1/* 2 * Low-level system-call handling, trap handlers and context-switching 3 * 4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> 5 * Copyright (C) 2008-2009 PetaLogix 6 * Copyright (C) 2003 John Williams <jwilliams@itee.uq.edu.au> 7 * Copyright (C) 2001,2002 NEC Corporation 8 * Copyright (C) 2001,2002 Miles Bader <miles@gnu.org> 9 * 10 * This file is subject to the terms and conditions of the GNU General 11 * Public License. See the file COPYING in the main directory of this 12 * archive for more details. 13 * 14 * Written by Miles Bader <miles@gnu.org> 15 * Heavily modified by John Williams for Microblaze 16 */ 17 18#include <linux/sys.h> 19#include <linux/linkage.h> 20 21#include <asm/entry.h> 22#include <asm/current.h> 23#include <asm/processor.h> 24#include <asm/exceptions.h> 25#include <asm/asm-offsets.h> 26#include <asm/thread_info.h> 27 28#include <asm/page.h> 29#include <asm/unistd.h> 30 31#include <linux/errno.h> 32#include <asm/signal.h> 33 34#undef DEBUG 35 36#ifdef DEBUG 37/* Create space for syscalls counting. */ 38.section .data 39.global syscall_debug_table 40.align 4 41syscall_debug_table: 42 .space (__NR_syscalls * 4) 43#endif /* DEBUG */ 44 45#define C_ENTRY(name) .globl name; .align 4; name 46 47/* 48 * Various ways of setting and clearing BIP in flags reg. 49 * This is mucky, but necessary using microblaze version that 50 * allows msr ops to write to BIP 51 */ 52#if CONFIG_XILINX_MICROBLAZE0_USE_MSR_INSTR 53 .macro clear_bip 54 msrclr r0, MSR_BIP 55 .endm 56 57 .macro set_bip 58 msrset r0, MSR_BIP 59 .endm 60 61 .macro clear_eip 62 msrclr r0, MSR_EIP 63 .endm 64 65 .macro set_ee 66 msrset r0, MSR_EE 67 .endm 68 69 .macro disable_irq 70 msrclr r0, MSR_IE 71 .endm 72 73 .macro enable_irq 74 msrset r0, MSR_IE 75 .endm 76 77 .macro set_ums 78 msrset r0, MSR_UMS 79 msrclr r0, MSR_VMS 80 .endm 81 82 .macro set_vms 83 msrclr r0, MSR_UMS 84 msrset r0, MSR_VMS 85 .endm 86 87 .macro clear_ums 88 msrclr r0, MSR_UMS 89 .endm 90 91 .macro clear_vms_ums 92 msrclr r0, MSR_VMS | MSR_UMS 93 .endm 94#else 95 .macro clear_bip 96 mfs r11, rmsr 97 andi r11, r11, ~MSR_BIP 98 mts rmsr, r11 99 .endm 100 101 .macro set_bip 102 mfs r11, rmsr 103 ori r11, r11, MSR_BIP 104 mts rmsr, r11 105 .endm 106 107 .macro clear_eip 108 mfs r11, rmsr 109 andi r11, r11, ~MSR_EIP 110 mts rmsr, r11 111 .endm 112 113 .macro set_ee 114 mfs r11, rmsr 115 ori r11, r11, MSR_EE 116 mts rmsr, r11 117 .endm 118 119 .macro disable_irq 120 mfs r11, rmsr 121 andi r11, r11, ~MSR_IE 122 mts rmsr, r11 123 .endm 124 125 .macro enable_irq 126 mfs r11, rmsr 127 ori r11, r11, MSR_IE 128 mts rmsr, r11 129 .endm 130 131 .macro set_ums 132 mfs r11, rmsr 133 ori r11, r11, MSR_VMS 134 andni r11, r11, MSR_UMS 135 mts rmsr, r11 136 .endm 137 138 .macro set_vms 139 mfs r11, rmsr 140 ori r11, r11, MSR_VMS 141 andni r11, r11, MSR_UMS 142 mts rmsr, r11 143 .endm 144 145 .macro clear_ums 146 mfs r11, rmsr 147 andni r11, r11, MSR_UMS 148 mts rmsr,r11 149 .endm 150 151 .macro clear_vms_ums 152 mfs r11, rmsr 153 andni r11, r11, (MSR_VMS|MSR_UMS) 154 mts rmsr,r11 155 .endm 156#endif 157 158/* Define how to call high-level functions. With MMU, virtual mode must be 159 * enabled when calling the high-level function. Clobbers R11. 160 * VM_ON, VM_OFF, DO_JUMP_BIPCLR, DO_CALL 161 */ 162 163/* turn on virtual protected mode save */ 164#define VM_ON \ 165 set_ums; \ 166 rted r0, 2f; \ 167 nop; \ 1682: 169 170/* turn off virtual protected mode save and user mode save*/ 171#define VM_OFF \ 172 clear_vms_ums; \ 173 rted r0, TOPHYS(1f); \ 174 nop; \ 1751: 176 177#define SAVE_REGS \ 178 swi r2, r1, PT_R2; /* Save SDA */ \ 179 swi r3, r1, PT_R3; \ 180 swi r4, r1, PT_R4; \ 181 swi r5, r1, PT_R5; \ 182 swi r6, r1, PT_R6; \ 183 swi r7, r1, PT_R7; \ 184 swi r8, r1, PT_R8; \ 185 swi r9, r1, PT_R9; \ 186 swi r10, r1, PT_R10; \ 187 swi r11, r1, PT_R11; /* save clobbered regs after rval */\ 188 swi r12, r1, PT_R12; \ 189 swi r13, r1, PT_R13; /* Save