3eddddcf23
This patch implements a stack trace for a thread, not unlike sysrq-t does. The advantage to this is that a break point can be placed on showreqs, so that upon showing the stack, you jump immediately into the debugger. While sysrq-t does the same thing, sysrq-t shows *all* threads stacks. It also doesn't work right now. In the future, I thought it might be acceptable to make this show all pids stacks, but perhaps leaving well enough alone and just using sysrq-t would be okay. For now, upon receiving the stack command, UML switches context to that thread, dumps its registers, and then switches context back to the original thread. Since UML compacts all threads into one of 4 host threads, this sort of mechanism could be expanded in the future to include other debugging helpers that sysrq does not cover. Note by jdike - The main benefit to this is that it brings an arbitrary thread back into context, where it can be examined by gdb. The fact that it dumps it stack is secondary. This provides the capability to examine a sleeping thread, which has existed in tt mode, but not in skas mode until now. Also, the other threads, that sysrq doesn't cover, can be gdb-ed directly anyway. Signed-off-by: Allan Graves<allan.graves@gmail.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
155 lines
3.3 KiB
C
155 lines
3.3 KiB
C
/*
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* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#ifndef __UM_PROCESSOR_GENERIC_H
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#define __UM_PROCESSOR_GENERIC_H
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struct pt_regs;
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struct task_struct;
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#include "linux/config.h"
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#include "asm/ptrace.h"
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#include "choose-mode.h"
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struct mm_struct;
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struct thread_struct {
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/* This flag is set to 1 before calling do_fork (and analyzed in
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* copy_thread) to mark that we are begin called from userspace (fork /
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* vfork / clone), and reset to 0 after. It is left to 0 when called
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* from kernelspace (i.e. kernel_thread() or fork_idle(), as of 2.6.11). */
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struct task_struct *saved_task;
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int forking;
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int nsyscalls;
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struct pt_regs regs;
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int singlestep_syscall;
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void *fault_addr;
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void *fault_catcher;
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struct task_struct *prev_sched;
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unsigned long temp_stack;
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void *exec_buf;
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struct arch_thread arch;
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union {
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#ifdef CONFIG_MODE_TT
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struct {
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int extern_pid;
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int tracing;
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int switch_pipe[2];
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int vm_seq;
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} tt;
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#endif
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#ifdef CONFIG_MODE_SKAS
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struct {
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void *switch_buf;
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void *fork_buf;
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int mm_count;
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} skas;
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#endif
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} mode;
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struct {
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int op;
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union {
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struct {
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int pid;
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} fork, exec;
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struct {
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int (*proc)(void *);
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void *arg;
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} thread;
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struct {
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void (*proc)(void *);
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void *arg;
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} cb;
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} u;
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} request;
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};
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#define INIT_THREAD \
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{ \
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.forking = 0, \
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.nsyscalls = 0, \
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.regs = EMPTY_REGS, \
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.fault_addr = NULL, \
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.prev_sched = NULL, \
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.temp_stack = 0, \
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.exec_buf = NULL, \
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.arch = INIT_ARCH_THREAD, \
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.request = { 0 } \
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}
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typedef struct {
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unsigned long seg;
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} mm_segment_t;
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extern struct task_struct *alloc_task_struct(void);
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extern void release_thread(struct task_struct *);
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extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
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extern void dump_thread(struct pt_regs *regs, struct user *u);
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static inline void prepare_to_copy(struct task_struct *tsk)
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{
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}
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extern unsigned long thread_saved_pc(struct task_struct *t);
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static inline void mm_copy_segments(struct mm_struct *from_mm,
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struct mm_struct *new_mm)
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{
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}
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#define init_stack (init_thread_union.stack)
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/*
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* User space process size: 3GB (default).
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*/
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extern unsigned long task_size;
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#define TASK_SIZE (task_size)
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/* This decides where the kernel will search for a free chunk of vm
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* space during mmap's.
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*/
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#define TASK_UNMAPPED_BASE (0x40000000)
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extern void start_thread(struct pt_regs *regs, unsigned long entry,
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unsigned long stack);
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struct cpuinfo_um {
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unsigned long loops_per_jiffy;
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int ipi_pipe[2];
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};
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extern struct cpuinfo_um boot_cpu_data;
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#define my_cpu_data cpu_data[smp_processor_id()]
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#ifdef CONFIG_SMP
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extern struct cpuinfo_um cpu_data[];
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#define current_cpu_data cpu_data[smp_processor_id()]
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#else
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#define cpu_data (&boot_cpu_data)
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#define current_cpu_data boot_cpu_data
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#endif
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#define KSTK_EIP(tsk) (PT_REGS_IP(&tsk->thread.regs))
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#define KSTK_ESP(tsk) (PT_REGS_SP(&tsk->thread.regs))
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#define get_wchan(p) (0)
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#endif
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/*
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* Overrides for Emacs so that we follow Linus's tabbing style.
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* Emacs will notice this stuff at the end of the file and automatically
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* adjust the settings for this buffer only. This must remain at the end
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* of the file.
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* ---------------------------------------------------------------------------
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* Local variables:
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* c-file-style: "linux"
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* End:
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*/
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