From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>,
Linux-Arch <linux-arch@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andi Kleen <ak@linux.intel.com>, Peter Anvin <hpa@zytor.com>,
Mike Galbraith <bitbucket@online.de>,
Arjan van de Ven <arjan@linux.intel.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
"Linux/m68k" <linux-m68k@vger.kernel.org>
Subject: Re: [patch 1/6] hardirq: Make hardirq bits generic
Date: Tue, 17 Sep 2013 22:00:03 +0200 [thread overview]
Message-ID: <CAMuHMdWgrQf+ULDrZyY5R+vT3GtiWEgpsWxmfk0b5pivN7wBmg@mail.gmail.com> (raw)
In-Reply-To: <20130917183628.534494408@linutronix.de>
On Tue, Sep 17, 2013 at 8:53 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> --- linux-2.6.orig/arch/m68k/include/asm/hardirq.h
> +++ linux-2.6/arch/m68k/include/asm/hardirq.h
> @@ -5,17 +5,6 @@
> #include <linux/cache.h>
> #include <asm/irq.h>
>
> -#define HARDIRQ_BITS 8
> --- linux-2.6.orig/include/linux/preempt_mask.h
> +++ linux-2.6/include/linux/preempt_mask.h
> @@ -11,36 +11,22 @@
> * - bits 0-7 are the preemption count (max preemption depth: 256)
> * - bits 8-15 are the softirq count (max # of softirqs: 256)
> *
> - * The hardirq count can in theory reach the same as NR_IRQS.
> - * In reality, the number of nested IRQS is limited to the stack
> - * size as well. For archs with over 1000 IRQS it is not practical
> - * to expect that they will all nest. We give a max of 10 bits for
> - * hardirq nesting. An arch may choose to give less than 10 bits.
> - * m68k expects it to be 8.
m68k needs some changes in arch/m68k/kernel/entry.S, cfr. this check
in arch/m68k/kernel/ints.c:
/* assembly irq entry code relies on this... */
if (HARDIRQ_MASK != 0x00ff0000) {
extern void hardirq_mask_is_broken(void);
hardirq_mask_is_broken();
}
Haven't looked into the details yet...
> - * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024)
> - * - bit 26 is the NMI_MASK
> - * - bit 27 is the PREEMPT_ACTIVE flag
> + * The hardirq count could in theory be the same as the number of
> + * interrupts in the system, but we run all interrupt handlers with
> + * interrupts disabled, so we cannot have nesting interrupts. Though
> + * there are a few palaeontologic drivers which reenable interrupts in
> + * the handler, so we need more than one bit here.
> *
> * PREEMPT_MASK: 0x000000ff
> * SOFTIRQ_MASK: 0x0000ff00
> - * HARDIRQ_MASK: 0x03ff0000
> - * NMI_MASK: 0x04000000
> + * HARDIRQ_MASK: 0x000f0000
> + * NMI_MASK: 0x00100000
> */
> #define PREEMPT_BITS 8
> #define SOFTIRQ_BITS 8
> +#define HARDIRQ_BITS 4
> #define NMI_BITS 1
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2013-09-17 20:00 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-17 9:10 [PATCH 00/11] preempt_count rework -v3 Peter Zijlstra
2013-09-17 9:10 ` [PATCH 01/11] x86: Use asm goto to implement better modify_and_test() functions Peter Zijlstra
2013-09-18 18:44 ` Linus Torvalds
[not found] ` <4ec87843-c29a-401a-a54f-2cd4d61fba62@email.android.com>
2013-09-19 8:31 ` Andi Kleen
2013-09-19 9:39 ` Ingo Molnar
2013-09-20 4:43 ` H. Peter Anvin
2013-09-17 9:10 ` [PATCH 02/11] sched, rcu: Make RCU use resched_cpu() Peter Zijlstra
2013-09-17 14:40 ` Peter Zijlstra
2013-09-23 16:55 ` Paul E. McKenney
2013-09-23 21:18 ` Paul E. McKenney
2013-09-24 8:07 ` Peter Zijlstra
2013-09-24 13:37 ` Paul E. McKenney
2013-09-17 9:10 ` [PATCH 03/11] sched: Remove {set,clear}_need_resched Peter Zijlstra