SDA2 */ \ 190 swi r14, r1, PT_PC; /* PC, before IRQ/trap */ \ 191 swi r15, r1, PT_R15; /* Save LP */ \ 192 swi r16, r1, PT_R16; \ 193 swi r17, r1, PT_R17; \ 194 swi r18, r1, PT_R18; /* Save asm scratch reg */ \ 195 swi r19, r1, PT_R19; \ 196 swi r20, r1, PT_R20; \ 197 swi r21, r1, PT_R21; \ 198 swi r22, r1, PT_R22; \ 199 swi r23, r1, PT_R23; \ 200 swi r24, r1, PT_R24; \ 201 swi r25, r1, PT_R25; \ 202 swi r26, r1, PT_R26; \ 203 swi r27, r1, PT_R27; \ 204 swi r28, r1, PT_R28; \ 205 swi r29, r1, PT_R29; \ 206 swi r30, r1, PT_R30; \ 207 swi r31, r1, PT_R31; /* Save current task reg */ \ 208 mfs r11, rmsr; /* save MSR */ \ 209 swi r11, r1, PT_MSR; 210 211#define RESTORE_REGS \ 212 lwi r11, r1, PT_MSR; \ 213 mts rmsr , r11; \ 214 lwi r2, r1, PT_R2; /* restore SDA */ \ 215 lwi r3, r1, PT_R3; \ 216 lwi r4, r1, PT_R4; \ 217 lwi r5, r1, PT_R5; \ 218 lwi r6, r1, PT_R6; \ 219 lwi r7, r1, PT_R7; \ 220 lwi r8, r1, PT_R8; \ 221 lwi r9, r1, PT_R9; \ 222 lwi r10, r1, PT_R10; \ 223 lwi r11, r1, PT_R11; /* restore clobbered regs after rval */\ 224 lwi r12, r1, PT_R12; \ 225 lwi r13, r1, PT_R13; /* restore SDA2 */ \ 226 lwi r14, r1, PT_PC; /* RESTORE_LINK PC, before IRQ/trap */\ 227 lwi r15, r1, PT_R15; /* restore LP */ \ 228 lwi r16, r1, PT_R16; \ 229 lwi r17, r1, PT_R17; \ 230 lwi r18, r1, PT_R18; /* restore asm scratch reg */ \ 231 lwi r19, r1, PT_R19; \ 232 lwi r20, r1, PT_R20; \ 233 lwi r21, r1, PT_R21; \ 234 lwi r22, r1, PT_R22; \ 235 lwi r23, r1, PT_R23; \ 236 lwi r24, r1, PT_R24; \ 237 lwi r25, r1, PT_R25; \ 238 lwi r26, r1, PT_R26; \ 239 lwi r27, r1, PT_R27; \ 240 lwi r28, r1, PT_R28; \ 241 lwi r29, r1, PT_R29; \ 242 lwi r30, r1, PT_R30; \ 243 lwi r31, r1, PT_R31; /* Restore cur task reg */ 244 245#define SAVE_STATE \ 246 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* save stack */ \ 247 /* See if already in kernel mode.*/ \ 248 mfs r1, rmsr; \ 249 andi r1, r1, MSR_UMS; \ 250 bnei r1, 1f; \ 251 /* Kernel-mode state save. */ \ 252 /* Reload kernel stack-ptr. */ \ 253 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); \ 254 /* FIXME: I can add these two lines to one */ \ 255 /* tophys(r1,r1); */ \ 256 /* addik r1, r1, -PT_SIZE; */ \ 257 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \ 258 SAVE_REGS \ 259 brid 2f; \ 260 swi r1, r1, PT_MODE; \ 2611: /* User-mode state save. */ \ 262 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */\ 263 tophys(r1,r1); \ 264 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */ \ 265 /* MS these three instructions can be added to one */ \ 266 /* addik r1, r1, THREAD_SIZE; */ \ 267 /* tophys(r1,r1); */ \ 268 /* addik r1, r1, -PT_SIZE; */ \ 269 addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \ 270 SAVE_REGS \ 271 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \ 272 swi r11, r1, PT_R1; /* Store user SP. */ \ 273 swi r0, r1, PT_MODE; /* Was in user-mode. */ \ 274 /* MS: I am clearing UMS even in case when I come from kernel space */ \ 275 clear_ums; \ 2762: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); 277 278.text 279 280/* 281 * User trap. 282 * 283 * System calls are handled here. 284 * 285 * Syscall protocol: 286 * Syscall number in r12, args in r5-r10 287 * Return value in r3 288 * 289 * Trap entered via brki instruction, so BIP bit is set, and interrupts 290 * are masked. This is nice, means we don't have to CLI before state save 291 */ 292C_ENTRY(_user_exception): 293 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */ 294 addi r14, r14, 4 /* return address is 4 byte after call */ 295 296 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */ 297 tophys(r1,r1); 298 lwi r1, r1, TS_THREAD_INFO; /* get stack from task_struct */ 299/* calculate kernel stack pointer from task struct 8k */ 300 addik r1, r1, THREAD_SIZE; 301 tophys(r1,r1); 302 303 addik r1, r1, -PT_SIZE; /* Make room on the stack. */ 304 SAVE_REGS 305 swi r0, r1, PT_R3 306 swi r0, r1, PT_R4 307 308 swi r0, r1, PT_MODE; /* Was in user-mode. */ 309 