |
(proc->extension_enabled(EXT_ZICFISS) ? MENVCFG_SSE : 0) |
(proc->extension_enabled(EXT_SSDBLTRP) ? MENVCFG_DTE : 0)|
(proc->extension_enabled(EXT_SMCDELEG) ? MENVCFG_CDE : 0);
menvcfg = std::make_shared<envcfg_csr_t>(proc, CSR_MENVCFG, menvcfg_mask, 0);
if (xlen == 32) {
add_user_csr(CSR_MENVCFG, std::make_shared<rv32_low_csr_t>(proc, CSR_MENVCFG, menvcfg));
add_user_csr(CSR_MENVCFGH, std::make_shared<rv32_high_csr_t>(proc, CSR_MENVCFGH, menvcfg));
} else {
add_user_csr(CSR_MENVCFG, menvcfg);
}

const reg_t hedeleg_mask =
(1 << CAUSE_MISALIGNED_FETCH) |
(1 << CAUSE_FETCH_ACCESS) |
Expand Down Expand Up @@ -310,23 +329,6 @@ void state_t::csr_init(processor_t* const proc, reg_t max_isa)
add_csr(CSR_MVENDORID, std::make_shared<const_csr_t>(proc, CSR_MVENDORID, 0));
add_csr(CSR_MHARTID, std::make_shared<const_csr_t>(proc, CSR_MHARTID, proc->get_id()));
add_csr(CSR_MCONFIGPTR, std::make_shared<const_csr_t>(proc, CSR_MCONFIGPTR, 0));
const reg_t menvcfg_mask = (proc->extension_enabled(EXT_ZICBOM) ? MENVCFG_CBCFE | MENVCFG_CBIE : 0) |
(proc->extension_enabled(EXT_ZICBOZ) ? MENVCFG_CBZE : 0) |
(proc->extension_enabled(EXT_SMNPM) ? MENVCFG_PMM : 0) |
(proc->extension_enabled(EXT_SVADU) ? MENVCFG_ADUE: 0) |
(proc->extension_enabled(EXT_SVPBMT) ? MENVCFG_PBMTE : 0) |
(proc->extension_enabled(EXT_SSTC) ? MENVCFG_STCE : 0) |
(proc->extension_enabled(EXT_ZICFILP) ? MENVCFG_LPE : 0) |
(proc->extension_enabled(EXT_ZICFISS) ? MENVCFG_SSE : 0) |
(proc->extension_enabled(EXT_SSDBLTRP) ? MENVCFG_DTE : 0)|
(proc->extension_enabled(EXT_SMCDELEG) ? MENVCFG_CDE : 0);
menvcfg = std::make_shared<envcfg_csr_t>(proc, CSR_MENVCFG, menvcfg_mask, 0);
if (xlen == 32) {
add_user_csr(CSR_MENVCFG, std::make_shared<rv32_low_csr_t>(proc, CSR_MENVCFG, menvcfg));
add_user_csr(CSR_MENVCFGH, std::make_shared<rv32_high_csr_t>(proc, CSR_MENVCFGH, menvcfg));
} else {
add_user_csr(CSR_MENVCFG, menvcfg);
}
const reg_t senvcfg_mask = (proc->extension_enabled(EXT_ZICBOM) ? SENVCFG_CBCFE | SENVCFG_CBIE : 0) |
(proc->extension_enabled(EXT_ZICBOZ) ? SENVCFG_CBZE : 0) |
(proc->extension_enabled(EXT_SVUKTE) ? SENVCFG_UKTE : 0) |
Expand Down
10 changes: 7 additions & 3 deletions riscv/csrs.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -544,11 +544,16 @@ mstatus_csr_t::mstatus_csr_t(processor_t* const proc, const reg_t addr):
val(compute_mstatus_initial_value()) {
}

reg_t mstatus_csr_t::read() const noexcept {
return val & ~reg_t(state->menvcfg->read() & MENVCFG_DTE ? 0 : MSTATUS_SDT);
}

bool mstatus_csr_t::unlogged_write(const reg_t val) noexcept {
const bool has_mpv = proc->extension_enabled('H');
const bool has_gva = has_mpv;
const reg_t adj_write_mask = sstatus_write_mask & ~reg_t(state->menvcfg->read() & MENVCFG_DTE ? 0 : SSTATUS_SDT);

const reg_t mask = sstatus_write_mask
const reg_t mask = adj_write_mask
| MSTATUS_MIE | MSTATUS_MPIE
| (proc->extension_enabled('U') ? MSTATUS_MPRV : 0)
| MSTATUS_MPP | MSTATUS_TW
Expand All @@ -558,12 +563,11 @@ bool mstatus_csr_t::unlogged_write(const reg_t val) noexcept {
| (has_mpv ? MSTATUS_MPV : 0)
| (proc->extension_enabled(EXT_SMDBLTRP) ? MSTATUS_MDT : 0)
| (proc->extension_enabled(EXT_ZICFILP) ? (MSTATUS_SPELP | MSTATUS_MPELP) : 0)
| (proc->extension_enabled(EXT_SSDBLTRP) ? SSTATUS_SDT : 0)
;

const reg_t requested_mpp = proc->legalize_privilege(get_field(val, MSTATUS_MPP));
const reg_t adjusted_val = set_field(val, MSTATUS_MPP, requested_mpp);
reg_t new_mstatus = (read() & ~mask) | (adjusted_val & mask);
reg_t new_mstatus = (this->val & ~mask) | (adjusted_val & mask);
new_mstatus = (new_mstatus & MSTATUS_MDT) ? (new_mstatus & ~MSTATUS_MIE) : new_mstatus;
new_mstatus = (new_mstatus & MSTATUS_SDT) ? (new_mstatus & ~MSTATUS_SIE) : new_mstatus;
maybe_flush_tlb(new_mstatus);
Expand Down
4 changes: 1 addition & 3 deletions riscv/csrs.h
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Expand Up @@ -255,9 +255,7 @@ class mstatus_csr_t final: public base_status_csr_t {
public:
mstatus_csr_t(processor_t* const proc, const reg_t addr);

reg_t read() const noexcept override {
return val;
}
reg_t read() const noexcept override;

protected:
virtual bool unlogged_write(const reg_t val) noexcept override;
Expand Down
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