diff options
Diffstat (limited to 'lume-legacy/src/kernel/trap/handler.cc')
| -rw-r--r-- | lume-legacy/src/kernel/trap/handler.cc | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/lume-legacy/src/kernel/trap/handler.cc b/lume-legacy/src/kernel/trap/handler.cc new file mode 100644 index 0000000..b7bd5f0 --- /dev/null +++ b/lume-legacy/src/kernel/trap/handler.cc @@ -0,0 +1,217 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2026 Richard QIn + */ +#include "kernel/trap.h" +#include "kernel/riscv.h" +#include "kernel/proc.h" +#include "drivers/uart.h" +#include "kernel/syscall.h" +#include "kernel/mm.h" +#include "kernel/timer.h" +#include "drivers/plic.h" +#include "drivers/virtio.h" +#include "kernel/fdt.h" +#include "lib/string.h" + + +extern "C" void kernelvec(); + +// Handle Function + +void panic(const char *s) +{ + Drivers::uart_puts("\n\n!!! KERNEL PANIC !!!\n"); + Drivers::uart_puts(s); + Drivers::uart_puts("\nSystem Halted.\n"); + while (1) + ; +} + +// Trap Implementation + +namespace Trap +{ + void init() + { + Drivers::uart_puts("[Trap] Global init done.\n"); + } + + // Each CPU core needs to call this function when starting to set its own stvec + void inithart() + { + w_stvec((uint64)kernelvec); + + // Ensure that the S-Mode interrupt enable bit (SIE) is cleared during initialization + // Interrupt enabling will be done by the scheduler when the first process runs + w_sstatus(r_sstatus() & ~SSTATUS_SIE); + + // Enable the external interrupt, clock interrupt, and software interrupt bits in S-Mode (in SIE register) + uint64 sie = r_sie(); + sie |= SIE_SEIE | SIE_STIE | SIE_SSIE; + w_sie(sie); + + Drivers::uart_puts("[Trap] Hart initialized (stvec set).\n"); + } + + // Device Interrupt Check + int devintr() + { + uint64 scause = r_scause(); + + bool is_interrupt = (scause & 0x8000000000000000L) != 0; + uint64 code = scause & 0xff; + + if (is_interrupt && code == 9) + { + // Supervisor External Interrupt (IRQ 9) + int irq = PLIC::claim(); + + if (irq == (int)g_devices.uart.irq) + { + Drivers::uart_intr(); + } + else + { + // Check if it's a VirtIO IRQ + bool handled = false; + for (int i = 0; i < g_devices.virtio_count; i++) + { + if (irq == (int)g_devices.virtio[i].irq) + { + VirtIO::intr(); + handled = true; + break; + } + } + } + + if (irq > 0) + { + PLIC::complete(irq); + } + + return 1; + } + else if (is_interrupt && code == 5) + { + // Supervisor Timer Interrupt (IRQ 5) + // Timer::set_next_trigger(); + Timer::tick(); + // w_sip(r_sip() & ~2); + return 2; + } + + return 0; + } +} + +// Exception Handling Entry + +extern "C" void kerneltrap(struct Trapframe *tf) +{ + uint64 sepc = r_sepc(); + uint64 sstatus = r_sstatus(); + uint64 scause = r_scause(); + + if ((sstatus & SSTATUS_SPP) == 0) + panic("kerneltrap: not from supervisor mode"); + + if (intr_get() != 0) + panic("kerneltrap: interrupts enabled"); + + if (Trap::devintr() == 0) + { + Drivers::uart_puts("\n--- KERNEL EXCEPTION ---\n"); + Drivers::uart_puts("scause: "); + Drivers::print_hex(scause); + Drivers::uart_puts("\n"); + Drivers::uart_puts("sepc: "); + Drivers::print_hex(sepc); + Drivers::uart_puts("\n"); + Drivers::uart_puts("stval: "); + Drivers::print_hex(r_stval()); + Drivers::uart_puts("\n"); + panic("kerneltrap exception"); + } + + w_sepc(sepc); + w_sstatus(sstatus); +} + +extern "C" void usertrap() +{ + // Drivers::uart_puts("[Debug] Entered usertrap!\n"); + int which_dev = 0; + + if ((r_sstatus() & SSTATUS_SPP) != 0) + panic("usertrap: not from user mode"); + + w_stvec((uint64)kernelvec); + + struct Proc *p = myproc(); + if (!p) + panic("usertrap: no process"); + + p->tf->epc = r_sepc(); + + uint64 scause = r_scause(); + uint64 stval = r_stval(); + + if (scause == 8) // Syscall + { + if (p->state == ZOMBIE) + ProcManager::exit(-1); + p->tf->epc += 4; + intr_on(); + syscall(); + intr_off(); + } + else if (scause == 15) // Store Page Fault + { + if (VM::handle_cow_fault(p->pagetable, PGROUNDDOWN(stval)) != 0) + { + uint64 pa = VM::walkaddr(p->pagetable, stval); + + if (pa == 0) + { + Drivers::uart_puts("usertrap: Segmentation Fault (unmapped) at "); + } + else + { + Drivers::uart_puts("usertrap: Protection Fault (or OOM) at "); + } + + Drivers::print_hex(stval); + Drivers::uart_puts("\n"); + p->state = ZOMBIE; + ProcManager::exit(-1); + } + } + else if ((which_dev = Trap::devintr()) != 0) + { + if (which_dev == 2) + { + ProcManager::yield(); + } + } + else + { + Drivers::uart_puts("\nusertrap(): unexpected scause "); + Drivers::print_hex(scause); + Drivers::uart_puts(" pid="); + Drivers::uart_put_int(p->pid); + Drivers::uart_puts(" sepc="); + Drivers::print_hex(p->tf->epc); + Drivers::uart_puts(" stval="); + Drivers::print_hex(stval); + Drivers::uart_puts("\n"); + p->state = ZOMBIE; + ProcManager::exit(-1); + } + + if (p->state == ZOMBIE) + ProcManager::exit(-1); + + usertrapret(); +}
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