2 * arch/ppc64/kernel/entry.S
5 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
6 * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
7 * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
8 * Adapted for Power Macintosh by Paul Mackerras.
9 * Low-level exception handlers and MMU support
10 * rewritten by Paul Mackerras.
11 * Copyright (C) 1996 Paul Mackerras.
12 * MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
14 * This file contains the system call entry code, context switch
15 * code, and exception/interrupt return code for PowerPC.
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License
19 * as published by the Free Software Foundation; either version
20 * 2 of the License, or (at your option) any later version.
23 #include <linux/config.h>
24 #include <linux/errno.h>
25 #include <asm/unistd.h>
26 #include <asm/processor.h>
29 #include <asm/thread_info.h>
30 #include <asm/ppc_asm.h>
31 #include <asm/offsets.h>
32 #include <asm/cputable.h>
34 #ifdef CONFIG_PPC_ISERIES
35 #define DO_SOFT_DISABLE
43 .tc .sys_call_table[TC],.sys_call_table
46 .tc .sys_call_table32[TC],.sys_call_table32
48 /* This value is used to mark exception frames on the stack. */
50 .tc ID_72656773_68657265[TC],0x7265677368657265
57 .globl SystemCall_common
61 addi r1,r1,-INT_FRAME_SIZE
95 addi r9,r1,STACK_FRAME_OVERHEAD
96 ld r11,exception_marker@toc(r2)
97 std r11,-16(r9) /* "regshere" marker */
98 #ifdef CONFIG_PPC_ISERIES
99 /* Hack for handling interrupts when soft-enabling on iSeries */
100 cmpdi cr1,r0,0x5555 /* syscall 0x5555 */
101 andi. r10,r12,MSR_PR /* from kernel */
102 crand 4*cr0+eq,4*cr1+eq,4*cr0+eq
103 beq HardwareInterrupt_entry
104 lbz r10,PACAPROCENABLED(r13)
116 addi r9,r1,STACK_FRAME_OVERHEAD
118 clrrdi r11,r1,THREAD_SHIFT
121 stb r12,TI_SC_NOERR(r11)
122 andi. r11,r10,_TIF_SYSCALL_T_OR_A
124 syscall_dotrace_cont:
125 cmpli 0,r0,NR_syscalls
128 system_call: /* label this so stack traces look sane */
130 * Need to vector to 32 Bit or default sys_call_table here,
131 * based on caller's run-mode / personality.
133 ld r11,.SYS_CALL_TABLE@toc(2)
134 andi. r10,r10,_TIF_32BIT
136 ld r11,.SYS_CALL_TABLE32@toc(2)
145 ldx r10,r11,r0 /* Fetch system call handler [ptr] */
147 blrl /* Call handler */
152 bl .do_show_syscall_exit
159 clrrdi r12,r1,THREAD_SHIFT
163 /* check for syscall tracing or audit */
165 andi. r0,r9,_TIF_SYSCALL_T_OR_A
166 bne- syscall_exit_trace
167 syscall_exit_trace_cont:
169 /* disable interrupts so current_thread_info()->flags can't change,
170 and so that we don't get interrupted after loading SRR0/1. */
179 andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SIGPENDING|_TIF_NEED_RESCHED)
180 bne- syscall_exit_work
182 stdcx. r0,0,r1 /* to clear the reservation */
185 beq 1f /* only restore r13 if */
186 ld r13,GPR13(r1) /* returning to usermode */
191 mtmsrd r10,1 /* clear MSR.RI */
201 clrrdi r12,r1,THREAD_SHIFT
205 lbz r11,TI_SC_NOERR(r12)
207 bne- syscall_error_cont
209 oris r5,r5,0x1000 /* Set SO bit in CR */
213 /* Traced system call support */
216 addi r3,r1,STACK_FRAME_OVERHEAD
217 bl .do_syscall_trace_enter
218 ld r0,GPR0(r1) /* Restore original registers */
225 addi r9,r1,STACK_FRAME_OVERHEAD
226 clrrdi r10,r1,THREAD_SHIFT
228 b syscall_dotrace_cont
233 bl .do_syscall_trace_leave
237 clrrdi r12,r1,THREAD_SHIFT
238 b syscall_exit_trace_cont
240 /* Stuff to do on exit from a system call. */
244 b .ret_from_except_lite
246 /* Save non-volatile GPRs, if not already saved. */
257 * The sigsuspend and rt_sigsuspend system calls can call do_signal
258 * and thus put the process into the stopped state where we might
259 * want to examine its user state with ptrace. Therefore we need
260 * to save all the nonvolatile registers (r14 - r31) before calling
261 * the C code. Similarly, fork, vfork and clone need the full
262 * register state on the stack so that it can be copied to the child.
