This class represents the return value from an emulated system call, including any errno setting. More...

#include <syscall_return.hh>

Public Member Functions
	SyscallReturn (int64_t v)
	For simplicity, allow the object to be initialized with a single signed integer using the same positive=success, negative=-errno convention described above. More...

	SyscallReturn ()
	A SyscallReturn constructed with no value means don't return anything. More...

	SyscallReturn (int64_t v1, int64_t v2)
	A SyscallReturn constructed with two values means put the second value in additional return registers as defined by the ABI, if they exist. More...

	~SyscallReturn ()

bool	successful () const
	Was the system call successful? More...

bool	needsRetry () const
	Does the syscall need to be retried? More...

bool	suppressed () const
	Should returning this value be suppressed? More...

int	count () const
	How many values did the syscall attempt to return? More...

int64_t	returnValue () const
	The return value. More...

int	errnoValue () const
	The errno value. More...

int64_t	encodedValue () const
	The encoded value (as described above) More...

int64_t	value2 () const

Static Public Member Functions
static SyscallReturn	retry ()
	Pseudo-constructor to create an instance with the retry flag set. More...

Private Attributes
int64_t	_value

int64_t	_value2

int	_count

bool	retryFlag = false

Detailed Description

This class represents the return value from an emulated system call, including any errno setting.

On some platforms, the return value and errno are encoded in a single signed integer. A value less than zero but greater than -4096 indicates an error, and the value is the negation of the errno value. Otherwise, the call was successful and the integer is the return value. (Large negative numbers are considered successful to allow syscalls to return pointers to high memory, e.g., stack addresses.) See, for example, Appendix A of the AMD64 ABI spec at http://www.x86-64.org/documentation/abi.pdf.

Other platforms use a more complex interface, returning a value and an error code in separate registers.

This class is designed to support both types of interfaces.

Definition at line 52 of file syscall_return.hh.

Constructor & Destructor Documentation

◆ SyscallReturn() [1/3]

SyscallReturn::SyscallReturn ( int64_t v )

inline

For simplicity, allow the object to be initialized with a single signed integer using the same positive=success, negative=-errno convention described above.

Typically this constructor is used as a default type conversion, so a bare integer is used where a SyscallReturn value is expected, e.g., as the return value from a system call emulation function ('return 0;' or 'return -EFAULT;').

Definition at line 64 of file syscall_return.hh.

◆ SyscallReturn() [2/3]

SyscallReturn::SyscallReturn ( )

inline

A SyscallReturn constructed with no value means don't return anything.

Definition at line 67 of file syscall_return.hh.

◆ SyscallReturn() [3/3]

SyscallReturn::SyscallReturn	(	int64_t	v1,
		int64_t	v2
	)

inline

A SyscallReturn constructed with two values means put the second value in additional return registers as defined by the ABI, if they exist.

Definition at line 71 of file syscall_return.hh.

◆ ~SyscallReturn()

SyscallReturn::~SyscallReturn ( )

inline

Definition at line 84 of file syscall_return.hh.

Member Function Documentation

◆ count()

int SyscallReturn::count ( ) const

inline

How many values did the syscall attempt to return?

Definition at line 100 of file syscall_return.hh.

References _count.

Referenced by GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmFreebsdProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmLinuxProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< MipsProcess::SyscallABI, SyscallReturn >::store(), and GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< SparcProcess::SyscallABI, ABI >::value >::type >::store().

◆ encodedValue()

int64_t SyscallReturn::encodedValue ( ) const

inline

The encoded value (as described above)

Definition at line 119 of file syscall_return.hh.

References _value.

Referenced by SyscallDesc::doSyscall(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmFreebsdProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmLinuxProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< PowerProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< RiscvProcess::SyscallABI, SyscallReturn >::store(), and GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< X86Linux::SyscallABI, ABI >::value >::type >::store().

◆ errnoValue()

int SyscallReturn::errnoValue ( ) const

inline

The errno value.

Definition at line 112 of file syscall_return.hh.

References _value, and successful().

