L4::Pager Class Reference

Pager interface including the Io_pager interface. More...

#include <pager>

Inheritance diagram for L4::Pager:

Collaboration diagram for L4::Pager:

Public Member Functions
l4_msgtag_t	page_fault (l4_umword_t pfa, l4_umword_t pc, L4::Ipc::Rcv_fpage rwin, L4::Ipc::Opt< L4::Ipc::Snd_fpage & > fp)
	Page-fault protocol message.
Public Member Functions inherited from L4::Io_pager
l4_msgtag_t	io_page_fault (l4_fpage_t io_pfa, l4_umword_t pc, L4::Ipc::Rcv_fpage rwin, L4::Ipc::Opt< L4::Ipc::Snd_fpage & > fp)
	IO page fault protocol message.

Additional Inherited Members
Protected Types inherited from L4::Kobject_t< Pager, Io_pager, L4_PROTO_PAGE_FAULT >
typedef Pager	Class
	The target interface type (inheriting from Kobject_t)
typedef Typeid::Iface< PROTO, Pager >	__Iface
	The interface description for the derived class.
typedef Typeid::Merge_list< Typeid::Iface_list< __Iface >, typename Base::__Iface_list >	__Iface_list
	The list of all RPC interfaces provided directly or through inheritance.
Protected Member Functions inherited from L4::Kobject_t< Pager, Io_pager, L4_PROTO_PAGE_FAULT >
L4::Cap< Class >	c () const noexcept
	Get the capability to ourselves.
Static Protected Member Functions inherited from L4::Kobject_t< Pager, Io_pager, L4_PROTO_PAGE_FAULT >
static void	__check_protocols__ () noexcept
	Helper to check for protocol conflicts.

Detailed Description

Pager interface including the Io_pager interface.

This class defines the interface for handling page fault IPC. If a thread causes a page fault, the microkernel synthesises a page fault IPC message and sends it to the thread's page fault handler (pager). The pager can then handle the message, for example by establishing a suitable page mapping.

The page fault handler is set with the L4::Thread::control interface.

Definition at line 98 of file pager.

Member Function Documentation

page_fault()

l4_msgtag_t L4::Pager::page_fault	(	l4_umword_t	pfa,
		l4_umword_t	pc,
		L4::Ipc::Rcv_fpage	rwin,
		L4::Ipc::Opt< L4::Ipc::Snd_fpage & >	fp
	)

Page-fault protocol message.

Parameters

	pfa	Faulting address including failure reason: bits [0:2].
	pc	Faulting program counter.
	rwin	Receive window for a flex-page mapping resolving the page fault.
[out]	fp	Optional: flex-page descriptor to send to the task raising the page fault.

Returns

System call message tag; use l4_error() to check for errors.

Page-fault messages are usually generated by the kernel and need to be handled by an appropriate handler function, potentially filling in fp for the reply.

pfa encoding is as shown:

[63/31 .. 3]	2	1	0
PFA	X	W	r

• PFA Bits 63/31..3 of pfa are the page fault address bits 63/31 to 3, bits 2..0 are masked.
• X Bit 2 of pfa if set, indicates a page fault during instruction fetch. Note, this bit is implementation-defined and might always be clear. Therefore, if this bit is clear it does not imply that the page fault is not due to an instruction fetch.
• W Bit 1 of pfa is set to 1 for a page fault due to a write operation.
• r Bit0: reserved, undefined.

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

• l4/sys/pager