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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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f56141e3e2
If an attacker can cause a controlled kernel stack overflow, overwriting the restart block is a very juicy exploit target. This is because the restart_block is held in the same memory allocation as the kernel stack. Moving the restart block to struct task_struct prevents this exploit by making the restart_block harder to locate. Note that there are other fields in thread_info that are also easy targets, at least on some architectures. It's also a decent simplification, since the restart code is more or less identical on all architectures. [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: David Miller <davem@davemloft.net> Acked-by: Richard Weinberger <richard@nod.at> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Steven Miao <realmz6@gmail.com> Cc: Mark Salter <msalter@redhat.com> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
185 lines
5.6 KiB
C
185 lines
5.6 KiB
C
/*
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* arch/arm/include/asm/thread_info.h
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*
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* Copyright (C) 2002 Russell King.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __ASM_ARM_THREAD_INFO_H
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#define __ASM_ARM_THREAD_INFO_H
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#ifdef __KERNEL__
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#include <linux/compiler.h>
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#include <asm/fpstate.h>
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#include <asm/page.h>
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#define THREAD_SIZE_ORDER 1
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#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
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#define THREAD_START_SP (THREAD_SIZE - 8)
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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/types.h>
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#include <asm/domain.h>
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typedef unsigned long mm_segment_t;
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struct cpu_context_save {
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__u32 r4;
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__u32 r5;
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__u32 r6;
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__u32 r7;
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__u32 r8;
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__u32 r9;
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__u32 sl;
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__u32 fp;
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__u32 sp;
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__u32 pc;
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__u32 extra[2]; /* Xscale 'acc' register, etc */
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};
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/*
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* low level task data that entry.S needs immediate access to.
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* __switch_to() assumes cpu_context follows immediately after cpu_domain.
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*/
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struct thread_info {
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unsigned long flags; /* low level flags */
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int preempt_count; /* 0 => preemptable, <0 => bug */
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mm_segment_t addr_limit; /* address limit */
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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 cpu; /* cpu */
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__u32 cpu_domain; /* cpu domain */
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struct cpu_context_save cpu_context; /* cpu context */
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__u32 syscall; /* syscall number */
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__u8 used_cp[16]; /* thread used copro */
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unsigned long tp_value[2]; /* TLS registers */
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#ifdef CONFIG_CRUNCH
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struct crunch_state crunchstate;
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#endif
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union fp_state fpstate __attribute__((aligned(8)));
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union vfp_state vfpstate;
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#ifdef CONFIG_ARM_THUMBEE
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unsigned long thumbee_state; /* ThumbEE Handler Base register */
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#endif
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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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.preempt_count = INIT_PREEMPT_COUNT, \
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.addr_limit = KERNEL_DS, \
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.cpu_domain = domain_val(DOMAIN_USER, DOMAIN_MANAGER) | \
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domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \
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domain_val(DOMAIN_IO, DOMAIN_CLIENT), \
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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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/*
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* how to get the current stack pointer in C
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*/
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register unsigned long current_stack_pointer asm ("sp");
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/*
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* how to get the thread information struct from C
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*/
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static inline struct thread_info *current_thread_info(void) __attribute_const__;
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static inline struct thread_info *current_thread_info(void)
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{
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return (struct thread_info *)
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(current_stack_pointer & ~(THREAD_SIZE - 1));
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}
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#define thread_saved_pc(tsk) \
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((unsigned long)(task_thread_info(tsk)->cpu_context.pc))
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#define thread_saved_sp(tsk) \
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((unsigned long)(task_thread_info(tsk)->cpu_context.sp))
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#ifndef CONFIG_THUMB2_KERNEL
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#define thread_saved_fp(tsk) \
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((unsigned long)(task_thread_info(tsk)->cpu_context.fp))
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#else
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#define thread_saved_fp(tsk) \
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((unsigned long)(task_thread_info(tsk)->cpu_context.r7))
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#endif
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extern void crunch_task_disable(struct thread_info *);
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extern void crunch_task_copy(struct thread_info *, void *);
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extern void crunch_task_restore(struct thread_info *, void *);
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extern void crunch_task_release(struct thread_info *);
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extern void iwmmxt_task_disable(struct thread_info *);
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extern void iwmmxt_task_copy(struct thread_info *, void *);
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extern void iwmmxt_task_restore(struct thread_info *, void *);
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extern void iwmmxt_task_release(struct thread_info *);
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extern void iwmmxt_task_switch(struct thread_info *);
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extern void vfp_sync_hwstate(struct thread_info *);
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extern void vfp_flush_hwstate(struct thread_info *);
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struct user_vfp;
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struct user_vfp_exc;
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extern int vfp_preserve_user_clear_hwstate(struct user_vfp __user *,
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struct user_vfp_exc __user *);
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extern int vfp_restore_user_hwstate(struct user_vfp __user *,
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struct user_vfp_exc __user *);
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#endif
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/*
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* thread information flags:
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* TIF_SYSCALL_TRACE - syscall trace active
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* TIF_SYSCAL_AUDIT - syscall auditing active
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* TIF_SIGPENDING - signal pending
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* TIF_NEED_RESCHED - rescheduling necessary
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* TIF_NOTIFY_RESUME - callback before returning to user
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* TIF_USEDFPU - FPU was used by this task this quantum (SMP)
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* TIF_POLLING_NRFLAG - true if poll_idle() is polling TIF_NEED_RESCHED
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*/
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#define TIF_SIGPENDING 0
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#define TIF_NEED_RESCHED 1
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#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
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#define TIF_UPROBE 7
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#define TIF_SYSCALL_TRACE 8
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#define TIF_SYSCALL_AUDIT 9
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#define TIF_SYSCALL_TRACEPOINT 10
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#define TIF_SECCOMP 11 /* seccomp syscall filtering active */
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#define TIF_NOHZ 12 /* in adaptive nohz mode */
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#define TIF_USING_IWMMXT 17
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#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
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#define TIF_RESTORE_SIGMASK 20
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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_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
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#define _TIF_UPROBE (1 << TIF_UPROBE)
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#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
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#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
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#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
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#define _TIF_SECCOMP (1 << TIF_SECCOMP)
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#define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT)
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/* Checks for any syscall work in entry-common.S */
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#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
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_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
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/*
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* Change these and you break ASM code in entry-common.S
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*/
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#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
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_TIF_NOTIFY_RESUME | _TIF_UPROBE)
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#endif /* __KERNEL__ */
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#endif /* __ASM_ARM_THREAD_INFO_H */
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