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); 310 swi r11, r1, PT_R1; /* Store user SP. */ 311 clear_ums; 3122: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); 313 /* Save away the syscall number. */ 314 swi r12, r1, PT_R0; 315 tovirt(r1,r1) 316 317/* where the trap should return need -8 to adjust for rtsd r15, 8*/ 318/* Jump to the appropriate function for the system call number in r12 319 * (r12 is not preserved), or return an error if r12 is not valid. The LP 320 * register should point to the location where 321 * the called function should return. [note that MAKE_SYS_CALL uses label 1] */ 322 323 /* Step into virtual mode */ 324 rtbd r0, 3f 325 nop 3263: 327 lwi r11, CURRENT_TASK, TS_THREAD_INFO /* get thread info */ 328 lwi r11, r11, TI_FLAGS /* get flags in thread info */ 329 andi r11, r11, _TIF_WORK_SYSCALL_MASK 330 beqi r11, 4f 331 332 addik r3, r0, -ENOSYS 333 swi r3, r1, PT_R3 334 brlid r15, do_syscall_trace_enter 335 addik r5, r1, PT_R0 336 337 # do_syscall_trace_enter returns the new syscall nr. 338 addk r12, r0, r3 339 lwi r5, r1, PT_R5; 340 lwi r6, r1, PT_R6; 341 lwi r7, r1, PT_R7; 342 lwi r8, r1, PT_R8; 343 lwi r9, r1, PT_R9; 344 lwi r10, r1, PT_R10; 3454: 346/* Jump to the appropriate function for the system call number in r12 347 * (r12 is not preserved), or return an error if r12 is not valid. 348 * The LP register should point to the location where the called function 349 * should return. [note that MAKE_SYS_CALL uses label 1] */ 350 /* See if the system call number is valid */ 351 addi r11, r12, -__NR_syscalls; 352 bgei r11,5f; 353 /* Figure out which function to use for this system call. */ 354 /* Note Microblaze barrel shift is optional, so don't rely on it */ 355 add r12, r12, r12; /* convert num -> ptr */ 356 add r12, r12, r12; 357 358#ifdef DEBUG 359 /* Trac syscalls and stored them to syscall_debug_table */ 360 /* The first syscall location stores total syscall number */ 361 lwi r3, r0, syscall_debug_table 362 addi r3, r3, 1 363 swi r3, r0, syscall_debug_table 364 lwi r3, r12, syscall_debug_table 365 addi r3, r3, 1 366 swi r3, r12, syscall_debug_table 367#endif 368 369 # Find and jump into the syscall handler. 370 lwi r12, r12, sys_call_table 371 /* where the trap should return need -8 to adjust for rtsd r15, 8 */ 372 addi r15, r0, ret_from_trap-8 373 bra r12 374 375 /* The syscall number is invalid, return an error. */ 3765: 377 rtsd r15, 8; /* looks like a normal subroutine return */ 378 addi r3, r0, -ENOSYS; 379 380/* Entry point used to return from a syscall/trap */ 381/* We re-enable BIP bit before state restore */ 382C_ENTRY(ret_from_trap): 383 swi r3, r1, PT_R3 384 swi r4, r1, PT_R4 385 386 lwi r11, r1, PT_MODE; 387/* See if returning to kernel mode, if so, skip resched &c. */ 388 bnei r11, 2f; 389 /* We're returning to user mode, so check for various conditions that 390 * trigger rescheduling. */ 391 /* FIXME: Restructure all these flag checks. */ 392 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */ 393 lwi r11, r11, TI_FLAGS; /* get flags in thread info */ 394 andi r11, r11, _TIF_WORK_SYSCALL_MASK 395 beqi r11, 1f 396 397 brlid r15, do_syscall_trace_leave 398 addik r5, r1, PT_R0 3991: 400 /* We're returning to user mode, so check for various conditions that 401 * trigger rescheduling. */ 402 /* get thread info from current task */ 403 lwi r11, CURRENT_TASK, TS_THREAD_INFO; 404 lwi r11, r11, TI_FLAGS; /* get flags in thread info */ 405 andi r11, r11, _TIF_NEED_RESCHED; 406 beqi r11, 5f; 407 408 bralid r15, schedule; /* Call scheduler */ 409 nop; /* delay slot */ 410 411 /* Maybe handle a signal */ 4125: /* get thread info from current task*/ 413 lwi r11, CURRENT_TASK, TS_THREAD_INFO; 414 lwi r11, r11, TI_FLAGS; /* get flags in thread info */ 415 andi r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME; 416 beqi r11, 1f; /* Signals to handle, handle them */ 417 418 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */ 419 