1 /* 2 * User-space Probes (UProbes) for s390 3 * 4 * Copyright IBM Corp. 2014 5 * Author(s): Jan Willeke, 6 */ 7 8 #include <linux/uaccess.h> 9 #include <linux/uprobes.h> 10 #include <linux/compat.h> 11 #include <linux/kdebug.h> 12 #include <asm/switch_to.h> 13 #include <asm/facility.h> 14 #include <asm/kprobes.h> 15 #include <asm/dis.h> 16 #include "entry.h" 17 18 #define UPROBE_TRAP_NR UINT_MAX 19 20 int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, 21 unsigned long addr) 22 { 23 return probe_is_prohibited_opcode(auprobe->insn); 24 } 25 26 int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 27 { 28 if (psw_bits(regs->psw).eaba == PSW_AMODE_24BIT) 29 return -EINVAL; 30 if (!is_compat_task() && psw_bits(regs->psw).eaba == PSW_AMODE_31BIT) 31 return -EINVAL; 32 clear_pt_regs_flag(regs, PIF_PER_TRAP); 33 auprobe->saved_per = psw_bits(regs->psw).r; 34 auprobe->saved_int_code = regs->int_code; 35 regs->int_code = UPROBE_TRAP_NR; 36 regs->psw.addr = current->utask->xol_vaddr; 37 set_tsk_thread_flag(current, TIF_UPROBE_SINGLESTEP); 38 update_cr_regs(current); 39 return 0; 40 } 41 42 bool arch_uprobe_xol_was_trapped(struct task_struct *tsk) 43 { 44 struct pt_regs *regs = task_pt_regs(tsk); 45 46 if (regs->int_code != UPROBE_TRAP_NR) 47 return true; 48 return false; 49 } 50 51 static int check_per_event(unsigned short cause, unsigned long control, 52 struct pt_regs *regs) 53 { 54 if (!(regs->psw.mask & PSW_MASK_PER)) 55 return 0; 56 /* user space single step */ 57 if (control == 0) 58 return 1; 59 /* over indication for storage alteration */ 60 if ((control & 0x20200000) && (cause & 0x2000)) 61 return 1; 62 if (cause & 0x8000) { 63 /* all branches */ 64 if ((control & 0x80800000) == 0x80000000) 65 return 1; 66 /* branch into selected range */ 67 if (((control & 0x80800000) == 0x80800000) && 68 regs->psw.addr >= current->thread.per_user.start && 69 regs->psw.addr <= current->thread.per_user.end) 70 return 1; 71 } 72 return 0; 73 } 74 75 int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 76 { 77 int fixup = probe_get_fixup_type(auprobe->insn); 78 struct uprobe_task *utask = current->utask; 79 80 clear_tsk_thread_flag(current, TIF_UPROBE_SINGLESTEP); 81 update_cr_regs(current); 82 psw_bits(regs->psw).r = auprobe->saved_per; 83 regs->int_code = auprobe->saved_int_code; 84 85 if (fixup & FIXUP_PSW_NORMAL) 86 regs->psw.addr += utask->vaddr - utask->xol_vaddr; 87 if (fixup & FIXUP_RETURN_REGISTER) { 88 int reg = (auprobe->insn[0] & 0xf0) >> 4; 89 90 regs->gprs[reg] += utask->vaddr - utask->xol_vaddr; 91 } 92 if (fixup & FIXUP_BRANCH_NOT_TAKEN) { 93 int ilen = insn_length(auprobe->insn[0] >> 8); 94 95 if (regs->psw.addr - utask->xol_vaddr == ilen) 96 regs->psw.addr = utask->vaddr + ilen; 97 } 98 if (check_per_event(current->thread.per_event.cause, 99 current->thread.per_user.control, regs)) { 100 /* fix per address */ 101 current->thread.per_event.address = utask->vaddr; 102 /* trigger per event */ 103 set_pt_regs_flag(regs, PIF_PER_TRAP); 104 } 105 return 0; 106 } 107 108 int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, 109 void *data) 110 { 111 struct die_args *args = data; 112 struct pt_regs *regs = args->regs; 113 114 if (!user_mode(regs)) 115 return NOTIFY_DONE; 116 if (regs->int_code & 0x200) /* Trap during transaction */ 117 return NOTIFY_DONE; 118 switch (val) { 119 case DIE_BPT: 120 if (uprobe_pre_sstep_notifier(regs)) 121 return NOTIFY_STOP; 122 break; 123 case DIE_SSTEP: 124 if (uprobe_post_sstep_notifier(regs)) 125 return NOTIFY_STOP; 