/* * Microblaze MMU emulation for qemu. * * Copyright (c) 2009 Edgar E. Iglesias * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, see <http://www.gnu.org/licenses/>. */ #include "cpu.h" #define D(x) static unsigned int tlb_decode_size(unsigned int f) { static const unsigned int sizes[] = { 1 * 1024, 4 * 1024, 16 * 1024, 64 * 1024, 256 * 1024, 1 * 1024 * 1024, 4 * 1024 * 1024, 16 * 1024 * 1024 }; assert(f < ARRAY_SIZE(sizes)); return sizes[f]; } static void mmu_flush_idx(CPUState *env, unsigned int idx) { struct microblaze_mmu *mmu = &env->mmu; unsigned int tlb_size; uint32_t tlb_tag, end, t; t = mmu->rams[RAM_TAG][idx]; if (!(t & TLB_VALID)) return; tlb_tag = t & TLB_EPN_MASK; tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7); end = tlb_tag + tlb_size; while (tlb_tag < end) { tlb_flush_page(env, tlb_tag); tlb_tag += TARGET_PAGE_SIZE; } } static void mmu_change_pid(CPUState *env, unsigned int newpid) { struct microblaze_mmu *mmu = &env->mmu; unsigned int i; uint32_t t; if (newpid & ~0xff) qemu_log("Illegal rpid=%x\n", newpid); for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) { /* Lookup and decode. */ t = mmu->rams[RAM_TAG][i]; if (t & TLB_VALID) { if (mmu->tids[i] && ((mmu->regs[MMU_R_PID] & 0xff) == mmu->tids[i])) mmu_flush_idx(env, i); } } } /* rw - 0 = read, 1 = write, 2 = fetch. */ unsigned int mmu_translate(struct microblaze_mmu *mmu, struct microblaze_mmu_lookup *lu, target_ulong vaddr, int rw, int mmu_idx) { unsigned int i, hit = 0; unsigned int tlb_ex = 0, tlb_wr = 0, tlb_zsel; unsigned int tlb_size; uint32_t tlb_tag, tlb_rpn, mask, t0; lu->err = ERR_MISS; for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) { uint32_t t, d; /* Lookup and decode. */ t = mmu->rams[RAM_TAG][i]; D(qemu_log("TLB %d valid=%d\n", i, t & TLB_VALID)); if (t & TLB_VALID) { tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7); if (tlb_size < TARGET_PAGE_SIZE) { qemu_log("%d pages not supported\n", tlb_size); abort(); } mask = ~(tlb_size - 1); tlb_tag = t & TLB_EPN_MASK; if ((vaddr & mask) != (tlb_tag & mask)) { D(qemu_log("TLB %d vaddr=%x != tag=%x\n", i, vaddr & mask, tlb_tag & mask)); continue; } if (mmu->tids[i] && ((mmu->regs[MMU_R_PID] & 0xff) != mmu->tids[i])) { D(qemu_log("TLB %d pid=%x != tid=%x\n", i, mmu->regs[MMU_R_PID], mmu->tids[i])); continue; } /* Bring in the data part. */ d = mmu->rams[RAM_DATA][i]; tlb_ex = d & TLB_EX; tlb_wr = d & TLB_WR; /* Now lets see if there is a zone that overrides the protbits. */ tlb_zsel = (d >> 4) & 0xf; t0 = mmu->regs[MMU_R_ZPR] >> (30 - (tlb_zsel * 2)); t0 &= 0x3; if (tlb_zsel > mmu->c_mmu_zones) { qemu_log("tlb zone select out of range! %d\n", tlb_zsel); t0 = 1; /* Ignore. */ } if (mmu->c_mmu == 1) { t0 = 1; /* Zones are disabled. */ } switch (t0) { case 0: if (mmu_idx == MMU_USER_IDX) continue; break; case 2: if (mmu_idx != MMU_USER_IDX) { tlb_ex = 1; tlb_wr = 1; } break; case 3: tlb_ex = 1; tlb_wr = 1; break; default: break; } lu->err = ERR_PROT; lu->prot = PAGE_READ; if (tlb_wr) lu->prot |= PAGE_WRITE; else if (rw == 1) goto done; if (tlb_ex) lu->prot |=PAGE_EXEC; else if (rw == 2) { goto done; } tlb_rpn = d & TLB_RPN_MASK; lu->vaddr = tlb_tag; lu->paddr = tlb_rpn; lu->size = tlb_size; lu->err = ERR_HIT; lu->idx = i; hit = 1; goto done; } } done: D(qemu_log("MMU vaddr=%x rw=%d tlb_wr=%d tlb_ex=%d hit=%d\n", vaddr, rw, tlb_wr, tlb_ex, hit)); return hit; } /* Writes/reads to the MMU's special regs end up here. */ uint32_t mmu_read(CPUState *env, uint32_t rn) { unsigned int i; uint32_t r; if (env->mmu.c_mmu < 2 || !env->mmu.c_mmu_tlb_access) { qemu_log("MMU access on MMU-less system\n"); return 0; } switch (rn) { /* Reads to HI/LO trig reads from the mmu rams. */ case MMU_R_TLBLO: case MMU_R_TLBHI: if (!(env->mmu.c_mmu_tlb_access & 1)) { qemu_log("Invalid access to MMU reg %d\n", rn); return 0; } i = env->mmu.regs[MMU_R_TLBX] & 0xff; r = env->mmu.rams[rn & 1][i]; if (rn == MMU_R_TLBHI) env->mmu.regs[MMU_R_PID] = env->mmu.tids[i]; break; case MMU_R_PID: case MMU_R_ZPR: if (!(env->mmu.c_mmu_tlb_access & 1)) { qemu_log("Invalid access to MMU reg %d\n", rn); return 0; } r = env->mmu.regs[rn]; break; default: r = env->mmu.regs[rn]; break; } D(qemu_log("%s rn=%d=%x\n", __func__, rn, r)); return r; } void mmu_write(CPUState *env, uint32_t rn, uint32_t v) { unsigned int i; D(qemu_log("%s rn=%d=%x old=%x\n", __func__, rn, v, env->mmu.regs[rn])); if (env->mmu.c_mmu < 2 || !env->mmu.c_mmu_tlb_access) { qemu_log("MMU access on MMU-less system\n"); return; } switch (rn) { /* Writes to HI/LO trig writes to the mmu rams. */ case MMU_R_TLBLO: case MMU_R_TLBHI: i = env->mmu.regs[MMU_R_TLBX] & 0xff; if (rn == MMU_R_TLBHI) { if (i < 3 && !(v & TLB_VALID) && qemu_loglevel_mask(~0)) qemu_log("invalidating index %x at pc=%x\n", i, env->sregs[SR_PC]); env->mmu.tids[i] = env->mmu.regs[MMU_R_PID] & 0xff; mmu_flush_idx(env, i); } env->mmu.rams[rn & 1][i] = v; D(qemu_log("%s ram[%d][%d]=%x\n", __func__, rn & 1, i, v)); break; case MMU_R_ZPR: if (env->mmu.c_mmu_tlb_access <= 1) { qemu_log("Invalid access to MMU reg %d\n", rn); return; } /* Changes to the zone protection reg flush the QEMU TLB. Fortunately, these are very uncommon. */ if (v != env->mmu.regs[rn]) { tlb_flush(env, 1); } env->mmu.regs[rn] = v; break; case MMU_R_PID: if (env->mmu.c_mmu_tlb_access <= 1) { qemu_log("Invalid access to MMU reg %d\n", rn); return; } if (v != env->mmu.regs[rn]) { mmu_change_pid(env, v); env->mmu.regs[rn] = v; } break; case MMU_R_TLBSX: { struct microblaze_mmu_lookup lu; int hit; if (env->mmu.c_mmu_tlb_access <= 1) { qemu_log("Invalid access to MMU reg %d\n", rn); return; } hit = mmu_translate(&env->mmu, &lu, v & TLB_EPN_MASK, 0, cpu_mmu_index(env)); if (hit) { env->mmu.regs[MMU_R_TLBX] = lu.idx; } else env->mmu.regs[MMU_R_TLBX] |= 0x80000000; break; } default: env->mmu.regs[rn] = v; break; } } void mmu_init(struct microblaze_mmu *mmu) { int i; for (i = 0; i < ARRAY_SIZE(mmu->regs); i++) { mmu->regs[i] = 0; } }