Fix signal delivery during context switch.
This commit is contained in:
Jonas 'Sortie' Termansen
parent
82775c4803
commit
12b5044bc7
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@ -175,6 +175,86 @@ void LoadInterruptedContext(struct interrupt_context* intctx,
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#endif
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}
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extern "C" void fake_interrupt(void);
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// Pretend a particular interrupt arrived on another thread's stack. This
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// assumes we're _not_ on current_thread's stack right now. This sets up the
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// interrupt context such that the interrupt handler runs in that thread.
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// The interrupt handler runs with premption enabled. This is used to deliver
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// signals during context switches, as the signal handler needs to have
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// preemption enabled.
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static void FakeInterruptedContext(struct interrupt_context* intctx, int int_no)
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{
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#if defined(__i386__)
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uintptr_t stack = current_thread->kernelstackpos +
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current_thread->kernelstacksize;
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stack -= sizeof(struct interrupt_context);
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struct interrupt_context* fakectx = (struct interrupt_context*) stack;
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memcpy(fakectx, intctx, sizeof(struct interrupt_context));
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fakectx->int_no = int_no;
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fakectx->err_code = 0;
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stack -= 4;
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stack &= 0xFFFFFFF0;
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intctx->signal_pending = intctx->signal_pending;
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intctx->kerrno = 0;
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intctx->cr2 = 0;
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intctx->ds = KDS | KRPL;
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intctx->edi = intctx->edi;
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intctx->esi = intctx->esi;
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intctx->ebp = intctx->signal_pending;
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intctx->not_esp = intctx->not_esp;
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intctx->ebx = (uintptr_t) fakectx;
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intctx->edx = intctx->edx;
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intctx->ecx = intctx->ecx;
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intctx->eax = intctx->eax;
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intctx->int_no = intctx->int_no;
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intctx->err_code = intctx->err_code;
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intctx->eip = (uintptr_t) fake_interrupt;
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intctx->cs = KCS | KRPL;
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intctx->eflags = FLAGS_RESERVED1 | FLAGS_INTERRUPT | FLAGS_ID;
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intctx->esp = stack;
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intctx->ss = KDS | KRPL;
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#elif defined(__x86_64__)
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uintptr_t stack = current_thread->kernelstackpos +
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current_thread->kernelstacksize;
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stack -= sizeof(struct interrupt_context);
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struct interrupt_context* fakectx = (struct interrupt_context*) stack;
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memcpy(fakectx, intctx, sizeof(struct interrupt_context));
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fakectx->int_no = int_no;
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fakectx->err_code = 0;
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stack &= 0xFFFFFFFFFFFFFFF0;
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intctx->signal_pending = intctx->signal_pending;
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intctx->kerrno = 0;
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intctx->cr2 = 0;
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intctx->ds = KDS | KRPL;
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intctx->rdi = (uintptr_t) fakectx;
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intctx->rsi = intctx->rsi;
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intctx->rbp = intctx->signal_pending;
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intctx->not_rsp = intctx->not_rsp;
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intctx->rbx = (uintptr_t) fakectx;
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intctx->rdx = intctx->rdx;
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intctx->rcx = intctx->rcx;
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intctx->rax = intctx->rax;
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intctx->r8 = intctx->r8;
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intctx->r9 = intctx->r9;
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intctx->r10 = intctx->r10;
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intctx->r11 = intctx->r11;
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intctx->r12 = intctx->r12;
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intctx->r13 = intctx->r13;
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intctx->r14 = intctx->r14;
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intctx->r15 = intctx->r15;
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intctx->int_no = intctx->int_no;
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intctx->err_code = intctx->err_code;
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intctx->rip = (uintptr_t) fake_interrupt;
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intctx->cs = KCS | KRPL;
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intctx->rflags = FLAGS_RESERVED1 | FLAGS_INTERRUPT | FLAGS_ID;
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intctx->rsp = stack;
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intctx->ss = KDS | KRPL;
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#else
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#warning "You need to implement faking an interrupt"
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#endif
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}
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static
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void SwitchThread(struct interrupt_context* intctx, Thread* prev, Thread* next)
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{
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@ -237,12 +317,25 @@ static Thread* PopNextThread(bool yielded)
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static void RealSwitch(struct interrupt_context* intctx, bool yielded)
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{
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SwitchThread(intctx, CurrentThread(), PopNextThread(yielded));
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Thread* old_thread = CurrentThread();
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Thread* new_thread = PopNextThread(yielded);
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SwitchThread(intctx, old_thread, new_thread);
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if ( intctx->signal_pending && InUserspace(intctx) )
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{
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Interrupt::Enable();
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Signal::DispatchHandler(intctx, NULL);
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// Become the thread for real and run the signal handler.
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if ( old_thread == new_thread )
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{
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// We're already this thread, so run the signal handler.
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Interrupt::Enable();
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Signal::DispatchHandler(intctx, NULL);
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}
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else
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{
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// We need to transfer execution to the correct stack. We know the
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// the thread is in user-space and isn't using its kernel stack, and
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// we know we're not using the stack right now.
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FakeInterruptedContext(intctx, 130);
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}
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}
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}
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@ -388,6 +388,9 @@ interrupt_handler_prepare:
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movq %rsp, %rdi
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movq %rsp, %rbx
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andq $0xFFFFFFFFFFFFFFF0, %rsp
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.global fake_interrupt
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.type fake_interrupt, @function
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fake_interrupt:
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call interrupt_handler
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movq %rbx, %rsp
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@ -385,6 +385,9 @@ fixup_relocate_stack_complete:
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movl %esp, %ebx
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subl $4, %esp
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andl $0xFFFFFFF0, %esp
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.global fake_interrupt
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.type fake_interrupt, @function
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fake_interrupt:
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movl %ebx, (%esp)
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call interrupt_handler
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movl %ebx, %esp
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