| /* |
| * RISC-V emulation helpers for qemu. |
| * |
| * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu |
| * Copyright (c) 2017-2018 SiFive, Inc. |
| * |
| * 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 "qemu/log.h" |
| #include "cpu.h" |
| #include "exec/exec-all.h" |
| #include "tcg-op.h" |
| |
| #define RISCV_DEBUG_INTERRUPT 0 |
| |
| int riscv_cpu_mmu_index(CPURISCVState *env, bool ifetch) |
| { |
| #ifdef CONFIG_USER_ONLY |
| return 0; |
| #else |
| return env->priv; |
| #endif |
| } |
| |
| #ifndef CONFIG_USER_ONLY |
| /* |
| * Return RISC-V IRQ number if an interrupt should be taken, else -1. |
| * Used in cpu-exec.c |
| * |
| * Adapted from Spike's processor_t::take_interrupt() |
| */ |
| static int riscv_cpu_hw_interrupts_pending(CPURISCVState *env) |
| { |
| target_ulong pending_interrupts = atomic_read(&env->mip) & env->mie; |
| |
| target_ulong mie = get_field(env->mstatus, MSTATUS_MIE); |
| target_ulong m_enabled = env->priv < PRV_M || (env->priv == PRV_M && mie); |
| target_ulong enabled_interrupts = pending_interrupts & |
| ~env->mideleg & -m_enabled; |
| |
| target_ulong sie = get_field(env->mstatus, MSTATUS_SIE); |
| target_ulong s_enabled = env->priv < PRV_S || (env->priv == PRV_S && sie); |
| enabled_interrupts |= pending_interrupts & env->mideleg & |
| -s_enabled; |
| |
| if (enabled_interrupts) { |
| return ctz64(enabled_interrupts); /* since non-zero */ |
| } else { |
| return EXCP_NONE; /* indicates no pending interrupt */ |
| } |
| } |
| #endif |
| |
| bool riscv_cpu_exec_interrupt(CPUState *cs, int interrupt_request) |
| { |
| #if !defined(CONFIG_USER_ONLY) |
| if (interrupt_request & CPU_INTERRUPT_HARD) { |
| RISCVCPU *cpu = RISCV_CPU(cs); |
| CPURISCVState *env = &cpu->env; |
| int interruptno = riscv_cpu_hw_interrupts_pending(env); |
| if (interruptno >= 0) { |
| cs->exception_index = RISCV_EXCP_INT_FLAG | interruptno; |
| riscv_cpu_do_interrupt(cs); |
| return true; |
| } |
| } |
| #endif |
| return false; |
| } |
| |
| #if !defined(CONFIG_USER_ONLY) |
| |
| /* get_physical_address - get the physical address for this virtual address |
| * |
| * Do a page table walk to obtain the physical address corresponding to a |
| * virtual address. Returns 0 if the translation was successful |
| * |
| * Adapted from Spike's mmu_t::translate and mmu_t::walk |
| * |
| */ |
| static int get_physical_address(CPURISCVState *env, hwaddr *physical, |
| int *prot, target_ulong addr, |
| int access_type, int mmu_idx) |
| { |
| /* NOTE: the env->pc value visible here will not be |
| * correct, but the value visible to the exception handler |
| * (riscv_cpu_do_interrupt) is correct */ |
| |
| int mode = mmu_idx; |
| |
| if (mode == PRV_M && access_type != MMU_INST_FETCH) { |
| if (get_field(env->mstatus, MSTATUS_MPRV)) { |
| mode = get_field(env->mstatus, MSTATUS_MPP); |
| } |
| } |
| |
| if (mode == PRV_M || !riscv_feature(env, RISCV_FEATURE_MMU)) { |
| *physical = addr; |
| *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC; |
| return TRANSLATE_SUCCESS; |
| } |
| |
| *prot = 0; |
| |
| target_ulong base; |
| int levels, ptidxbits, ptesize, vm, sum; |
