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Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 1000 |
1 files changed, 1000 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S new file mode 100644 index 00000000000..2e99ae41723 --- /dev/null +++ b/arch/powerpc/kernel/entry_32.S @@ -0,0 +1,1000 @@ +/* + * PowerPC version + * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) + * Rewritten by Cort Dougan (cort@fsmlabs.com) for PReP + * Copyright (C) 1996 Cort Dougan <cort@fsmlabs.com> + * Adapted for Power Macintosh by Paul Mackerras. + * Low-level exception handlers and MMU support + * rewritten by Paul Mackerras. + * Copyright (C) 1996 Paul Mackerras. + * MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net). + * + * This file contains the system call entry code, context switch + * code, and exception/interrupt return code for PowerPC. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + */ + +#include <linux/config.h> +#include <linux/errno.h> +#include <linux/sys.h> +#include <linux/threads.h> +#include <asm/reg.h> +#include <asm/page.h> +#include <asm/mmu.h> +#include <asm/cputable.h> +#include <asm/thread_info.h> +#include <asm/ppc_asm.h> +#include <asm/asm-offsets.h> +#include <asm/unistd.h> + +#undef SHOW_SYSCALLS +#undef SHOW_SYSCALLS_TASK + +/* + * MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE. + */ +#if MSR_KERNEL >= 0x10000 +#define LOAD_MSR_KERNEL(r, x) lis r,(x)@h; ori r,r,(x)@l +#else +#define LOAD_MSR_KERNEL(r, x) li r,(x) +#endif + +#ifdef CONFIG_BOOKE +#include "head_booke.h" +#define TRANSFER_TO_HANDLER_EXC_LEVEL(exc_level) \ + mtspr exc_level##_SPRG,r8; \ + BOOKE_LOAD_EXC_LEVEL_STACK(exc_level); \ + lwz r0,GPR10-INT_FRAME_SIZE(r8); \ + stw r0,GPR10(r11); \ + lwz r0,GPR11-INT_FRAME_SIZE(r8); \ + stw r0,GPR11(r11); \ + mfspr r8,exc_level##_SPRG + + .globl mcheck_transfer_to_handler +mcheck_transfer_to_handler: + TRANSFER_TO_HANDLER_EXC_LEVEL(MCHECK) + b transfer_to_handler_full + + .globl debug_transfer_to_handler +debug_transfer_to_handler: + TRANSFER_TO_HANDLER_EXC_LEVEL(DEBUG) + b transfer_to_handler_full + + .globl crit_transfer_to_handler +crit_transfer_to_handler: + TRANSFER_TO_HANDLER_EXC_LEVEL(CRIT) + /* fall through */ +#endif + +#ifdef CONFIG_40x + .globl crit_transfer_to_handler +crit_transfer_to_handler: + lwz r0,crit_r10@l(0) + stw r0,GPR10(r11) + lwz r0,crit_r11@l(0) + stw r0,GPR11(r11) + /* fall through */ +#endif + +/* + * This code finishes saving the registers to the exception frame + * and jumps to the appropriate handler for the exception, turning + * on address translation. + * Note that we rely on the caller having set cr0.eq iff the exception + * occurred in kernel mode (i.e. MSR:PR = 0). + */ + .globl transfer_to_handler_full +transfer_to_handler_full: + SAVE_NVGPRS(r11) + /* fall through */ + + .globl transfer_to_handler +transfer_to_handler: + stw r2,GPR2(r11) + stw r12,_NIP(r11) + stw r9,_MSR(r11) + andi. r2,r9,MSR_PR + mfctr r12 + mfspr r2,SPRN_XER + stw r12,_CTR(r11) + stw r2,_XER(r11) + mfspr r12,SPRN_SPRG3 + addi r2,r12,-THREAD + tovirt(r2,r2) /* set r2 to current */ + beq 2f /* if from user, fix up THREAD.regs */ + addi