[mirror_ubuntu-artful-kernel.git] / arch / x86 / include / asm / orc_lookup.h

/*
 * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */
#ifndef _ORC_LOOKUP_H
#define _ORC_LOOKUP_H

/*
 * This is a lookup table for speeding up access to the .orc_unwind table.
 * Given an input address offset, the corresponding lookup table entry
 * specifies a subset of the .orc_unwind table to search.
 *
 * Each block represents the end of the previous range and the start of the
 * next range.  An extra block is added to give the last range an end.
 *
 * The block size should be a power of 2 to avoid a costly 'div' instruction.
 *
 * A block size of 256 was chosen because it roughly doubles unwinder
 * performance while only adding ~5% to the ORC data footprint.
 */
#define LOOKUP_BLOCK_ORDER	8
#define LOOKUP_BLOCK_SIZE	(1 << LOOKUP_BLOCK_ORDER)

#ifndef LINKER_SCRIPT

extern unsigned int orc_lookup[];
extern unsigned int orc_lookup_end[];

#define LOOKUP_START_IP		(unsigned long)_stext
#define LOOKUP_STOP_IP		(unsigned long)_etext

#endif /* LINKER_SCRIPT */

#endif /* _ORC_LOOKUP_H */
Commit	Line	Data
dccbf63d JP	1	/*
	2	* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version 2
	7	* of the License, or (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	16	*/
	17	#ifndef _ORC_LOOKUP_H
	18	#define _ORC_LOOKUP_H
	19
	20	/*
	21	* This is a lookup table for speeding up access to the .orc_unwind table.
	22	* Given an input address offset, the corresponding lookup table entry
	23	* specifies a subset of the .orc_unwind table to search.
	24	*
	25	* Each block represents the end of the previous range and the start of the
	26	* next range. An extra block is added to give the last range an end.
	27	*
	28	* The block size should be a power of 2 to avoid a costly 'div' instruction.
	29	*
	30	* A block size of 256 was chosen because it roughly doubles unwinder
	31	* performance while only adding ~5% to the ORC data footprint.
	32	*/
	33	#define LOOKUP_BLOCK_ORDER 8
	34	#define LOOKUP_BLOCK_SIZE (1 << LOOKUP_BLOCK_ORDER)
	35
	36	#ifndef LINKER_SCRIPT
	37
	38	extern unsigned int orc_lookup[];
	39	extern unsigned int orc_lookup_end[];
	40
	41	#define LOOKUP_START_IP (unsigned long)_stext
	42	#define LOOKUP_STOP_IP (unsigned long)_etext
	43
	44	#endif /* LINKER_SCRIPT */
	45
	46	#endif /* _ORC_LOOKUP_H */