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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 | /* $Id: winfixup.S,v 1.30 2002/02/09 19:49:30 davem Exp $ * * winfixup.S: Handle cases where user stack pointer is found to be bogus. * * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu) */ #include <asm/asi.h> #include <asm/head.h> #include <asm/page.h> #include <asm/ptrace.h> #include <asm/processor.h> #include <asm/spitfire.h> #include <asm/thread_info.h> .text .align 32 /* Here are the rules, pay attention. * * The kernel is disallowed from touching user space while * the trap level is greater than zero, except for from within * the window spill/fill handlers. This must be followed * so that we can easily detect the case where we tried to * spill/fill with a bogus (or unmapped) user stack pointer. * * These are layed out in a special way for cache reasons, * don't touch... */ .globl fill_fixup, spill_fixup fill_fixup: rdpr %tstate, %g1 andcc %g1, TSTATE_PRIV, %g0 or %g4, FAULT_CODE_WINFIXUP, %g4 be,pt %xcc, window_scheisse_from_user_common and %g1, TSTATE_CWP, %g1 /* This is the extremely complex case, but it does happen from * time to time if things are just right. Essentially the restore * done in rtrap right before going back to user mode, with tl=1 * and that levels trap stack registers all setup, took a fill trap, * the user stack was not mapped in the tlb, and tlb miss occurred, * the pte found was not valid, and a simple ref bit watch update * could not satisfy the miss, so we got here. * * We must carefully unwind the state so we get back to tl=0, preserve * all the register values we were going to give to the user. Luckily * most things are where they need to be, we also have the address * which triggered the fault handy as well. * * Also note that we must preserve %l5 and %l6. If the user was * returning from a system call, we must make it look this way * after we process the fill fault on the users stack. * * First, get into the window where the original restore was executed. */ rdpr %wstate, %g2 ! Grab user mode wstate. wrpr %g1, %cwp ! Get into the right window. sll %g2, 3, %g2 ! NORMAL-->OTHER wrpr %g0, 0x0, %canrestore ! Standard etrap stuff. wrpr %g2, 0x0, %wstate ! This must be consistant. wrpr %g0, 0x0, %otherwin ! We know this. mov PRIMARY_CONTEXT, %g1 ! Change contexts... stxa %g0, [%g1] ASI_DMMU ! Back into the nucleus. flush %g6 ! Flush instruction buffers rdpr %pstate, %l1 ! Prepare to change globals. mov %g6, %o7 ! Get current. andn %l1, PSTATE_MM, %l1 ! We want to be in RMO stb %g4, [%g6 + TI_FAULT_CODE] stx %g5, [%g6 + TI_FAULT_ADDR] wrpr %g0, 0x0, %tl ! Out of trap levels. wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate mov %o7, %g6 ldx [%g6 + TI_TASK], %g4 /* This is the same as below, except