r11,r1,STACK_FRAME_OVERHEAD + stw r11,PT_REGS(r12) +#if defined(CONFIG_40x) || defined(CONFIG_BOOKE) + /* Check to see if the dbcr0 register is set up to debug. Use the + single-step bit to do this. */ + lwz r12,THREAD_DBCR0(r12) + andis. r12,r12,DBCR0_IC@h + beq+ 3f + /* From user and task is ptraced - load up global dbcr0 */ + li r12,-1 /* clear all pending debug events */ + mtspr SPRN_DBSR,r12 + lis r11,global_dbcr0@ha + tophys(r11,r11) + addi r11,r11,global_dbcr0@l + lwz r12,0(r11) + mtspr SPRN_DBCR0,r12 + lwz r12,4(r11) + addi r12,r12,-1 + stw r12,4(r11) +#endif + b 3f +2: /* if from kernel, check interrupted DOZE/NAP mode and + * check for stack overflow + */ +#ifdef CONFIG_6xx + mfspr r11,SPRN_HID0 + mtcr r11 +BEGIN_FTR_SECTION + bt- 8,power_save_6xx_restore /* Check DOZE */ +END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE) +BEGIN_FTR_SECTION + bt- 9,power_save_6xx_restore /* Check NAP */ +END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP) +#endif /* CONFIG_6xx */ + .globl transfer_to_handler_cont +transfer_to_handler_cont: + lwz r11,THREAD_INFO-THREAD(r12) + cmplw r1,r11 /* if r1 <= current->thread_info */ + ble- stack_ovf /* then the kernel stack overflowed */ +3: + mflr r9 + lwz r11,0(r9) /* virtual address of handler */ + lwz r9,4(r9) /* where to go when done */ + FIX_SRR1(r10,r12) + mtspr SPRN_SRR0,r11 + mtspr SPRN_SRR1,r10 + mtlr r9 + SYNC + RFI /* jump to handler, enable MMU */ + +/* + * On kernel stack overflow, load up an initial stack pointer + * and call StackOverflow(regs), which should not return. + */ +stack_ovf: + /* sometimes we use a statically-allocated stack, which is OK. */ + lis r11,_end@h + ori r11,r11,_end@l + cmplw r1,r11 + ble 3b /* r1 <= &_end is OK */ + SAVE_NVGPRS(r11) + addi r3,r1,STACK_FRAME_OVERHEAD + lis r1,init_thread_union@ha + addi r1,r1,init_thread_union@l + addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD + lis r9,StackOverflow@ha + addi r9,r9,StackOverflow@l + LOAD_MSR_KERNEL(r10,MSR_KERNEL) + FIX_SRR1(r10,r12) + mtspr SPRN_SRR0,r9 + mtspr SPRN_SRR1,r10 + SYNC + RFI + +/* + * Handle a system call. + */ + .stabs "arch/powerpc/kernel/",N_SO,0,0,0f + .stabs "entry_32.S",N_SO,0,0,0f +0: + +_GLOBAL(DoSyscall) + stw r0,THREAD+LAST_SYSCALL(r2) + stw r3,ORIG_GPR3(r1) + li r12,0 + stw r12,RESULT(r1) + lwz r11,_CCR(r1) /* Clear SO bit in CR */ + rlwinm r11,r11,0,4,2 + stw r11,_CCR(r1) +#ifdef SHOW_SYSCALLS + bl do_show_syscall +#endif /* SHOW_SYSCALLS */ + rlwinm r10,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */ + li r11,0 + stb r11,TI_SC_NOERR(r10) + lwz r11,TI_FLAGS(r10) + andi. r11,r11,_TIF_SYSCALL_T_OR_A + bne- syscall_dotrace +syscall_dotrace_cont: + cmplwi 0,r0,NR_syscalls + lis r10,sys_call_table@h + ori r10,r10,sys_call_table@l + slwi r0,r0,2 + bge- 66f + lwzx r10,r10,r0 /* Fetch system call handler [ptr] */ + mtlr r10 + addi r9,r1,STACK_FRAME_OVERHEAD + PPC440EP_ERR42 + blrl /* Call handler */ + .globl ret_from_syscall +ret_from_syscall: +#ifdef SHOW_SYSCALLS + bl do_show_syscall_exit +#endif + mr r6,r3 + li r11,-_LAST_ERRNO + cmplw 0,r3,r11 + rlwinm r12,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */ + blt+ 30f + lbz