[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / asm-generic / syscall.h

/*
 * Access to user system call parameters and results
 *
 * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License v.2.
 *
 * This file is a stub providing documentation for what functions
 * asm-ARCH/syscall.h files need to define.  Most arch definitions
 * will be simple inlines.
 *
 * All of these functions expect to be called with no locks,
 * and only when the caller is sure that the task of interest
 * cannot return to user mode while we are looking at it.
 */

#ifndef _ASM_SYSCALL_H
#define _ASM_SYSCALL_H	1

struct task_struct;
struct pt_regs;

/**
 * syscall_get_nr - find what system call a task is executing
 * @task:	task of interest, must be blocked
 * @regs:	task_pt_regs() of @task
 *
 * If @task is executing a system call or is at system call
 * tracing about to attempt one, returns the system call number.
 * If @task is not executing a system call, i.e. it's blocked
 * inside the kernel for a fault or signal, returns -1.
 *
 * Note this returns int even on 64-bit machines.  Only 32 bits of
 * system call number can be meaningful.  If the actual arch value
 * is 64 bits, this truncates to 32 bits so 0xffffffff means -1.
 *
 * It's only valid to call this when @task is known to be blocked.
 */
int syscall_get_nr(struct task_struct *task, struct pt_regs *regs);

/**
 * syscall_rollback - roll back registers after an aborted system call
 * @task:	task of interest, must be in system call exit tracing
 * @regs:	task_pt_regs() of @task
 *
 * It's only valid to call this when @task is stopped for system
 * call exit tracing (due to TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT),
 * after tracehook_report_syscall_entry() returned nonzero to prevent
 * the system call from taking place.
 *
 * This rolls back the register state in @regs so it's as if the
 * system call instruction was a no-op.  The registers containing
 * the system call number and arguments are as they were before the
 * system call instruction.  This may not be the same as what the
 * register state looked like at system call entry tracing.
 */
void syscall_rollback(struct task_struct *task, struct pt_regs *regs);

/**
 * syscall_get_error - check result of traced system call
 * @task:	task of interest, must be blocked
 * @regs:	task_pt_regs() of @task
 *
 * Returns 0 if the system call succeeded, or -ERRORCODE if it failed.
 *
 * It's only valid to call this when @task is stopped for tracing on exit
 * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
 */
long syscall_get_error(struct task_struct *task, struct pt_regs *regs);

/**
 * syscall_get_return_value - get the return value of a traced system call
 * @task:	task of interest, must be blocked
 * @regs:	task_pt_regs() of @task
 *
 * Returns the return value of the successful system call.
 * This value is meaningless if syscall_get_error() returned nonzero.
 *
 * It's only valid to call this when @task is stopped for tracing on exit
 * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
 */
long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs);

/**
 * syscall_set_return_value - change the return value of a traced system call
 * @task:	task of interest, must be blocked
 * @regs:	task_pt_regs() of @task
 * @error:	negative error code, or zero to indicate success
 * @val:	user return value if @error is zero
 *
 * This changes the results of the system call that user mode will see.
 * If @error is zero, the user sees a successful system call with a
 * return value of @val.  If @error is nonzero, it's a negated errno
 * code; the user sees a failed system call with this errno code.
 *
 * It's only valid to call this when @task is stopped for tracing on exit
 * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
 */
void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
			      int error, long val);

/**
 * syscall_get_arguments - extract system call parameter values
 * @task:	task of interest, must be blocked
 * @regs:	task_pt_regs() of @task
 * @i:		argument index [0,5]
 * @n:		number of arguments; n+i must be [1,6].
 * @args:	array filled with argument values
 *
 * Fetches @n arguments to the system call starting with the @i'th argument
 * (from 0 through 5).  Argument @i is stored in @args[0], and so on.
 * An arch inline version is probably optimal when @i and @n are constants.
 *
 * It's only valid to call this when @task is stopped for tracing on
 * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
 * It's invalid to call this with @i + @n > 6; we only support system calls
 * taking up to 6 arguments.
 */
void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
			   unsigned int i, unsigned int n, unsigned long *args);

