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/*
* RISC-V Emulation Helpers for QEMU.
*
* Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
* Copyright (c) 2017-2018 SiFive, Inc.
* Copyright (c) 2022 VRULL GmbH
*
* 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/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "internals.h"
#include "exec/exec-all.h"
#include "exec/cpu_ldst.h"
#include "exec/helper-proto.h"
/* Exceptions processing helpers */
G_NORETURN void riscv_raise_exception(CPURISCVState *env,
uint32_t exception, uintptr_t pc)
{
CPUState *cs = env_cpu(env);
cs->exception_index = exception;
cpu_loop_exit_restore(cs, pc);
}
void helper_raise_exception(CPURISCVState *env, uint32_t exception)
{
riscv_raise_exception(env, exception, 0);
}
target_ulong helper_csrr(CPURISCVState *env, int csr)
{
/*
* The seed CSR must be accessed with a read-write instruction. A
* read-only instruction such as CSRRS/CSRRC with rs1=x0 or CSRRSI/
* CSRRCI with uimm=0 will raise an illegal instruction exception.
*/
if (csr == CSR_SEED) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
}
target_ulong val = 0;
RISCVException ret = riscv_csrrw(env, csr, &val, 0, 0);
if (ret != RISCV_EXCP_NONE) {
riscv_raise_exception(env, ret, GETPC());
}
return val;
}
void helper_csrw(CPURISCVState *env, int csr, target_ulong src)
{
target_ulong mask = env->xl == MXL_RV32 ? UINT32_MAX : (target_ulong)-1;
RISCVException ret = riscv_csrrw(env, csr, NULL, src, mask);
if (ret != RISCV_EXCP_NONE) {
riscv_raise_exception(env, ret, GETPC());
}
}
target_ulong helper_csrrw(CPURISCVState *env, int csr,
target_ulong src, target_ulong write_mask)
{
target_ulong val = 0;
RISCVException ret = riscv_csrrw(env, csr, &val, src, write_mask);
if (ret != RISCV_EXCP_NONE) {
riscv_raise_exception(env, ret, GETPC());
}
return val;
}
target_ulong helper_csrr_i128(CPURISCVState *env, int csr)
{
Int128 rv = int128_zero();
RISCVException ret = riscv_csrrw_i128(env, csr, &rv,
int128_zero(),
int128_zero());
if (ret != RISCV_EXCP_NONE) {
riscv_raise_exception(env, ret, GETPC());
}
env->retxh = int128_gethi(rv);
return int128_getlo(rv);
}
void helper_csrw_i128(CPURISCVState *env, int csr,
target_ulong srcl, target_ulong srch)
{
RISCVException ret = riscv_csrrw_i128(env, csr, NULL,
int128_make128(srcl, srch),
UINT128_MAX);
if (ret != RISCV_EXCP_NONE) {
riscv_raise_exception(env, ret, GETPC());
}
}
target_ulong helper_csrrw_i128(CPURISCVState *env, int csr,
target_ulong srcl, target_ulong srch,
target_ulong maskl, target_ulong maskh)
{
Int128 rv = int128_zero();
RISCVException ret = riscv_csrrw_i128(env, csr, &rv,
int128_make128(srcl, srch),
int128_make128(maskl, maskh));
if (ret != RISCV_EXCP_NONE) {
riscv_raise_exception(env, ret, GETPC());
}
env->retxh = int128_gethi(rv);
return int128_getlo(rv);
}
/*
* check_zicbo_envcfg
*
* Raise virtual exceptions and illegal instruction exceptions for
* Zicbo[mz] instructions based on the settings of [mhs]envcfg as
* specified in section 2.5.1 of the CMO specification.
