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db8466c581
When the separate IRQ stack was introduced, stack unwinding only
proceeded as far as the top of the IRQ stack, leading to kernel
backtraces being less useful, lacking the trace of what was interrupted.
Fix this by providing a means for the kernel to unwind the IRQ stack
onto the interrupted task stack. The processor state is saved to the
kernel task stack on interrupt. The IRQ_STACK_START macro reserves an
unsigned long at the top of the IRQ stack where the interrupted task
stack pointer can be saved. After the active stack is switched to the
IRQ stack, save the interrupted tasks stack pointer to the reserved
location.
Fix the stack unwinding code to look for the frame being the top of the
IRQ stack and if so get the next frame from the saved location. The
existing test does not work with the separate stack since the ra is no
longer pointed at ret_from_{irq,exception}.
The test to stop unwinding the stack 32 bytes from the top of a stack
must be modified to allow unwinding to continue up to the location of
the saved task stack pointer when on the IRQ stack. The low / high marks
of the stack are set depending on whether the sp is on an irq stack or
not.
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: Masanari Iida <standby24x7@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason A. Donenfeld <jason@zx2c4.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/15788/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
85 lines
2.3 KiB
C
85 lines
2.3 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1994 by Waldorf GMBH, written by Ralf Baechle
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* Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02, 03 by Ralf Baechle
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*/
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#ifndef _ASM_IRQ_H
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#define _ASM_IRQ_H
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#include <linux/linkage.h>
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#include <linux/smp.h>
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#include <linux/irqdomain.h>
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#include <asm/mipsmtregs.h>
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#include <irq.h>
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#define IRQ_STACK_SIZE THREAD_SIZE
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#define IRQ_STACK_START (IRQ_STACK_SIZE - sizeof(unsigned long))
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extern void *irq_stack[NR_CPUS];
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/*
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* The highest address on the IRQ stack contains a dummy frame put down in
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* genex.S (handle_int & except_vec_vi_handler) which is structured as follows:
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*
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* top ------------
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* | task sp | <- irq_stack[cpu] + IRQ_STACK_START
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* ------------
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* | | <- First frame of IRQ context
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* ------------
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*
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* task sp holds a copy of the task stack pointer where the struct pt_regs
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* from exception entry can be found.
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*/
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static inline bool on_irq_stack(int cpu, unsigned long sp)
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{
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unsigned long low = (unsigned long)irq_stack[cpu];
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unsigned long high = low + IRQ_STACK_SIZE;
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return (low <= sp && sp <= high);
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}
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#ifdef CONFIG_I8259
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static inline int irq_canonicalize(int irq)
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{
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return ((irq == I8259A_IRQ_BASE + 2) ? I8259A_IRQ_BASE + 9 : irq);
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}
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#else
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#define irq_canonicalize(irq) (irq) /* Sane hardware, sane code ... */
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#endif
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asmlinkage void plat_irq_dispatch(void);
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extern void do_IRQ(unsigned int irq);
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extern void arch_init_irq(void);
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extern void spurious_interrupt(void);
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extern int allocate_irqno(void);
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extern void alloc_legacy_irqno(void);
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extern void free_irqno(unsigned int irq);
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/*
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* Before R2 the timer and performance counter interrupts were both fixed to
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* IE7. Since R2 their number has to be read from the c0_intctl register.
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*/
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#define CP0_LEGACY_COMPARE_IRQ 7
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#define CP0_LEGACY_PERFCNT_IRQ 7
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extern int cp0_compare_irq;
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extern int cp0_compare_irq_shift;
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extern int cp0_perfcount_irq;
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extern int cp0_fdc_irq;
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extern int get_c0_fdc_int(void);
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void arch_trigger_cpumask_backtrace(const struct cpumask *mask,
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bool exclude_self);
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#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
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#endif /* _ASM_IRQ_H */
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