r11,TI_SC_NOERR(r12) + cmpwi r11,0 + bne 30f + neg r3,r3 + lwz r10,_CCR(r1) /* Set SO bit in CR */ + oris r10,r10,0x1000 + stw r10,_CCR(r1) + + /* disable interrupts so current_thread_info()->flags can't change */ +30: LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */ + SYNC + MTMSRD(r10) + lwz r9,TI_FLAGS(r12) + andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SIGPENDING|_TIF_NEED_RESCHED) + bne- syscall_exit_work +syscall_exit_cont: +#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) + /* If the process has its own DBCR0 value, load it up. The single + step bit tells us that dbcr0 should be loaded. */ + lwz r0,THREAD+THREAD_DBCR0(r2) + andis. r10,r0,DBCR0_IC@h + bnel- load_dbcr0 +#endif + stwcx. r0,0,r1 /* to clear the reservation */ + lwz r4,_LINK(r1) + lwz r5,_CCR(r1) + mtlr r4 + mtcr r5 + lwz r7,_NIP(r1) + lwz r8,_MSR(r1) + FIX_SRR1(r8, r0) + lwz r2,GPR2(r1) + lwz r1,GPR1(r1) + mtspr SPRN_SRR0,r7 + mtspr SPRN_SRR1,r8 + SYNC + RFI + +66: li r3,-ENOSYS + b ret_from_syscall + + .globl ret_from_fork +ret_from_fork: + REST_NVGPRS(r1) + bl schedule_tail + li r3,0 + b ret_from_syscall + +/* Traced system call support */ +syscall_dotrace: + SAVE_NVGPRS(r1) + li r0,0xc00 + stw r0,_TRAP(r1) + addi r3,r1,STACK_FRAME_OVERHEAD + bl do_syscall_trace_enter + lwz r0,GPR0(r1) /* Restore original registers */ + lwz r3,GPR3(r1) + lwz r4,GPR4(r1) + lwz r5,GPR5(r1) + lwz r6,GPR6(r1) + lwz r7,GPR7(r1) + lwz r8,GPR8(r1) + REST_NVGPRS(r1) + b syscall_dotrace_cont + +syscall_exit_work: + stw r6,RESULT(r1) /* Save result */ + stw r3,GPR3(r1) /* Update return value */ + andi. r0,r9,_TIF_SYSCALL_T_OR_A + beq 5f + ori r10,r10,MSR_EE + SYNC + MTMSRD(r10) /* re-enable interrupts */ + lwz r4,_TRAP(r1) + andi. r4,r4,1 + beq 4f + SAVE_NVGPRS(r1) + li r4,0xc00 + stw r4,_TRAP(r1) +4: + addi r3,r1,STACK_FRAME_OVERHEAD + bl do_syscall_trace_leave + REST_NVGPRS(r1) +2: + lwz r3,GPR3(r1) + LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */ + SYNC + MTMSRD(r10) /* disable interrupts again */ + rlwinm r12,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */ + lwz r9,TI_FLAGS(r12) +5: + andi. r0,r9,_TIF_NEED_RESCHED + bne 1f + lwz r5,_MSR(r1) + andi. r5,r5,MSR_PR + beq syscall_exit_cont + andi. r0,r9,_TIF_SIGPENDING + beq syscall_exit_cont + b do_user_signal +1: + ori r10,r10,MSR_EE + SYNC + MTMSRD(r10) /* re-enable interrupts */ + bl schedule + b 2b + +#ifdef SHOW_SYSCALLS +do_show_syscall: +#ifdef SHOW_SYSCALLS_TASK + lis r11,show_syscalls_task@ha + lwz r11,show_syscalls_task@l(r11) + cmp 0,r2,r11 + bnelr +#endif + stw r31,GPR31(r1) + mflr r31 + lis r3,7f@ha + addi r3,r3,7f@l + lwz r4,GPR0(r1) + lwz r5,GPR3(r1) + lwz r6,GPR4(r1) + lwz r7,GPR5(r1) + lwz r8,GPR6(r1) + lwz r9,GPR7(r1) + bl printk + lis r3,77f@ha + addi r3,r3,77f@l + lwz r4,GPR8(r1) + mr r5,r2 + bl printk + lwz r0,GPR0(r1) + lwz r3,GPR3(r1) + lwz r4,GPR4(r1) + lwz r5,GPR5(r1) + lwz r6,GPR6(r1) + lwz r7,GPR7(r1) + lwz r8,GPR8(r1) + mtlr r31 + lwz r31,GPR31(r1) + blr + +do_show_syscall_exit: +#ifdef SHOW_SYSCALLS_TASK + lis r11,show_syscalls_task@ha + lwz r11,show_syscalls_task@l(r11) + cmp 0,r2,r11 + bnelr +#endif + stw r31,GPR31(r1) + mflr r31 + stw