*/
static void check_zicbo_envcfg(CPURISCVState *env, target_ulong envbits,
uintptr_t ra)
{
#ifndef CONFIG_USER_ONLY
if ((env->priv < PRV_M) && !get_field(env->menvcfg, envbits)) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, ra);
}
if (env->virt_enabled &&
(((env->priv <= PRV_S) && !get_field(env->henvcfg, envbits)) ||
((env->priv < PRV_S) && !get_field(env->senvcfg, envbits)))) {
riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, ra);
}
if ((env->priv < PRV_S) && !get_field(env->senvcfg, envbits)) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, ra);
}
#endif
}
void helper_cbo_zero(CPURISCVState *env, target_ulong address)
{
RISCVCPU *cpu = env_archcpu(env);
uint16_t cbozlen = cpu->cfg.cboz_blocksize;
int mmu_idx = riscv_env_mmu_index(env, false);
uintptr_t ra = GETPC();
void *mem;
check_zicbo_envcfg(env, MENVCFG_CBZE, ra);
/* Mask off low-bits to align-down to the cache-block. */
address &= ~(cbozlen - 1);
/*
* cbo.zero requires MMU_DATA_STORE access. Do a probe_write()
* to raise any exceptions, including PMP.
*/
mem = probe_write(env, address, cbozlen, mmu_idx, ra);
if (likely(mem)) {
memset(mem, 0, cbozlen);
} else {
/*
* This means that we're dealing with an I/O page. Section 4.2
* of cmobase v1.0.1 says:
*
* "Cache-block zero instructions store zeros independently
* of whether data from the underlying memory locations are
* cacheable."
*
* Write zeros in address + cbozlen regardless of not being
* a RAM page.
*/
for (int i = 0; i < cbozlen; i++) {
cpu_stb_mmuidx_ra(env, address + i, 0, mmu_idx, ra);
}
}
}
/*
* check_zicbom_access
*
* Check access permissions (LOAD, STORE or FETCH as specified in
* section 2.5.2 of the CMO specification) for Zicbom, raising
* either store page-fault (non-virtualized) or store guest-page
* fault (virtualized).
*/
static void check_zicbom_access(CPURISCVState *env,
target_ulong address,
uintptr_t ra)
{
RISCVCPU *cpu = env_archcpu(env);
int mmu_idx = riscv_env_mmu_index(env, false);
uint16_t cbomlen = cpu->cfg.cbom_blocksize;
void *phost;
int ret;
/* Mask off low-bits to align-down to the cache-block. */
address &= ~(cbomlen - 1);
/*
* Section 2.5.2 of cmobase v1.0.1:
*
* "A cache-block management instruction is permitted to
* access the specified cache block whenever a load instruction
* or store instruction is permitted to access the corresponding
* physical addresses. If neither a load instruction nor store
* instruction is permitted to access the physical addresses,
* but an instruction fetch is permitted to access the physical
* addresses, whether a cache-block management instruction is
* permitted to access the cache block is UNSPECIFIED."
*/
ret = probe_access_flags(env, address, cbomlen, MMU_DATA_LOAD,
mmu_idx, true, &phost, ra);
if (ret != TLB_INVALID_MASK) {
/* Success: readable */
return;
}
/*
* Since not readable, must be writable. On failure, store
* fault/store guest amo fault will be raised by
* riscv_cpu_tlb_fill(). PMP exceptions will be caught
* there as well.
*/
probe_write(env, address, cbomlen, mmu_idx, ra);
}
void helper_cbo_clean_flush(CPURISCVState *env, target_ulong address)
{
uintptr_t ra = GETPC();
check_zicbo_envcfg(env, MENVCFG_CBCFE, ra);
check_zicbom_access(env, address, ra);
/* We don't emulate the cache-hierarchy, so we're done. */
}
void helper_cbo_inval(CPURISCVState *env, target_ulong address)
{
uintptr_t ra = GETPC();
check_zicbo_envcfg(env, MENVCFG_CBIE, ra);
check_zicbom_access(env, address, ra);
/* We don't emulate the cache-hierarchy, so we're done. */
}
#ifndef CONFIG_USER_ONLY
target_ulong helper_sret(CPURISCVState *env)
{
uint64_t mstatus;
target_ulong prev_priv, prev_virt;
if (!(env->priv >= PRV_S)) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
}
