linux/arch/arm64/include/asm/stacktrace.h
Mark Rutland f60fe78f13 arm64: use an irq stack pointer
We allocate our IRQ stacks using a percpu array. This allows us to generate our
IRQ stack pointers with adr_this_cpu, but bloats the kernel Image with the boot
CPU's IRQ stack. Additionally, these are packed with other percpu variables,
and aren't guaranteed to have guard pages.

When we enable VMAP_STACK we'll want to vmap our IRQ stacks also, in order to
provide guard pages and to permit more stringent alignment requirements. Doing
so will require that we use a percpu pointer to each IRQ stack, rather than
allocating a percpu IRQ stack in the kernel image.

This patch updates our IRQ stack code to use a percpu pointer to the base of
each IRQ stack. This will allow us to change the way the stack is allocated
with minimal changes elsewhere. In some cases we may try to backtrace before
the IRQ stack pointers are initialised, so on_irq_stack() is updated to account
for this.

In testing with cyclictest, there was no measureable difference between using
adr_this_cpu (for irq_stack) and ldr_this_cpu (for irq_stack_ptr) in the IRQ
entry path.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
2017-08-15 18:35:54 +01:00

61 lines
1.7 KiB
C

/*
* 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/>.
*/
#ifndef __ASM_STACKTRACE_H
#define __ASM_STACKTRACE_H
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <asm/memory.h>
#include <asm/ptrace.h>
struct stackframe {
unsigned long fp;
unsigned long pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
unsigned int graph;
#endif
};
extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
int (*fn)(struct stackframe *, void *), void *data);
extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk);
DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
static inline bool on_irq_stack(unsigned long sp)
{
unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
unsigned long high = low + IRQ_STACK_SIZE;
if (!low)
return false;
return (low <= sp && sp < high);
}
static inline bool on_task_stack(struct task_struct *tsk, unsigned long sp)
{
unsigned long low = (unsigned long)task_stack_page(tsk);
unsigned long high = low + THREAD_SIZE;
return (low <= sp && sp < high);
}
#endif /* __ASM_STACKTRACE_H */