126 default: 127 break; 128 } 129 return NOTIFY_DONE; 130 } 131 132 void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 133 { 134 clear_thread_flag(TIF_UPROBE_SINGLESTEP); 135 regs->int_code = auprobe->saved_int_code; 136 regs->psw.addr = current->utask->vaddr; 137 current->thread.per_event.address = current->utask->vaddr; 138 } 139 140 unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline, 141 struct pt_regs *regs) 142 { 143 unsigned long orig; 144 145 orig = regs->gprs[14]; 146 regs->gprs[14] = trampoline; 147 return orig; 148 } 149 150 /* Instruction Emulation */ 151 152 static void adjust_psw_addr(psw_t *psw, unsigned long len) 153 { 154 psw->addr = __rewind_psw(*psw, -len); 155 } 156 157 #define EMU_ILLEGAL_OP 1 158 #define EMU_SPECIFICATION 2 159 #define EMU_ADDRESSING 3 160 161 #define emu_load_ril(ptr, output) \ 162 ({ \ 163 unsigned int mask = sizeof(*(ptr)) - 1; \ 164 __typeof__(*(ptr)) input; \ 165 int __rc = 0; \ 166 \ 167 if (!test_facility(34)) \ 168 __rc = EMU_ILLEGAL_OP; \ 169 else if ((u64 __force)ptr & mask) \ 170 __rc = EMU_SPECIFICATION; \ 171 else if (get_user(input, ptr)) \ 172 __rc = EMU_ADDRESSING; \ 173 else \ 174 *(output) = input; \ 175 __rc; \ 176 }) 177 178 #define emu_store_ril(regs, ptr, input) \ 179 ({ \ 180 unsigned int mask = sizeof(*(ptr)) - 1; \ 181 __typeof__(ptr) __ptr = (ptr); \ 182 int __rc = 0; \ 183 \ 184 if (!test_facility(34)) \ 185 __rc = EMU_ILLEGAL_OP; \ 186 else if ((u64 __force)__ptr & mask) \ 187 __rc = EMU_SPECIFICATION; \ 188 else if (put_user(*(input), __ptr)) \ 189 __rc = EMU_ADDRESSING; \ 190 if (__rc == 0) \ 191 sim_stor_event(regs, \ 192 (void __force *)__ptr, \ 193 mask + 1); \ 194 __rc; \ 195 }) 196 197 #define emu_cmp_ril(regs, ptr, cmp) \ 198 ({ \ 199 unsigned int mask = sizeof(*(ptr)) - 1; \ 200 __typeof__(*(ptr)) input; \ 201 int __rc = 0; \ 202 \ 203 if (!test_facility(34)) \ 204 __rc = EMU_ILLEGAL_OP; \ 205 else if ((u64 __force)ptr & mask) \ 206 __rc = EMU_SPECIFICATION; \ 207 else if (get_user(input, ptr)) \ 208 __rc = EMU_ADDRESSING; \ 209 else if (input > *(cmp)) \ 210 psw_bits((regs)->psw).cc = 1; \ 211 else if (input < *(cmp)) \ 212 psw_bits((regs)->psw).cc = 2; \ 213 else \ 214 psw_bits((regs)->psw).cc = 0; \ 215 __rc; \ 216 }) 217 218 struct insn_ril { 219 u8 opc0; 220 u8 reg : 4; 221 u8 opc1 : 4; 222 s32 disp; 223 } __packed; 224 225 union split_register { 226 u64 u64; 227 u32 u32[2]; 228 u16 u16[4]; 229 s64 s64; 230 s32 s32[2]; 231 s16 s16[4]; 232 }; 233 234 /* 235 * If user per registers are setup to trace storage alterations and an 236 * emulated store took place on a fitting address a user trap is generated. 237 */ 238 static void sim_stor_event(struct pt_regs *regs, void *addr, int len) 239 { 240 if (!(regs->psw.mask & PSW_MASK_PER)) 241 return; 242 if (!(current->thread.per_user.control & PER_EVENT_STORE)) 243 return; 244 if ((void *)current->thread.per_user.start > (addr + len)) 245 return; 246 if ((void *)current->thread.per_user.end < addr) 247 return; 248 current->thread.per_event.address = regs->psw.addr; 249 current->thread.per_event.cause = PER_EVENT_STORE >> 16; 250 set_pt_regs_flag(regs, PIF_PER_TRAP); 251 } 252 253 /* 254 * pc relative instructions are emulated, since parameters may not be 255 * accessible from the xol area due to range limitations. 