bralid r15, do_notify_resume; /* Handle any signals */ 420 addi r6, r0, 1; /* Arg 2: int in_syscall */ 421 422/* Finally, return to user state. */ 4231: set_bip; /* Ints masked for state restore */ 424 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */ 425 VM_OFF; 426 tophys(r1,r1); 427 RESTORE_REGS; 428 addik r1, r1, PT_SIZE /* Clean up stack space. */ 429 lwi r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */ 430 bri 6f; 431 432/* Return to kernel state. */ 4332: set_bip; /* Ints masked for state restore */ 434 VM_OFF; 435 tophys(r1,r1); 436 RESTORE_REGS; 437 addik r1, r1, PT_SIZE /* Clean up stack space. */ 438 tovirt(r1,r1); 4396: 440TRAP_return: /* Make global symbol for debugging */ 441 rtbd r14, 0; /* Instructions to return from an IRQ */ 442 nop; 443 444 445/* This the initial entry point for a new child thread, with an appropriate 446 stack in place that makes it look the the child is in the middle of an 447 syscall. This function is actually `returned to' from switch_thread 448 (copy_thread makes ret_from_fork the return address in each new thread's 449 saved context). */ 450C_ENTRY(ret_from_fork): 451 bralid r15, schedule_tail; /* ...which is schedule_tail's arg */ 452 add r5, r3, r0; /* switch_thread returns the prev task */ 453 /* ( in the delay slot ) */ 454 brid ret_from_trap; /* Do normal trap return */ 455 add r3, r0, r0; /* Child's fork call should return 0. */ 456 457C_ENTRY(ret_from_kernel_thread): 458 bralid r15, schedule_tail; /* ...which is schedule_tail's arg */ 459 add r5, r3, r0; /* switch_thread returns the prev task */ 460 /* ( in the delay slot ) */ 461 brald r15, r20 /* fn was left in r20 */ 462 addk r5, r0, r19 /* ... and argument - in r19 */ 463 brid ret_from_trap 464 add r3, r0, r0 465 466C_ENTRY(sys_rt_sigreturn_wrapper): 467 brid sys_rt_sigreturn /* Do real work */ 468 addik r5, r1, 0; /* add user context as 1st arg */ 469 470/* 471 * HW EXCEPTION rutine start 472 */ 473C_ENTRY(full_exception_trap): 474 /* adjust exception address for privileged instruction 475 * for finding where is it */ 476 addik r17, r17, -4 477 SAVE_STATE /* Save registers */ 478 /* PC, before IRQ/trap - this is one instruction above */ 479 swi r17, r1, PT_PC; 480 tovirt(r1,r1) 481 /* FIXME this can be store directly in PT_ESR reg. 482 * I tested it but there is a fault */ 483 /* where the trap should return need -8 to adjust for rtsd r15, 8 */ 484 addik r15, r0, ret_from_exc - 8 485 mfs r6, resr 486 mfs r7, rfsr; /* save FSR */ 487 mts rfsr, r0; /* Clear sticky fsr */ 488 rted r0, full_exception 489 addik r5, r1, 0 /* parameter struct pt_regs * regs */ 490 491/* 492 * Unaligned data trap. 493 * 494 * Unaligned data trap last on 4k page is handled here. 495 * 496 * Trap entered via exception, so EE bit is set, and interrupts 497 * are masked. This is nice, means we don't have to CLI before state save 498 * 499 * The assembler routine is in "arch/microblaze/kernel/hw_exception_handler.S" 500 */ 501C_ENTRY(unaligned_data_trap): 502 /* MS: I have to save r11 value and then restore it because 503 * set_bit, clear_eip, set_ee use r11 as temp register if MSR 504 * instructions are not used. We don't need to do if MSR instructions 505 * are used and they use r0 instead of r11. 506 * I am using ENTRY_SP which should be primary used only for stack 507 * pointer saving. */ 508 swi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); 509 set_bip; /* equalize initial state for all possible entries */ 510 clear_eip; 511 set_ee; 512 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); 513 SAVE_STATE /* Save registers.*/ 514 /* PC, before IRQ/trap - this is one instruction above */ 515 swi r17, r1, PT_PC; 516 tovirt(r1,r1) 517 /* where the trap should return need -8 to adjust for rtsd r15, 8 */ 518 addik r15, r0, ret_from_exc-8 519 mfs r3, resr /* ESR */ 520 mfs r4, rear /* EAR */ 521 rtbd r0, _unaligned_data_exception 522 addik r7, r1, 0 /* parameter struct pt_regs * regs */ 523 524/* 525 * Page fault traps. 