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
|
|
#define _LINUX_HW_BREAKPOINT_H
|
|
|
|
enum {
|
|
HW_BREAKPOINT_LEN_1 = 1,
|
|
HW_BREAKPOINT_LEN_2 = 2,
|
|
HW_BREAKPOINT_LEN_4 = 4,
|
|
HW_BREAKPOINT_LEN_8 = 8,
|
|
};
|
|
|
|
enum {
|
|
HW_BREAKPOINT_EMPTY = 0,
|
|
HW_BREAKPOINT_R = 1,
|
|
HW_BREAKPOINT_W = 2,
|
|
HW_BREAKPOINT_RW = HW_BREAKPOINT_R | HW_BREAKPOINT_W,
|
|
HW_BREAKPOINT_X = 4,
|
|
HW_BREAKPOINT_INVALID = HW_BREAKPOINT_RW | HW_BREAKPOINT_X,
|
|
};
|
|
|
|
enum bp_type_idx {
|
|
TYPE_INST = 0,
|
|
#ifdef CONFIG_HAVE_MIXED_BREAKPOINTS_REGS
|
|
TYPE_DATA = 0,
|
|
#else
|
|
TYPE_DATA = 1,
|
|
#endif
|
|
TYPE_MAX
|
|
};
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#include <linux/perf_event.h>
|
|
|
|
#ifdef CONFIG_HAVE_HW_BREAKPOINT
|
|
|
|
extern int __init init_hw_breakpoint(void);
|
|
|
|
static inline void hw_breakpoint_init(struct perf_event_attr *attr)
|
|
{
|
|
memset(attr, 0, sizeof(*attr));
|
|
|
|
attr->type = PERF_TYPE_BREAKPOINT;
|
|
attr->size = sizeof(*attr);
|
|
/*
|
|
* As it's for in-kernel or ptrace use, we want it to be pinned
|
|
* and to call its callback every hits.
|
|
*/
|
|
attr->pinned = 1;
|
|
attr->sample_period = 1;
|
|
}
|
|
|
|
static inline void ptrace_breakpoint_init(struct perf_event_attr *attr)
|
|
{
|
|
hw_breakpoint_init(attr);
|
|
attr->exclude_kernel = 1;
|
|
}
|
|
|
|
static inline unsigned long hw_breakpoint_addr(struct perf_event *bp)
|
|
{
|
|
return bp->attr.bp_addr;
|
|
}
|
|
|
|
static inline int hw_breakpoint_type(struct perf_event *bp)
|
|
{
|
|
return bp->attr.bp_type;
|
|
}
|
|
|
|
static inline unsigned long hw_breakpoint_len(struct perf_event *bp)
|
|
{
|
|
return bp->attr.bp_len;
|
|
}
|
|
|
|
extern struct perf_event *
|
|
register_user_hw_breakpoint(struct perf_event_attr *attr,
|
|
perf_overflow_handler_t triggered,
|
|
struct task_struct *tsk);
|
|
|
|
/* FIXME: only change from the attr, and don't unregister */
|
|
extern int
|
|
modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr);
|
|
|
|
/*
|
|
* Kernel breakpoints are not associated with any particular thread.
|
|
*/
|
|
extern struct perf_event *
|
|
register_wide_hw_breakpoint_cpu(struct perf_event_attr *attr,
|
|
perf_overflow_handler_t triggered,
|
|
int cpu);
|
|
|
|
extern struct perf_event * __percpu *
|
|
register_wide_hw_breakpoint(struct perf_event_attr *attr,
|
|
perf_overflow_handler_t triggered);
|
|
|
|
extern int register_perf_hw_breakpoint(struct perf_event *bp);
|
|
extern int __register_perf_hw_breakpoint(struct perf_event *bp);
|
|
extern void unregister_hw_breakpoint(struct perf_event *bp);
|
|
extern void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events);
|
|
|
|
extern int dbg_reserve_bp_slot(struct perf_event *bp);
|
|
extern int dbg_release_bp_slot(struct perf_event *bp);
|
|
extern int reserve_bp_slot(struct perf_event *bp);
|
|
extern void release_bp_slot(struct perf_event *bp);
|
|
|
|
extern void flush_ptrace_hw_breakpoint(struct task_struct *tsk);
|
|
|
|
static inline struct arch_hw_breakpoint *counter_arch_bp(struct perf_event *bp)
|
|
{
|
|
return &bp->hw.info;
|
|
}
|
|
|
|
#else /* !CONFIG_HAVE_HW_BREAKPOINT */
|
|
|
|
static inline int __init init_hw_breakpoint(void) { return 0; }
|
|
|
|
static inline struct perf_event *
|
|
register_user_hw_breakpoint(struct perf_event_attr *attr,
|
|
perf_overflow_handler_t triggered,
|
|
struct task_struct *tsk) { return NULL; }
|
|
static inline int
|
|
modify_user_hw_breakpoint(struct perf_event *bp,
|
|
struct perf_event_attr *attr) { return -ENOSYS; }
|
|
static inline struct perf_event *
|
|
register_wide_hw_breakpoint_cpu(struct perf_event_attr *attr,
|
|
perf_overflow_handler_t triggered,
|
|
int cpu) { return NULL; }
|
|
static inline struct perf_event * __percpu *
|
|
register_wide_hw_breakpoint(struct perf_event_attr *attr,
|
|
perf_overflow_handler_t triggered) { return NULL; }
|
|
static inline int
|
|
register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; }
|
|
static inline int
|
|
__register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; }
|
|
static inline void unregister_hw_breakpoint(struct perf_event *bp) { }
|
|
static inline void
|
|
unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) { }
|
|
static inline int
|
|
reserve_bp_slot(struct perf_event *bp) {return -ENOSYS; }
|
|
static inline void release_bp_slot(struct perf_event *bp) { }
|
|
|
|
static inline void flush_ptrace_hw_breakpoint(struct task_struct *tsk) { }
|
|
|
|
static inline struct arch_hw_breakpoint *counter_arch_bp(struct perf_event *bp)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
|
|
#endif /* __KERNEL__ */
|
|
|
|
#endif /* _LINUX_HW_BREAKPOINT_H */
|