| int mxr = get_field(env->mstatus, MSTATUS_MXR); |
| |
| if (env->priv_ver >= PRIV_VERSION_1_10_0) { |
| base = get_field(env->satp, SATP_PPN) << PGSHIFT; |
| sum = get_field(env->mstatus, MSTATUS_SUM); |
| vm = get_field(env->satp, SATP_MODE); |
| switch (vm) { |
| case VM_1_10_SV32: |
| levels = 2; ptidxbits = 10; ptesize = 4; break; |
| case VM_1_10_SV39: |
| levels = 3; ptidxbits = 9; ptesize = 8; break; |
| case VM_1_10_SV48: |
| levels = 4; ptidxbits = 9; ptesize = 8; break; |
| case VM_1_10_SV57: |
| levels = 5; ptidxbits = 9; ptesize = 8; break; |
| case VM_1_10_MBARE: |
| *physical = addr; |
| *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC; |
| return TRANSLATE_SUCCESS; |
| default: |
| g_assert_not_reached(); |
| } |
| } else { |
| base = env->sptbr << PGSHIFT; |
| sum = !get_field(env->mstatus, MSTATUS_PUM); |
| vm = get_field(env->mstatus, MSTATUS_VM); |
| switch (vm) { |
| case VM_1_09_SV32: |
| levels = 2; ptidxbits = 10; ptesize = 4; break; |
| case VM_1_09_SV39: |
| levels = 3; ptidxbits = 9; ptesize = 8; break; |
| case VM_1_09_SV48: |
| levels = 4; ptidxbits = 9; ptesize = 8; break; |
| case VM_1_09_MBARE: |
| *physical = addr; |
| *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC; |
| return TRANSLATE_SUCCESS; |
| default: |
| g_assert_not_reached(); |
| } |
| } |
| |
| CPUState *cs = CPU(riscv_env_get_cpu(env)); |
| int va_bits = PGSHIFT + levels * ptidxbits; |
| target_ulong mask = (1L << (TARGET_LONG_BITS - (va_bits - 1))) - 1; |
| target_ulong masked_msbs = (addr >> (va_bits - 1)) & mask; |
| if (masked_msbs != 0 && masked_msbs != mask) { |
| return TRANSLATE_FAIL; |
| } |
| |
| int ptshift = (levels - 1) * ptidxbits; |
| int i; |
| |
| #if !TCG_OVERSIZED_GUEST |
| restart: |
| #endif |
| for (i = 0; i < levels; i++, ptshift -= ptidxbits) { |
| target_ulong idx = (addr >> (PGSHIFT + ptshift)) & |
| ((1 << ptidxbits) - 1); |
| |
| /* check that physical address of PTE is legal */ |
| target_ulong pte_addr = base + idx * ptesize; |
| #if defined(TARGET_RISCV32) |
| target_ulong pte = ldl_phys(cs->as, pte_addr); |
| #elif defined(TARGET_RISCV64) |
| target_ulong pte = ldq_phys(cs->as, pte_addr); |
| #endif |
| target_ulong ppn = pte >> PTE_PPN_SHIFT; |
| |
| if (PTE_TABLE(pte)) { /* next level of page table */ |
| base = ppn << PGSHIFT; |
| } else if ((pte & PTE_U) ? (mode == PRV_S) && !sum : !(mode == PRV_S)) { |
| break; |
| } else if (!(pte & PTE_V) || (!(pte & PTE_R) && (pte & PTE_W))) { |
| break; |
| } else if (access_type == MMU_INST_FETCH ? !(pte & PTE_X) : |
| access_type == MMU_DATA_LOAD ? !(pte & PTE_R) && |
| !(mxr && (pte & PTE_X)) : !((pte & PTE_R) && (pte & PTE_W))) { |
| break; |
| } else { |
| /* if necessary, set accessed and dirty bits. */ |
| target_ulong updated_pte = pte | PTE_A | |
| (access_type == MMU_DATA_STORE ? PTE_D : 0); |
| |
| /* Page table updates need to be atomic with MTTCG enabled */ |
| if (updated_pte != pte) { |
| /* if accessed or dirty bits need updating, and the PTE is |
| * in RAM, then we do so atomically with a compare and swap. |
| * if the PTE is in IO space, then it can't be updated. |