we handle this a bit special * since we must preserve %l5 and %l6, see comment above. */ call do_sparc64_fault add %sp, STACK_BIAS + REGWIN_SZ, %o0 ba,pt %xcc, rtrap nop ! yes, nop is correct /* Be very careful about usage of the alternate globals here. * You cannot touch %g4/%g5 as that has the fault information * should this be from usermode. Also be careful for the case * where we get here from the save instruction in etrap.S when * coming from either user or kernel (does not matter which, it * is the same problem in both cases). Essentially this means * do not touch %g7 or %g2 so we handle the two cases fine. */ spill_fixup: ldx [%g6 + TI_FLAGS], %g1 andcc %g1, _TIF_32BIT, %g0 ldub [%g6 + TI_WSAVED], %g1 sll %g1, 3, %g3 add %g6, %g3, %g3 stx %sp, [%g3 + TI_RWIN_SPTRS] sll %g1, 7, %g3 bne,pt %xcc, 1f add %g6, %g3, %g3 stx %l0, [%g3 + TI_REG_WINDOW + 0x00] stx %l1, [%g3 + TI_REG_WINDOW + 0x08] stx %l2, [%g3 + TI_REG_WINDOW + 0x10] stx %l3, [%g3 + TI_REG_WINDOW + 0x18] stx %l4, [%g3 + TI_REG_WINDOW + 0x20] stx %l5, [%g3 + TI_REG_WINDOW + 0x28] stx %l6, [%g3 + TI_REG_WINDOW + 0x30] stx %l7, [%g3 + TI_REG_WINDOW + 0x38] stx %i0, [%g3 + TI_REG_WINDOW + 0x40] stx %i1, [%g3 + TI_REG_WINDOW + 0x48] stx %i2, [%g3 + TI_REG_WINDOW + 0x50] stx %i3, [%g3 + TI_REG_WINDOW + 0x58] stx %i4, [%g3 + TI_REG_WINDOW + 0x60] stx %i5, [%g3 + TI_REG_WINDOW + 0x68] stx %i6, [%g3 + TI_REG_WINDOW + 0x70] b,pt %xcc, 2f stx %i7, [%g3 + TI_REG_WINDOW + 0x78] 1: stw %l0, [%g3 + TI_REG_WINDOW + 0x00] stw %l1, [%g3 + TI_REG_WINDOW + 0x04] stw %l2, [%g3 + TI_REG_WINDOW + 0x08] stw %l3, [%g3 + TI_REG_WINDOW + 0x0c] stw %l4, [%g3 + TI_REG_WINDOW + 0x10] stw %l5, [%g3 + TI_REG_WINDOW + 0x14] stw %l6, [%g3 + TI_REG_WINDOW + 0x18] stw %l7, [%g3 + TI_REG_WINDOW + 0x1c] stw %i0, [%g3 + TI_REG_WINDOW + 0x20] stw %i1, [%g3 + TI_REG_WINDOW + 0x24] stw %i2, [%g3 + TI_REG_WINDOW + 0x28] stw %i3, [%g3 + TI_REG_WINDOW + 0x2c] stw %i4, [%g3 + TI_REG_WINDOW + 0x30] stw %i5, [%g3 + TI_REG_WINDOW + 0x34] stw %i6, [%g3 + TI_REG_WINDOW + 0x38] stw %i7, [%g3 + TI_REG_WINDOW + 0x3c] 2: add %g1, 1, %g1 stb %g1, [%g6 + TI_WSAVED] rdpr %tstate, %g1 andcc %g1, TSTATE_PRIV, %g0 saved and %g1, TSTATE_CWP, %g1 be,pn %xcc, window_scheisse_from_user_common mov FAULT_CODE_WRITE | FAULT_CODE_DTLB | FAULT_CODE_WINFIXUP, %g4 retry window_scheisse_from_user_common: stb %g4, [%g6 + TI_FAULT_CODE] stx %g5, [%g6 + TI_FAULT_ADDR] wrpr %g1, %cwp ba,pt %xcc, etrap rd %pc, %g7 call do_sparc64_fault add %sp, STACK_BIAS + REGWIN_SZ, %o0 ba,a,pt %xcc, rtrap_clr_l6 .globl winfix_mna, fill_fixup_mna, spill_fixup_mna winfix_mna: andn %g3, 0x7f, %g3 add %g3, 0x78, %g3 wrpr %g3, %tnpc done fill_fixup_mna: rdpr %tstate, %g1 andcc %g1, TSTATE_PRIV, %g0 be,pt %xcc, window_mna_from_user_common and %g1, TSTATE_CWP, %g1 /* Please, see fill_fixup commentary about why we must preserve * %l5 and %l6 to preserve absolute correct semantics. */ rdpr %wstate, %g2 ! Grab user mode wstate. wrpr %g1, %cwp ! Get into the right window. sll %g2, 3, %g2 ! NORMAL-->OTHER wrpr %g0, 0x0, %canrestore ! Standard etrap stuff. wrpr %g2, 0x0, %wstate ! This must be consistant. wrpr %g0, 0x0, %otherwin ! We know this. mov PRIMARY_CONTEXT, %g1 ! Change contexts... stxa %g0, [%g1] ASI_DMMU ! Back into the nucleus. flush %g6 ! Flush instruction buffers rdpr %pstate, %l1 ! Prepare to change globals. mov %g4, %o2 ! Setup args for mov %g5, %o1 ! final call to mem_address_unaligned. andn %l1, PSTATE_MM, %l1 ! We want to be in RMO mov %g6, %o7 ! Stash away current. wrpr %g0, 0x0, %tl ! Out of trap levels. wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate mov %o7, %g6 ! Get current back. ldx [%g6 + TI_TASK], %g4 ! Finish it. call mem_address_unaligned add %sp, STACK_BIAS + REGWIN_SZ, %o0 b,pt %xcc, rtrap nop ! yes, the nop is correct spill_fixup_mna: ldx [%g6 + TI_FLAGS], %g1 andcc %g1, _TIF_32BIT, %g0 ldub [%g6 + TI_WSAVED], %g1 sll %g1, 3, %g3 add %g6, %g3, %g3 stx %sp, [%g3 + TI_RWIN_SPTRS] sll %g1, 7, %g3 bne,pt %xcc, 1f add %g6, %g3, %g3 stx %l0, [%g3 + TI_REG_WINDOW + 0x00] stx %l1, [%g3 + TI_REG_WINDOW + 0x08] stx %l2, [%g3 + TI_REG_WINDOW + 0x10] stx %l3, [%g3 + TI_REG_WINDOW + 0x18] stx %l4, [%g3 + TI_REG_WINDOW + 0x20] stx %l5, [%g3 + TI_REG_WINDOW + 0x28] stx %l6, [%g3 + TI_REG_WINDOW + 0x30] stx %l7, [%g3 + TI_REG_WINDOW + 0x38] stx %i0, [%g3 + TI_REG_WINDOW + 0x40] stx %i1, [%g3 + TI_REG_WINDOW + 0x48] stx %i2, [%g3 + TI_REG_WINDOW + 0x50] stx %i3, [%g3 + TI_REG_WINDOW + 0x58] stx %i4, [%g3 + TI_REG_WINDOW + 0x60] stx %i5, [%g3 + TI_REG_WINDOW + 0x68] stx %i6, [%g3 + TI_REG_WINDOW + 0x70] stx %i7, [%g3 + TI_REG_WINDOW + 0x78] b,pt %xcc, 2f add %g1, 1, %g1 1: std %l0, [%g3 + TI_REG_WINDOW + 0x00] std %l2, [%g3 + TI_REG_WINDOW + 0x08] std %l4, [%g3 + TI_REG_WINDOW + 0x10] std %l6, [%g3 + TI_REG_WINDOW + 0x18] std %i0, [%g3 + TI_REG_WINDOW + 0x20] std %i2, [%g3 + TI_REG_WINDOW + 0x28] std %i4, [%g3 + TI_REG_WINDOW + 0x30] std %i6, [%g3 + TI_REG_WINDOW + 0x38] add %g1, 1, %g1 2: stb %g1, [%g6 + TI_WSAVED] rdpr %tstate, %g1 andcc %g1, TSTATE_PRIV, %g0 saved be,pn %xcc, window_mna_from_user_common and %g1, TSTATE_CWP, %g1 retry window_mna_from_user_common: wrpr %g1, %cwp sethi %hi(109f), %g7 ba,pt %xcc, etrap 109: or %g7, %lo(109b), %g7 mov %l4, %o2 mov %l5, %o1 call mem_address_unaligned add %sp, STACK_BIAS + REGWIN_SZ, %o0 ba,pt %xcc, rtrap clr %l6 /* These are only needed for 64-bit mode processes which * put their stack pointer into the VPTE area and there * happens to be a VPTE tlb entry mapped there during * a spill/fill trap to that stack frame. */ .globl