526 * 527 * If the real exception handler (from hw_exception_handler.S) didn't find 528 * the mapping for the process, then we're thrown here to handle such situation. 529 * 530 * Trap entered via exceptions, so EE bit is set, and interrupts 531 * are masked. This is nice, means we don't have to CLI before state save 532 * 533 * Build a standard exception frame for TLB Access errors. All TLB exceptions 534 * will bail out to this point if they can't resolve the lightweight TLB fault. 535 * 536 * The C function called is in "arch/microblaze/mm/fault.c", declared as: 537 * void do_page_fault(struct pt_regs *regs, 538 * unsigned long address, 539 * unsigned long error_code) 540 */ 541/* data and intruction trap - which is choose is resolved int fault.c */ 542C_ENTRY(page_fault_data_trap): 543 SAVE_STATE /* Save registers.*/ 544 /* PC, before IRQ/trap - this is one instruction above */ 545 swi r17, r1, PT_PC; 546 tovirt(r1,r1) 547 /* where the trap should return need -8 to adjust for rtsd r15, 8 */ 548 addik r15, r0, ret_from_exc-8 549 mfs r6, rear /* parameter unsigned long address */ 550 mfs r7, resr /* parameter unsigned long error_code */ 551 rted r0, do_page_fault 552 addik r5, r1, 0 /* parameter struct pt_regs * regs */ 553 554C_ENTRY(page_fault_instr_trap): 555 SAVE_STATE /* Save registers.*/ 556 /* PC, before IRQ/trap - this is one instruction above */ 557 swi r17, r1, PT_PC; 558 tovirt(r1,r1) 559 /* where the trap should return need -8 to adjust for rtsd r15, 8 */ 560 addik r15, r0, ret_from_exc-8 561 mfs r6, rear /* parameter unsigned long address */ 562 ori r7, r0, 0 /* parameter unsigned long error_code */ 563 rted r0, do_page_fault 564 addik r5, r1, 0 /* parameter struct pt_regs * regs */ 565 566/* Entry point used to return from an exception. */ 567C_ENTRY(ret_from_exc): 568 lwi r11, r1, PT_MODE; 569 bnei r11, 2f; /* See if returning to kernel mode, */ 570 /* ... if so, skip resched &c. */ 571 572 /* We're returning to user mode, so check for various conditions that 573 trigger rescheduling. */ 574 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */ 575 lwi r11, r11, TI_FLAGS; /* get flags in thread info */ 576 andi r11, r11, _TIF_NEED_RESCHED; 577 beqi r11, 5f; 578 579/* Call the scheduler before returning from a syscall/trap. */ 580 bralid r15, schedule; /* Call scheduler */ 581 nop; /* delay slot */ 582 583 /* Maybe handle a signal */ 5845: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */ 585 lwi r11, r11, TI_FLAGS; /* get flags in thread info */ 586 andi r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME; 587 beqi r11, 1f; /* Signals to handle, handle them */ 588 589 /* 590 * Handle a signal return; Pending signals should be in r18. 591 * 592 * Not all registers are saved by the normal trap/interrupt entry 593 * points (for instance, call-saved registers (because the normal 594 * C-compiler calling sequence in the kernel makes sure they're 595 * preserved), and call-clobbered registers in the case of 596 * traps), but signal handlers may want to examine or change the 597 * complete register state. Here we save anything not saved by 598 * the normal entry sequence, so that it may be safely restored 599 * (in a possibly modified form) after do_notify_resume returns. */ 600 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */ 601 bralid r15, do_notify_resume; /* Handle any signals */ 602 addi r6, r0, 0; /* Arg 2: int in_syscall */ 603 604/* Finally, return to user state. */ 6051: set_bip; /* Ints masked for state restore */ 606 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */ 607 VM_OFF; 608 tophys(r1,r1); 609 610 RESTORE_REGS; 611 addik r1, r1, PT_SIZE /* Clean up stack space. */ 612 613 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */ 614 bri 6f; 615/* Return to kernel state. */ 6162: set_bip; /* Ints masked for state restore */ 617 VM_OFF; 618 tophys(r1,r1); 619 RESTORE_REGS; 620 addik r1, r1, PT_SIZE /* Clean up stack space. */ 621 622 tovirt(r1,r1); 6236: 624EXC_return: /* Make global symbol for debugging */ 625 rtbd r14, 0; /* Instructions to return from an IRQ */ 626 nop; 627 628/* 629 * HW EXCEPTION rutine end 630 */ 631 632/* 633 * Hardware maskable interrupts. 