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8c49d9a74b
Variables that are shared between the vdso and the kernel are currently a bit of a mess. They are each defined with their own magic, they are accessed differently in the kernel, the vsyscall page, and the vdso, and one of them (vsyscall_clock) doesn't even really exist. This changes them all to use a common mechanism. All of them are delcared in vvar.h with a fixed address (validated by the linker script). In the kernel (as before), they look like ordinary read-write variables. In the vsyscall page and the vdso, they are accessed through a new macro VVAR, which gives read-only access. The vdso is now loaded verbatim into memory without any fixups. As a side bonus, access from the vdso is faster because a level of indirection is removed. While we're at it, pack jiffies and vgetcpu_mode into the same cacheline. Signed-off-by: Andy Lutomirski <luto@mit.edu> Cc: Andi Kleen <andi@firstfloor.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Borislav Petkov <bp@amd64.org> Link: http://lkml.kernel.org/r/%3C7357882fbb51fa30491636a7b6528747301b7ee9.1306156808.git.luto%40mit.edu%3E Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
103 lines
2.2 KiB
C
103 lines
2.2 KiB
C
/*
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* Copyright (c) 1991,1992,1995 Linus Torvalds
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* Copyright (c) 1994 Alan Modra
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* Copyright (c) 1995 Markus Kuhn
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* Copyright (c) 1996 Ingo Molnar
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* Copyright (c) 1998 Andrea Arcangeli
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* Copyright (c) 2002,2006 Vojtech Pavlik
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* Copyright (c) 2003 Andi Kleen
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*
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*/
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#include <linux/clockchips.h>
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#include <linux/interrupt.h>
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#include <linux/time.h>
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#include <linux/mca.h>
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#include <asm/vsyscall.h>
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#include <asm/x86_init.h>
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#include <asm/i8259.h>
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#include <asm/i8253.h>
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#include <asm/timer.h>
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#include <asm/hpet.h>
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#include <asm/time.h>
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#ifdef CONFIG_X86_64
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DEFINE_VVAR(volatile unsigned long, jiffies) = INITIAL_JIFFIES;
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#endif
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unsigned long profile_pc(struct pt_regs *regs)
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{
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unsigned long pc = instruction_pointer(regs);
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if (!user_mode_vm(regs) && in_lock_functions(pc)) {
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#ifdef CONFIG_FRAME_POINTER
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return *(unsigned long *)(regs->bp + sizeof(long));
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#else
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unsigned long *sp =
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(unsigned long *)kernel_stack_pointer(regs);
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/*
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* Return address is either directly at stack pointer
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* or above a saved flags. Eflags has bits 22-31 zero,
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* kernel addresses don't.
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*/
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if (sp[0] >> 22)
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return sp[0];
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if (sp[1] >> 22)
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return sp[1];
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#endif
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}
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return pc;
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}
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EXPORT_SYMBOL(profile_pc);
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/*
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* Default timer interrupt handler for PIT/HPET
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*/
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static irqreturn_t timer_interrupt(int irq, void *dev_id)
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{
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/* Keep nmi watchdog up to date */
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inc_irq_stat(irq0_irqs);
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global_clock_event->event_handler(global_clock_event);
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/* MCA bus quirk: Acknowledge irq0 by setting bit 7 in port 0x61 */
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if (MCA_bus)
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outb_p(inb_p(0x61)| 0x80, 0x61);
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return IRQ_HANDLED;
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}
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static struct irqaction irq0 = {
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.handler = timer_interrupt,
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.flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
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.name = "timer"
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};
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void __init setup_default_timer_irq(void)
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{
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setup_irq(0, &irq0);
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}
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/* Default timer init function */
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void __init hpet_time_init(void)
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{
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if (!hpet_enable())
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setup_pit_timer();
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setup_default_timer_irq();
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}
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static __init void x86_late_time_init(void)
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{
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x86_init.timers.timer_init();
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tsc_init();
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}
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/*
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* Initialize TSC and delay the periodic timer init to
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* late x86_late_time_init() so ioremap works.
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*/
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void __init time_init(void)
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{
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late_time_init = x86_late_time_init;
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}
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