/* * ARM helper routines * * Copyright (c) 2005-2007 CodeSourcery, LLC * * 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 . */ #include "cpu.h" #include "exec/helper-proto.h" #include "internals.h" #include "exec/cpu_ldst.h" #define SIGNBIT (uint32_t)0x80000000 #define SIGNBIT64 ((uint64_t)1 << 63) static void raise_exception(CPUARMState *env, int tt) { ARMCPU *cpu = arm_env_get_cpu(env); CPUState *cs = CPU(cpu); cs->exception_index = tt; cpu_loop_exit(cs); } uint32_t HELPER(neon_tbl)(CPUARMState *env, uint32_t ireg, uint32_t def, uint32_t rn, uint32_t maxindex) { uint32_t val; uint32_t tmp; int index; int shift; uint64_t *table; table = (uint64_t *)&env->vfp.regs[rn]; val = 0; for (shift = 0; shift < 32; shift += 8) { index = (ireg >> shift) & 0xff; if (index < maxindex) { tmp = (table[index >> 3] >> ((index & 7) << 3)) & 0xff; val |= tmp << shift; } else { val |= def & (0xff << shift); } } return val; } #if !defined(CONFIG_USER_ONLY) /* try to fill the TLB and return an exception if error. If retaddr is * NULL, it means that the function was called in C code (i.e. not * from generated code or from helper.c) */ void tlb_fill(CPUState *cs, target_ulong addr, int is_write, int mmu_idx, uintptr_t retaddr) { int ret; ret = arm_cpu_handle_mmu_fault(cs, addr, is_write, mmu_idx); if (unlikely(ret)) { ARMCPU *cpu = ARM_CPU(cs); CPUARMState *env = &cpu->env; if (retaddr) { /* now we have a real cpu fault */ cpu_restore_state(cs, retaddr); } raise_exception(env, cs->exception_index); } } #endif uint32_t HELPER(add_setq)(CPUARMState *env, uint32_t a, uint32_t b) { uint32_t res = a + b; if (((res ^ a) & SIGNBIT) && !((a ^ b) & SIGNBIT)) env->QF = 1; return res; } uint32_t HELPER(add_saturate)(CPUARMState *env, uint32_t a, uint32_t b) { uint32_t res = a + b; if (((res ^ a) & SIGNBIT) && !((a ^ b) & SIGNBIT)) { env->QF = 1; res = ~(((int32_t)a >> 31) ^ SIGNBIT); } return res; } uint32_t HELPER(sub_saturate)(CPUARMState *env, uint32_t a, uint32_t b) { uint32_t res = a - b; if (((res ^ a) & SIGNBIT) && ((a ^ b) & SIGNBIT)) { env->QF = 1; res = ~(((int32_t)a >> 31) ^ SIGNBIT); } return res; } uint32_t HELPER(double_saturate)(CPUARMState *env, int32_t val) { uint32_t res; if (val >= 0x40000000) { res = ~SIGNBIT; env->QF = 1; } else if (val <= (int32_t)0xc0000000) { res = SIGNBIT; env->QF = 1; } else { res = val << 1; } return res; } uint32_t HELPER(add_usaturate)(CPUARMState *env, uint32_t a, uint32_t b) { uint32_t res = a + b; if (res < a) { env->QF = 1; res = ~0; } return res; } uint32_t HELPER(sub_usaturate)(CPUARMState *env, uint32_t a, uint32_t b) { uint32_t res = a - b; if (res > a) { env->QF = 1; res = 0; } return res; } /* Signed saturation. */ static inline uint32_t do_ssat(CPUARMState *env, int32_t val, int shift) { int32_t top; uint32_t mask; top = val >> shift; mask = (1u << shift) - 1; if (top > 0) { env->QF = 1; return mask; } else if (top < -1) { env->QF = 1; return ~mask; } return val; } /* Unsigned saturation. */ static inline uint32_t do_usat(CPUARMState *env, int32_t val, int shift) { uint32_t max; max = (1u << shift) - 1; if (val < 0) { env->QF = 1; return 0; } else if (val > max) { env->QF = 1; return max; } return val; } /* Signed