3171a0305d
Pass ticks to do_timer() and update_times(), and adjust x86_64 and s390 timer interrupt handler with this change. Currently update_times() calculates ticks by "jiffies - wall_jiffies", but callers of do_timer() should know how many ticks to update. Passing ticks get rid of this redundant calculation. Also there are another redundancy pointed out by Martin Schwidefsky. This cleanup make a barrier added by 5aee405c662ca644980c184774277fc6d0769a84 needless. So this patch removes it. As a bonus, this cleanup make wall_jiffies can be removed easily, since now wall_jiffies is always synced with jiffies. (This patch does not really remove wall_jiffies. It would be another cleanup patch) Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Acked-by: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Mikael Starvik <starvik@axis.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Hirokazu Takata <takata.hirokazu@renesas.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Acked-by: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
/* defines for inline arch setup functions */
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#include <asm/apic.h>
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#include <asm/i8259.h>
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/**
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* do_timer_interrupt_hook - hook into timer tick
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* @regs: standard registers from interrupt
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*
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* Description:
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* This hook is called immediately after the timer interrupt is ack'd.
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* It's primary purpose is to allow architectures that don't possess
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* individual per CPU clocks (like the CPU APICs supply) to broadcast the
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* timer interrupt as a means of triggering reschedules etc.
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**/
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static inline void do_timer_interrupt_hook(struct pt_regs *regs)
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{
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do_timer(1);
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#ifndef CONFIG_SMP
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update_process_times(user_mode_vm(regs));
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#endif
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/*
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* In the SMP case we use the local APIC timer interrupt to do the
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* profiling, except when we simulate SMP mode on a uniprocessor
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* system, in that case we have to call the local interrupt handler.
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*/
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#ifndef CONFIG_X86_LOCAL_APIC
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profile_tick(CPU_PROFILING, regs);
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#else
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if (!using_apic_timer)
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smp_local_timer_interrupt(regs);
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#endif
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}
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/* you can safely undefine this if you don't have the Neptune chipset */
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#define BUGGY_NEPTUN_TIMER
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/**
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* do_timer_overflow - process a detected timer overflow condition
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* @count: hardware timer interrupt count on overflow
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*
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* Description:
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* This call is invoked when the jiffies count has not incremented but
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* the hardware timer interrupt has. It means that a timer tick interrupt
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* came along while the previous one was pending, thus a tick was missed
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**/
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static inline int do_timer_overflow(int count)
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{
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int i;
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spin_lock(&i8259A_lock);
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/*
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* This is tricky when I/O APICs are used;
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* see do_timer_interrupt().
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*/
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i = inb(0x20);
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spin_unlock(&i8259A_lock);
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/* assumption about timer being IRQ0 */
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if (i & 0x01) {
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/*
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* We cannot detect lost timer interrupts ...
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* well, that's why we call them lost, don't we? :)
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* [hmm, on the Pentium and Alpha we can ... sort of]
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*/
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count -= LATCH;
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} else {
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#ifdef BUGGY_NEPTUN_TIMER
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/*
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* for the Neptun bug we know that the 'latch'
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* command doesn't latch the high and low value
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* of the counter atomically. Thus we have to
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* substract 256 from the counter
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* ... funny, isnt it? :)
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*/
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count -= 256;
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#else
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printk("do_slow_gettimeoffset(): hardware timer problem?\n");
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#endif
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}
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return count;
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}
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