264 _GLOBAL(ppc32_sigsuspend)
269 _GLOBAL(ppc64_rt_sigsuspend)
271 bl .sys_rt_sigsuspend
274 _GLOBAL(ppc32_rt_sigsuspend)
276 bl .sys32_rt_sigsuspend
294 _GLOBAL(ppc32_swapcontext)
296 bl .sys32_swapcontext
299 _GLOBAL(ppc64_swapcontext)
304 _GLOBAL(ppc32_sigreturn)
308 _GLOBAL(ppc32_rt_sigreturn)
309 bl .sys32_rt_sigreturn
312 _GLOBAL(ppc64_rt_sigreturn)
317 clrrdi r4,r1,THREAD_SHIFT
319 andi. r4,r4,_TIF_SYSCALL_T_OR_A
321 bl .do_syscall_trace_leave
322 81: b .ret_from_except
324 _GLOBAL(ret_from_fork)
331 * This routine switches between two different tasks. The process
332 * state of one is saved on its kernel stack. Then the state
333 * of the other is restored from its kernel stack. The memory
334 * management hardware is updated to the second process's state.
335 * Finally, we can return to the second process, via ret_from_except.
336 * On entry, r3 points to the THREAD for the current task, r4
337 * points to the THREAD for the new task.
339 * Note: there are two ways to get to the "going out" portion
340 * of this code; either by coming in via the entry (_switch)
341 * or via "fork" which must set up an environment equivalent
342 * to the "_switch" path. If you change this you'll have to change
343 * the fork code also.
345 * The code which creates the new task context is in 'copy_thread'
346 * in arch/ppc64/kernel/process.c
352 stdu r1,-SWITCH_FRAME_SIZE(r1)
353 /* r3-r13 are caller saved -- Cort */
356 mflr r20 /* Return to switch caller */
359 #ifdef CONFIG_ALTIVEC
361 oris r0,r0,MSR_VEC@h /* Disable altivec */
362 mfspr r24,SPRN_VRSAVE /* save vrsave register value */
363 std r24,THREAD_VRSAVE(r3)
364 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
365 #endif /* CONFIG_ALTIVEC */
374 std r1,KSP(r3) /* Set old stack pointer */
377 /* We need a sync somewhere here to make sure that if the
378 * previous task gets rescheduled on another CPU, it sees all
379 * stores it has performed on this one.