r3,RESULT(r1) /* Save result */ + mr r4,r3 + lis r3,79f@ha + addi r3,r3,79f@l + bl printk + lwz r3,RESULT(r1) + mtlr r31 + lwz r31,GPR31(r1) + blr + +7: .string "syscall %d(%x, %x, %x, %x, %x, " +77: .string "%x), current=%p\n" +79: .string " -> %x\n" + .align 2,0 + +#ifdef SHOW_SYSCALLS_TASK + .data + .globl show_syscalls_task +show_syscalls_task: + .long -1 + .text +#endif +#endif /* SHOW_SYSCALLS */ + +/* + * The sigsuspend and rt_sigsuspend system calls can call do_signal + * and thus put the process into the stopped state where we might + * want to examine its user state with ptrace. Therefore we need + * to save all the nonvolatile registers (r13 - r31) before calling + * the C code. + */ + .globl ppc_sigsuspend +ppc_sigsuspend: + SAVE_NVGPRS(r1) + lwz r0,_TRAP(r1) + rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ + stw r0,_TRAP(r1) /* register set saved */ + b sys_sigsuspend + + .globl ppc_rt_sigsuspend +ppc_rt_sigsuspend: + SAVE_NVGPRS(r1) + lwz r0,_TRAP(r1) + rlwinm r0,r0,0,0,30 + stw r0,_TRAP(r1) + b sys_rt_sigsuspend + + .globl ppc_fork +ppc_fork: + SAVE_NVGPRS(r1) + lwz r0,_TRAP(r1) + rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ + stw r0,_TRAP(r1) /* register set saved */ + b sys_fork + + .globl ppc_vfork +ppc_vfork: + SAVE_NVGPRS(r1) + lwz r0,_TRAP(r1) + rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ + stw r0,_TRAP(r1) /* register set saved */ + b sys_vfork + + .globl ppc_clone +ppc_clone: + SAVE_NVGPRS(r1) + lwz r0,_TRAP(r1) + rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ + stw r0,_TRAP(r1) /* register set saved */ + b sys_clone + + .globl ppc_swapcontext +ppc_swapcontext: + SAVE_NVGPRS(r1) + lwz r0,_TRAP(r1) + rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ + stw r0,_TRAP(r1) /* register set saved */ + b sys_swapcontext + +/* + * Top-level page fault handling. + * This is in assembler because if do_page_fault tells us that + * it is a bad kernel page fault, we want to save the non-volatile + * registers before calling bad_page_fault. + */ + .globl handle_page_fault +handle_page_fault: + stw r4,_DAR(r1) + addi r3,r1,STACK_FRAME_OVERHEAD + bl do_page_fault + cmpwi r3,0 + beq+ ret_from_except + SAVE_NVGPRS(r1) + lwz r0,_TRAP(r1) + clrrwi r0,r0,1 + stw r0,_TRAP(r1) + mr r5,r3 + addi r3,r1,STACK_FRAME_OVERHEAD + lwz r4,_DAR(r1) + bl bad_page_fault + b ret_from_except_full + +/* + * This routine switches between two different tasks. The process + * state of one is saved on its kernel stack. Then the state + * of the other is restored from its kernel stack. The memory + * management hardware is updated to the second process's state. + * Finally, we can return to the second process. + * On entry, r3 points to the THREAD for the current task, r4 + * points to the THREAD for the new task. + * + * This routine is always called with interrupts disabled. + * + * Note: there are two ways to get to the "going out" portion + * of this code; either by coming in via the entry (_switch) + * or via "fork" which must set up an environment equivalent + * to the "_switch" path. If you change this , you'll have to + * change the fork code also. + * + * The code which