Function report

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:arch\x86\kernel\apic\io_apic.c Create Date:2022-07-28 08:30:12
Last Modify:2020-03-16 21:24:45 Copyright©Brick
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Annotation kernel can get tool activityDownload SCCTChinese

Name:There is a nasty bug in some older SMP boards, their mptable lies* about the timer IRQ

Proto:static int __init timer_irq_works(void)

Type:int

Parameter:Nothing

1633  t1 = jiffies
1636  If no_timer_check Then Return 1
1639  local_save_flags(flags)
1640  The local_irq_*() APIs are equal to the raw_local_irq*()* if !TRACE_IRQFLAGS.()
1642  If boot_cpu_has(Time Stamp Counter ) Then delay_with_tsc()
1644  Else delay_without_tsc()
1647  local_irq_restore(flags)
1658  If These inlines deal with timer wrapping correctly. You are * strongly encouraged to use them* 1. Because people otherwise forget* 2. Because if the timer wrap changes in future you won't have to* alter your driver code.(jiffies, t1 + 4) Then Return 1
1660  Return 0
Caller
NameDescribe
check_timerThis code may look a bit paranoid, but it's supposed to cooperate with* a wide range of boards and BIOS bugs. Fortunately only the timer IRQ* is so screwy. Thanks to Brian Perkins for testing/hacking this beast* fanatically on his truly buggy board.