1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0-or-later */ 2*4882a593Smuzhiyun /* 3*4882a593Smuzhiyun * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com> 4*4882a593Smuzhiyun */ 5*4882a593Smuzhiyun #ifndef _ORC_LOOKUP_H 6*4882a593Smuzhiyun #define _ORC_LOOKUP_H 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun /* 9*4882a593Smuzhiyun * This is a lookup table for speeding up access to the .orc_unwind table. 10*4882a593Smuzhiyun * Given an input address offset, the corresponding lookup table entry 11*4882a593Smuzhiyun * specifies a subset of the .orc_unwind table to search. 12*4882a593Smuzhiyun * 13*4882a593Smuzhiyun * Each block represents the end of the previous range and the start of the 14*4882a593Smuzhiyun * next range. An extra block is added to give the last range an end. 15*4882a593Smuzhiyun * 16*4882a593Smuzhiyun * The block size should be a power of 2 to avoid a costly 'div' instruction. 17*4882a593Smuzhiyun * 18*4882a593Smuzhiyun * A block size of 256 was chosen because it roughly doubles unwinder 19*4882a593Smuzhiyun * performance while only adding ~5% to the ORC data footprint. 20*4882a593Smuzhiyun */ 21*4882a593Smuzhiyun #define LOOKUP_BLOCK_ORDER 8 22*4882a593Smuzhiyun #define LOOKUP_BLOCK_SIZE (1 << LOOKUP_BLOCK_ORDER) 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun #ifndef LINKER_SCRIPT 25*4882a593Smuzhiyun 26*4882a593Smuzhiyun extern unsigned int orc_lookup[]; 27*4882a593Smuzhiyun extern unsigned int orc_lookup_end[]; 28*4882a593Smuzhiyun 29*4882a593Smuzhiyun #define LOOKUP_START_IP (unsigned long)_stext 30*4882a593Smuzhiyun #define LOOKUP_STOP_IP (unsigned long)_etext 31*4882a593Smuzhiyun 32*4882a593Smuzhiyun #endif /* LINKER_SCRIPT */ 33*4882a593Smuzhiyun 34*4882a593Smuzhiyun #endif /* _ORC_LOOKUP_H */ 35