| /* |
| * QEMU RISC-V PMP (Physical Memory Protection) |
| * |
| * Author: Daire McNamara, daire.mcnamara@emdalo.com |
| * Ivan Griffin, ivan.griffin@emdalo.com |
| * |
| * This provides a RISC-V Physical Memory Protection implementation |
| * |
| * 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/>. |
| */ |
| |
| /* |
| * PMP (Physical Memory Protection) is as-of-yet unused and needs testing. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qemu/log.h" |
| #include "qapi/error.h" |
| #include "cpu.h" |
| #include "trace.h" |
| #include "exec/exec-all.h" |
| |
| static void pmp_write_cfg(CPURISCVState *env, uint32_t addr_index, |
| uint8_t val); |
| static uint8_t pmp_read_cfg(CPURISCVState *env, uint32_t addr_index); |
| static void pmp_update_rule(CPURISCVState *env, uint32_t pmp_index); |
| |
| /* |
| * Accessor method to extract address matching type 'a field' from cfg reg |
| */ |
| static inline uint8_t pmp_get_a_field(uint8_t cfg) |
| { |
| uint8_t a = cfg >> 3; |
| return a & 0x3; |
| } |
| |
| /* |
| * Check whether a PMP is locked or not. |
| */ |
| static inline int pmp_is_locked(CPURISCVState *env, uint32_t pmp_index) |
| { |
| |
| if (env->pmp_state.pmp[pmp_index].cfg_reg & PMP_LOCK) { |
| return 1; |
| } |
| |
| /* Top PMP has no 'next' to check */ |
| if ((pmp_index + 1u) >= MAX_RISCV_PMPS) { |
| return 0; |
| } |
| |
| /* In TOR mode, need to check the lock bit of the next pmp |
| * (if there is a next) |
| */ |
| const uint8_t a_field = |
| pmp_get_a_field(env->pmp_state.pmp[pmp_index + 1].cfg_reg); |
| if ((env->pmp_state.pmp[pmp_index + 1u].cfg_reg & PMP_LOCK) && |
| (PMP_AMATCH_TOR == a_field)) { |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Count the number of active rules. |
| */ |
| uint32_t pmp_get_num_rules(CPURISCVState *env) |
| { |
| return env->pmp_state.num_rules; |
| } |
| |
| /* |
| * Accessor to get the cfg reg for a specific PMP/HART |
| */ |
| static inline uint8_t pmp_read_cfg(CPURISCVState *env, uint32_t pmp_index) |
| { |
| if (pmp_index < MAX_RISCV_PMPS) { |
| return env->pmp_state.pmp[pmp_index].cfg_reg; |
| } |
| |
| return 0; |
| } |
| |
| |
| /* |
| * Accessor to set the cfg reg for a specific PMP/HART |
| * Bounds checks and relevant lock bit. |
| */ |
| static void pmp_write_cfg(CPURISCVState *env, uint32_t pmp_index, uint8_t val) |
| { |
| if (pmp_index < MAX_RISCV_PMPS) { |
| if (!pmp_is_locked(env, pmp_index)) { |
| env->pmp_state.pmp[pmp_index].cfg_reg = val; |
| pmp_update_rule(env, pmp_index); |
| } else { |
| qemu_log_mask(LOG_GUEST_ERROR, "ignoring pmpcfg write - locked\n"); |
| } |
| } else { |
| qemu_log_mask(LOG_GUEST_ERROR, |
| "ignoring pmpcfg write - out of bounds\n"); |
| } |
| } |
| |
| static void pmp_decode_napot(target_ulong a, target_ulong *sa, target_ulong *ea) |
| { |
| /* |
| aaaa...aaa0 8-byte NAPOT range |
| aaaa...aa01 16-byte NAPOT range |
| aaaa...a011 32-byte NAPOT range |
| ... |
| aa01...1111 2^XLEN-byte NAPOT range |
| a011...1111 2^(XLEN+1)-byte NAPOT range |
| 0111...1111 2^(XLEN+2)-byte NAPOT range |