382 #endif /* CONFIG_SMP */
384 addi r6,r4,-THREAD /* Convert THREAD to 'current' */
385 std r6,PACACURRENT(r13) /* Set new 'current' */
387 ld r8,KSP(r4) /* new stack pointer */
389 clrrdi r6,r8,28 /* get its ESID */
390 clrrdi r9,r1,28 /* get current sp ESID */
391 clrldi. r0,r6,2 /* is new ESID c00000000? */
392 cmpd cr1,r6,r9 /* or is new ESID the same as current ESID? */
394 beq 2f /* if yes, don't slbie it */
395 oris r6,r6,0x0800 /* set C (class) bit */
397 slbie r6 /* Workaround POWER5 < DD2.1 issue */
399 END_FTR_SECTION_IFSET(CPU_FTR_SLB)
400 clrrdi r7,r8,THREAD_SHIFT /* base of new stack */
401 /* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE
402 because we don't need to leave the 288-byte ABI gap at the
403 top of the kernel stack. */
404 addi r7,r7,THREAD_SIZE-SWITCH_FRAME_SIZE
406 mr r1,r8 /* start using new stack pointer */
407 std r7,PACAKSAVE(r13)
412 #ifdef CONFIG_ALTIVEC
414 ld r0,THREAD_VRSAVE(r4)
415 mtspr SPRN_VRSAVE,r0 /* if G4, restore VRSAVE reg */
416 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
417 #endif /* CONFIG_ALTIVEC */
419 /* r3-r13 are destroyed -- Cort */
423 #ifdef CONFIG_PPC_ISERIES
424 clrrdi r7,r1,THREAD_SHIFT /* get current_thread_info() */
425 ld r7,TI_FLAGS(r7) /* Get run light flag */
427 srdi r7,r7,TIF_RUN_LIGHT
428 insrdi r9,r7,1,63 /* Insert run light into CTRL */
432 /* convert old thread to its task_struct for return value */
434 ld r7,_NIP(r1) /* Return to _switch caller in new task */
436 addi r1,r1,SWITCH_FRAME_SIZE
440 _GLOBAL(ret_from_except)
443 bne .ret_from_except_lite
446 _GLOBAL(ret_from_except_lite)
448 * Disable interrupts so that current_thread_info()->flags
449 * can't change between when we test it and when we return
450 * from the interrupt.
452 mfmsr r10 /* Get current interrupt state */
453 rldicl r9,r10,48,1 /* clear MSR_EE */
455 mtmsrd r9,1 /* Update machine state */
457 #ifdef CONFIG_PREEMPT
458 clrrdi r9,r1,THREAD_SHIFT /* current_thread_info() */
459 li r0,_TIF_NEED_RESCHED /* bits to check */
462 /* Move MSR_PR bit in r3 to _TIF_SIGPENDING position in r0 */
463 rlwimi r0,r3,32+TIF_SIGPENDING-MSR_PR_LG,_TIF_SIGPENDING
464 and. r0,r4,r0 /* check NEED_RESCHED and maybe SIGPENDING */
467 #else /* !CONFIG_PREEMPT */
468 ld r3,_MSR(r1) /* Returning to user mode? */
470 beq restore /* if not, just restore regs and return */
472 /* Check current_thread_info()->flags */
473 clrrdi r9,r1,THREAD_SHIFT
475 andi. r0,r4,_TIF_USER_WORK_MASK
480 #ifdef CONFIG_PPC_ISERIES
484 /* Check for pending interrupts (iSeries) */
485 ld r3,PACALPPACA+LPPACAANYINT(r13)
487 beq+ 4f /* skip do_IRQ if no interrupts */
490 stb r3,PACAPROCENABLED(r13) /* ensure we are soft-disabled */
491 mtmsrd r10 /* hard-enable again */
492 addi r3,r1,STACK_FRAME_OVERHEAD
494 b .ret_from_except /* loop back and handle more */
496 4: stb r5,PACAPROCENABLED(r13)
506 * r13 is our per cpu area, only restore it if we are returning to
521 stdcx. r0,0,r1 /* to clear the reservation */
545 /* Note: this must change if we start using the TIF_NOTIFY_RESUME bit */
547 #ifdef CONFIG_PREEMPT
548 andi. r0,r3,MSR_PR /* Returning to user mode? */
550 /* Check that preempt_count() == 0 and interrupts are enabled */
551 lwz r8,TI_PREEMPT(r9)
553 #ifdef CONFIG_PPC_ISERIES
559 crandc eq,cr1*4+eq,eq
561 /* here we are preempting the current task */
562 1: lis r0,PREEMPT_ACTIVE@h
563 stw r0,TI_PREEMPT(r9)
564 #ifdef CONFIG_PPC_ISERIES
566 stb r0,PACAPROCENABLED(r13)
568 mtmsrd r10,1 /* reenable interrupts */
571 clrrdi r9,r1,THREAD_SHIFT
572 rldicl r10,r10,48,1 /* disable interrupts again */
577 andi. r0,r4,_TIF_NEED_RESCHED
579 stw r0,TI_PREEMPT(r9)
584 /* Enable interrupts */
587 andi. r0,r4,_TIF_NEED_RESCHED
590 b .ret_from_except_lite
594 addi r4,r1,STACK_FRAME_OVERHEAD
599 addi r3,r1,STACK_FRAME_OVERHEAD
600 bl .unrecoverable_exception
603 #ifdef CONFIG_PPC_PSERIES
605 * On CHRP, the Run-Time Abstraction Services (RTAS) have to be
606 * called with the MMU off.