target_ulong retpc = env->sepc;
if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
}
if (get_field(env->mstatus, MSTATUS_TSR) && !(env->priv >= PRV_M)) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
}
if (env->virt_enabled && get_field(env->hstatus, HSTATUS_VTSR)) {
riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
}
mstatus = env->mstatus;
prev_priv = get_field(mstatus, MSTATUS_SPP);
mstatus = set_field(mstatus, MSTATUS_SIE,
get_field(mstatus, MSTATUS_SPIE));
mstatus = set_field(mstatus, MSTATUS_SPIE, 1);
mstatus = set_field(mstatus, MSTATUS_SPP, PRV_U);
if (env->priv_ver >= PRIV_VERSION_1_12_0) {
mstatus = set_field(mstatus, MSTATUS_MPRV, 0);
}
env->mstatus = mstatus;
if (riscv_has_ext(env, RVH) && !env->virt_enabled) {
/* We support Hypervisor extensions and virtulisation is disabled */
target_ulong hstatus = env->hstatus;
prev_virt = get_field(hstatus, HSTATUS_SPV);
hstatus = set_field(hstatus, HSTATUS_SPV, 0);
env->hstatus = hstatus;
if (prev_virt) {
riscv_cpu_swap_hypervisor_regs(env);
}
riscv_cpu_set_virt_enabled(env, prev_virt);
}
riscv_cpu_set_mode(env, prev_priv);
return retpc;
}
target_ulong helper_mret(CPURISCVState *env)
{
if (!(env->priv >= PRV_M)) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
}
target_ulong retpc = env->mepc;
if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
}
uint64_t mstatus = env->mstatus;
target_ulong prev_priv = get_field(mstatus, MSTATUS_MPP);
if (riscv_cpu_cfg(env)->pmp &&
!pmp_get_num_rules(env) && (prev_priv != PRV_M)) {
riscv_raise_exception(env, RISCV_EXCP_INST_ACCESS_FAULT, GETPC());
}
target_ulong prev_virt = get_field(env->mstatus, MSTATUS_MPV) &&
(prev_priv != PRV_M);
mstatus = set_field(mstatus, MSTATUS_MIE,
get_field(mstatus, MSTATUS_MPIE));
mstatus = set_field(mstatus, MSTATUS_MPIE, 1);
mstatus = set_field(mstatus, MSTATUS_MPP,
riscv_has_ext(env, RVU) ? PRV_U : PRV_M);
mstatus = set_field(mstatus, MSTATUS_MPV, 0);
if ((env->priv_ver >= PRIV_VERSION_1_12_0) && (prev_priv != PRV_M)) {
mstatus = set_field(mstatus, MSTATUS_MPRV, 0);
}
env->mstatus = mstatus;
riscv_cpu_set_mode(env, prev_priv);
if (riscv_has_ext(env, RVH)) {
if (prev_virt) {
riscv_cpu_swap_hypervisor_regs(env);
}
riscv_cpu_set_virt_enabled(env, prev_virt);
}
return retpc;
}
void helper_wfi(CPURISCVState *env)
{
CPUState *cs = env_cpu(env);
bool rvs = riscv_has_ext(env, RVS);
bool prv_u = env->priv == PRV_U;
bool prv_s = env->priv == PRV_S;
if (((prv_s || (!rvs && prv_u)) && get_field(env->mstatus, MSTATUS_TW)) ||
(rvs && prv_u && !env->virt_enabled)) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
} else if (env->virt_enabled &&
(prv_u || (prv_s && get_field(env->hstatus, HSTATUS_VTW)))) {
riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
} else {
cs->halted = 1;
cs->exception_index = EXCP_HLT;
cpu_loop_exit(cs);
}
}
void helper_wrs_nto(CPURISCVState *env)
{
if (env->virt_enabled && (env->priv == PRV_S || env->priv == PRV_U) &&
get_field(env->hstatus, HSTATUS_VTW) &&
!get_field(env->mstatus, MSTATUS_TW)) {
riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
} else if (env->priv != PRV_M && get_field(env->mstatus, MSTATUS_TW)) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
}
}
void helper_tlb_flush(CPURISCVState *env)
{
CPUState *cs = env_cpu(env);
if (!env->virt_enabled &&
(env->priv == PRV_U ||
(env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)))) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
} else if (env->virt_enabled &&
(env->priv == PRV_U || get_field(env->hstatus, HSTATUS_VTVM))) {
riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
} else {
tlb_flush(cs);
}
}
void helper_tlb_flush_all(CPURISCVState *env)
{
CPUState *cs = env_cpu(env);
tlb_flush_all_cpus_synced(cs);
