5141c46c61
Emulate single stepping in KGDB on MN10300 by way of temporary breakpoint insertion. These breakpoints are never actually seen by KGDB, and will overlay KGDB's own breakpoints. The breakpoints are removed by switch_to() and reinstalled on switching back so that if preemption occurs, the preempting task doesn't hit them (though it will still hit KGDB's regular breakpoints). If KGDB is reentered for any reason, then the single step breakpoint is completely erased and must be set again by the debugger. We take advantage of the fact that KGDB will effectively halt all other CPUs whilst this CPU is single-stepping to avoid SMP problems. If the single-stepping task is preempted and killed without KGDB being reinvoked, then the breakpoint(s) will be cleared and KGDB will be jumped back into. Signed-off-by: David Howells <dhowells@redhat.com>
183 lines
5.0 KiB
C
183 lines
5.0 KiB
C
/* MN10300 Low-level thread information
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#ifndef _ASM_THREAD_INFO_H
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#define _ASM_THREAD_INFO_H
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#ifdef __KERNEL__
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#include <asm/page.h>
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#define PREEMPT_ACTIVE 0x10000000
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#ifdef CONFIG_4KSTACKS
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#define THREAD_SIZE (4096)
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#else
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#define THREAD_SIZE (8192)
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#endif
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#define STACK_WARN (THREAD_SIZE / 8)
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/*
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* low level task data that entry.S needs immediate access to
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* - this struct should fit entirely inside of one cache line
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* - this struct shares the supervisor stack pages
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* - if the contents of this structure are changed, the assembly constants
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* must also be changed
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*/
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#ifndef __ASSEMBLY__
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typedef struct {
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unsigned long seg;
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} mm_segment_t;
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struct thread_info {
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struct task_struct *task; /* main task structure */
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struct exec_domain *exec_domain; /* execution domain */
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struct pt_regs *frame; /* current exception frame */
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unsigned long flags; /* low level flags */
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__u32 cpu; /* current CPU */
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__s32 preempt_count; /* 0 => preemptable, <0 => BUG */
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mm_segment_t addr_limit; /* thread address space:
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0-0xBFFFFFFF for user-thead
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0-0xFFFFFFFF for kernel-thread
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*/
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struct restart_block restart_block;
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__u8 supervisor_stack[0];
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};
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#define thread_info_to_uregs(ti) \
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((struct pt_regs *) \
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((unsigned long)ti + THREAD_SIZE - sizeof(struct pt_regs)))
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#else /* !__ASSEMBLY__ */
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#ifndef __ASM_OFFSETS_H__
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#include <asm/asm-offsets.h>
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#endif
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#endif
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/*
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* macros/functions for gaining access to the thread information structure
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*/
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#ifndef __ASSEMBLY__
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.task = &tsk, \
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.exec_domain = &default_exec_domain, \
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.flags = 0, \
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.cpu = 0, \
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.preempt_count = INIT_PREEMPT_COUNT, \
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.addr_limit = KERNEL_DS, \
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.restart_block = { \
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.fn = do_no_restart_syscall, \
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}, \
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}
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#define init_thread_info (init_thread_union.thread_info)
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#define init_stack (init_thread_union.stack)
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#define init_uregs \
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((struct pt_regs *) \
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((unsigned long) init_stack + THREAD_SIZE - sizeof(struct pt_regs)))
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extern struct thread_info *__current_ti;
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/* how to get the thread information struct from C */
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static inline __attribute__((const))
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struct thread_info *current_thread_info(void)
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{
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struct thread_info *ti;
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asm("mov sp,%0\n"
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"and %1,%0\n"
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: "=d" (ti)
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: "i" (~(THREAD_SIZE - 1))
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: "cc");
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return ti;
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}
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static inline __attribute__((const))
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struct pt_regs *current_frame(void)
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{
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return current_thread_info()->frame;
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}
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/* how to get the current stack pointer from C */
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static inline unsigned long current_stack_pointer(void)
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{
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unsigned long sp;
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asm("mov sp,%0; ":"=r" (sp));
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return sp;
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}
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#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
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/* thread information allocation */
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#ifdef CONFIG_DEBUG_STACK_USAGE
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#define alloc_thread_info(tsk) kzalloc(THREAD_SIZE, GFP_KERNEL)
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#else
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#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
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#endif
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#ifndef CONFIG_KGDB
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#define free_thread_info(ti) kfree((ti))
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#else
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extern void free_thread_info(struct thread_info *);
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#endif
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#define get_thread_info(ti) get_task_struct((ti)->task)
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#define put_thread_info(ti) put_task_struct((ti)->task)
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#else /* !__ASSEMBLY__ */
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#ifndef __VMLINUX_LDS__
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/* how to get the thread information struct from ASM */
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.macro GET_THREAD_INFO reg
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mov sp,\reg
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and -THREAD_SIZE,\reg
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.endm
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#endif
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#endif
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/*
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* thread information flags
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* - these are process state flags that various assembly files may need to
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* access
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* - pending work-to-be-done flags are in LSW
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* - other flags in MSW
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*/
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#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
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#define TIF_NOTIFY_RESUME 1 /* resumption notification requested */
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#define TIF_SIGPENDING 2 /* signal pending */
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#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
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#define TIF_SINGLESTEP 4 /* restore singlestep on return to user mode */
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#define TIF_RESTORE_SIGMASK 5 /* restore signal mask in do_signal() */
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#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
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#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
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#define TIF_FREEZE 18 /* freezing for suspend */
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#define _TIF_SYSCALL_TRACE +(1 << TIF_SYSCALL_TRACE)
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#define _TIF_NOTIFY_RESUME +(1 << TIF_NOTIFY_RESUME)
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#define _TIF_SIGPENDING +(1 << TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED +(1 << TIF_NEED_RESCHED)
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#define _TIF_SINGLESTEP +(1 << TIF_SINGLESTEP)
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#define _TIF_RESTORE_SIGMASK +(1 << TIF_RESTORE_SIGMASK)
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#define _TIF_POLLING_NRFLAG +(1 << TIF_POLLING_NRFLAG)
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#define _TIF_FREEZE +(1 << TIF_FREEZE)
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#define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
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#define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
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#endif /* __KERNEL__ */
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#endif /* _ASM_THREAD_INFO_H */
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