saturate. */ uint32_t HELPER(ssat)(CPUARMState *env, uint32_t x, uint32_t shift) { return do_ssat(env, x, shift); } /* Dual halfword signed saturate. */ uint32_t HELPER(ssat16)(CPUARMState *env, uint32_t x, uint32_t shift) { uint32_t res; res = (uint16_t)do_ssat(env, (int16_t)x, shift); res |= do_ssat(env, ((int32_t)x) >> 16, shift) << 16; return res; } /* Unsigned saturate. */ uint32_t HELPER(usat)(CPUARMState *env, uint32_t x, uint32_t shift) { return do_usat(env, x, shift); } /* Dual halfword unsigned saturate. */ uint32_t HELPER(usat16)(CPUARMState *env, uint32_t x, uint32_t shift) { uint32_t res; res = (uint16_t)do_usat(env, (int16_t)x, shift); res |= do_usat(env, ((int32_t)x) >> 16, shift) << 16; return res; } void HELPER(wfi)(CPUARMState *env) { CPUState *cs = CPU(arm_env_get_cpu(env)); cs->exception_index = EXCP_HLT; cs->halted = 1; cpu_loop_exit(cs); } void HELPER(wfe)(CPUARMState *env) { CPUState *cs = CPU(arm_env_get_cpu(env)); /* Don't actually halt the CPU, just yield back to top * level loop */ cs->exception_index = EXCP_YIELD; cpu_loop_exit(cs); } /* Raise an internal-to-QEMU exception. This is limited to only * those EXCP values which are special cases for QEMU to interrupt * execution and not to be used for exceptions which are passed to * the guest (those must all have syndrome information and thus should * use exception_with_syndrome). */ void HELPER(exception_internal)(CPUARMState *env, uint32_t excp) { CPUState *cs = CPU(arm_env_get_cpu(env)); assert(excp_is_internal(excp)); cs->exception_index = excp; cpu_loop_exit(cs); } /* Raise an exception with the specified syndrome register value */ void HELPER(exception_with_syndrome)(CPUARMState *env, uint32_t excp, uint32_t syndrome) { CPUState *cs = CPU(arm_env_get_cpu(env)); assert(!excp_is_internal(excp)); cs->exception_index = excp; env->exception.syndrome = syndrome; cpu_loop_exit(cs); } uint32_t HELPER(cpsr_read)(CPUARMState *env) { return cpsr_read(env) & ~(CPSR_EXEC | CPSR_RESERVED); } void HELPER(cpsr_write)(CPUARMState *env, uint32_t val, uint32_t mask) { cpsr_write(env, val, mask); } /* Access to user mode registers from privileged modes. */ uint32_t HELPER(get_user_reg)(CPUARMState *env, uint32_t regno) { uint32_t val; if (regno == 13) { val = env->banked_r13[0]; } else if (regno == 14) { val = env->banked_r14[0]; } else if (regno >= 8 && (env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_FIQ) { val = env->usr_regs[regno - 8]; } else { val = env->regs[regno]; } return val; } void HELPER(set_user_reg)(CPUARMState *env, uint32_t regno, uint32_t val) { if (regno == 13) { env->banked_r13[0] = val; } else if (regno == 14) { env->banked_r14[0] = val; } else if (regno >= 8 && (env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_FIQ) { env->usr_regs[regno - 8] = val; } else { env->regs[regno] = val; } } void HELPER(access_check_cp_reg)(CPUARMState *env, void *rip, uint32_t syndrome) { const ARMCPRegInfo *ri = rip; if (arm_feature(env, ARM_FEATURE_XSCALE) && ri->cp < 14 && extract32(env->cp15.c15_cpar, ri->cp, 1) == 0) { env->exception.syndrome = syndrome; raise_exception(env, EXCP_UDEF); } if (!ri->accessfn) { return; } switch (ri->accessfn(env, ri)) { case