256 */ 257 static void handle_insn_ril(struct arch_uprobe *auprobe, struct pt_regs *regs) 258 { 259 union split_register *rx; 260 struct insn_ril *insn; 261 unsigned int ilen; 262 void *uptr; 263 int rc = 0; 264 265 insn = (struct insn_ril *) &auprobe->insn; 266 rx = (union split_register *) ®s->gprs[insn->reg]; 267 uptr = (void *)(regs->psw.addr + (insn->disp * 2)); 268 ilen = insn_length(insn->opc0); 269 270 switch (insn->opc0) { 271 case 0xc0: 272 switch (insn->opc1) { 273 case 0x00: /* larl */ 274 rx->u64 = (unsigned long)uptr; 275 break; 276 } 277 break; 278 case 0xc4: 279 switch (insn->opc1) { 280 case 0x02: /* llhrl */ 281 rc = emu_load_ril((u16 __user *)uptr, &rx->u32[1]); 282 break; 283 case 0x04: /* lghrl */ 284 rc = emu_load_ril((s16 __user *)uptr, &rx->u64); 285 break; 286 case 0x05: /* lhrl */ 287 rc = emu_load_ril((s16 __user *)uptr, &rx->u32[1]); 288 break; 289 case 0x06: /* llghrl */ 290 rc = emu_load_ril((u16 __user *)uptr, &rx->u64); 291 break; 292 case 0x08: /* lgrl */ 293 rc = emu_load_ril((u64 __user *)uptr, &rx->u64); 294 break; 295 case 0x0c: /* lgfrl */ 296 rc = emu_load_ril((s32 __user *)uptr, &rx->u64); 297 break; 298 case 0x0d: /* lrl */ 299 rc = emu_load_ril((u32 __user *)uptr, &rx->u32[1]); 300 break; 301 case 0x0e: /* llgfrl */ 302 rc = emu_load_ril((u32 __user *)uptr, &rx->u64); 303 break; 304 case 0x07: /* sthrl */ 305 rc = emu_store_ril(regs, (u16 __user *)uptr, &rx->u16[3]); 306 break; 307 case 0x0b: /* stgrl */ 308 rc = emu_store_ril(regs, (u64 __user *)uptr, &rx->u64); 309 break; 310 case 0x0f: /* strl */ 311 rc = emu_store_ril(regs, (u32 __user *)uptr, &rx->u32[1]); 312 break; 313 } 314 break; 315 case 0xc6: 316 switch (insn->opc1) { 317 case 0x02: /* pfdrl */ 318 if (!test_facility(34)) 319 rc = EMU_ILLEGAL_OP; 320 break; 321 case 0x04: /* cghrl */ 322 rc = emu_cmp_ril(regs, (s16 __user *)uptr, &rx->s64); 323 break; 324 case 0x05: /* chrl */ 325 rc = emu_cmp_ril(regs, (s16 __user *)uptr, &rx->s32[1]); 326 break; 327 case 0x06: /* clghrl */ 328 rc = emu_cmp_ril(regs, (u16 __user *)uptr, &rx->u64); 329 break; 330 case 0x07: /* clhrl */ 331 rc = emu_cmp_ril(regs, (u16 __user *)uptr, &rx->u32[1]); 332 break; 333 case 0x08: /* cgrl */ 334 rc = emu_cmp_ril(regs, (s64 __user *)uptr, &rx->s64); 335 break; 336 case 0x0a: /* clgrl */ 337 rc = emu_cmp_ril(regs, (u64 __user *)uptr, &rx->u64); 338 break; 339 case 0x0c: /* cgfrl */ 340 rc = emu_cmp_ril(regs, (s32 __user *)uptr, &rx->s64); 341 break; 342 case 0x0d: /* crl */ 343 rc = emu_cmp_ril(regs, (s32 __user *)uptr, &rx->s32[1]); 344 break; 345 case 0x0e: /* clgfrl */ 346 rc = emu_cmp_ril(regs, (u32 __user *)uptr, &rx->u64); 347 break; 348 case 0x0f: /* clrl */ 349 rc = emu_cmp_ril(regs, (u32 __user *)uptr, &rx->u32[1]); 350 break; 351 } 352 break; 353 } 354 adjust_psw_addr(®s->psw, ilen); 355 switch (rc) { 356 case EMU_ILLEGAL_OP: 357 regs->int_code = ilen << 16 | 0x0001; 358 do_report_trap(regs, SIGILL, ILL_ILLOPC, NULL); 359 break; 360 case EMU_SPECIFICATION: 361 regs->int_code = ilen << 16 | 0x0006; 362 do_report_trap(regs, SIGILL, ILL_ILLOPC , NULL); 363 break; 364 case EMU_ADDRESSING: 365 regs->int_code = ilen << 16 | 0x0005; 366 do_report_trap(regs, SIGSEGV, SEGV_MAPERR, NULL); 367 break; 368 } 369 } 370 371 bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) 372 { 373 if ((psw_bits(regs->psw).eaba == PSW_AMODE_24BIT) || 374 ((psw_bits(regs->psw).eaba == PSW_AMODE_31BIT) && 375 !is_compat_task())) { 376 regs->psw.addr = __rewind_psw(regs->psw, UPROBE_SWBP_INSN_SIZE); 377 do_report_trap(regs, SIGILL, ILL_ILLADR, NULL); 378 return true; 379 } 380 if (probe_is_insn_relative_long(auprobe->insn)) { 381 handle_insn_ril(auprobe, regs); 382 return true; 383 } 384 return false; 385 } 386