On Tue, Sep 17, 2013 at 8:53 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx
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
--
To unsubscribe from this list: send the line "unsubscribe linux-m68k" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