winfix_dax, fill_fixup_dax, spill_fixup_dax winfix_dax: andn %g3, 0x7f, %g3 add %g3, 0x74, %g3 wrpr %g3, %tnpc done fill_fixup_dax: rdpr %tstate, %g1 andcc %g1, TSTATE_PRIV, %g0 be,pt %xcc, window_dax_from_user_common and %g1, TSTATE_CWP, %g1 /* Please, see fill_fixup commentary about why we must preserve * %l5 and %l6 to preserve absolute correct semantics. */ rdpr %wstate, %g2 ! Grab user mode wstate. wrpr %g1, %cwp ! Get into the right window. sll %g2, 3, %g2 ! NORMAL-->OTHER wrpr %g0, 0x0, %canrestore ! Standard etrap stuff. wrpr %g2, 0x0, %wstate ! This must be consistant. wrpr %g0, 0x0, %otherwin ! We know this. mov PRIMARY_CONTEXT, %g1 ! Change contexts... stxa %g0, [%g1] ASI_DMMU ! Back into the nucleus. flush %g6 ! Flush instruction buffers rdpr %pstate, %l1 ! Prepare to change globals. mov %g4, %o1 ! Setup args for mov %g5, %o2 ! final call to data_access_exception. andn %l1, PSTATE_MM, %l1 ! We want to be in RMO mov %g6, %o7 ! Stash away current. wrpr %g0, 0x0, %tl ! Out of trap levels. wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate mov %o7, %g6 ! Get current back. ldx [%g6 + TI_TASK], %g4 ! Finish it. call data_access_exception add %sp, STACK_BIAS + REGWIN_SZ, %o0 b,pt %xcc, rtrap nop ! yes, the nop is correct spill_fixup_dax: ldx [%g6 + TI_FLAGS], %g1 andcc %g1, _TIF_32BIT, %g0 ldub [%g6 + TI_WSAVED], %g1 sll %g1, 3, %g3 add %g6, %g3, %g3 stx %sp, [%g3 + TI_RWIN_SPTRS] sll %g1, 7, %g3 bne,pt %xcc, 1f add %g6, %g3, %g3 stx %l0, [%g3 + TI_REG_WINDOW + 0x00] stx %l1, [%g3 + TI_REG_WINDOW + 0x08] stx %l2, [%g3 + TI_REG_WINDOW + 0x10] stx %l3, [%g3 + TI_REG_WINDOW + 0x18] stx %l4, [%g3 + TI_REG_WINDOW + 0x20] stx %l5, [%g3 + TI_REG_WINDOW + 0x28] stx %l6, [%g3 + TI_REG_WINDOW + 0x30] stx %l7, [%g3 + TI_REG_WINDOW + 0x38] stx %i0, [%g3 + TI_REG_WINDOW + 0x40] stx %i1, [%g3 + TI_REG_WINDOW + 0x48] stx %i2, [%g3 + TI_REG_WINDOW + 0x50] stx %i3, [%g3 + TI_REG_WINDOW + 0x58] stx %i4, [%g3 + TI_REG_WINDOW + 0x60] stx %i5, [%g3 + TI_REG_WINDOW + 0x68] stx %i6, [%g3 + TI_REG_WINDOW + 0x70] stx %i7, [%g3 + TI_REG_WINDOW + 0x78] b,pt %xcc, 2f add %g1, 1, %g1 1: std %l0, [%g3 + TI_REG_WINDOW + 0x00] std %l2, [%g3 + TI_REG_WINDOW + 0x08] std %l4, [%g3 + TI_REG_WINDOW + 0x10] std %l6, [%g3 + TI_REG_WINDOW + 0x18] std %i0, [%g3 + TI_REG_WINDOW + 0x20] std %i2, [%g3 + TI_REG_WINDOW + 0x28] std %i4, [%g3 + TI_REG_WINDOW + 0x30] std %i6, [%g3 + TI_REG_WINDOW + 0x38] add %g1, 1, %g1 2: stb %g1, [%g6 + TI_WSAVED] rdpr %tstate, %g1 andcc %g1, TSTATE_PRIV, %g0 saved be,pn %xcc, window_dax_from_user_common and %g1, TSTATE_CWP, %g1 retry window_dax_from_user_common: wrpr %g1, %cwp sethi %hi(109f), %g7 ba,pt %xcc, etrap 109: or %g7, %lo(109b), %g7 mov %l4, %o1 mov %l5, %o2 call data_access_exception add %sp, STACK_BIAS + REGWIN_SZ, %o0 ba,pt %xcc, rtrap clr %l6 |