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f80c5b39b8
Standardize the idle polling indicator to TIF_POLLING_NRFLAG such that both TIF_NEED_RESCHED and TIF_POLLING_NRFLAG are in the same word. This will allow us, using fetch_or(), to both set NEED_RESCHED and check for POLLING_NRFLAG in a single operation and avoid pointless wakeups. Changing from the non-atomic thread_info::status flags to the atomic thread_info::flags shouldn't be a big issue since most polling state changes were followed/preceded by a full memory barrier anyway. Also, fix up the apm_32 idle function, clearly that was forgotten in the last conversion. The default idle state is !POLLING so just kill the lot. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <srostedt@redhat.com> Link: http://lkml.kernel.org/n/tip-7yksmqtlv4nfowmlqr1rifoi@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
242 lines
7.7 KiB
C
242 lines
7.7 KiB
C
/* thread_info.h: low-level thread information
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*
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* Copyright (C) 2002 David Howells (dhowells@redhat.com)
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* - Incorporating suggestions made by Linus Torvalds and Dave Miller
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*/
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#ifndef _ASM_X86_THREAD_INFO_H
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#define _ASM_X86_THREAD_INFO_H
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#include <linux/compiler.h>
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#include <asm/page.h>
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#include <asm/percpu.h>
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#include <asm/types.h>
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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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*/
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#ifndef __ASSEMBLY__
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struct task_struct;
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struct exec_domain;
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#include <asm/processor.h>
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#include <linux/atomic.h>
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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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__u32 flags; /* low level flags */
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__u32 status; /* thread synchronous flags */
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__u32 cpu; /* current CPU */
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int saved_preempt_count;
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mm_segment_t addr_limit;
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struct restart_block restart_block;
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void __user *sysenter_return;
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unsigned int sig_on_uaccess_error:1;
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unsigned int uaccess_err:1; /* uaccess failed */
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};
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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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.saved_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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#else /* !__ASSEMBLY__ */
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#include <asm/asm-offsets.h>
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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
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* 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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* Warning: layout of LSW is hardcoded in entry.S
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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 /* callback before returning to user */
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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 /* reenable singlestep on user return*/
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#define TIF_SYSCALL_EMU 6 /* syscall emulation active */
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#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
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#define TIF_SECCOMP 8 /* secure computing */
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#define TIF_MCE_NOTIFY 10 /* notify userspace of an MCE */
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#define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
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#define TIF_UPROBE 12 /* breakpointed or singlestepping */
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#define TIF_NOTSC 16 /* TSC is not accessible in userland */
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#define TIF_IA32 17 /* IA32 compatibility process */
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#define TIF_FORK 18 /* ret_from_fork */
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#define TIF_NOHZ 19 /* in adaptive nohz mode */
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#define TIF_MEMDIE 20 /* is terminating due to OOM killer */
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#define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */
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#define TIF_IO_BITMAP 22 /* uses I/O bitmap */
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#define TIF_FORCED_TF 24 /* true if TF in eflags artificially */
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#define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */
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#define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */
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#define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */
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#define TIF_ADDR32 29 /* 32-bit address space on 64 bits */
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#define TIF_X32 30 /* 32-bit native x86-64 binary */
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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_SINGLESTEP (1 << TIF_SINGLESTEP)
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#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
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#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
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#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
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#define _TIF_SECCOMP (1 << TIF_SECCOMP)
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#define _TIF_MCE_NOTIFY (1 << TIF_MCE_NOTIFY)
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#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
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#define _TIF_UPROBE (1 << TIF_UPROBE)
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#define _TIF_NOTSC (1 << TIF_NOTSC)
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#define _TIF_IA32 (1 << TIF_IA32)
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#define _TIF_FORK (1 << TIF_FORK)
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#define _TIF_NOHZ (1 << TIF_NOHZ)
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#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
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#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
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#define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
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#define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP)
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#define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES)
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#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
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#define _TIF_ADDR32 (1 << TIF_ADDR32)
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#define _TIF_X32 (1 << TIF_X32)
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/* work to do in syscall_trace_enter() */
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#define _TIF_WORK_SYSCALL_ENTRY \
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(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \
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_TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT | \
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_TIF_NOHZ)
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/* work to do in syscall_trace_leave() */
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#define _TIF_WORK_SYSCALL_EXIT \
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(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP | \
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_TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ)
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/* work to do on interrupt/exception return */
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#define _TIF_WORK_MASK \
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(0x0000FFFF & \
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~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT| \
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_TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU))
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/* work to do on any return to user space */
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#define _TIF_ALLWORK_MASK \
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((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \
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_TIF_NOHZ)
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/* Only used for 64 bit */
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#define _TIF_DO_NOTIFY_MASK \
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(_TIF_SIGPENDING | _TIF_MCE_NOTIFY | _TIF_NOTIFY_RESUME | \
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_TIF_USER_RETURN_NOTIFY)
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/* flags to check in __switch_to() */
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#define _TIF_WORK_CTXSW \
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(_TIF_IO_BITMAP|_TIF_NOTSC|_TIF_BLOCKSTEP)
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#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
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#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
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#define STACK_WARN (THREAD_SIZE/8)
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#define KERNEL_STACK_OFFSET (5*(BITS_PER_LONG/8))
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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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DECLARE_PER_CPU(unsigned long, kernel_stack);
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static inline struct thread_info *current_thread_info(void)
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{
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struct thread_info *ti;
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ti = (void *)(this_cpu_read_stable(kernel_stack) +
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KERNEL_STACK_OFFSET - THREAD_SIZE);
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return ti;
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}
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#else /* !__ASSEMBLY__ */
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/* how to get the thread information struct from ASM */
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#define GET_THREAD_INFO(reg) \
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_ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
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_ASM_SUB $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg ;
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/*
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* Same if PER_CPU_VAR(kernel_stack) is, perhaps with some offset, already in
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* a certain register (to be used in assembler memory operands).
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*/
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#define THREAD_INFO(reg, off) KERNEL_STACK_OFFSET+(off)-THREAD_SIZE(reg)
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#endif
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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_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/
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#define TS_RESTORE_SIGMASK 0x0008 /* restore signal mask in do_signal() */
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#ifndef __ASSEMBLY__
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#define HAVE_SET_RESTORE_SIGMASK 1
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static inline void set_restore_sigmask(void)
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{
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struct thread_info *ti = current_thread_info();
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ti->status |= TS_RESTORE_SIGMASK;
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WARN_ON(!test_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags));
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}
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static inline void clear_restore_sigmask(void)
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{
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current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
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}
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static inline bool test_restore_sigmask(void)
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{
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return current_thread_info()->status & TS_RESTORE_SIGMASK;
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}
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static inline bool test_and_clear_restore_sigmask(void)
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{
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struct thread_info *ti = current_thread_info();
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if (!(ti->status & TS_RESTORE_SIGMASK))
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return false;
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ti->status &= ~TS_RESTORE_SIGMASK;
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return true;
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}
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static inline bool is_ia32_task(void)
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{
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#ifdef CONFIG_X86_32
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return true;
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#endif
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#ifdef CONFIG_IA32_EMULATION
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if (current_thread_info()->status & TS_COMPAT)
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return true;
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#endif
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return false;
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}
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#endif /* !__ASSEMBLY__ */
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#ifndef __ASSEMBLY__
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extern void arch_task_cache_init(void);
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extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
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extern void arch_release_task_struct(struct task_struct *tsk);
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#endif
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#endif /* _ASM_X86_THREAD_INFO_H */
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