/**
 * syscall_set_arguments - change system call parameter value
 * @task:	task of interest, must be in system call entry tracing
 * @regs:	task_pt_regs() of @task
 * @i:		argument index [0,5]
 * @n:		number of arguments; n+i must be [1,6].
 * @args:	array of argument values to store
 *
 * Changes @n arguments to the system call starting with the @i'th argument.
 * Argument @i gets value @args[0], and so on.
 * An arch inline version is probably optimal when @i and @n are constants.
 *
 * It's only valid to call this when @task is stopped for tracing on
 * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
 * It's invalid to call this with @i + @n > 6; we only support system calls
 * taking up to 6 arguments.
 */
void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
			   unsigned int i, unsigned int n,
			   const unsigned long *args);

/**
 * syscall_get_arch - return the AUDIT_ARCH for the current system call
 *
 * Returns the AUDIT_ARCH_* based on the system call convention in use.
 *
 * It's only valid to call this when @task is stopped on entry to a system
 * call, due to %TIF_SYSCALL_TRACE, %TIF_SYSCALL_AUDIT, or %TIF_SECCOMP.
 *
 * Architectures which permit CONFIG_HAVE_ARCH_SECCOMP_FILTER must
 * provide an implementation of this.
 */
int syscall_get_arch(void);
#endif	/* _ASM_SYSCALL_H */
Commit	Line	Data
828c365c RM	1	/*
	2	* Access to user system call parameters and results
	3	*
268e4671	4	* Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
828c365c RM	5	*
	6	* This copyrighted material is made available to anyone wishing to use,
	7	* modify, copy, or redistribute it subject to the terms and conditions
	8	* of the GNU General Public License v.2.
	9	*
	10	* This file is a stub providing documentation for what functions
	11	* asm-ARCH/syscall.h files need to define. Most arch definitions
	12	* will be simple inlines.
	13	*
	14	* All of these functions expect to be called with no locks,
	15	* and only when the caller is sure that the task of interest
	16	* cannot return to user mode while we are looking at it.
	17	*/
	18
	19	#ifndef _ASM_SYSCALL_H
	20	#define _ASM_SYSCALL_H 1
	21
	22	struct task_struct;
	23	struct pt_regs;
	24
	25	/**
	26	* syscall_get_nr - find what system call a task is executing
	27	* @task: task of interest, must be blocked
	28	* @regs: task_pt_regs() of @task
	29	*
	30	* If @task is executing a system call or is at system call
	31	* tracing about to attempt one, returns the system call number.
	32	* If @task is not executing a system call, i.e. it's blocked
	33	* inside the kernel for a fault or signal, returns -1.
	34	*
268e4671 RM	35	* Note this returns int even on 64-bit machines. Only 32 bits of
	36	* system call number can be meaningful. If the actual arch value
	37	* is 64 bits, this truncates to 32 bits so 0xffffffff means -1.
	38	*
828c365c RM	39	* It's only valid to call this when @task is known to be blocked.
828c365c RM	40	*/
268e4671	41	int syscall_get_nr(struct task_struct task, struct pt_regs regs);
828c365c RM	42
	43	/**
	44	* syscall_rollback - roll back registers after an aborted system call
	45	* @task: task of interest, must be in system call exit tracing
	46	* @regs: task_pt_regs() of @task
	47	*
	48	* It's only valid to call this when @task is stopped for system
	49	* call exit tracing (due to TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT),
	50	* after tracehook_report_syscall_entry() returned nonzero to prevent
	51	* the system call from taking place.
	52	*
	53	* This rolls back the register state in @regs so it's as if the
	54	* system call instruction was a no-op. The registers containing
	55	* the system call number and arguments are as they were before the
	56	* system call instruction. This may not be the same as what the
	57	* register state looked like at system call entry tracing.
	58	*/
	59	void syscall_rollback(struct task_struct task, struct pt_regs regs);
	60
	61	/**
	62	* syscall_get_error - check result of traced system call
	63	* @task: task of interest, must be blocked
	64	* @regs: task_pt_regs() of @task
	65	*
	66	* Returns 0 if the system call succeeded, or -ERRORCODE if it failed.