}
void helper_hyp_tlb_flush(CPURISCVState *env)
{
CPUState *cs = env_cpu(env);
if (env->virt_enabled) {
riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
}
if (env->priv == PRV_M ||
(env->priv == PRV_S && !env->virt_enabled)) {
tlb_flush(cs);
return;
}
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
}
void helper_hyp_gvma_tlb_flush(CPURISCVState *env)
{
if (env->priv == PRV_S && !env->virt_enabled &&
get_field(env->mstatus, MSTATUS_TVM)) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
}
helper_hyp_tlb_flush(env);
}
static int check_access_hlsv(CPURISCVState *env, bool x, uintptr_t ra)
{
if (env->priv == PRV_M) {
/* always allowed */
} else if (env->virt_enabled) {
riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, ra);
} else if (env->priv == PRV_U && !get_field(env->hstatus, HSTATUS_HU)) {
riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, ra);
}
int mode = get_field(env->hstatus, HSTATUS_SPVP);
if (!x && mode == PRV_S && get_field(env->vsstatus, MSTATUS_SUM)) {
mode = MMUIdx_S_SUM;
}
return mode | MMU_2STAGE_BIT;
}
target_ulong helper_hyp_hlv_bu(CPURISCVState *env, target_ulong addr)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, false, ra);
MemOpIdx oi = make_memop_idx(MO_UB, mmu_idx);
return cpu_ldb_mmu(env, addr, oi, ra);
}
target_ulong helper_hyp_hlv_hu(CPURISCVState *env, target_ulong addr)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, false, ra);
MemOpIdx oi = make_memop_idx(MO_TEUW, mmu_idx);
return cpu_ldw_mmu(env, addr, oi, ra);
}
target_ulong helper_hyp_hlv_wu(CPURISCVState *env, target_ulong addr)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, false, ra);
MemOpIdx oi = make_memop_idx(MO_TEUL, mmu_idx);
return cpu_ldl_mmu(env, addr, oi, ra);
}
target_ulong helper_hyp_hlv_d(CPURISCVState *env, target_ulong addr)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, false, ra);
MemOpIdx oi = make_memop_idx(MO_TEUQ, mmu_idx);
return cpu_ldq_mmu(env, addr, oi, ra);
}
void helper_hyp_hsv_b(CPURISCVState *env, target_ulong addr, target_ulong val)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, false, ra);
MemOpIdx oi = make_memop_idx(MO_UB, mmu_idx);
cpu_stb_mmu(env, addr, val, oi, ra);
}
void helper_hyp_hsv_h(CPURISCVState *env, target_ulong addr, target_ulong val)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, false, ra);
MemOpIdx oi = make_memop_idx(MO_TEUW, mmu_idx);
cpu_stw_mmu(env, addr, val, oi, ra);
}
void helper_hyp_hsv_w(CPURISCVState *env, target_ulong addr, target_ulong val)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, false, ra);
MemOpIdx oi = make_memop_idx(MO_TEUL, mmu_idx);
cpu_stl_mmu(env, addr, val, oi, ra);
}
void helper_hyp_hsv_d(CPURISCVState *env, target_ulong addr, target_ulong val)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, false, ra);
MemOpIdx oi = make_memop_idx(MO_TEUQ, mmu_idx);
cpu_stq_mmu(env, addr, val, oi, ra);
}
/*
* TODO: These implementations are not quite correct. They perform the
* access using execute permission just fine, but the final PMP check
* is supposed to have read permission as well. Without replicating
* a fair fraction of cputlb.c, fixing this requires adding new mmu_idx
* which would imply that exact check in tlb_fill.
*/
target_ulong helper_hyp_hlvx_hu(CPURISCVState *env, target_ulong addr)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, true, ra);
MemOpIdx oi = make_memop_idx(MO_TEUW, mmu_idx);
return cpu_ldw_code_mmu(env, addr, oi, GETPC());
}
target_ulong helper_hyp_hlvx_wu(CPURISCVState *env, target_ulong addr)
{
uintptr_t ra = GETPC();
int mmu_idx = check_access_hlsv(env, true, ra);
MemOpIdx oi = make_memop_idx(MO_TEUL, mmu_idx);
return cpu_ldl_code_mmu(env, addr, oi, ra);
}
#endif /* !CONFIG_USER_ONLY */