| 1111...1111 Reserved |
| */ |
| if (a == -1) { |
| *sa = 0u; |
| *ea = -1; |
| return; |
| } else { |
| target_ulong t1 = ctz64(~a); |
| target_ulong base = (a & ~(((target_ulong)1 << t1) - 1)) << 2; |
| target_ulong range = ((target_ulong)1 << (t1 + 3)) - 1; |
| *sa = base; |
| *ea = base + range; |
| } |
| } |
| |
| void pmp_update_rule_addr(CPURISCVState *env, uint32_t pmp_index) |
| { |
| uint8_t this_cfg = env->pmp_state.pmp[pmp_index].cfg_reg; |
| target_ulong this_addr = env->pmp_state.pmp[pmp_index].addr_reg; |
| target_ulong prev_addr = 0u; |
| target_ulong sa = 0u; |
| target_ulong ea = 0u; |
| |
| if (pmp_index >= 1u) { |
| prev_addr = env->pmp_state.pmp[pmp_index - 1].addr_reg; |
| } |
| |
| switch (pmp_get_a_field(this_cfg)) { |
| case PMP_AMATCH_OFF: |
| sa = 0u; |
| ea = -1; |
| break; |
| |
| case PMP_AMATCH_TOR: |
| sa = prev_addr << 2; /* shift up from [xx:0] to [xx+2:2] */ |
| ea = (this_addr << 2) - 1u; |
| break; |
| |
| case PMP_AMATCH_NA4: |
| sa = this_addr << 2; /* shift up from [xx:0] to [xx+2:2] */ |
| ea = (sa + 4u) - 1u; |
| break; |
| |
| case PMP_AMATCH_NAPOT: |
| pmp_decode_napot(this_addr, &sa, &ea); |
| break; |
| |
| default: |
| sa = 0u; |
| ea = 0u; |
| break; |
| } |
| |
| env->pmp_state.addr[pmp_index].sa = sa; |
| env->pmp_state.addr[pmp_index].ea = ea; |
| } |
| |
| void pmp_update_rule_nums(CPURISCVState *env) |
| { |
| int i; |
| |
| env->pmp_state.num_rules = 0; |
| for (i = 0; i < MAX_RISCV_PMPS; i++) { |
| const uint8_t a_field = |
| pmp_get_a_field(env->pmp_state.pmp[i].cfg_reg); |
| if (PMP_AMATCH_OFF != a_field) { |
| env->pmp_state.num_rules++; |
| } |
| } |
| } |
| |
| /* Convert cfg/addr reg values here into simple 'sa' --> start address and 'ea' |
| * end address values. |
| * This function is called relatively infrequently whereas the check that |
| * an address is within a pmp rule is called often, so optimise that one |
| */ |
| static void pmp_update_rule(CPURISCVState *env, uint32_t pmp_index) |
| { |
| pmp_update_rule_addr(env, pmp_index); |
| pmp_update_rule_nums(env); |
| } |
| |
| static int pmp_is_in_range(CPURISCVState *env, int pmp_index, target_ulong addr) |
| { |
| int result = 0; |
| |
| if ((addr >= env->pmp_state.addr[pmp_index].sa) |
| && (addr <= env->pmp_state.addr[pmp_index].ea)) { |
| result = 1; |
| } else { |
| result = 0; |
| } |
| |
| return result; |
| } |
| |
| /* |
| * Check if the address has required RWX privs when no PMP entry is matched. |
| */ |
| static bool pmp_hart_has_privs_default(CPURISCVState *env, target_ulong addr, |
| target_ulong size, pmp_priv_t privs, pmp_priv_t *allowed_privs, |
| target_ulong mode) |
| { |
| bool ret; |
| |
| if ((!riscv_feature(env, RISCV_FEATURE_PMP)) || (mode == PRV_M)) { |
| /* |
| * Privileged spec v1.10 states if HW doesn't implement any PMP entry |
| * or no PMP entry matches an M-Mode access, the access succeeds. |
| */ |
| ret = true; |
| *allowed_privs = PMP_READ | PMP_WRITE | PMP_EXEC; |
| } else { |
| /* |
