linux/arch/arm64/kernel/irq.c
James Morse d224a69e3d arm64: remove irq_count and do_softirq_own_stack()
sysrq_handle_reboot() re-enables interrupts while on the irq stack. The
irq_stack implementation wrongly assumed this would only ever happen
via the softirq path, allowing it to update irq_count late, in
do_softirq_own_stack().

This means if an irq occurs in sysrq_handle_reboot(), during
emergency_restart() the stack will be corrupted, as irq_count wasn't
updated.

Lose the optimisation, and instead of moving the adding/subtracting of
irq_count into irq_stack_entry/irq_stack_exit, remove it, and compare
sp_el0 (struct thread_info) with sp & ~(THREAD_SIZE - 1). This tells us
if we are on a task stack, if so, we can safely switch to the irq stack.
Finally, remove do_softirq_own_stack(), we don't need it anymore.

Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
[will: use get_thread_info macro]
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-12-21 17:26:01 +00:00

59 lines
1.7 KiB
C

/*
* Based on arch/arm/kernel/irq.c
*
* Copyright (C) 1992 Linus Torvalds
* Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
* Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
* Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
* Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/kernel_stat.h>
#include <linux/irq.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/irqchip.h>
#include <linux/seq_file.h>
unsigned long irq_err_count;
/* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */
DEFINE_PER_CPU(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack) __aligned(16);
int arch_show_interrupts(struct seq_file *p, int prec)
{
show_ipi_list(p, prec);
seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
return 0;
}
void (*handle_arch_irq)(struct pt_regs *) = NULL;
void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
{
if (handle_arch_irq)
return;
handle_arch_irq = handle_irq;
}
void __init init_IRQ(void)
{
irqchip_init();
if (!handle_arch_irq)
panic("No interrupt controller found.");
}