634 * 635 * The stack-pointer (r1) should have already been saved to the memory 636 * location PER_CPU(ENTRY_SP). 637 */ 638C_ENTRY(_interrupt): 639/* MS: we are in physical address */ 640/* Save registers, switch to proper stack, convert SP to virtual.*/ 641 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) 642 /* MS: See if already in kernel mode. */ 643 mfs r1, rmsr 644 nop 645 andi r1, r1, MSR_UMS 646 bnei r1, 1f 647 648/* Kernel-mode state save. */ 649 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) 650 tophys(r1,r1); /* MS: I have in r1 physical address where stack is */ 651 /* save registers */ 652/* MS: Make room on the stack -> activation record */ 653 addik r1, r1, -PT_SIZE; 654 SAVE_REGS 655 brid 2f; 656 swi r1, r1, PT_MODE; /* 0 - user mode, 1 - kernel mode */ 6571: 658/* User-mode state save. */ 659 /* MS: get the saved current */ 660 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); 661 tophys(r1,r1); 662 lwi r1, r1, TS_THREAD_INFO; 663 addik r1, r1, THREAD_SIZE; 664 tophys(r1,r1); 665 /* save registers */ 666 addik r1, r1, -PT_SIZE; 667 SAVE_REGS 668 /* calculate mode */ 669 swi r0, r1, PT_MODE; 670 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); 671 swi r11, r1, PT_R1; 672 clear_ums; 6732: 674 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); 675 tovirt(r1,r1) 676 addik r15, r0, irq_call; 677irq_call:rtbd r0, do_IRQ; 678 addik r5, r1, 0; 679 680/* MS: we are in virtual mode */ 681ret_from_irq: 682 lwi r11, r1, PT_MODE; 683 bnei r11, 2f; 684 685 lwi r11, CURRENT_TASK, TS_THREAD_INFO; 686 lwi r11, r11, TI_FLAGS; /* MS: get flags from thread info */ 687 andi r11, r11, _TIF_NEED_RESCHED; 688 beqi r11, 5f 689 bralid r15, schedule; 690 nop; /* delay slot */ 691 692 /* Maybe handle a signal */ 6935: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* MS: get thread info */ 694 lwi r11, r11, TI_FLAGS; /* get flags in thread info */ 695 andi r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME; 696 beqid r11, no_intr_resched 697/* Handle a signal return; Pending signals should be in r18. */ 698 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */ 699 bralid r15, do_notify_resume; /* Handle any signals */ 700 addi r6, r0, 0; /* Arg 2: int in_syscall */ 701 702/* Finally, return to user state. */ 703no_intr_resched: 704 /* Disable interrupts, we are now committed to the state restore */ 705 disable_irq 706 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); 707 VM_OFF; 708 tophys(r1,r1); 709 RESTORE_REGS 710 addik r1, r1, PT_SIZE /* MS: Clean up stack space. */ 711 lwi r1, r1, PT_R1 - PT_SIZE; 712 bri 6f; 713/* MS: Return to kernel state. */ 7142: 715#ifdef CONFIG_PREEMPT 716 lwi r11, CURRENT_TASK, TS_THREAD_INFO; 717 /* MS: get preempt_count from thread info */ 718 lwi r5, r11, TI_PREEMPT_COUNT; 719 bgti r5, restore; 720 721 lwi r5, r11, TI_FLAGS; /* get flags in thread info */ 722 andi r5, r5, _TIF_NEED_RESCHED; 723 beqi r5, restore /* if zero jump over */ 724 725preempt: 726 /* interrupts are off that's why I am calling preempt_chedule_irq */ 727 bralid r15, preempt_schedule_irq 728 nop 729 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */ 730 lwi r5, r11, TI_FLAGS; /* get flags in thread info */ 731 andi r5, r5, _TIF_NEED_RESCHED; 732 bnei r5, preempt /* if non zero jump to resched */ 733restore: 734#endif 735 VM_OFF /* MS: turn off MMU */ 736 tophys(r1,r1) 737 RESTORE_REGS 738 addik r1, r1, PT_SIZE /* MS: Clean up stack space. */ 739 tovirt(r1,r1); 7406: 741IRQ_return: /* MS: Make global symbol for debugging */ 742 rtid r14, 0 743 nop 744 745/* 746 * Debug trap for KGDB. Enter to _debug_exception by brki r16, 0x18 747 * and call handling function with saved pt_regs 