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freebsd/sys/ddb/db_variables.h
Robert Watson eddfbb763d Build on Jeff Roberson's linker-set based dynamic per-CPU allocator
(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator.  Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...).  This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.

Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack.  Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory.  Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.

Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy.  Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address.  When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.

This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.

Bump __FreeBSD_version and update UPDATING.

Portions submitted by:  bz
Reviewed by:            bz, zec
Discussed with:         gnn, jamie, jeff, jhb, julian, sam
Suggested by:           peter
Approved by:            re (kensmith)
2009-07-14 22:48:30 +00:00

64 lines
2.0 KiB
C

/*-
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $FreeBSD$
*/
/*
* Author: David B. Golub, Carnegie Mellon University
* Date: 7/90
*/
#ifndef _DDB_DB_VARIABLES_H_
#define _DDB_DB_VARIABLES_H_
/*
* Debugger variables.
*/
struct db_variable;
typedef int db_varfcn_t(struct db_variable *vp, db_expr_t *valuep, int op);
struct db_variable {
char *name; /* Name of variable */
db_expr_t *valuep; /* value of variable */
/* function to call when reading/writing */
db_varfcn_t *fcn;
#define DB_VAR_GET 0
#define DB_VAR_SET 1
};
#define FCN_NULL ((db_varfcn_t *)0)
extern struct db_variable db_regs[]; /* machine registers */
extern struct db_variable *db_eregs;
extern db_varfcn_t db_var_curcpu; /* DPCPU default CPU */
extern db_varfcn_t db_var_curvnet; /* Default vnet */
extern db_varfcn_t db_var_db_cpu; /* DPCPU active CPU */
extern db_varfcn_t db_var_db_vnet; /* Active vnet */
int db_read_variable(struct db_variable *, db_expr_t *);
int db_write_variable(struct db_variable *, db_expr_t);
#endif /* _!DDB_DB_VARIABLES_H_ */