CP_ACCESS_OK: return; case CP_ACCESS_TRAP: env->exception.syndrome = syndrome; break; case CP_ACCESS_TRAP_UNCATEGORIZED: env->exception.syndrome = syn_uncategorized(); break; default: g_assert_not_reached(); } raise_exception(env, EXCP_UDEF); } void HELPER(set_cp_reg)(CPUARMState *env, void *rip, uint32_t value) { const ARMCPRegInfo *ri = rip; ri->writefn(env, ri, value); } uint32_t HELPER(get_cp_reg)(CPUARMState *env, void *rip) { const ARMCPRegInfo *ri = rip; return ri->readfn(env, ri); } void HELPER(set_cp_reg64)(CPUARMState *env, void *rip, uint64_t value) { const ARMCPRegInfo *ri = rip; ri->writefn(env, ri, value); } uint64_t HELPER(get_cp_reg64)(CPUARMState *env, void *rip) { const ARMCPRegInfo *ri = rip; return ri->readfn(env, ri); } void HELPER(msr_i_pstate)(CPUARMState *env, uint32_t op, uint32_t imm) { /* MSR_i to update PSTATE. This is OK from EL0 only if UMA is set. * Note that SPSel is never OK from EL0; we rely on handle_msr_i() * to catch that case at translate time. */ if (arm_current_el(env) == 0 && !(env->cp15.c1_sys & SCTLR_UMA)) { raise_exception(env, EXCP_UDEF); } switch (op) { case 0x05: /* SPSel */ update_spsel(env, imm); break; case 0x1e: /* DAIFSet */ env->daif |= (imm << 6) & PSTATE_DAIF; break; case 0x1f: /* DAIFClear */ env->daif &= ~((imm << 6) & PSTATE_DAIF); break; default: g_assert_not_reached(); } } void HELPER(clear_pstate_ss)(CPUARMState *env) { env->pstate &= ~PSTATE_SS; } void HELPER(pre_hvc)(CPUARMState *env) { ARMCPU *cpu = arm_env_get_cpu(env); int cur_el = arm_current_el(env); /* FIXME: Use actual secure state. */ bool secure = false; bool undef; if (arm_is_psci_call(cpu, EXCP_HVC)) { /* If PSCI is enabled and this looks like a valid PSCI call then * that overrides the architecturally mandated HVC behaviour. */ return; } if (!arm_feature(env, ARM_FEATURE_EL2)) { /* If EL2 doesn't exist, HVC always UNDEFs */ undef = true; } else if (arm_feature(env, ARM_FEATURE_EL3)) { /* EL3.HCE has priority over EL2.HCD. */ undef = !(env->cp15.scr_el3 & SCR_HCE); } else { undef = env->cp15.hcr_el2 & HCR_HCD; } /* In ARMv7 and ARMv8/AArch32, HVC is undef in secure state. * For ARMv8/AArch64, HVC is allowed in EL3. * Note that we've already trapped HVC from EL0 at translation * time. */ if (secure && (!is_a64(env) || cur_el == 1)) { undef = true; } if (undef) { env->exception.syndrome = syn_uncategorized(); raise_exception(env, EXCP_UDEF); } } void HELPER(pre_smc)(CPUARMState *env, uint32_t syndrome) { ARMCPU *cpu = arm_env_get_cpu(env); int cur_el = arm_current_el(env); bool secure = arm_is_secure(env); bool smd = env->cp15.scr_el3 & SCR_SMD; /* On ARMv8 AArch32, SMD only applies to NS state. * On ARMv7 SMD only applies to NS state and only if EL2 is available. * For ARMv7 non EL2, we force SMD to zero so we don't need to re-check * the EL2 condition here. */ bool undef = is_a64(env) ? smd : (!secure && smd); if (arm_is_psci_call(cpu, EXCP_SMC)) { /* If PSCI is enabled and this looks like a valid PSCI call then * that overrides the architecturally mandated SMC behaviour. */ return; } if (!arm_feature(env, ARM_FEATURE_EL3)) { /* If we have no EL3 then SMC always UNDEFs */ undef = true; } else if (!secure && cur_el == 1 && (env->cp15.hcr_el2 & HCR_TSC)) { /* In NS EL1, HCR controlled routing to EL2 has priority over SMD. */ env->exception.syndrome = syndrome; raise_exception(env, EXCP_HYP_TRAP); } if (undef) { env->exception.syndrome = syn_uncategorized(); raise_exception(env, EXCP_UDEF); } } void HELPER(exception_return)(CPUARMState *env) { int cur_el = arm_current_el(env); unsigned int spsr_idx = aarch64_banked_spsr_index(cur_el); uint32_t spsr = env->banked_spsr[spsr_idx]; int new_el, i; aarch64_save_sp(env, cur_el); env->exclusive_addr = -1; /* We must squash the PSTATE.SS bit to zero unless both of the * following hold: * 1. debug exceptions are currently disabled * 2. singlestep will be active in the EL we return to * We check 1 here and 2 after we've done the pstate/cpsr write() to * transition to the EL we're going to. */ if (arm_generate_debug_exceptions(env)) { spsr &= ~PSTATE_SS; } if (spsr & PSTATE_nRW) { /* TODO: We currently assume EL1/2/3 are running in AArch64. */ env->aarch64 = 0; new_el = 0; env->uncached_cpsr = 0x10; cpsr_write(env, spsr, ~0); if (!arm_singlestep_active(env)) { env->uncached_cpsr &= ~PSTATE_SS; } for (i = 0; i < 15; i++) { env->regs[i] = env->xregs[i]; } env->regs[15] = env->elr_el[1] & ~0x1; } else { new_el = extract32(spsr, 2, 2); if (new_el > cur_el || (new_el == 2 && !arm_feature(env, ARM_FEATURE_EL2))) { /* Disallow return to an EL which is unimplemented or higher * than the current one. */ goto illegal_return; } if (extract32(spsr, 1, 1)) { /* Return with reserved M[1] bit set */ goto illegal_return; } if (new_el == 0 && (spsr & PSTATE_SP)) { /* Return to EL0 with M[0] bit set */ goto illegal_return; } env->aarch64 = 1; pstate_write(env, spsr); if (!arm_singlestep_active(env)) { env->pstate &= ~PSTATE_SS; } aarch64_restore_sp(env, new_el); env->pc = env->elr_el[cur_el]; } return; illegal_return: /* Illegal return events of various kinds have architecturally * mandated behaviour: * restore NZCV and DAIF from SPSR_ELx * set PSTATE.IL * restore PC from ELR_ELx * no change to exception level, execution state or stack pointer */ env->pstate |= PSTATE_IL; env->pc = env->elr_el[cur_el]; spsr &= PSTATE_NZCV | PSTATE_DAIF; spsr |= pstate_read(env) & ~(PSTATE_NZCV | PSTATE_DAIF); pstate_write(env, spsr); if (!arm_singlestep_active(env)) { env->pstate &= ~PSTATE_SS; } } /* Return true if the linked breakpoint entry lbn passes its checks */ static bool linked_bp_matches(ARMCPU *cpu, int lbn) { CPUARMState *env = &cpu->env; uint64_t bcr = env->cp15.dbgbcr[lbn]; int brps = extract32(cpu->dbgdidr, 24, 4); int ctx_cmps = extract32(cpu->dbgdidr, 20, 4); int bt; uint32_t contextidr; /* Links to unimplemented or non-context aware breakpoints are * CONSTRAINED UNPREDICTABLE: either behave as if disabled, or * as if linked to an UNKNOWN context-aware breakpoint (in which * case DBGWCR_EL1.LBN must indicate that breakpoint). * We choose the former. */ if (lbn > brps || lbn < (brps - ctx_cmps)) { return false; } bcr = env->cp15.dbgbcr[lbn]; if (extract64(bcr, 0, 1) == 0) { /* Linked breakpoint disabled : generate no events */ return false; } bt = extract64(bcr, 20, 4); /* We match the whole register even if this is AArch32 using the * short