748 */ 749C_ENTRY(_debug_exception): 750 /* BIP bit is set on entry, no interrupts can occur */ 751 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) 752 753 mfs r1, rmsr 754 nop 755 andi r1, r1, MSR_UMS 756 bnei r1, 1f 757/* MS: Kernel-mode state save - kgdb */ 758 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/ 759 760 /* BIP bit is set on entry, no interrupts can occur */ 761 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; 762 SAVE_REGS; 763 /* save all regs to pt_reg structure */ 764 swi r0, r1, PT_R0; /* R0 must be saved too */ 765 swi r14, r1, PT_R14 /* rewrite saved R14 value */ 766 swi r16, r1, PT_PC; /* PC and r16 are the same */ 767 /* save special purpose registers to pt_regs */ 768 mfs r11, rear; 769 swi r11, r1, PT_EAR; 770 mfs r11, resr; 771 swi r11, r1, PT_ESR; 772 mfs r11, rfsr; 773 swi r11, r1, PT_FSR; 774 775 /* stack pointer is in physical address at it is decrease 776 * by PT_SIZE but we need to get correct R1 value */ 777 addik r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + PT_SIZE; 778 swi r11, r1, PT_R1 779 /* MS: r31 - current pointer isn't changed */ 780 tovirt(r1,r1) 781#ifdef CONFIG_KGDB 782 addi r5, r1, 0 /* pass pt_reg address as the first arg */ 783 addik r15, r0, dbtrap_call; /* return address */ 784 rtbd r0, microblaze_kgdb_break 785 nop; 786#endif 787 /* MS: Place handler for brki from kernel space if KGDB is OFF. 788 * It is very unlikely that another brki instruction is called. */ 789 bri 0 790 791/* MS: User-mode state save - gdb */ 7921: lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */ 793 tophys(r1,r1); 794 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */ 795 addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */ 796 tophys(r1,r1); 797 798 addik r1, r1, -PT_SIZE; /* Make room on the stack. */ 799 SAVE_REGS; 800 swi r16, r1, PT_PC; /* Save LP */ 801 swi r0, r1, PT_MODE; /* Was in user-mode. */ 802 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); 803 swi r11, r1, PT_R1; /* Store user SP. */ 804 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); 805 tovirt(r1,r1) 806 set_vms; 807 addik r5, r1, 0; 808 addik r15, r0, dbtrap_call; 809dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */ 810 rtbd r0, sw_exception 811 nop 812 813 /* MS: The first instruction for the second part of the gdb/kgdb */ 814 set_bip; /* Ints masked for state restore */ 815 lwi r11, r1, PT_MODE; 816 bnei r11, 2f; 817/* MS: Return to user space - gdb */ 818 /* Get current task ptr into r11 */ 819 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */ 820 lwi r11, r11, TI_FLAGS; /* get flags in thread info */ 821 andi r11, r11, _TIF_NEED_RESCHED; 822 beqi r11, 5f; 823 824 /* Call the scheduler before returning from a syscall/trap. */ 825 bralid r15, schedule; /* Call scheduler */ 826 nop; /* delay slot */ 827 828 /* Maybe handle a signal */ 8295: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */ 830 lwi r11, r11, TI_FLAGS; /* get flags in thread info */ 831 andi r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME; 832 beqi r11, 1f; /* Signals to handle, handle them */ 833 834 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */ 835 bralid r15, do_notify_resume; /* Handle any signals */ 836 addi r6, r0, 0; /* Arg 2: int in_syscall */ 837 838/* Finally, return to user state. */ 8391: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */ 840 VM_OFF; 841 tophys(r1,r1); 842 /* MS: Restore all regs */ 843 RESTORE_REGS 844 addik r1, r1, PT_SIZE /* Clean up stack space */ 845 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer */ 846DBTRAP_return_user: /* MS: Make global symbol for debugging */ 847 rtbd r16, 0; /* MS: Instructions to return from a debug trap */ 848 nop; 849 850/* MS: Return to kernel state - kgdb */ 8512: VM_OFF; 852 tophys(r1,r1); 853 /* MS: Restore all regs */ 854 RESTORE_REGS 855 lwi r14, r1, PT_R14; 856 lwi r16, r1, PT_PC; 857 addik r1, r1, PT_SIZE; /* MS: Clean up stack space */ 858 tovirt(r1,r1); 859DBTRAP_return_kernel: /* MS: Make global symbol for debugging */ 860 rtbd r16, 0; /* MS: Instructions to return from a debug trap */ 861 nop; 862 863 864ENTRY(_switch_to) 865 /* prepare return value */ 866 addk r3, r0, CURRENT_TASK 867 868 /* save registers in cpu_context */ 869 /* use r11 and r12, volatile registers, as temp register */ 870 /* give start of cpu_context for previous process */ 871 addik r11, r5, TI_CPU_CONTEXT 872 swi r1, r11, CC_R1 873 swi r2, r11, CC_R2 874 /* skip volatile registers. 