| * if the PTE changed, then we must re-walk the page table |
| as the PTE is no longer valid */ |
| MemoryRegion *mr; |
| hwaddr l = sizeof(target_ulong), addr1; |
| mr = address_space_translate(cs->as, pte_addr, |
| &addr1, &l, false, MEMTXATTRS_UNSPECIFIED); |
| if (memory_access_is_direct(mr, true)) { |
| target_ulong *pte_pa = |
| qemu_map_ram_ptr(mr->ram_block, addr1); |
| #if TCG_OVERSIZED_GUEST |
| /* MTTCG is not enabled on oversized TCG guests so |
| * page table updates do not need to be atomic */ |
| *pte_pa = pte = updated_pte; |
| #else |
| target_ulong old_pte = |
| atomic_cmpxchg(pte_pa, pte, updated_pte); |
| if (old_pte != pte) { |
| goto restart; |
| } else { |
| pte = updated_pte; |
| } |
| #endif |
| } else { |
| /* misconfigured PTE in ROM (AD bits are not preset) or |
| * PTE is in IO space and can't be updated atomically */ |
| return TRANSLATE_FAIL; |
| } |
| } |
| |
| /* for superpage mappings, make a fake leaf PTE for the TLB's |
| benefit. */ |
| target_ulong vpn = addr >> PGSHIFT; |
| *physical = (ppn | (vpn & ((1L << ptshift) - 1))) << PGSHIFT; |
| |
| if ((pte & PTE_R)) { |
| *prot |= PAGE_READ; |
| } |
| if ((pte & PTE_X)) { |
| *prot |= PAGE_EXEC; |
| } |
| /* only add write permission on stores or if the page |
| is already dirty, so that we don't miss further |
| page table walks to update the dirty bit */ |
| if ((pte & PTE_W) && |
| (access_type == MMU_DATA_STORE || (pte & PTE_D))) { |
| *prot |= PAGE_WRITE; |
| } |
| return TRANSLATE_SUCCESS; |
| } |
| } |
| return TRANSLATE_FAIL; |
| } |
| |
| static void raise_mmu_exception(CPURISCVState *env, target_ulong address, |
| MMUAccessType access_type) |
| { |
| CPUState *cs = CPU(riscv_env_get_cpu(env)); |
| int page_fault_exceptions = |
| (env->priv_ver >= PRIV_VERSION_1_10_0) && |
| get_field(env->satp, SATP_MODE) != VM_1_10_MBARE; |
| switch (access_type) { |
| case MMU_INST_FETCH: |
| cs->exception_index = page_fault_exceptions ? |
| RISCV_EXCP_INST_PAGE_FAULT : RISCV_EXCP_INST_ACCESS_FAULT; |
| break; |
| case MMU_DATA_LOAD: |
| cs->exception_index = page_fault_exceptions ? |
| RISCV_EXCP_LOAD_PAGE_FAULT : RISCV_EXCP_LOAD_ACCESS_FAULT; |
| break; |
| case MMU_DATA_STORE: |
| cs->exception_index = page_fault_exceptions ? |
| RISCV_EXCP_STORE_PAGE_FAULT : RISCV_EXCP_STORE_AMO_ACCESS_FAULT; |
| break; |
| default: |
| g_assert_not_reached(); |
| } |
| env->badaddr = address; |
| } |
| |
| hwaddr riscv_cpu_get_phys_page_debug(CPUState *cs, vaddr addr) |
| { |
| RISCVCPU *cpu = RISCV_CPU(cs); |
| hwaddr phys_addr; |
| int prot; |
| int mmu_idx = cpu_mmu_index(&cpu->env, false); |
| |
| if (get_physical_address(&cpu->env, &phys_addr, &prot, addr, 0, mmu_idx)) { |
| return -1; |
| } |
| return phys_addr; |
| } |
| |
| void riscv_cpu_do_unaligned_access(CPUState *cs, vaddr addr, |
| MMUAccessType access_type, int mmu_idx, |
| uintptr_t retaddr) |
| { |
| RISCVCPU *cpu = RISCV_CPU(cs); |
| CPURISCVState *env = &cpu->env; |
| switch (access_type) { |
| case MMU_INST_FETCH: |
| cs->exception_index = RISCV_EXCP_INST_ADDR_MIS; |
| break; |
| case MMU_DATA_LOAD: |
| cs->exception_index = RISCV_EXCP_LOAD_ADDR_MIS; |
| break; |
| case MMU_DATA_STORE: |
