1// SPDX-License-Identifier: GPL-2.0 2 3#include <linux/bitfield.h> 4#include <linux/extable.h> 5#include <linux/string.h> 6#include <linux/errno.h> 7#include <linux/panic.h> 8#include <asm/asm-extable.h> 9#include <asm/extable.h> 10 11const struct exception_table_entry *s390_search_extables(unsigned long addr) 12{ 13 const struct exception_table_entry *fixup; 14 size_t num; 15 16 fixup = search_exception_tables(addr); 17 if (fixup) 18 return fixup; 19 num = __stop_amode31_ex_table - __start_amode31_ex_table; 20 return search_extable(__start_amode31_ex_table, num, addr); 21} 22 23static bool ex_handler_fixup(const struct exception_table_entry *ex, struct pt_regs *regs) 24{ 25 regs->psw.addr = extable_fixup(ex); 26 return true; 27} 28 29static bool ex_handler_ua_store(const struct exception_table_entry *ex, struct pt_regs *regs) 30{ 31 unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data); 32 33 regs->gprs[reg_err] = -EFAULT; 34 regs->psw.addr = extable_fixup(ex); 35 return true; 36} 37 38static bool ex_handler_ua_load_mem(const struct exception_table_entry *ex, struct pt_regs *regs) 39{ 40 unsigned int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data); 41 unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data); 42 size_t len = FIELD_GET(EX_DATA_LEN, ex->data); 43 44 regs->gprs[reg_err] = -EFAULT; 45 memset((void *)regs->gprs[reg_addr], 0, len); 46 regs->psw.addr = extable_fixup(ex); 47 return true; 48} 49 50static bool ex_handler_ua_load_reg(const struct exception_table_entry *ex, 51 bool pair, struct pt_regs *regs) 52{ 53 unsigned int reg_zero = FIELD_GET(EX_DATA_REG_ADDR, ex->data); 54 unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data); 55 56 regs->gprs[reg_err] = -EFAULT; 57 regs->gprs[reg_zero] = 0; 58 if (pair) 59 regs->gprs[reg_zero + 1] = 0; 60 regs->psw.addr = extable_fixup(ex); 61 return true; 62} 63 64bool fixup_exception(struct pt_regs *regs) 65{ 66 const struct exception_table_entry *ex; 67 68 ex = s390_search_extables(instruction_pointer(regs)); 69 if (!ex) 70 return false; 71 switch (ex->type) { 72 case EX_TYPE_FIXUP: 73 return ex_handler_fixup(ex, regs); 74 case EX_TYPE_BPF: 75 return ex_handler_bpf(ex, regs); 76 case EX_TYPE_UA_STORE: 77 return ex_handler_ua_store(ex, regs); 78 case EX_TYPE_UA_LOAD_MEM: 79 return ex_handler_ua_load_mem(ex, regs); 80 case EX_TYPE_UA_LOAD_REG: 81 return ex_handler_ua_load_reg(ex, false, regs); 82 case EX_TYPE_UA_LOAD_REGPAIR: 83 return ex_handler_ua_load_reg(ex, true, regs); 84 } 85 panic("invalid exception table entry"); 86} 87