x86: I/O APIC: keep IRQ off when changing LVT registers

[mirror_ubuntu-bionic-kernel.git] / arch / x86 / kernel / io_apic_64.c

diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index ef1a8dfcc529a36643bdbe34f835eb1819c5f265..aa45a85c4d11392dcb0ce503ad503418c4f58e8e 100644 (file)
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -90,7 +90,6 @@ static int no_timer_check;
 
 static int disable_timer_pin_1 __initdata;
 
-int timer_over_8254 __initdata = 1;
 
 /* Where if anywhere is the i8259 connect in external int mode */
 static struct { int pin, apic; } ioapic_i8259 = { -1, -1 };
@@ -430,20 +429,6 @@ static int __init disable_timer_pin_setup(char *arg)
 }
 __setup("disable_timer_pin_1", disable_timer_pin_setup);
 
-static int __init setup_disable_8254_timer(char *s)
-{
-       timer_over_8254 = -1;
-       return 1;
-}
-static int __init setup_enable_8254_timer(char *s)
-{
-       timer_over_8254 = 2;
-       return 1;
-}
-
-__setup("disable_8254_timer", setup_disable_8254_timer);
-__setup("enable_8254_timer", setup_enable_8254_timer);
-
 
 /*
  * Find the IRQ entry number of a certain pin.
@@ -1669,16 +1654,11 @@ static inline void __init check_timer(void)
        assign_irq_vector(0, TARGET_CPUS);
 
        /*
-        * Subtle, code in do_timer_interrupt() expects an AEOI
-        * mode for the 8259A whenever interrupts are routed
-        * through I/O APICs.  Also IRQ0 has to be enabled in
-        * the 8259A which implies the virtual wire has to be
-        * disabled in the local APIC.
+        * As IRQ0 is to be enabled in the 8259A, the virtual
+        * wire has to be disabled in the local APIC.
         */
        apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT);
        init_8259A(1);
-       if (timer_over_8254 > 0)
-               enable_8259A_irq(0);
 
        pin1  = find_isa_irq_pin(0, mp_INT);
        apic1 = find_isa_irq_apic(0, mp_INT);
@@ -1696,7 +1676,6 @@ static inline void __init check_timer(void)
                if (!no_timer_check && timer_irq_works()) {
                        nmi_watchdog_default();
                        if (nmi_watchdog == NMI_IO_APIC) {
-                               disable_8259A_irq(0);
                                setup_nmi();
                                enable_8259A_irq(0);
                        }
@@ -1718,17 +1697,21 @@ static inline void __init check_timer(void)
                 * legacy devices should be connected to IO APIC #0
                 */
                setup_ExtINT_IRQ0_pin(apic2, pin2, cfg->vector);
+               enable_8259A_irq(0);
                if (timer_irq_works()) {
                        apic_printk(APIC_VERBOSE," works.\n");
                        nmi_watchdog_default();
                        if (nmi_watchdog == NMI_IO_APIC) {
+                               disable_8259A_irq(0);
                                setup_nmi();
+                               enable_8259A_irq(0);
                        }
                        goto out;
                }
                /*
                 * Cleanup, just in case ...
                 */
+               disable_8259A_irq(0);
                clear_IO_APIC_pin(apic2, pin2);
        }
        apic_printk(APIC_VERBOSE," failed.\n");
@@ -1740,7 +1723,6 @@ static inline void __init check_timer(void)
 
        apic_printk(APIC_VERBOSE, KERN_INFO "...trying to set up timer as Virtual Wire IRQ...");
 
-       disable_8259A_irq(0);
        irq_desc[0].chip = &lapic_irq_type;
        apic_write(APIC_LVT0, APIC_DM_FIXED | cfg->vector);     /* Fixed mode */
        enable_8259A_irq(0);
@@ -1749,6 +1731,7 @@ static inline void __init check_timer(void)
                apic_printk(APIC_VERBOSE," works.\n");
                goto out;
        }
+       disable_8259A_irq(0);
        apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_FIXED | cfg->vector);
        apic_printk(APIC_VERBOSE," failed.\n");