dcd497f99a
The preempt_count member of struct thread_info is currently either defined as int, unsigned int or __s32 depending on arch. This patch makes the type of preempt_count an int on all archs. Having preempt_count be an unsigned type prevents the catching of preempt_count < 0 bugs, and using int on some archs and __s32 on others is not exactely "neat" - much nicer when it's just int all over. A previous version of this patch was already ACK'ed by Robert Love, and the only change in this version of the patch compared to the one he ACK'ed is that this one also makes sure the preempt_count member is consistently commented. Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
159 lines
4.6 KiB
C
159 lines
4.6 KiB
C
/* thread_info.h: description
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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* Derived from include/asm-i386/thread_info.h
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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 License
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* as published by the Free Software Foundation; either version
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* 2 of the License, 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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#ifndef __ASSEMBLY__
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#include <asm/processor.h>
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#endif
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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 must also be changed
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*/
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#ifndef __ASSEMBLY__
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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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unsigned long flags; /* low level flags */
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unsigned long status; /* thread-synchronous flags */
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__u32 cpu; /* current CPU */
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int 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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#else /* !__ASSEMBLY__ */
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/* offsets into the thread_info struct for assembly code access */
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#define TI_TASK 0x00000000
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#define TI_EXEC_DOMAIN 0x00000004
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#define TI_FLAGS 0x00000008
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#define TI_STATUS 0x0000000C
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#define TI_CPU 0x00000010
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#define TI_PRE_COUNT 0x00000014
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#define TI_ADDR_LIMIT 0x00000018
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#define TI_RESTART_BLOCK 0x0000001C
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#endif
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#define PREEMPT_ACTIVE 0x4000000
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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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* preempt_count needs to be 1 initially, until the scheduler is functional.
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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 = 1, \
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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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#ifdef CONFIG_SMALL_TASKS
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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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/* how to get the thread information struct from C */
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register struct thread_info *__current_thread_info asm("gr15");
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#define current_thread_info() ({ __current_thread_info; })
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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) \
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({ \
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struct thread_info *ret; \
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\
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ret = kmalloc(THREAD_SIZE, GFP_KERNEL); \
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if (ret) \
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memset(ret, 0, THREAD_SIZE); \
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ret; \
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})
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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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#define free_thread_info(info) kfree(info)
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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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#define THREAD_SIZE 8192
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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 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_IRET 5 /* return with iret */
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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 /* OOM killer killed process */
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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_IRET (1 << TIF_IRET)
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#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
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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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/*
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* Thread-synchronous status.
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*
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* This is different from the flags in that nobody else
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* ever touches our thread-synchronous status, so we don't
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* have to worry about atomic accesses.
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*/
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#define TS_USEDFPM 0x0001 /* FPU/Media was used by this task this quantum (SMP) */
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#endif /* __KERNEL__ */
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#endif /* _ASM_THREAD_INFO_H */
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