608 * In addition, we need to be in 32b mode, at least for now.
610 * Note: r3 is an input parameter to rtas, so don't trash it...
615 stdu r1,-RTAS_FRAME_SIZE(r1) /* Save SP and create stack space. */
617 /* Because RTAS is running in 32b mode, it clobbers the high order half
618 * of all registers that it saves. We therefore save those registers
619 * RTAS might touch to the stack. (r0, r3-r13 are caller saved)
621 SAVE_GPR(2, r1) /* Save the TOC */
622 SAVE_GPR(13, r1) /* Save paca */
623 SAVE_8GPRS(14, r1) /* Save the non-volatiles */
624 SAVE_10GPRS(22, r1) /* ditto */
641 /* There is no way it is acceptable to get here with interrupts enabled,
642 * check it with the asm equivalent of WARN_ON
647 .section __bug_table,"a"
648 .llong 1b,__LINE__ + 0x1000000, 1f, 2f
652 2: .asciz "enter_rtas"
655 /* Unfortunately, the stack pointer and the MSR are also clobbered,
656 * so they are saved in the PACA which allows us to restore
657 * our original state after RTAS returns.
660 std r6,PACASAVEDMSR(r13)
662 /* Setup our real return addr */
663 SET_REG_TO_LABEL(r4,.rtas_return_loc)
664 SET_REG_TO_CONST(r9,KERNELBASE)
669 ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI
673 rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG)
674 ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP
677 sync /* disable interrupts so SRR0/1 */
678 mtmsrd r0 /* don't get trashed */
680 SET_REG_TO_LABEL(r4,rtas)
681 ld r5,RTASENTRY(r4) /* get the rtas->entry value */
682 ld r4,RTASBASE(r4) /* get the rtas->base value */
688 _STATIC(rtas_return_loc)
689 /* relocation is off at this point */
690 mfspr r4,SPRG3 /* Get PACA */
691 SET_REG_TO_CONST(r5, KERNELBASE)
692 sub r4,r4,r5 /* RELOC the PACA base pointer */
700 ld r1,PACAR1(r4) /* Restore our SP */
701 LOADADDR(r3,.rtas_restore_regs)
702 ld r4,PACASAVEDMSR(r4) /* Restore our MSR */
708 _STATIC(rtas_restore_regs)
709 /* relocation is on at this point */
710 REST_GPR(2, r1) /* Restore the TOC */
711 REST_GPR(13, r1) /* Restore paca */
712 REST_8GPRS(14, r1) /* Restore the non-volatiles */
713 REST_10GPRS(22, r1) /* ditto */
732 addi r1,r1,RTAS_FRAME_SIZE /* Unstack our frame */
733 ld r0,16(r1) /* get return address */
736 blr /* return to caller */
741 stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */
743 /* Because PROM is running in 32b mode, it clobbers the high order half
744 * of all registers that it saves. We therefore save those registers
745 * PROM might touch to the stack. (r0, r3-r13 are caller saved)
768 /* Get the PROM entrypoint */
772 ld r12,PROMENTRY(r12)
775 /* Switch MSR to 32 bits mode
779 rldicr r12,r12,MSR_SF_LG,(63-MSR_SF_LG)
782 rldicr r12,r12,MSR_ISF_LG,(63-MSR_ISF_LG)
787 /* Restore arguments & enter PROM here... */
791 /* Just make sure that r1 top 32 bits didn't get
796 /* Restore the MSR (back to 64 bits) */
801 /* Restore other registers */
821 addi r1,r1,PROM_FRAME_SIZE
826 #endif /* defined(CONFIG_PPC_PSERIES) */