From acbbb94e5730c9808830938e869d243014e2923a Mon Sep 17 00:00:00 2001 From: Michael Clark Date: Sat, 16 Mar 2019 01:21:03 +0000 Subject: [PATCH] RISC-V: Add support for vectored interrupts If vectored interrupts are enabled (bits[1:0] of mtvec/stvec == 1) then use the following logic for trap entry address calculation: pc = mtvec + cause * 4 In addition to adding support for vectored interrupts this patch simplifies the interrupt delivery logic by making sync/async cause decoding and encoding steps distinct. The cause code and the sign bit indicating sync/async is split at the beginning of the function and fixed cause is renamed to cause. The MSB setting for async traps is delayed until setting mcause/scause to allow redundant variables to be eliminated. Some variables are renamed for conciseness and moved so that decls are at the start of the block. Cc: Palmer Dabbelt Cc: Alistair Francis Signed-off-by: Michael Clark Signed-off-by: Alistair Francis Signed-off-by: Palmer Dabbelt --- target/riscv/cpu_helper.c | 151 ++++++++++++++------------------------ target/riscv/csr.c | 12 +-- 2 files changed, 63 insertions(+), 100 deletions(-) diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index 073bdcfe74..a02f4dad8c 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -454,118 +454,81 @@ void riscv_cpu_do_interrupt(CPUState *cs) RISCVCPU *cpu = RISCV_CPU(cs); CPURISCVState *env = &cpu->env; + /* cs->exception is 32-bits wide unlike mcause which is XLEN-bits wide + * so we mask off the MSB and separate into trap type and cause. + */ + bool async = !!(cs->exception_index & RISCV_EXCP_INT_FLAG); + target_ulong cause = cs->exception_index & RISCV_EXCP_INT_MASK; + target_ulong deleg = async ? env->mideleg : env->medeleg; + target_ulong tval = 0; + + static const int ecall_cause_map[] = { + [PRV_U] = RISCV_EXCP_U_ECALL, + [PRV_S] = RISCV_EXCP_S_ECALL, + [PRV_H] = RISCV_EXCP_H_ECALL, + [PRV_M] = RISCV_EXCP_M_ECALL + }; + + if (!async) { + /* set tval to badaddr for traps with address information */ + switch (cause) { + case RISCV_EXCP_INST_ADDR_MIS: + case RISCV_EXCP_INST_ACCESS_FAULT: + case RISCV_EXCP_LOAD_ADDR_MIS: + case RISCV_EXCP_STORE_AMO_ADDR_MIS: + case RISCV_EXCP_LOAD_ACCESS_FAULT: + case RISCV_EXCP_STORE_AMO_ACCESS_FAULT: + case RISCV_EXCP_INST_PAGE_FAULT: + case RISCV_EXCP_LOAD_PAGE_FAULT: + case RISCV_EXCP_STORE_PAGE_FAULT: + tval = env->badaddr; + break; + default: + break; + } + /* ecall is dispatched as one cause so translate based on mode */ + if (cause == RISCV_EXCP_U_ECALL) { + assert(env->priv <= 3); + cause = ecall_cause_map[env->priv]; + } + } + 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 " - TARGET_FMT_ld ": trap %s, epc 0x" TARGET_FMT_lx "\n", - env->mhartid, riscv_intr_names[log_cause], env->pc); - } else { - qemu_log_mask(LOG_TRACE, "core " - TARGET_FMT_ld ": intr %s, epc 0x" TARGET_FMT_lx "\n", - env->mhartid, riscv_excp_names[log_cause], env->pc); - } + qemu_log_mask(LOG_TRACE, "core " TARGET_FMT_ld ": %s %s, " + "epc 0x" TARGET_FMT_lx ": tval 0x" TARGET_FMT_lx "\n", + env->mhartid, async ? "intr" : "trap", + (async ? riscv_intr_names : riscv_excp_names)[cause], + env->pc, tval); } - 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)) { + if (env->priv <= PRV_S && + cause < TARGET_LONG_BITS && ((deleg >> cause) & 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 "\n", 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); env->mstatus = s; + env->scause = cause | ~(((target_ulong)-1) >> async); + env->sepc = env->pc; + env->sbadaddr = tval; + env->pc = (env->stvec >> 2 << 2) + + ((async && (env->stvec & 3) == 1) ? cause * 4 : 0); riscv_cpu_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 "\n", 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; - } - + /* handle the trap in M-mode */ 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); env->mstatus = s; + env->mcause = cause | ~(((target_ulong)-1) >> async); + env->mepc = env->pc; + env->mbadaddr = tval; + env->pc = (env->mtvec >> 2 << 2) + + ((async && (env->mtvec & 3) == 1) ? cause * 4 : 0); riscv_cpu_set_mode(env, PRV_M); } /* TODO yield load reservation */ diff --git a/target/riscv/csr.c b/target/riscv/csr.c index 385bb38768..e1d91b6c60 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -435,10 +435,10 @@ static int read_mtvec(CPURISCVState *env, int csrno, target_ulong *val) static int write_mtvec(CPURISCVState *env, int csrno, target_ulong val) { /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */ - if ((val & 3) == 0) { - env->mtvec = val >> 2 << 2; + if ((val & 3) < 2) { + env->mtvec = val; } else { - qemu_log_mask(LOG_UNIMP, "CSR_MTVEC: vectored traps not supported"); + qemu_log_mask(LOG_UNIMP, "CSR_MTVEC: reserved mode not supported\n"); } return 0; } @@ -607,10 +607,10 @@ static int read_stvec(CPURISCVState *env, int csrno, target_ulong *val) static int write_stvec(CPURISCVState *env, int csrno, target_ulong val) { /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */ - if ((val & 3) == 0) { - env->stvec = val >> 2 << 2; + if ((val & 3) < 2) { + env->stvec = val; } else { - qemu_log_mask(LOG_UNIMP, "CSR_STVEC: vectored traps not supported"); + qemu_log_mask(LOG_UNIMP, "CSR_STVEC: reserved mode not supported\n"); } return 0; }