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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 424 | giacomo | 1 | /* defines for inline arch setup functions */ |
| 2 | |||
| 3 | #include <asm/apic.h> |
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| 4 | |||
| 5 | /** |
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| 6 | * do_timer_interrupt_hook - hook into timer tick |
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| 7 | * @regs: standard registers from interrupt |
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| 8 | * |
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| 9 | * Description: |
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| 10 | * This hook is called immediately after the timer interrupt is ack'd. |
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| 11 | * It's primary purpose is to allow architectures that don't possess |
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| 12 | * individual per CPU clocks (like the CPU APICs supply) to broadcast the |
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| 13 | * timer interrupt as a means of triggering reschedules etc. |
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| 14 | **/ |
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| 15 | |||
| 16 | static inline void do_timer_interrupt_hook(struct pt_regs *regs) |
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| 17 | { |
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| 18 | do_timer(regs); |
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| 19 | /* |
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| 20 | * In the SMP case we use the local APIC timer interrupt to do the |
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| 21 | * profiling, except when we simulate SMP mode on a uniprocessor |
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| 22 | * system, in that case we have to call the local interrupt handler. |
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| 23 | */ |
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| 24 | #ifndef CONFIG_X86_LOCAL_APIC |
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| 25 | x86_do_profile(regs); |
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| 26 | #else |
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| 27 | if (!using_apic_timer) |
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| 28 | smp_local_timer_interrupt(regs); |
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| 29 | #endif |
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| 30 | } |
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| 31 | |||
| 32 | |||
| 33 | /* you can safely undefine this if you don't have the Neptune chipset */ |
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| 34 | |||
| 35 | #define BUGGY_NEPTUN_TIMER |
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| 36 | |||
| 37 | /** |
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| 38 | * do_timer_overflow - process a detected timer overflow condition |
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| 39 | * @count: hardware timer interrupt count on overflow |
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| 40 | * |
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| 41 | * Description: |
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| 42 | * This call is invoked when the jiffies count has not incremented but |
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| 43 | * the hardware timer interrupt has. It means that a timer tick interrupt |
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| 44 | * came along while the previous one was pending, thus a tick was missed |
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| 45 | **/ |
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| 46 | static inline int do_timer_overflow(int count) |
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| 47 | { |
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| 48 | int i; |
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| 49 | |||
| 50 | spin_lock(&i8259A_lock); |
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| 51 | /* |
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| 52 | * This is tricky when I/O APICs are used; |
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| 53 | * see do_timer_interrupt(). |
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| 54 | */ |
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| 55 | i = inb(0x00); |
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| 56 | spin_unlock(&i8259A_lock); |
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| 57 | |||
| 58 | /* assumption about timer being IRQ0 */ |
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| 59 | if (i & 0x01) { |
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| 60 | /* |
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| 61 | * We cannot detect lost timer interrupts ... |
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| 62 | * well, that's why we call them lost, don't we? :) |
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| 63 | * [hmm, on the Pentium and Alpha we can ... sort of] |
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| 64 | */ |
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| 65 | count -= LATCH; |
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| 66 | } else { |
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| 67 | #ifdef BUGGY_NEPTUN_TIMER |
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| 68 | /* |
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| 69 | * for the Neptun bug we know that the 'latch' |
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| 70 | * command doesn't latch the high and low value |
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| 71 | * of the counter atomically. Thus we have to |
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| 72 | * substract 256 from the counter |
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| 73 | * ... funny, isnt it? :) |
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| 74 | */ |
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| 75 | |||
| 76 | count -= 256; |
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| 77 | #else |
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| 78 | printk("do_slow_gettimeoffset(): hardware timer problem?\n"); |
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| 79 | #endif |
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| 80 | } |
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| 81 | return count; |
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| 82 | } |