| * Other modes are not allowed to succeed if they don't * match a rule, |
| * but there are rules. We've checked for no rule earlier in this |
| * function. |
| */ |
| ret = false; |
| *allowed_privs = 0; |
| } |
| |
| return ret; |
| } |
| |
| |
| /* |
| * Public Interface |
| */ |
| |
| /* |
| * Check if the address has required RWX privs to complete desired operation |
| */ |
| bool pmp_hart_has_privs(CPURISCVState *env, target_ulong addr, |
| target_ulong size, pmp_priv_t privs, pmp_priv_t *allowed_privs, |
| target_ulong mode) |
| { |
| int i = 0; |
| int ret = -1; |
| int pmp_size = 0; |
| target_ulong s = 0; |
| target_ulong e = 0; |
| |
| /* Short cut if no rules */ |
| if (0 == pmp_get_num_rules(env)) { |
| return pmp_hart_has_privs_default(env, addr, size, privs, |
| allowed_privs, mode); |
| } |
| |
| if (size == 0) { |
| if (riscv_feature(env, RISCV_FEATURE_MMU)) { |
| /* |
| * If size is unknown (0), assume that all bytes |
| * from addr to the end of the page will be accessed. |
| */ |
| pmp_size = -(addr | TARGET_PAGE_MASK); |
| } else { |
| pmp_size = sizeof(target_ulong); |
| } |
| } else { |
| pmp_size = size; |
| } |
| |
| /* 1.10 draft priv spec states there is an implicit order |
| from low to high */ |
| for (i = 0; i < MAX_RISCV_PMPS; i++) { |
| s = pmp_is_in_range(env, i, addr); |
| e = pmp_is_in_range(env, i, addr + pmp_size - 1); |
| |
| /* partially inside */ |
| if ((s + e) == 1) { |
| qemu_log_mask(LOG_GUEST_ERROR, |
| "pmp violation - access is partially inside\n"); |
| ret = 0; |
| break; |
| } |
| |
| /* fully inside */ |
| const uint8_t a_field = |
| pmp_get_a_field(env->pmp_state.pmp[i].cfg_reg); |
| |
| /* |
| * If the PMP entry is not off and the address is in range, do the priv |
| * check |
| */ |
| if (((s + e) == 2) && (PMP_AMATCH_OFF != a_field)) { |
| *allowed_privs = PMP_READ | PMP_WRITE | PMP_EXEC; |
| if ((mode != PRV_M) || pmp_is_locked(env, i)) { |
| *allowed_privs &= env->pmp_state.pmp[i].cfg_reg; |
| } |
| |
| ret = ((privs & *allowed_privs) == privs); |
| break; |
| } |
| } |
| |
| /* No rule matched */ |
| if (ret == -1) { |
| return pmp_hart_has_privs_default(env, addr, size, privs, |
| allowed_privs, mode); |
| } |
| |
| return ret == 1 ? true : false; |
| } |
| |
| /* |
| * Handle a write to a pmpcfg CSP |
| */ |
| void pmpcfg_csr_write(CPURISCVState *env, uint32_t reg_index, |
| target_ulong val) |
| { |
| int i; |
| uint8_t cfg_val; |
| |
| trace_pmpcfg_csr_write(env->mhartid, reg_index, val); |
| |
| if ((reg_index & 1) && (sizeof(target_ulong) == 8)) { |
| qemu_log_mask(LOG_GUEST_ERROR, |
| "ignoring pmpcfg write - incorrect address\n"); |
| return; |
| } |
| |
| for (i = 0; i < sizeof(target_ulong); i++) { |
| cfg_val = (val >> 8 * i) & 0xff; |
| pmp_write_cfg(env, (reg_index * 4) + i, cfg_val); |
| } |
| |
| /* If PMP permission of any addr has been changed, flush TLB pages. */ |
| tlb_flush(env_cpu(env)); |
| } |
| |
| |
| /* |
| * Handle a read from a pmpcfg CSP |
| */ |
| target_ulong pmpcfg_csr_read(CPURISCVState *env, uint32_t reg_index) |
| { |
