enable docker ppp

hc

2023-12-09 95099d4622f8cb224d94e314c7a8e0df60b13f87

 kernel/arch/x86/kernel/i8253.c
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@@ -8,6 +8,7 @@
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 #include <linux/timex.h>
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 #include <linux/i8253.h>
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+#include <asm/apic.h>
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 #include <asm/hpet.h>
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 #include <asm/time.h>
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 #include <asm/smp.h>
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@@ -18,10 +19,32 @@
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  */
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 struct clock_event_device *global_clock_event;
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-void __init setup_pit_timer(void)
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+/*
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+ * Modern chipsets can disable the PIT clock which makes it unusable. It
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+ * would be possible to enable the clock but the registers are chipset
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+ * specific and not discoverable. Avoid the whack a mole game.
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+ *
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+ * These platforms have discoverable TSC/CPU frequencies but this also
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+ * requires to know the local APIC timer frequency as it normally is
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+ * calibrated against the PIT interrupt.
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+ */
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+static bool __init use_pit(void)
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 {
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+	if (!IS_ENABLED(CONFIG_X86_TSC) || !boot_cpu_has(X86_FEATURE_TSC))
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+		return true;
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+
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+	/* This also returns true when APIC is disabled */
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+	return apic_needs_pit();
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+}
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+
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+bool __init pit_timer_init(void)
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+{
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+	if (!use_pit())
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+		return false;
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+
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 	clockevent_i8253_init(true);
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 	global_clock_event = &i8253_clockevent;
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+	return true;
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 }
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 #ifndef CONFIG_X86_64