/* * Early initialization code for riscv * * Copyright 2015 Google Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; version 2 of * the License. * * This program 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 General Public License for more details. */ #include <arch/encoding.h> #include <arch/exception.h> #include <console/console.h> #include <vm.h> #include <mcall.h> #include <sbi.h> static const char *const exception_names[] = { "Instruction address misaligned", "Instruction access fault", "Illegal instruction", "Breakpoint", "Load address misaligned", "Load access fault", "Store address misaligned", "Store access fault", "Environment call from U-mode", "Environment call from S-mode", "Reserved (10)", "Environment call from M-mode", "Instruction page fault", "Load page fault", "Reserved (14)", "Store page fault", }; static const char *mstatus_to_previous_mode(uintptr_t ms) { switch (ms & MSTATUS_MPP) { case 0x00000000: return "user"; case 0x00000800: return "supervisor"; case 0x00001000: return "hypervisor"; case 0x00001800: return "machine"; } return "unknown"; } static void print_trap_information(const trapframe *tf) { const char *previous_mode; bool mprv = !!(tf->status & MSTATUS_MPRV); int hart_id = read_csr(mhartid); /* Leave some space around the trap message */ printk(BIOS_DEBUG, "\n"); if (tf->cause < ARRAY_SIZE(exception_names)) printk(BIOS_DEBUG, "Exception: %s\n", exception_names[tf->cause]); else printk(BIOS_DEBUG, "Trap: Unknown cause %p\n", (void *)tf->cause); previous_mode = mstatus_to_previous_mode(read_csr(mstatus)); printk(BIOS_DEBUG, "Hart ID: %d\n", hart_id); printk(BIOS_DEBUG, "Previous mode: %s%s\n", previous_mode, mprv? " (MPRV)":""); printk(BIOS_DEBUG, "Bad instruction pc: %p\n", (void *)tf->epc); printk(BIOS_DEBUG, "Bad address: %p\n", (void *)tf->badvaddr); printk(BIOS_DEBUG, "Stored ra: %p\n", (void*) tf->gpr[1]); printk(BIOS_DEBUG, "Stored sp: %p\n", (void*) tf->gpr[2]); } static void interrupt_handler(trapframe *tf) { uint64_t cause = tf->cause & ~0x8000000000000000ULL; switch (cause) { case IRQ_M_TIMER: /* * Set interrupt pending for supervisor mode and disable timer * interrupt in machine mode. * To receive another timer interrupt just set timecmp and * enable machine mode timer interrupt again. */ clear_csr(mie, MIP_MTIP); set_csr(mip, MIP_STIP); break; case IRQ_M_SOFT: if (HLS()->ipi_pending & IPI_SOFT) { set_csr(mip, MIP_SSIP); } else if (HLS()->ipi_pending & IPI_FENCE_I) { asm volatile("fence.i"); } else if (HLS()->ipi_pending & IPI_SFENCE_VMA) { asm volatile("sfence.vma"); } else if (HLS()->ipi_pending & IPI_SFENCE_VMA_ASID) { asm volatile("sfence.vma"); } else if (HLS()->ipi_pending & IPI_SHUTDOWN) { while (HLS()->ipi_pending & IPI_SHUTDOWN) asm volatile("wfi"); } break; default: printk(BIOS_EMERG, "======================================\n"); printk(BIOS_EMERG, "coreboot: Unknown machine interrupt: 0x%llx\n", cause); printk(BIOS_EMERG, "======================================\n"); print_trap_information(tf); break; } } void trap_handler(trapframe *tf) { write_csr(mscratch, tf); if (tf->cause & 0x8000000000000000ULL) { interrupt_handler(tf); return; } switch (tf->cause) { case CAUSE_MISALIGNED_FETCH: case CAUSE_FETCH_ACCESS: case CAUSE_ILLEGAL_INSTRUCTION: case CAUSE_BREAKPOINT: case CAUSE_LOAD_ACCESS: case CAUSE_STORE_ACCESS: case CAUSE_USER_ECALL: case CAUSE_HYPERVISOR_ECALL: case CAUSE_MACHINE_ECALL: print_trap_information(tf); break; case CAUSE_SUPERVISOR_ECALL: handle_sbi(tf); return; case CAUSE_MISALIGNED_LOAD: case CAUSE_MISALIGNED_STORE: print_trap_information(tf); handle_misaligned(tf); return; default: printk(BIOS_EMERG, "================================\n"); printk(BIOS_EMERG, "coreboot: can not handle a trap:\n"); printk(BIOS_EMERG, "================================\n"); print_trap_information(tf); break; } die("Can't recover from trap. Halting.\n"); } /* This function used to redirect trap to s-mode. */ void redirect_trap(void) { write_csr(sbadaddr, read_csr(mbadaddr)); write_csr(sepc, read_csr(mepc)); write_csr(scause, read_csr(mcause)); write_csr(mepc, read_csr(stvec)); uintptr_t status = read_csr(mstatus); uintptr_t mpp = EXTRACT_FIELD(status, MSTATUS_MPP); status = INSERT_FIELD(status, MSTATUS_MPP, 1); status = INSERT_FIELD(status, MSTATUS_SPP, mpp & 1); write_csr(mstatus, status); }