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	On architectures using the generic syscall entry code the architecture independent syscall work is moved to flags in thread_info::syscall_work. This removes architecture dependencies and frees up TIF bits. Define SYSCALL_WORK_SYSCALL_AUDIT, use it in the generic entry code and convert the code which uses the TIF specific helper functions to use the new *_syscall_work() helpers which either resolve to the new mode for users of the generic entry code or to the TIF based functions for the other architectures. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20201116174206.2639648-9-krisman@collabora.com
		
			
				
	
	
		
			150 lines
		
	
	
	
		
			5.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			150 lines
		
	
	
	
		
			5.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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 * Access to user system call parameters and results
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 *
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 * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
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 *
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 * This file is a stub providing documentation for what functions
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 * asm-ARCH/syscall.h files need to define.  Most arch definitions
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 * will be simple inlines.
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 *
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 * All of these functions expect to be called with no locks,
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 * and only when the caller is sure that the task of interest
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 * cannot return to user mode while we are looking at it.
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 */
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#ifndef _ASM_SYSCALL_H
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#define _ASM_SYSCALL_H	1
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struct task_struct;
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struct pt_regs;
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/**
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 * syscall_get_nr - find what system call a task is executing
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 * @task:	task of interest, must be blocked
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 * @regs:	task_pt_regs() of @task
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 *
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 * If @task is executing a system call or is at system call
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 * tracing about to attempt one, returns the system call number.
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 * If @task is not executing a system call, i.e. it's blocked
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 * inside the kernel for a fault or signal, returns -1.
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 *
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 * Note this returns int even on 64-bit machines.  Only 32 bits of
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 * system call number can be meaningful.  If the actual arch value
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 * is 64 bits, this truncates to 32 bits so 0xffffffff means -1.
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 *
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 * It's only valid to call this when @task is known to be blocked.
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 */
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int syscall_get_nr(struct task_struct *task, struct pt_regs *regs);
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/**
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 * syscall_rollback - roll back registers after an aborted system call
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 * @task:	task of interest, must be in system call exit tracing
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 * @regs:	task_pt_regs() of @task
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 *
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 * It's only valid to call this when @task is stopped for system
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 * call exit tracing (due to %SYSCALL_WORK_SYSCALL_TRACE or
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 * %SYSCALL_WORK_SYSCALL_AUDIT), after tracehook_report_syscall_entry()
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 * returned nonzero to prevent the system call from taking place.
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 *
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 * This rolls back the register state in @regs so it's as if the
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 * system call instruction was a no-op.  The registers containing
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 * the system call number and arguments are as they were before the
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 * system call instruction.  This may not be the same as what the
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 * register state looked like at system call entry tracing.
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 */
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void syscall_rollback(struct task_struct *task, struct pt_regs *regs);
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/**
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 * syscall_get_error - check result of traced system call
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 * @task:	task of interest, must be blocked
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 * @regs:	task_pt_regs() of @task
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 *
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 * Returns 0 if the system call succeeded, or -ERRORCODE if it failed.
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 *
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 * It's only valid to call this when @task is stopped for tracing on exit
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 * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
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 * %SYSCALL_WORK_SYSCALL_AUDIT.
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 */
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long syscall_get_error(struct task_struct *task, struct pt_regs *regs);
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/**
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 * syscall_get_return_value - get the return value of a traced system call
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 * @task:	task of interest, must be blocked
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 * @regs:	task_pt_regs() of @task
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 *
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 * Returns the return value of the successful system call.
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 * This value is meaningless if syscall_get_error() returned nonzero.
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 *
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 * It's only valid to call this when @task is stopped for tracing on exit
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 * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
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 * %SYSCALL_WORK_SYSCALL_AUDIT.
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 */
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long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs);
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/**
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 * syscall_set_return_value - change the return value of a traced system call
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 * @task:	task of interest, must be blocked
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 * @regs:	task_pt_regs() of @task
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 * @error:	negative error code, or zero to indicate success
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 * @val:	user return value if @error is zero
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 *
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 * This changes the results of the system call that user mode will see.
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 * If @error is zero, the user sees a successful system call with a
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 * return value of @val.  If @error is nonzero, it's a negated errno
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 * code; the user sees a failed system call with this errno code.
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 *
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 * It's only valid to call this when @task is stopped for tracing on exit
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 * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
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 * %SYSCALL_WORK_SYSCALL_AUDIT.
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 */
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void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
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			      int error, long val);
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/**
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 * syscall_get_arguments - extract system call parameter values
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 * @task:	task of interest, must be blocked
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 * @regs:	task_pt_regs() of @task
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 * @args:	array filled with argument values
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 *
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 * Fetches 6 arguments to the system call.  First argument is stored in
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*  @args[0], and so on.
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 *
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 * It's only valid to call this when @task is stopped for tracing on
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 * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
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 * %SYSCALL_WORK_SYSCALL_AUDIT.
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 */
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void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
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			   unsigned long *args);
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/**
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 * syscall_set_arguments - change system call parameter value
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 * @task:	task of interest, must be in system call entry tracing
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 * @regs:	task_pt_regs() of @task
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 * @args:	array of argument values to store
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 *
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 * Changes 6 arguments to the system call.
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 * The first argument gets value @args[0], and so on.
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 *
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 * It's only valid to call this when @task is stopped for tracing on
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 * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
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 * %SYSCALL_WORK_SYSCALL_AUDIT.
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 */
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void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
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			   const unsigned long *args);
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/**
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 * syscall_get_arch - return the AUDIT_ARCH for the current system call
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 * @task:	task of interest, must be blocked
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 *
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 * Returns the AUDIT_ARCH_* based on the system call convention in use.
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 *
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 * It's only valid to call this when @task is stopped on entry to a system
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 * call, due to %SYSCALL_WORK_SYSCALL_TRACE, %SYSCALL_WORK_SYSCALL_AUDIT, or
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 * %SYSCALL_WORK_SECCOMP.
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 *
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 * Architectures which permit CONFIG_HAVE_ARCH_SECCOMP_FILTER must
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 * provide an implementation of this.
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 */
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int syscall_get_arch(struct task_struct *task);
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#endif	/* _ASM_SYSCALL_H */
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