mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-06 05:16:38 +07:00
09f90f6685
The low level interrupt entry code of m68k contains the following: add_preempt_count(HARDIRQ_OFFSET); do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; <---- On m68k always taken! if (local_softirq_pending()) do_softirq(); sub_preempt_count(HARDIRQ_OFFSET); if (in_hardirq()) return; if (status_on_stack_has_interrupt_priority_mask > 0) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: .... I tried to find a proper explanation for this, but the changelog is sparse and there are no mails explaining it further. But obviously this relates to the interrupt priority levels of the m68k and tries to be extra clever with nested interrupts. Though this cleverness just adds code bloat to the interrupt hotpath. For the common case of non nested interrupts the code runs through two extra conditionals to the only important one, which checks whether the return is to kernel or user space. For the nested case the checks for in_hardirq() and the priority mask value on stack catch only the case where the nested interrupt happens inside the hard irq context of the first interrupt. If the nested interrupt happens while the first interrupt handles soft interrupts, then these extra checks buy nothing. The nested interrupt will fall through to the final kernel/user space return check at ret_from_exception. Changing the code flow in the following way: do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: makes the region protected by the hardirq count slightly smaller and the softirq handling is invoked with a minimal deeper stack. But otherwise it's completely functional equivalent and saves 104 bytes of text in arch/m68k/kernel/entry.o. This modification allows us further to get rid of the limitations which m68k puts on the preempt_count layout, so we can make the preempt count bits completely generic. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Linux/m68k <linux-m68k@vger.kernel.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311112052360.30673@ionos.tec.linutronix.de
170 lines
4.0 KiB
C
170 lines
4.0 KiB
C
/*
|
|
* linux/arch/m68k/kernel/ints.c -- Linux/m68k general interrupt handling code
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file COPYING in the main directory of this archive
|
|
* for more details.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/types.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/init.h>
|
|
|
|
#include <asm/setup.h>
|
|
#include <asm/irq.h>
|
|
#include <asm/traps.h>
|
|
#include <asm/page.h>
|
|
#include <asm/machdep.h>
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/irq_regs.h>
|
|
|
|
#ifdef CONFIG_Q40
|
|
#include <asm/q40ints.h>
|
|
#endif
|
|
|
|
extern u32 auto_irqhandler_fixup[];
|
|
extern u16 user_irqvec_fixup[];
|
|
|
|
static int m68k_first_user_vec;
|
|
|
|
static struct irq_chip auto_irq_chip = {
|
|
.name = "auto",
|
|
.irq_startup = m68k_irq_startup,
|
|
.irq_shutdown = m68k_irq_shutdown,
|
|
};
|
|
|
|
static struct irq_chip user_irq_chip = {
|
|
.name = "user",
|
|
.irq_startup = m68k_irq_startup,
|
|
.irq_shutdown = m68k_irq_shutdown,
|
|
};
|
|
|
|
/*
|
|
* void init_IRQ(void)
|
|
*
|
|
* Parameters: None
|
|
*
|
|
* Returns: Nothing
|
|
*
|
|
* This function should be called during kernel startup to initialize
|
|
* the IRQ handling routines.
|
|
*/
|
|
|
|
void __init init_IRQ(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = IRQ_AUTO_1; i <= IRQ_AUTO_7; i++)
|
|
irq_set_chip_and_handler(i, &auto_irq_chip, handle_simple_irq);
|
|
|
|
mach_init_IRQ();
|
|
}
|
|
|
|
/**
|
|
* m68k_setup_auto_interrupt
|
|
* @handler: called from auto vector interrupts
|
|
*
|
|
* setup the handler to be called from auto vector interrupts instead of the
|
|
* standard do_IRQ(), it will be called with irq numbers in the range
|
|
* from IRQ_AUTO_1 - IRQ_AUTO_7.
|
|
*/
|
|
void __init m68k_setup_auto_interrupt(void (*handler)(unsigned int, struct pt_regs *))
|
|
{
|
|
if (handler)
|
|
*auto_irqhandler_fixup = (u32)handler;
|
|
flush_icache();
|
|
}
|
|
|
|
/**
|
|
* m68k_setup_user_interrupt
|
|
* @vec: first user vector interrupt to handle
|
|
* @cnt: number of active user vector interrupts
|
|
*
|
|
* setup user vector interrupts, this includes activating the specified range
|
|
* of interrupts, only then these interrupts can be requested (note: this is
|
|
* different from auto vector interrupts).
|
|
*/
|
|
void __init m68k_setup_user_interrupt(unsigned int vec, unsigned int cnt)
|
|
{
|
|
int i;
|
|
|
|
BUG_ON(IRQ_USER + cnt > NR_IRQS);
|
|
m68k_first_user_vec = vec;
|
|
for (i = 0; i < cnt; i++)
|
|
irq_set_chip_and_handler(i, &user_irq_chip, handle_simple_irq);
|
|
*user_irqvec_fixup = vec - IRQ_USER;
|
|
flush_icache();
|
|
}
|
|
|
|
/**
|
|
* m68k_setup_irq_controller
|
|
* @chip: irq chip which controls specified irq
|
|
* @handle: flow handler which handles specified irq
|
|
* @irq: first irq to be managed by the controller
|
|
* @cnt: number of irqs to be managed by the controller
|
|
*
|
|
* Change the controller for the specified range of irq, which will be used to
|
|
* manage these irq. auto/user irq already have a default controller, which can
|
|
* be changed as well, but the controller probably should use m68k_irq_startup/
|
|
* m68k_irq_shutdown.
|
|
*/
|
|
void m68k_setup_irq_controller(struct irq_chip *chip,
|
|
irq_flow_handler_t handle, unsigned int irq,
|
|
unsigned int cnt)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < cnt; i++) {
|
|
irq_set_chip(irq + i, chip);
|
|
if (handle)
|
|
irq_set_handler(irq + i, handle);
|
|
}
|
|
}
|
|
|
|
unsigned int m68k_irq_startup_irq(unsigned int irq)
|
|
{
|
|
if (irq <= IRQ_AUTO_7)
|
|
vectors[VEC_SPUR + irq] = auto_inthandler;
|
|
else
|
|
vectors[m68k_first_user_vec + irq - IRQ_USER] = user_inthandler;
|
|
return 0;
|
|
}
|
|
|
|
unsigned int m68k_irq_startup(struct irq_data *data)
|
|
{
|
|
return m68k_irq_startup_irq(data->irq);
|
|
}
|
|
|
|
void m68k_irq_shutdown(struct irq_data *data)
|
|
{
|
|
unsigned int irq = data->irq;
|
|
|
|
if (irq <= IRQ_AUTO_7)
|
|
vectors[VEC_SPUR + irq] = bad_inthandler;
|
|
else
|
|
vectors[m68k_first_user_vec + irq - IRQ_USER] = bad_inthandler;
|
|
}
|
|
|
|
|
|
unsigned int irq_canonicalize(unsigned int irq)
|
|
{
|
|
#ifdef CONFIG_Q40
|
|
if (MACH_IS_Q40 && irq == 11)
|
|
irq = 10;
|
|
#endif
|
|
return irq;
|
|
}
|
|
|
|
EXPORT_SYMBOL(irq_canonicalize);
|
|
|
|
|
|
asmlinkage void handle_badint(struct pt_regs *regs)
|
|
{
|
|
atomic_inc(&irq_err_count);
|
|
pr_warn("unexpected interrupt from %u\n", regs->vector);
|
|
}
|