Referenced by GuestABI::Result< MipsProcess::SyscallABI, SyscallReturn >::store(), and GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< SparcProcess::SyscallABI, ABI >::value >::type >::store().

◆ needsRetry()

bool SyscallReturn::needsRetry ( ) const

inline

Does the syscall need to be retried?

Definition at line 94 of file syscall_return.hh.

References retryFlag.

Referenced by SyscallDesc::doSyscall(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmFreebsdProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmLinuxProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< PowerProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< MipsProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< RiscvProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< X86Linux::SyscallABI, ABI >::value >::type >::store(), and GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< SparcProcess::SyscallABI, ABI >::value >::type >::store().

◆ retry()

static SyscallReturn SyscallReturn::retry ( )

inlinestatic

Pseudo-constructor to create an instance with the retry flag set.

Definition at line 77 of file syscall_return.hh.

References ArmISA::s.

Referenced by acceptFunc(), pollFunc(), readFunc(), selectFunc(), wait4Func(), and writeFunc().

◆ returnValue()

int64_t SyscallReturn::returnValue ( ) const

inline

The return value.

Definition at line 104 of file syscall_return.hh.

References _value, and successful().

Referenced by GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmFreebsdProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< MipsProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< RiscvProcess::SyscallABI, SyscallReturn >::store(), and GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< SparcProcess::SyscallABI, ABI >::value >::type >::store().

◆ successful()

bool SyscallReturn::successful ( ) const

inline

Was the system call successful?

Definition at line 88 of file syscall_return.hh.

References _value.

Referenced by errnoValue(), returnValue(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmFreebsdProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< MipsProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< PowerProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< RiscvProcess::SyscallABI, SyscallReturn >::store(), and GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< SparcProcess::SyscallABI, ABI >::value >::type >::store().

◆ suppressed()

bool SyscallReturn::suppressed ( ) const

inline

Should returning this value be suppressed?

Definition at line 97 of file syscall_return.hh.

References _count.

Referenced by SyscallDesc::doSyscall(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmFreebsdProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmLinuxProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< PowerProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< MipsProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< RiscvProcess::SyscallABI, SyscallReturn >::store(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< X86Linux::SyscallABI, ABI >::value >::type >::store(), and GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< SparcProcess::SyscallABI, ABI >::value >::type >::store().

◆ value2()

int64_t SyscallReturn::value2 ( ) const

inline

Definition at line 120 of file syscall_return.hh.

References _value2.

Referenced by GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmFreebsdProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< ArmLinuxProcessBits::SyscallABI, ABI >::value >::type >::store(), GuestABI::Result< MipsProcess::SyscallABI, SyscallReturn >::store(), and GuestABI::Result< ABI, SyscallReturn, typename std::enable_if< std::is_base_of< SparcProcess::SyscallABI, ABI >::value >::type >::store().

Member Data Documentation

◆ _count

int SyscallReturn::_count

private

Definition at line 124 of file syscall_return.hh.

Referenced by count(), and suppressed().

◆ _value

int64_t SyscallReturn::_value

private

Definition at line 123 of file syscall_return.hh.

Referenced by encodedValue(), errnoValue(), returnValue(), and successful().

◆ _value2

int64_t SyscallReturn::_value2

private

Definition at line 123 of file syscall_return.hh.

Referenced by value2().

◆ retryFlag

bool SyscallReturn::retryFlag = false

private

Definition at line 126 of file syscall_return.hh.

Referenced by needsRetry().

The documentation for this class was generated from the following file:

sim/syscall_return.hh

Public Member Functions

Static Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ SyscallReturn() [1/3]

◆ SyscallReturn() [2/3]

◆ SyscallReturn() [3/3]

◆ ~SyscallReturn()

Member Function Documentation

◆ count()

◆ encodedValue()

◆ errnoValue()

◆ needsRetry()

◆ retry()

◆ returnValue()

◆ successful()

◆ suppressed()

◆ value2()

Member Data Documentation

◆ _count

◆ _value

◆ _value2

◆ retryFlag