SchOS/include/traps.h
Nexoniarz 7e8d5e2821 irq: MSI first, and poll the INTx lines that never arrive
PCI drivers took their interrupt from INTERRUPT_LINE. On real hardware
that is the 8259's number, not the IOAPIC pin the device is wired to
(that is in ACPI _PRT, which needs AML), so nothing ever arrived. xHCI
is entirely interrupt-driven, so the USB keyboard and a USB root would
have hung even on a clean boot. Under QEMU the two numbers agree,
which is why it never showed.

- pci_irq_attach()/pci_irq_detach(): MSI, then MSI-X if the driver
  allows it, then INTx. The handler is registered before MSI is
  enabled, so no edge is lost. xHCI, e1000, r8169 and rtl8139 use it.
- Lines 24-29 are MSI vectors. The LAPIC error vector moves from 19,
  which is a PCI pin on Intel chipsets, to 30. Nothing is placed at or
  above vector 64 (T_SYSCALL).
- A storming line is masked and its handlers are polled instead of
  being left to eat the CPU. A level line that has had a handler for 2 s
  and never fired is polled every tick by a kernel thread.

Tested in QEMU q35 with the root on a USB stick: xHCI and e1000e on
MSI; then MSI disabled and INTx deliberately misrouted, where xHCI got
zero interrupts and the root still mounted through the poller. i440fx
INTx and the rtl8139 hand-over are unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HH7xukt4aaiGj1nQEAoQf1
2026-10-22 10:29:24 +02:00

71 lines
2 KiB
C

#pragma once
// x86 trap and interrupt constants.
// Processor-defined exceptions:
#define T_DIVIDE 0 // divide error
#define T_DEBUG 1 // debug exception
#define T_NMI 2 // non-maskable interrupt
#define T_BRKPT 3 // breakpoint
#define T_OFLOW 4 // overflow
#define T_BOUND 5 // bounds check
#define T_ILLOP 6 // illegal opcode
#define T_DEVICE 7 // device not available
#define T_DBLFLT 8 // double fault
#define T_TSS 10 // invalid task switch segment
#define T_SEGNP 11 // segment not present
#define T_STACK 12 // stack exception
#define T_GPFLT 13 // general protection fault
#define T_PGFLT 14 // page fault
#define T_FPERR 16 // floating point error
#define T_ALIGN 17 // aligment check
#define T_MCHK 18 // machine check
#define T_SIMDERR 19 // SIMD floating point error
// IRQ offsets
#define T_IRQ0 32 // IRQ 0 corresponds to int T_IRQ
#define IRQ_TIMER 0
#define IRQ_KBD 1
#define IRQ_COM1 4
#define IRQ_MOUSE 12
#define IRQ_IDE 14
// 30, not xv6's 19. Vector T_IRQ0+19 is IOAPIC pin 19, which real chipsets
// use for PCI; the LAPIC error interrupt would have shared it.
#define IRQ_ERROR 30
#define IRQ_SPURIOUS 31
// System call interrupt number for legacy int 0x40 or 0x80 if used
// although syscall/sysret is preferred for x64
#define T_SYSCALL 0x40
#ifndef __ASSEMBLER__
struct trapframe {
// Registers saved by trapasm.S
uint64 rax;
uint64 rbx;
uint64 rcx;
uint64 rdx;
uint64 rbp;
uint64 rsi;
uint64 rdi;
uint64 r8;
uint64 r9;
uint64 r10;
uint64 r11;
uint64 r12;
uint64 r13;
uint64 r14;
uint64 r15;
uint64 trapno;
// Error code and info saved by hardware
uint64 err;
uint64 rip;
uint64 cs;
uint64 rflags;
uint64 rsp;
uint64 ss;
};
#endif