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ARM: run softirqs on the per-CPU IRQ stack

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Now that we have enabled IRQ stacks, any softIRQs that are handled over
the back of a hard IRQ will run from the IRQ stack as well. However, any
synchronous softirq processing that happens when re-enabling softIRQs
from task context will still execute on that task's stack.

Since any call to local_bh_enable() at any level in the task's call
stack may trigger a softIRQ processing run, which could potentially
cause a task stack overflow if the combined stack footprints exceed the
stack's size, let's run these synchronous invocations of do_softirq() on
the IRQ stack as well.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
This commit is contained in:
Ard Biesheuvel 2021-10-05 09:15:42 +02:00
parent 0b78f2e92d
commit 9974f85776
2 changed files with 16 additions and 0 deletions
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2
arch/arm/Kconfig
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@ -1169,6 +1169,8 @@ config CURRENT_POINTER_IN_TPIDRURO
config IRQSTACKS
def_bool y
depends on GENERIC_IRQ_MULTI_HANDLER && THREAD_INFO_IN_TASK
select HAVE_IRQ_EXIT_ON_IRQ_STACK
select HAVE_SOFTIRQ_ON_OWN_STACK
config ARM_CPU_TOPOLOGY
bool "Support cpu topology definition"

14
arch/arm/kernel/irq.c
View File

@ -36,11 +36,14 @@
#include <asm/hardware/cache-l2x0.h>
#include <asm/hardware/cache-uniphier.h>
#include <asm/outercache.h>
#include <asm/softirq_stack.h>
#include <asm/exception.h>
#include <asm/mach/arch.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include "reboot.h"
unsigned long irq_err_count;
#ifdef CONFIG_IRQSTACKS
@ -60,6 +63,17 @@ static void __init init_irq_stacks(void)
}
}
static void ____do_softirq(void *arg)
{
__do_softirq();
}
void do_softirq_own_stack(void)
{
call_with_stack(____do_softirq, NULL,
__this_cpu_read(irq_stack_ptr));
}
#endif
int arch_show_interrupts(struct seq_file *p, int prec)