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3c502e7a02
When using early debugging, the kernel does not initialize the
hw_breakpoint API early enough and causes the late initialization of
the kernel debugger to fail. The boot arguments are:
earlyprintk=vga ekgdboc=kbd kgdbwait
Then simply type "go" at the kdb prompt and boot. The kernel will
later emit the message:
kgdb: Could not allocate hwbreakpoints
And at that point the kernel debugger will cease to work correctly.
The solution is to initialize the hw_breakpoint at the same time that
all the other perf call backs are initialized instead of using a
core_initcall() initialization which happens well after the kernel
debugger can make use of hardware breakpoints.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4CD3396D.1090308@windriver.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
150 lines
4.2 KiB
C
150 lines
4.2 KiB
C
#ifndef _LINUX_HW_BREAKPOINT_H
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#define _LINUX_HW_BREAKPOINT_H
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enum {
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HW_BREAKPOINT_LEN_1 = 1,
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HW_BREAKPOINT_LEN_2 = 2,
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HW_BREAKPOINT_LEN_4 = 4,
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HW_BREAKPOINT_LEN_8 = 8,
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};
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enum {
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HW_BREAKPOINT_EMPTY = 0,
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HW_BREAKPOINT_R = 1,
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HW_BREAKPOINT_W = 2,
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HW_BREAKPOINT_RW = HW_BREAKPOINT_R | HW_BREAKPOINT_W,
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HW_BREAKPOINT_X = 4,
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HW_BREAKPOINT_INVALID = HW_BREAKPOINT_RW | HW_BREAKPOINT_X,
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};
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enum bp_type_idx {
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TYPE_INST = 0,
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#ifdef CONFIG_HAVE_MIXED_BREAKPOINTS_REGS
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TYPE_DATA = 0,
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#else
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TYPE_DATA = 1,
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#endif
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TYPE_MAX
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};
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#ifdef __KERNEL__
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#include <linux/perf_event.h>
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#ifdef CONFIG_HAVE_HW_BREAKPOINT
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extern int __init init_hw_breakpoint(void);
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static inline void hw_breakpoint_init(struct perf_event_attr *attr)
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{
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memset(attr, 0, sizeof(*attr));
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attr->type = PERF_TYPE_BREAKPOINT;
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attr->size = sizeof(*attr);
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/*
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* As it's for in-kernel or ptrace use, we want it to be pinned
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* and to call its callback every hits.
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*/
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attr->pinned = 1;
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attr->sample_period = 1;
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}
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static inline void ptrace_breakpoint_init(struct perf_event_attr *attr)
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{
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hw_breakpoint_init(attr);
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attr->exclude_kernel = 1;
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}
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static inline unsigned long hw_breakpoint_addr(struct perf_event *bp)
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{
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return bp->attr.bp_addr;
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}
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static inline int hw_breakpoint_type(struct perf_event *bp)
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{
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return bp->attr.bp_type;
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}
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static inline unsigned long hw_breakpoint_len(struct perf_event *bp)
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{
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return bp->attr.bp_len;
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}
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extern struct perf_event *
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register_user_hw_breakpoint(struct perf_event_attr *attr,
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perf_overflow_handler_t triggered,
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struct task_struct *tsk);
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/* FIXME: only change from the attr, and don't unregister */
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extern int
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modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr);
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/*
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* Kernel breakpoints are not associated with any particular thread.
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*/
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extern struct perf_event *
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register_wide_hw_breakpoint_cpu(struct perf_event_attr *attr,
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perf_overflow_handler_t triggered,
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int cpu);
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extern struct perf_event * __percpu *
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register_wide_hw_breakpoint(struct perf_event_attr *attr,
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perf_overflow_handler_t triggered);
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extern int register_perf_hw_breakpoint(struct perf_event *bp);
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extern int __register_perf_hw_breakpoint(struct perf_event *bp);
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extern void unregister_hw_breakpoint(struct perf_event *bp);
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extern void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events);
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extern int dbg_reserve_bp_slot(struct perf_event *bp);
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extern int dbg_release_bp_slot(struct perf_event *bp);
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extern int reserve_bp_slot(struct perf_event *bp);
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extern void release_bp_slot(struct perf_event *bp);
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extern void flush_ptrace_hw_breakpoint(struct task_struct *tsk);
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static inline struct arch_hw_breakpoint *counter_arch_bp(struct perf_event *bp)
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{
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return &bp->hw.info;
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}
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#else /* !CONFIG_HAVE_HW_BREAKPOINT */
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static inline int __init init_hw_breakpoint(void) { return 0; }
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static inline struct perf_event *
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register_user_hw_breakpoint(struct perf_event_attr *attr,
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perf_overflow_handler_t triggered,
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struct task_struct *tsk) { return NULL; }
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static inline int
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modify_user_hw_breakpoint(struct perf_event *bp,
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struct perf_event_attr *attr) { return -ENOSYS; }
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static inline struct perf_event *
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register_wide_hw_breakpoint_cpu(struct perf_event_attr *attr,
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perf_overflow_handler_t triggered,
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int cpu) { return NULL; }
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static inline struct perf_event * __percpu *
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register_wide_hw_breakpoint(struct perf_event_attr *attr,
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perf_overflow_handler_t triggered) { return NULL; }
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static inline int
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register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; }
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static inline int
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__register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; }
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static inline void unregister_hw_breakpoint(struct perf_event *bp) { }
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static inline void
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unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) { }
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static inline int
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reserve_bp_slot(struct perf_event *bp) {return -ENOSYS; }
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static inline void release_bp_slot(struct perf_event *bp) { }
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static inline void flush_ptrace_hw_breakpoint(struct task_struct *tsk) { }
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static inline struct arch_hw_breakpoint *counter_arch_bp(struct perf_event *bp)
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{
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return NULL;
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}
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#endif /* CONFIG_HAVE_HW_BREAKPOINT */
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#endif /* __KERNEL__ */
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#endif /* _LINUX_HW_BREAKPOINT_H */
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