Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 | /* * linux/arch/nios2/kernel/misaligned.c * * basic emulation for mis-aligned accesses on the NIOS II cpu * modelled after the version for arm in arm/alignment.c * * Brad Parker <brad@heeltoe.com> * Copyright (C) 2010 Ambient Corporation * Copyright (c) 2010 Altera Corporation, San Jose, California, USA. * Copyright (c) 2010 Arrow Electronics, Inc. * * This file is subject to the terms and conditions of the GNU General * Public License. See the file COPYING in the main directory of * this archive for more details. */ #include <linux/errno.h> #include <linux/string.h> #include <linux/proc_fs.h> #include <linux/init.h> #include <linux/sched.h> #include <linux/uaccess.h> #include <linux/seq_file.h> #include <asm/traps.h> #include <asm/unaligned.h> /* instructions we emulate */ #define INST_LDHU 0x0b #define INST_STH 0x0d #define INST_LDH 0x0f #define INST_STW 0x15 #define INST_LDW 0x17 static unsigned int ma_usermode; #define UM_WARN 0x01 #define UM_FIXUP 0x02 #define UM_SIGNAL 0x04 #define KM_WARN 0x08 /* see arch/nios2/include/asm/ptrace.h */ static u8 sys_stack_frame_reg_offset[] = { /* struct pt_regs */ 8, 9, 10, 11, 12, 13, 14, 15, 1, 2, 3, 4, 5, 6, 7, 0, /* struct switch_stack */ 16, 17, 18, 19, 20, 21, 22, 23, 0, 0, 0, 0, 0, 0, 0, 0 }; static int reg_offsets[32]; static inline u32 get_reg_val(struct pt_regs *fp, int reg) { u8 *p = ((u8 *)fp) + reg_offsets[reg]; return *(u32 *)p; } static inline void put_reg_val(struct pt_regs *fp, int reg, u32 val) { u8 *p = ((u8 *)fp) + reg_offsets[reg]; *(u32 *)p = val; } /* * (mis)alignment handler */ asmlinkage void handle_unaligned_c(struct pt_regs *fp, int cause) { u32 isn, addr, val; int in_kernel; u8 a, b, d0, d1, d2, d3; s16 imm16; unsigned int fault; /* back up one instruction */ fp->ea -= 4; if (fixup_exception(fp)) { return; } in_kernel = !user_mode(fp); isn = *(unsigned long *)(fp->ea); fault = 0; /* do fixup if in kernel or mode turned on */ if (in_kernel || (ma_usermode & UM_FIXUP)) { /* decompose instruction */ a = (isn >> 27) & 0x1f; b = (isn >> 22) & 0x1f; imm16 = (isn >> 6) & 0xffff; addr = get_reg_val(fp, a) + imm16; /* do fixup to saved registers */ switch (isn & 0x3f) { case INST_LDHU: fault |= __get_user(d0, (u8 *)(addr+0)); fault |= __get_user(d1, (u8 *)(addr+1)); val = (d1 << 8) | d0; put_reg_val(fp, b, val); break; case INST_STH: val = get_reg_val(fp, b); d1 = val >> 8; d0 = val >> 0; if (in_kernel) { *(u8 *)(addr+0) = d0; *(u8 *)(addr+1) = d1; } else { fault |= __put_user(d0, (u8 *)(addr+0)); fault |= __put_user(d1, (u8 *)(addr+1)); } break; case INST_LDH: fault |= __get_user(d0, (u8 *)(addr+0)); fault |= __get_user(d1, (u8 *)(addr+1)); val = (short)((d1 << 8) | d0); put_reg_val(fp, b, val); break; case INST_STW: val = get_reg_val(fp, b); d3 = val >> 24; d2 = val >> 16; d1 = val >> 8; d0 = val >> 0; if (in_kernel) { *(u8 *)(addr+0) = d0; *(u8 *)(addr+1) = d1; *(u8 *)(addr+2) = d2; *(u8 *)(addr+3) = d3; } else { fault |= __put_user(d0, (u8 *)(addr+0)); fault |= __put_user(d1, (u8 *)(addr+1)); fault |= __put_user(d2, (u8 *)(addr+2)); fault |= __put_user(d3, (u8 *)(addr+3)); } break; case INST_LDW: fault |= __get_user(d0, (u8 *)(addr+0)); fault |= __get_user(d1, (u8 *)(addr+1)); fault |= __get_user(d2, (u8 *)(addr+2)); fault |= __get_user(d3, (u8 *)(addr+3)); val = (d3 << 24) | (d2 << 16) | (d1 << 8) | d0; put_reg_val(fp, b, val); break; } } addr = RDCTL(CTL_BADADDR); cause >>= 2; if (fault) { if (in_kernel) { pr_err("fault during kernel misaligned fixup @ %#lx; addr 0x%08x; isn=0x%08x\n", fp->ea, (unsigned int)addr, (unsigned int)isn); } else { pr_err("fault during user misaligned fixup @ %#lx; isn=%08x addr=0x%08x sp=0x%08lx pid=%d\n", fp->ea, (unsigned int)isn, addr, fp->sp, current->pid); _exception(SIGSEGV, fp, SEGV_MAPERR, fp->ea); return; } } /* * kernel mode - * note exception and skip bad instruction (return) */ if (in_kernel) { fp->ea += 4; if (ma_usermode & KM_WARN) { pr_err("kernel unaligned access @ %#lx; BADADDR 0x%08x; cause=%d, isn=0x%08x\n", fp->ea, (unsigned int)addr, cause, (unsigned int)isn); /* show_regs(fp); */ } return; } /* * user mode - * possibly warn, * possibly send SIGBUS signal to process */ if (ma_usermode & UM_WARN) { pr_err("user unaligned access @ %#lx; isn=0x%08lx ea=0x%08lx ra=0x%08lx sp=0x%08lx\n", (unsigned long)addr, (unsigned long)isn, fp->ea, fp->ra, fp->sp); } if (ma_usermode & UM_SIGNAL) _exception(SIGBUS, fp, BUS_ADRALN, fp->ea); else fp->ea += 4; /* else advance */ } static void __init misaligned_calc_reg_offsets(void) { int i, r, offset; /* pre-calc offsets of registers on sys call stack frame */ offset = 0; /* struct pt_regs */ for (i = 0; i < 16; i++) { r = sys_stack_frame_reg_offset[i]; reg_offsets[r] = offset; offset += 4; } /* struct switch_stack */ offset = -sizeof(struct switch_stack); for (i = 16; i < 32; i++) { r = sys_stack_frame_reg_offset[i]; reg_offsets[r] = offset; offset += 4; } } static int __init misaligned_init(void) { /* default mode - silent fix */ ma_usermode = UM_FIXUP | KM_WARN; misaligned_calc_reg_offsets(); return 0; } fs_initcall(misaligned_init); |