descriptor format (in which case it holds both PROCID and ASID), * since we don't implement the optional v7 context ID masking. */ contextidr = extract64(env->cp15.contextidr_el1, 0, 32); switch (bt) { case 3: /* linked context ID match */ if (arm_current_el(env) > 1) { /* Context matches never fire in EL2 or (AArch64) EL3 */ return false; } return (contextidr == extract64(env->cp15.dbgbvr[lbn], 0, 32)); case 5: /* linked address mismatch (reserved in AArch64) */ case 9: /* linked VMID match (reserved if no EL2) */ case 11: /* linked context ID and VMID match (reserved if no EL2) */ default: /* Links to Unlinked context breakpoints must generate no * events; we choose to do the same for reserved values too. */ return false; } return false; } static bool bp_wp_matches(ARMCPU *cpu, int n, bool is_wp) { CPUARMState *env = &cpu->env; uint64_t cr; int pac, hmc, ssc, wt, lbn; /* TODO: check against CPU security state when we implement TrustZone */ bool is_secure = false; if (is_wp) { if (!env->cpu_watchpoint[n] || !(env->cpu_watchpoint[n]->flags & BP_WATCHPOINT_HIT)) { return false; } cr = env->cp15.dbgwcr[n]; } else { uint64_t pc = is_a64(env) ? env->pc : env->regs[15]; if (!env->cpu_breakpoint[n] || env->cpu_breakpoint[n]->pc != pc) { return false; } cr = env->cp15.dbgbcr[n]; } /* The WATCHPOINT_HIT flag guarantees us that the watchpoint is * enabled and that the address and access type match; for breakpoints * we know the address matched; check the remaining fields, including * linked breakpoints. We rely on WCR and BCR having the same layout * for the LBN, SSC, HMC, PAC/PMC and is-linked fields. * Note that some combinations of {PAC, HMC, SSC} are reserved and * must act either like some valid combination or as if the watchpoint * were disabled. We choose the former, and use this together with * the fact that EL3 must always be Secure and EL2 must always be * Non-Secure to simplify the code slightly compared to the full * table in the ARM ARM. */ pac = extract64(cr, 1, 2); hmc = extract64(cr, 13, 1); ssc = extract64(cr, 14, 2); switch (ssc) { case 0: break; case 1: case 3: if (is_secure) { return false; } break; case 2: if (!is_secure) { return false; } break; } /* TODO: this is not strictly correct because the LDRT/STRT/LDT/STT * "unprivileged access" instructions should match watchpoints as if * they were accesses done at EL0, even if the CPU is at EL1 or higher. * Implementing this would require reworking the core watchpoint code * to plumb the mmu_idx through to this point. Luckily Linux does not * rely on this behaviour currently. * For breakpoints we do want to use the current CPU state. */ switch (arm_current_el(env)) { case 3: case 2: if (!hmc) { return false; } break; case 1: if (extract32(pac, 0, 1) == 0) { return false; } break; case 0: if (extract32(pac, 1, 1) == 0) { return false; } break; default: g_assert_not_reached(); } wt = extract64(cr, 20, 1); lbn = extract64(cr, 16, 4); if (wt && !linked_bp_matches(cpu, lbn)) { return false; } return true; } static bool check_watchpoints(ARMCPU *cpu) { CPUARMState *env = &cpu->env; int n; /* If watchpoints are disabled globally or we can't take debug * exceptions here then watchpoint firings