栈向下增长,先压的落在高地址,而要的布局是 [S+0]=调用号(rax)、[S+8]=arg4(r10),所以必须先 push r10 后 push rax;原实现反了 ⇒ mov rax,[rsp+40] 取到 arg4 当调用号、mov r8,[rsp+168] 取到调用号当 arg4 ⇒ syscall_handler 收到错误的 n。 现场(探针实测):用户线程出口跳板 mov eax,34(THREAD_EXIT); int 0x80; jmp $ —— int 0x80 带着错的 n 进 syscall_handler,不匹配任何分支返回 0,iretq 回用户态落到 jmp $ 死转。该线程永不再 yield ⇒ needs_reschedule 无人消费 ⇒ 全系统停止切换:探针显示 cur 冻结在 5、t5 恒为 RUNNING,intr_cs=2B intr_rip=0x7FFFFFDE0007(正是跳板页偏移 7 的 jmp $)rsp=0x7FFFFFDE0000 ⇒ 桌面线程(tid 6)饿死,[perf]/[chk] 永不再打印。 这条路径此前无任何调用者(vpsdk 全走 syscall 指令),所以从未暴露。同时移除定位用的临时探针(timer.vp 心跳/调度器快照、isr.s 的 _intr_*)。
109 lines
3.5 KiB
Plaintext
109 lines
3.5 KiB
Plaintext
import platform.pch.pic as pic
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import platform.pch.pit as pit
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import sched.sched as sched
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import drivers.core.cpu.apic as apic
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import asm
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define TIMER_FREQUENCY = 1000
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define TICKS_PER_SECOND = TIMER_FREQUENCY
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define MILLISECONDS_PER_TICK = (1000 / TIMER_FREQUENCY)
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static ticks: volatile uint64 = 0
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static seconds: volatile uint32 = 0
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static milliseconds: volatile uint32 = 0
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static timer_running: volatile bool = False
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def timer_init():
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global ticks, seconds, milliseconds, timer_running
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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ticks = 0
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seconds = 0
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milliseconds = 0
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timer_running = True
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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pit.pit_init(TIMER_FREQUENCY)
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def timer_handler():
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global ticks, seconds, milliseconds, timer_running
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if not timer_running:
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pic.eoi(0)
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apic.eoi()
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return
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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ticks = ticks + 1
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milliseconds = milliseconds + MILLISECONDS_PER_TICK
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if milliseconds >= 1000:
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seconds = seconds + 1
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milliseconds = milliseconds - 1000
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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sched.Scheduler.sched_tick()
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pic.eoi(0)
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# LAPIC EOI:APIC 启用后中断经 LINT0(EXTINT) 送达会置 LAPIC ISR,
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# 只发 PIC EOI 不清 LAPIC ISR → 首个定时中断后后续中断被屏蔽 →
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# ticks 不推进 → msleep 永久挂起(QEMU/OVMF 下 APIC 必启用)。
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apic.eoi()
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def timer_start():
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global timer_running
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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timer_running = True
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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def timer_stop():
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global timer_running
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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timer_running = False
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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def timer_reset():
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global ticks, seconds, milliseconds
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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ticks = 0
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seconds = 0
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milliseconds = 0
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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def timer_get_ticks() -> uint64:
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current_ticks: uint64
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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current_ticks = ticks
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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return current_ticks
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def timer_get_seconds() -> uint32:
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current_seconds: uint32
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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current_seconds = seconds
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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return current_seconds
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def timer_get_milliseconds() -> uint32:
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current_milliseconds: uint32
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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current_milliseconds = milliseconds
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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return current_milliseconds
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def timer_get_time(out_seconds: uint32*, out_milliseconds: uint32*):
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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if out_seconds:
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*out_seconds = seconds
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if out_milliseconds:
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*out_milliseconds = milliseconds
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__asm__("mfence", op=[ASM_DESCR.CLOBBER_MEMORY])
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def timer_msleep(ms: uint32):
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target: uint64 = ticks + (ms + MILLISECONDS_PER_TICK - 1) / MILLISECONDS_PER_TICK
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while ticks < target:
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asm.sti()
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asm.hlt()
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sched.Scheduler._yield()
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def timer_sleep(sec: uint32):
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target: uint64 = ticks + sec * TICKS_PER_SECOND
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while ticks < target:
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asm.sti()
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asm.hlt()
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sched.Scheduler._yield()
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