	67	*
	68	* It's only valid to call this when @task is stopped for tracing on exit
	69	* from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
	70	*/
	71	long syscall_get_error(struct task_struct task, struct pt_regs regs);
	72
	73	/**
	74	* syscall_get_return_value - get the return value of a traced system call
	75	* @task: task of interest, must be blocked
	76	* @regs: task_pt_regs() of @task
	77	*
	78	* Returns the return value of the successful system call.
	79	* This value is meaningless if syscall_get_error() returned nonzero.
	80	*
	81	* It's only valid to call this when @task is stopped for tracing on exit
	82	* from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
	83	*/
	84	long syscall_get_return_value(struct task_struct task, struct pt_regs regs);
	85
	86	/**
	87	* syscall_set_return_value - change the return value of a traced system call
	88	* @task: task of interest, must be blocked
	89	* @regs: task_pt_regs() of @task
	90	* @error: negative error code, or zero to indicate success
	91	* @val: user return value if @error is zero
	92	*
	93	* This changes the results of the system call that user mode will see.
	94	* If @error is zero, the user sees a successful system call with a
	95	* return value of @val. If @error is nonzero, it's a negated errno
	96	* code; the user sees a failed system call with this errno code.
	97	*
	98	* It's only valid to call this when @task is stopped for tracing on exit
	99	* from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
	100	*/
	101	void syscall_set_return_value(struct task_struct task, struct pt_regs regs,
	102	int error, long val);
	103
	104	/**
	105	* syscall_get_arguments - extract system call parameter values
106	* @task: task of interest, must be blocked
107	* @regs: task_pt_regs() of @task
108	* @i: argument index [0,5]
109	* @n: number of arguments; n+i must be [1,6].
110	* @args: array filled with argument values
111	*
112	* Fetches @n arguments to the system call starting with the @i'th argument
113	* (from 0 through 5). Argument @i is stored in @args[0], and so on.
114	* An arch inline version is probably optimal when @i and @n are constants.
115	*
116	* It's only valid to call this when @task is stopped for tracing on
117	* entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
118	* It's invalid to call this with @i + @n > 6; we only support system calls
119	* taking up to 6 arguments.
120	*/
121	void syscall_get_arguments(struct task_struct task, struct pt_regs regs,
122	unsigned int i, unsigned int n, unsigned long *args);
123
124	/**
125	* syscall_set_arguments - change system call parameter value
126	* @task: task of interest, must be in system call entry tracing
127	* @regs: task_pt_regs() of @task
128	* @i: argument index [0,5]
129	* @n: number of arguments; n+i must be [1,6].
130	* @args: array of argument values to store
131	*
132	* Changes @n arguments to the system call starting with the @i'th argument.
22f30168	133	* Argument @i gets value @args[0], and so on.
828c365c RM	134	* An arch inline version is probably optimal when @i and @n are constants.
	135	*
	136	* It's only valid to call this when @task is stopped for tracing on
	137	* entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
	138	* It's invalid to call this with @i + @n > 6; we only support system calls
	139	* taking up to 6 arguments.
	140	*/
	141	void syscall_set_arguments(struct task_struct task, struct pt_regs regs,
	142	unsigned int i, unsigned int n,
	143	const unsigned long *args);
	144
07bd18d0 WD	145	/**
07bd18d0 WD	146	* syscall_get_arch - return the AUDIT_ARCH for the current system call
07bd18d0 WD	147	*
	148	* Returns the AUDIT_ARCH_* based on the system call convention in use.
	149	*
	150	* It's only valid to call this when @task is stopped on entry to a system
	151	* call, due to %TIF_SYSCALL_TRACE, %TIF_SYSCALL_AUDIT, or %TIF_SECCOMP.
	152	*
	153	* Architectures which permit CONFIG_HAVE_ARCH_SECCOMP_FILTER must
	154	* provide an implementation of this.
	155	*/
6fa3eb70	156	int syscall_get_arch(void);
828c365c	157	#endif /* _ASM_SYSCALL_H */