875 * they are saved on stack when we jumped to _switch_to() */ 876 /* dedicated registers */ 877 swi r13, r11, CC_R13 878 swi r14, r11, CC_R14 879 swi r15, r11, CC_R15 880 swi r16, r11, CC_R16 881 swi r17, r11, CC_R17 882 swi r18, r11, CC_R18 883 /* save non-volatile registers */ 884 swi r19, r11, CC_R19 885 swi r20, r11, CC_R20 886 swi r21, r11, CC_R21 887 swi r22, r11, CC_R22 888 swi r23, r11, CC_R23 889 swi r24, r11, CC_R24 890 swi r25, r11, CC_R25 891 swi r26, r11, CC_R26 892 swi r27, r11, CC_R27 893 swi r28, r11, CC_R28 894 swi r29, r11, CC_R29 895 swi r30, r11, CC_R30 896 /* special purpose registers */ 897 mfs r12, rmsr 898 swi r12, r11, CC_MSR 899 mfs r12, rear 900 swi r12, r11, CC_EAR 901 mfs r12, resr 902 swi r12, r11, CC_ESR 903 mfs r12, rfsr 904 swi r12, r11, CC_FSR 905 906 /* update r31, the current-give me pointer to task which will be next */ 907 lwi CURRENT_TASK, r6, TI_TASK 908 /* stored it to current_save too */ 909 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE) 910 911 /* get new process' cpu context and restore */ 912 /* give me start where start context of next task */ 913 addik r11, r6, TI_CPU_CONTEXT 914 915 /* non-volatile registers */ 916 lwi r30, r11, CC_R30 917 lwi r29, r11, CC_R29 918 lwi r28, r11, CC_R28 919 lwi r27, r11, CC_R27 920 lwi r26, r11, CC_R26 921 lwi r25, r11, CC_R25 922 lwi r24, r11, CC_R24 923 lwi r23, r11, CC_R23 924 lwi r22, r11, CC_R22 925 lwi r21, r11, CC_R21 926 lwi r20, r11, CC_R20 927 lwi r19, r11, CC_R19 928 /* dedicated registers */ 929 lwi r18, r11, CC_R18 930 lwi r17, r11, CC_R17 931 lwi r16, r11, CC_R16 932 lwi r15, r11, CC_R15 933 lwi r14, r11, CC_R14 934 lwi r13, r11, CC_R13 935 /* skip volatile registers */ 936 lwi r2, r11, CC_R2 937 lwi r1, r11, CC_R1 938 939 /* special purpose registers */ 940 lwi r12, r11, CC_FSR 941 mts rfsr, r12 942 lwi r12, r11, CC_MSR 943 mts rmsr, r12 944 945 rtsd r15, 8 946 nop 947 948ENTRY(_reset) 949 brai 0; /* Jump to reset vector */ 950 951 /* These are compiled and loaded into high memory, then 952 * copied into place in mach_early_setup */ 953 .section .init.ivt, "ax" 954#if CONFIG_MANUAL_RESET_VECTOR 955 .org 0x0 956 brai CONFIG_MANUAL_RESET_VECTOR 957#endif 958 .org 0x8 959 brai TOPHYS(_user_exception); /* syscall handler */ 960 .org 0x10 961 brai TOPHYS(_interrupt); /* Interrupt handler */ 962 .org 0x18 963 brai TOPHYS(_debug_exception); /* debug trap handler */ 964 .org 0x20 965 brai TOPHYS(_hw_exception_handler); /* HW exception handler */ 966 967.section .rodata,"a" 968#include "syscall_table.S" 969 970syscall_table_size=(.-sys_call_table) 971 972type_SYSCALL: 973 .ascii "SYSCALL\0" 974type_IRQ: 975 .ascii "IRQ\0" 976type_IRQ_PREEMPT: 977 .ascii "IRQ (PREEMPTED)\0" 978type_SYSCALL_PREEMPT: 979 .ascii " SYSCALL (PREEMPTED)\0" 980 981 /* 982 * Trap decoding for stack unwinder 983 * Tuples are (start addr, end addr, string) 984 * If return address lies on [start addr, end addr], 985 * unwinder displays 'string' 986 */ 987 988 .align 4 989.global microblaze_trap_handlers 990microblaze_trap_handlers: 991 /* Exact matches come first */ 992 .word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL 993 .word ret_from_irq ; .word ret_from_irq ; .word type_IRQ 994 /* Fuzzy matches go here */ 995 .word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT 996 .word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT 997 /* End of table */ 998 .word 0 ; .word 0 ; .word 0 999