1 /* 2 * Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se> 3 * 4 * (C) Copyright 2000 5 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 6 * 7 * SPDX-License-Identifier: GPL-2.0+ 8 */ 9 #include <common.h> 10 11 /* 12 * The exception table consists of pairs of addresses: the first is the 13 * address of an instruction that is allowed to fault, and the second is 14 * the address at which the program should continue. No registers are 15 * modified, so it is entirely up to the continuation code to figure out 16 * what to do. 17 * 18 * All the routines below use bits of fixup code that are out of line 19 * with the main instruction path. This means when everything is well, 20 * we don't even have to jump over them. Further, they do not intrude 21 * on our cache or tlb entries. 22 */ 23 24 DECLARE_GLOBAL_DATA_PTR; 25 26 struct exception_table_entry 27 { 28 unsigned long insn, fixup; 29 }; 30 31 extern const struct exception_table_entry __start___ex_table[]; 32 extern const struct exception_table_entry __stop___ex_table[]; 33 34 static inline unsigned long 35 search_one_table(const struct exception_table_entry *first, 36 const struct exception_table_entry *last, 37 unsigned long value) 38 { 39 long diff; 40 while (first <= last) { 41 diff = first->insn - value; 42 if (diff == 0) 43 return first->fixup; 44 first++; 45 } 46 47 return 0; 48 } 49 50 unsigned long 51 search_exception_table(unsigned long addr) 52 { 53 unsigned long ret; 54 55 /* There is only the kernel to search. */ 56 ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr); 57 /* if the serial port does not hang in exception, printf can be used */ 58 #if !defined(CONFIG_SYS_SERIAL_HANG_IN_EXCEPTION) 59 debug("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret); 60 #endif 61 if (ret) return ret; 62 63 return 0; 64 } 65