| cs->exception_index = RISCV_EXCP_STORE_AMO_ADDR_MIS; |
| break; |
| default: |
| g_assert_not_reached(); |
| } |
| env->badaddr = addr; |
| do_raise_exception_err(env, cs->exception_index, retaddr); |
| } |
| |
| /* called by qemu's softmmu to fill the qemu tlb */ |
| void tlb_fill(CPUState *cs, target_ulong addr, int size, |
| MMUAccessType access_type, int mmu_idx, uintptr_t retaddr) |
| { |
| int ret; |
| ret = riscv_cpu_handle_mmu_fault(cs, addr, size, access_type, mmu_idx); |
| if (ret == TRANSLATE_FAIL) { |
| RISCVCPU *cpu = RISCV_CPU(cs); |
| CPURISCVState *env = &cpu->env; |
| do_raise_exception_err(env, cs->exception_index, retaddr); |
| } |
| } |
| |
| #endif |
| |
| int riscv_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int size, |
| int rw, int mmu_idx) |
| { |
| RISCVCPU *cpu = RISCV_CPU(cs); |
| CPURISCVState *env = &cpu->env; |
| #if !defined(CONFIG_USER_ONLY) |
| hwaddr pa = 0; |
| int prot; |
| #endif |
| int ret = TRANSLATE_FAIL; |
| |
| qemu_log_mask(CPU_LOG_MMU, |
| "%s pc " TARGET_FMT_lx " ad %" VADDR_PRIx " rw %d mmu_idx \ |
| %d\n", __func__, env->pc, address, rw, mmu_idx); |
| |
| #if !defined(CONFIG_USER_ONLY) |
| ret = get_physical_address(env, &pa, &prot, address, rw, mmu_idx); |
| qemu_log_mask(CPU_LOG_MMU, |
| "%s address=%" VADDR_PRIx " ret %d physical " TARGET_FMT_plx |
| " prot %d\n", __func__, address, ret, pa, prot); |
| if (!pmp_hart_has_privs(env, pa, TARGET_PAGE_SIZE, 1 << rw)) { |
| ret = TRANSLATE_FAIL; |
| } |
| if (ret == TRANSLATE_SUCCESS) { |
| tlb_set_page(cs, address & TARGET_PAGE_MASK, pa & TARGET_PAGE_MASK, |
| prot, mmu_idx, TARGET_PAGE_SIZE); |
| } else if (ret == TRANSLATE_FAIL) { |
| raise_mmu_exception(env, address, rw); |
| } |
| #else |
| switch (rw) { |
| case MMU_INST_FETCH: |
| cs->exception_index = RISCV_EXCP_INST_PAGE_FAULT; |
| break; |
| case MMU_DATA_LOAD: |
| cs->exception_index = RISCV_EXCP_LOAD_PAGE_FAULT; |
| break; |
| case MMU_DATA_STORE: |
| cs->exception_index = RISCV_EXCP_STORE_PAGE_FAULT; |
| break; |
| } |
| #endif |
| return ret; |
| } |
| |
| /* |
| * Handle Traps |
| * |
| * Adapted from Spike's processor_t::take_trap. |
| * |
| */ |
| void riscv_cpu_do_interrupt(CPUState *cs) |
| { |
| #if !defined(CONFIG_USER_ONLY) |
| |
| RISCVCPU *cpu = RISCV_CPU(cs); |
| CPURISCVState *env = &cpu->env; |
| |
| if (RISCV_DEBUG_INTERRUPT) { |
| int log_cause = cs->exception_index & RISCV_EXCP_INT_MASK; |
| if (cs->exception_index & RISCV_EXCP_INT_FLAG) { |
| qemu_log_mask(LOG_TRACE, "core 0: trap %s, epc 0x" TARGET_FMT_lx, |
| riscv_intr_names[log_cause], env->pc); |
| } else { |
| qemu_log_mask(LOG_TRACE, "core 0: intr %s, epc 0x" TARGET_FMT_lx, |
| riscv_excp_names[log_cause], env->pc); |
| } |
| } |
| |
| target_ulong fixed_cause = 0; |
| if (cs->exception_index & (RISCV_EXCP_INT_FLAG)) { |
| /* hacky for now. the MSB (bit 63) indicates interrupt but cs->exception |
| index is only 32 bits wide */ |
| fixed_cause = cs->exception_index & RISCV_EXCP_INT_MASK; |
| fixed_cause |= ((target_ulong)1) << (TARGET_LONG_BITS - 1); |
| } else { |
| /* fixup User ECALL -> correct priv ECALL */ |