| int i; |
| target_ulong cfg_val = 0; |
| target_ulong val = 0; |
| |
| for (i = 0; i < sizeof(target_ulong); i++) { |
| val = pmp_read_cfg(env, (reg_index * 4) + i); |
| cfg_val |= (val << (i * 8)); |
| } |
| trace_pmpcfg_csr_read(env->mhartid, reg_index, cfg_val); |
| |
| return cfg_val; |
| } |
| |
| |
| /* |
| * Handle a write to a pmpaddr CSP |
| */ |
| void pmpaddr_csr_write(CPURISCVState *env, uint32_t addr_index, |
| target_ulong val) |
| { |
| trace_pmpaddr_csr_write(env->mhartid, addr_index, val); |
| if (addr_index < MAX_RISCV_PMPS) { |
| if (!pmp_is_locked(env, addr_index)) { |
| env->pmp_state.pmp[addr_index].addr_reg = val; |
| pmp_update_rule(env, addr_index); |
| } else { |
| qemu_log_mask(LOG_GUEST_ERROR, |
| "ignoring pmpaddr write - locked\n"); |
| } |
| } else { |
| qemu_log_mask(LOG_GUEST_ERROR, |
| "ignoring pmpaddr write - out of bounds\n"); |
| } |
| } |
| |
| |
| /* |
| * Handle a read from a pmpaddr CSP |
| */ |
| target_ulong pmpaddr_csr_read(CPURISCVState *env, uint32_t addr_index) |
| { |
| target_ulong val = 0; |
| |
| if (addr_index < MAX_RISCV_PMPS) { |
| val = env->pmp_state.pmp[addr_index].addr_reg; |
| trace_pmpaddr_csr_read(env->mhartid, addr_index, val); |
| } else { |
| qemu_log_mask(LOG_GUEST_ERROR, |
| "ignoring pmpaddr read - out of bounds\n"); |
| } |
| |
| return val; |
| } |
| |
| /* |
| * Calculate the TLB size if the start address or the end address of |
| * PMP entry is presented in thie TLB page. |
| */ |
| static target_ulong pmp_get_tlb_size(CPURISCVState *env, int pmp_index, |
| target_ulong tlb_sa, target_ulong tlb_ea) |
| { |
| target_ulong pmp_sa = env->pmp_state.addr[pmp_index].sa; |
| target_ulong pmp_ea = env->pmp_state.addr[pmp_index].ea; |
| |
| if (pmp_sa >= tlb_sa && pmp_ea <= tlb_ea) { |
| return pmp_ea - pmp_sa + 1; |
| } |
| |
| if (pmp_sa >= tlb_sa && pmp_sa <= tlb_ea && pmp_ea >= tlb_ea) { |
| return tlb_ea - pmp_sa + 1; |
| } |
| |
| if (pmp_ea <= tlb_ea && pmp_ea >= tlb_sa && pmp_sa <= tlb_sa) { |
| return pmp_ea - tlb_sa + 1; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Check is there a PMP entry which range covers this page. If so, |
| * try to find the minimum granularity for the TLB size. |
| */ |
| bool pmp_is_range_in_tlb(CPURISCVState *env, hwaddr tlb_sa, |
| target_ulong *tlb_size) |
| { |
| int i; |
| target_ulong val; |
| target_ulong tlb_ea = (tlb_sa + TARGET_PAGE_SIZE - 1); |
| |
| for (i = 0; i < MAX_RISCV_PMPS; i++) { |
| val = pmp_get_tlb_size(env, i, tlb_sa, tlb_ea); |
| if (val) { |
| if (*tlb_size == 0 || *tlb_size > val) { |
| *tlb_size = val; |
| } |
| } |
| } |
| |
| if (*tlb_size != 0) { |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* |
| * Convert PMP privilege to TLB page privilege. |
| */ |
| int pmp_priv_to_page_prot(pmp_priv_t pmp_priv) |
| { |
| int prot = 0; |
| |
| if (pmp_priv & PMP_READ) { |
| prot |= PAGE_READ; |
| } |
| if (pmp_priv & PMP_WRITE) { |
| prot |= PAGE_WRITE; |
| } |
| if (pmp_priv & PMP_EXEC) { |
| prot |= PAGE_EXEC; |
| } |
| |
| return prot; |
| } |