2013-09-17 9:10 ` [PATCH 04/11] sched, idle: Fix the idle polling state logic Peter Zijlstra
2013-09-17 9:10 ` [PATCH 05/11] sched: Introduce preempt_count accessor functions Peter Zijlstra
2013-09-17 9:10 ` [PATCH 06/11] sched: Add NEED_RESCHED to the preempt_count Peter Zijlstra
2013-09-17 9:10 ` [PATCH 07/11] sched, arch: Create asm/preempt.h Peter Zijlstra
2013-09-17 9:10 ` [PATCH 08/11] sched: Create more preempt_count accessors Peter Zijlstra
2013-09-17 9:10 ` [PATCH 09/11] sched: Extract the basic add/sub preempt_count modifiers Peter Zijlstra
2013-09-17 9:10 ` [PATCH 10/11] sched, x86: Provide a per-cpu preempt_count implementation Peter Zijlstra
2013-09-17 9:10 ` [PATCH 11/11] sched, x86: Optimize the preempt_schedule() call Peter Zijlstra
2013-09-17 20:23 ` Peter Zijlstra
2013-09-17 10:53 ` [PATCH 00/11] preempt_count rework -v3 Ingo Molnar
2013-09-17 11:22 ` Peter Zijlstra
2013-09-17 18:53 ` [patch 0/6] Make all preempt_count related constants generic Thomas Gleixner
2013-09-17 18:53 ` [patch 1/6] hardirq: Make hardirq bits generic Thomas Gleixner
2013-09-17 20:00 ` Geert Uytterhoeven [this message]
2013-09-17 21:24 ` Thomas Gleixner
2013-09-18 14:06 ` Thomas Gleixner
2013-09-19 15:14 ` Thomas Gleixner
2013-09-19 17:02 ` Andreas Schwab
2013-09-19 18:19 ` Geert Uytterhoeven
2013-09-20 9:26 ` Thomas Gleixner
2013-11-04 12:06 ` Thomas Gleixner
2013-11-04 19:44 ` Geert Uytterhoeven
2013-11-06 17:23 ` Thomas Gleixner
2013-11-07 14:12 ` Geert Uytterhoeven
2013-11-07 16:39 ` Thomas Gleixner
2013-11-10 8:49 ` Michael Schmitz
2013-11-10 9:12 ` Geert Uytterhoeven
2013-11-11 14:11 ` Thomas Gleixner
2013-11-11 19:34 ` Thomas Gleixner
2013-11-11 20:52 ` Thomas Gleixner
2013-11-12 6:56 ` Michael Schmitz
2013-11-12 8:44 ` schmitz
2013-11-12 15:08 ` Geert Uytterhoeven
2013-11-13 19:42 ` [tip:irq/urgent] m68k: Simplify low level interrupt handling code tip-bot for Thomas Gleixner
2013-11-12 14:09 ` [patch 1/6] hardirq: Make hardirq bits generic Geert Uytterhoeven
2013-11-11 19:42 ` Andreas Schwab
2013-11-12 9:18 ` Thomas Gleixner
2013-11-13 19:42 ` [tip:irq/urgent] " tip-bot for Thomas Gleixner
2013-09-17 18:53 ` [patch 2/6] h8300: Use schedule_preempt_irq Thomas Gleixner
2013-09-20 17:41 ` Guenter Roeck
2013-09-20 21:46 ` Thomas Gleixner
2013-09-17 18:53 ` [patch 3/6] m32r: Use preempt_schedule_irq Thomas Gleixner
2013-11-13 19:42 ` [tip:irq/urgent] " tip-bot for Thomas Gleixner
2013-09-17 18:53 ` [patch 5/6] sparc: " Thomas Gleixner
2013-09-17 22:54 ` David Miller
2013-09-17 23:23 ` Thomas Gleixner
2013-09-18 0:12 ` David Miller
2013-11-13 19:43 ` [tip:irq/urgent] " tip-bot for Thomas Gleixner
2013-09-17 18:53 ` [patch 4/6] ia64: " Thomas Gleixner
2013-11-13 19:43 ` [tip:irq/urgent] " tip-bot for Thomas Gleixner
2013-11-20 19:59 ` [patch 4/6] " Tony Luck
2013-11-20 20:57 ` Thomas Gleixner
2013-11-21 11:41 ` Thomas Gleixner
2013-11-21 12:39 ` Frederic Weisbecker
2013-11-21 13:06 ` Peter Zijlstra
2013-11-21 13:30 ` Thomas Gleixner
2013-11-21 18:57 ` Tony Luck
2013-11-26 18:37 ` Tony Luck
2013-11-26 18:58 ` Peter Zijlstra
2013-11-27 13:36 ` Ingo Molnar
2013-11-27 14:07 ` [tip:sched/urgent] sched: Expose preempt_schedule_irq() tip-bot for Thomas Gleixner
2013-09-17 18:53 ` [patch 6/6] preempt: Make PREEMPT_ACTIVE generic Thomas Gleixner
2013-09-18 10:48 ` Peter Zijlstra
2013-11-13 19:43 ` [tip:irq/urgent] " tip-bot for Thomas Gleixner
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