| if (cs->exception_index == RISCV_EXCP_U_ECALL) { |
| switch (env->priv) { |
| case PRV_U: |
| fixed_cause = RISCV_EXCP_U_ECALL; |
| break; |
| case PRV_S: |
| fixed_cause = RISCV_EXCP_S_ECALL; |
| break; |
| case PRV_H: |
| fixed_cause = RISCV_EXCP_H_ECALL; |
| break; |
| case PRV_M: |
| fixed_cause = RISCV_EXCP_M_ECALL; |
| break; |
| } |
| } else { |
| fixed_cause = cs->exception_index; |
| } |
| } |
| |
| target_ulong backup_epc = env->pc; |
| |
| target_ulong bit = fixed_cause; |
| target_ulong deleg = env->medeleg; |
| |
| int hasbadaddr = |
| (fixed_cause == RISCV_EXCP_INST_ADDR_MIS) || |
| (fixed_cause == RISCV_EXCP_INST_ACCESS_FAULT) || |
| (fixed_cause == RISCV_EXCP_LOAD_ADDR_MIS) || |
| (fixed_cause == RISCV_EXCP_STORE_AMO_ADDR_MIS) || |
| (fixed_cause == RISCV_EXCP_LOAD_ACCESS_FAULT) || |
| (fixed_cause == RISCV_EXCP_STORE_AMO_ACCESS_FAULT) || |
| (fixed_cause == RISCV_EXCP_INST_PAGE_FAULT) || |
| (fixed_cause == RISCV_EXCP_LOAD_PAGE_FAULT) || |
| (fixed_cause == RISCV_EXCP_STORE_PAGE_FAULT); |
| |
| if (bit & ((target_ulong)1 << (TARGET_LONG_BITS - 1))) { |
| deleg = env->mideleg; |
| bit &= ~((target_ulong)1 << (TARGET_LONG_BITS - 1)); |
| } |
| |
| if (env->priv <= PRV_S && bit < 64 && ((deleg >> bit) & 1)) { |
| /* handle the trap in S-mode */ |
| /* No need to check STVEC for misaligned - lower 2 bits cannot be set */ |
| env->pc = env->stvec; |
| env->scause = fixed_cause; |
| env->sepc = backup_epc; |
| |
| if (hasbadaddr) { |
| if (RISCV_DEBUG_INTERRUPT) { |
| qemu_log_mask(LOG_TRACE, "core " TARGET_FMT_ld |
| ": badaddr 0x" TARGET_FMT_lx, env->mhartid, env->badaddr); |
| } |
| env->sbadaddr = env->badaddr; |
| } else { |
| /* otherwise we must clear sbadaddr/stval |
| * todo: support populating stval on illegal instructions */ |
| env->sbadaddr = 0; |
| } |
| |
| target_ulong s = env->mstatus; |
| s = set_field(s, MSTATUS_SPIE, env->priv_ver >= PRIV_VERSION_1_10_0 ? |
| get_field(s, MSTATUS_SIE) : get_field(s, MSTATUS_UIE << env->priv)); |
| s = set_field(s, MSTATUS_SPP, env->priv); |
| s = set_field(s, MSTATUS_SIE, 0); |
| csr_write_helper(env, s, CSR_MSTATUS); |
| riscv_set_mode(env, PRV_S); |
| } else { |
| /* No need to check MTVEC for misaligned - lower 2 bits cannot be set */ |
| env->pc = env->mtvec; |
| env->mepc = backup_epc; |
| env->mcause = fixed_cause; |
| |
| if (hasbadaddr) { |
| if (RISCV_DEBUG_INTERRUPT) { |
| qemu_log_mask(LOG_TRACE, "core " TARGET_FMT_ld |
| ": badaddr 0x" TARGET_FMT_lx, env->mhartid, env->badaddr); |
| } |
| env->mbadaddr = env->badaddr; |
| } else { |
| /* otherwise we must clear mbadaddr/mtval |
| * todo: support populating mtval on illegal instructions */ |
| env->mbadaddr = 0; |
| } |
| |
| target_ulong s = env->mstatus; |
| s = set_field(s, MSTATUS_MPIE, env->priv_ver >= PRIV_VERSION_1_10_0 ? |
| get_field(s, MSTATUS_MIE) : get_field(s, MSTATUS_UIE << env->priv)); |
| s = set_field(s, MSTATUS_MPP, env->priv); |
| s = set_field(s, MSTATUS_MIE, 0); |
| csr_write_helper(env, s, CSR_MSTATUS); |
| riscv_set_mode(env, PRV_M); |
| } |
| /* TODO yield load reservation */ |
| #endif |
| cs->exception_index = EXCP_NONE; /* mark handled to qemu */ |
| } |
