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Kernel: Don't update Thread TSS if scheduler tick reschedules it

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If we didn't find anything else that wants to run, we don't need to
update the current thread's TSS since we're just gonna return to the
same thread anyway.
This commit is contained in:
Andreas Kling 2019-10-02 13:45:26 +02:00
parent 5ab044beae
commit c33ac7f170
1 changed files with 26 additions and 24 deletions
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50
Kernel/Scheduler.cpp
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@ -540,33 +540,35 @@ void Scheduler::timer_tick(RegisterDump& regs)
if (current->tick())
return;
current->tss().gs = regs.gs;
current->tss().fs = regs.fs;
current->tss().es = regs.es;
current->tss().ds = regs.ds;
current->tss().edi = regs.edi;
current->tss().esi = regs.esi;
current->tss().ebp = regs.ebp;
current->tss().ebx = regs.ebx;
current->tss().edx = regs.edx;
current->tss().ecx = regs.ecx;
current->tss().eax = regs.eax;
current->tss().eip = regs.eip;
current->tss().cs = regs.cs;
current->tss().eflags = regs.eflags;
// Compute process stack pointer.
// Add 12 for CS, EIP, EFLAGS (interrupt mechanic)
current->tss().esp = regs.esp + 12;
current->tss().ss = regs.ss;
if ((current->tss().cs & 3) != 0) {
current->tss().ss = regs.ss_if_crossRing;
current->tss().esp = regs.esp_if_crossRing;
}
auto& outgoing_tss = current->tss();
if (!pick_next())
return;
outgoing_tss.gs = regs.gs;
outgoing_tss.fs = regs.fs;
outgoing_tss.es = regs.es;
outgoing_tss.ds = regs.ds;
outgoing_tss.edi = regs.edi;
outgoing_tss.esi = regs.esi;
outgoing_tss.ebp = regs.ebp;
outgoing_tss.ebx = regs.ebx;
outgoing_tss.edx = regs.edx;
outgoing_tss.ecx = regs.ecx;
outgoing_tss.eax = regs.eax;
outgoing_tss.eip = regs.eip;
outgoing_tss.cs = regs.cs;
outgoing_tss.eflags = regs.eflags;
// Compute process stack pointer.
// Add 12 for CS, EIP, EFLAGS (interrupt mechanic)
outgoing_tss.esp = regs.esp + 12;
outgoing_tss.ss = regs.ss;
if ((outgoing_tss.cs & 3) != 0) {
outgoing_tss.ss = regs.ss_if_crossRing;
outgoing_tss.esp = regs.esp_if_crossRing;
}
prepare_for_iret_to_new_process();
// Set the NT (nested task) flag.