are ignored. */ if (extract32(env->cp15.mdscr_el1, 15, 1) == 0 || !arm_generate_debug_exceptions(env)) { return false; } for (n = 0; n < ARRAY_SIZE(env->cpu_watchpoint); n++) { if (bp_wp_matches(cpu, n, true)) { return true; } } return false; } static bool check_breakpoints(ARMCPU *cpu) { CPUARMState *env = &cpu->env; int n; /* If breakpoints are disabled globally or we can't take debug * exceptions here then breakpoint firings are ignored. */ if (extract32(env->cp15.mdscr_el1, 15, 1) == 0 || !arm_generate_debug_exceptions(env)) { return false; } for (n = 0; n < ARRAY_SIZE(env->cpu_breakpoint); n++) { if (bp_wp_matches(cpu, n, false)) { return true; } } return false; } void arm_debug_excp_handler(CPUState *cs) { /* Called by core code when a watchpoint or breakpoint fires; * need to check which one and raise the appropriate exception. */ ARMCPU *cpu = ARM_CPU(cs); CPUARMState *env = &cpu->env; CPUWatchpoint *wp_hit = cs->watchpoint_hit; if (wp_hit) { if (wp_hit->flags & BP_CPU) { cs->watchpoint_hit = NULL; if (check_watchpoints(cpu)) { bool wnr = (wp_hit->flags & BP_WATCHPOINT_HIT_WRITE) != 0; bool same_el = arm_debug_target_el(env) == arm_current_el(env); env->exception.syndrome = syn_watchpoint(same_el, 0, wnr); if (extended_addresses_enabled(env)) { env->exception.fsr = (1 << 9) | 0x22; } else { env->exception.fsr = 0x2; } env->exception.vaddress = wp_hit->hitaddr; raise_exception(env, EXCP_DATA_ABORT); } else { cpu_resume_from_signal(cs, NULL); } } } else { if (check_breakpoints(cpu)) { bool same_el = (arm_debug_target_el(env) == arm_current_el(env)); env->exception.syndrome = syn_breakpoint(same_el); if (extended_addresses_enabled(env)) { env->exception.fsr = (1 << 9) | 0x22; } else { env->exception.fsr = 0x2; } /* FAR is UNKNOWN, so doesn't need setting */ raise_exception(env, EXCP_PREFETCH_ABORT); } } } /* ??? Flag setting arithmetic is awkward because we need to do comparisons. The only way to do that in TCG is a conditional branch, which clobbers all our temporaries. For now implement these as helper functions. */ /* Similarly for variable shift instructions. */ uint32_t HELPER(shl_cc)(CPUARMState *env, uint32_t x, uint32_t i) { int shift = i & 0xff; if (shift >= 32) { if (shift == 32) env->CF = x & 1; else env->CF = 0; return 0; } else if (shift != 0) { env->CF = (x >> (32 - shift)) & 1; return x << shift; } return x; } uint32_t HELPER(shr_cc)(CPUARMState *env, uint32_t x, uint32_t i) { int shift = i & 0xff; if (shift >= 32) { if (shift == 32) env->CF = (x >> 31) & 1; else env->CF = 0; return 0; } else if (shift != 0) { env->CF = (x >> (shift - 1)) & 1; return x >> shift; } return x; } uint32_t HELPER(sar_cc)(CPUARMState *env, uint32_t x, uint32_t i) { int shift = i & 0xff; if (shift >= 32) { env->CF = (x >> 31) & 1; return (int32_t)x >> 31; } else if (shift != 0) { env->CF = (x >> (shift - 1)) & 1; return (int32_t)x >> shift; } return x; } uint32_t HELPER(ror_cc)(CPUARMState *env, uint32_t x, uint32_t i) { int shift1, shift; shift1 = i & 0xff; shift = shift1 & 0x1f; if (shift == 0) { if (shift1 != 0) env->CF = (x >> 31) & 1; return x; } else { env->CF = (x >> (shift - 1)) & 1; return ((uint32_t)x >> shift) | (x << (32 - shift)); } }