creates the new task context is in 'copy_thread' + * in arch/ppc/kernel/process.c + */ +_GLOBAL(_switch) + stwu r1,-INT_FRAME_SIZE(r1) + mflr r0 + stw r0,INT_FRAME_SIZE+4(r1) + /* r3-r12 are caller saved -- Cort */ + SAVE_NVGPRS(r1) + stw r0,_NIP(r1) /* Return to switch caller */ + mfmsr r11 + li r0,MSR_FP /* Disable floating-point */ +#ifdef CONFIG_ALTIVEC +BEGIN_FTR_SECTION + oris r0,r0,MSR_VEC@h /* Disable altivec */ + mfspr r12,SPRN_VRSAVE /* save vrsave register value */ + stw r12,THREAD+THREAD_VRSAVE(r2) +END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) +#endif /* CONFIG_ALTIVEC */ +#ifdef CONFIG_SPE + oris r0,r0,MSR_SPE@h /* Disable SPE */ + mfspr r12,SPRN_SPEFSCR /* save spefscr register value */ + stw r12,THREAD+THREAD_SPEFSCR(r2) +#endif /* CONFIG_SPE */ + and. r0,r0,r11 /* FP or altivec or SPE enabled? */ + beq+ 1f + andc r11,r11,r0 + MTMSRD(r11) + isync +1: stw r11,_MSR(r1) + mfcr r10 + stw r10,_CCR(r1) + stw r1,KSP(r3) /* Set old stack pointer */ + +#ifdef CONFIG_SMP + /* We need a sync somewhere here to make sure that if the + * previous task gets rescheduled on another CPU, it sees all + * stores it has performed on this one. + */ + sync +#endif /* CONFIG_SMP */ + + tophys(r0,r4) + CLR_TOP32(r0) + mtspr SPRN_SPRG3,r0 /* Update current THREAD phys addr */ + lwz r1,KSP(r4) /* Load new stack pointer */ + + /* save the old current 'last' for return value */ + mr r3,r2 + addi r2,r4,-THREAD /* Update current */ + +#ifdef CONFIG_ALTIVEC +BEGIN_FTR_SECTION + lwz r0,THREAD+THREAD_VRSAVE(r2) + mtspr SPRN_VRSAVE,r0 /* if G4, restore VRSAVE reg */ +END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) +#endif /* CONFIG_ALTIVEC */ +#ifdef CONFIG_SPE + lwz r0,THREAD+THREAD_SPEFSCR(r2) + mtspr SPRN_SPEFSCR,r0 /* restore SPEFSCR reg */ +#endif /* CONFIG_SPE */ + + lwz r0,_CCR(r1) + mtcrf 0xFF,r0 + /* r3-r12 are destroyed -- Cort */ + REST_NVGPRS(r1) + + lwz r4,_NIP(r1) /* Return to _switch caller in new task */ + mtlr r4 + addi r1,r1,INT_FRAME_SIZE + blr + + .globl fast_exception_return +fast_exception_return: +#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) + andi. r10,r9,MSR_RI /* check for recoverable interrupt */ + beq 1f /* if not, we've got problems */ +#endif + +2: REST_4GPRS(3, r11) + lwz r10,_CCR(r11) + REST_GPR(1, r11) + mtcr r10 + lwz r10,_LINK(r11) + mtlr r10 + REST_GPR(10, r11) + mtspr SPRN_SRR1,r9 + mtspr SPRN_SRR0,r12 + REST_GPR(9, r11) + REST_GPR(12, r11) + lwz r11,GPR11(r11) + SYNC + RFI + +#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) +/* check if the exception happened in a restartable section */ +1: lis r3,exc_exit_restart_end@ha + addi r3,r3,exc_exit_restart_end@l + cmplw r12,r3 + bge 3f + lis r4,exc_exit_restart@ha + addi r4,r4,exc_exit_restart@l + cmplw r12,r4 + blt 3f + lis r3,fee_restarts@ha + tophys(r3,r3) + lwz r5,fee_restarts@l(r3) + addi r5,r5,1 + stw r5,fee_restarts@l(r3) + mr r12,r4 /* restart at exc_exit_restart */ + b 2b + + .comm fee_restarts,4 + +/* aargh, a nonrecoverable interrupt, panic */ +/* aargh, we don't know which trap this is */ +/* but the 601 doesn't implement the RI bit, so assume it's OK */ +3: +BEGIN_FTR_SECTION + b 2b +END_FTR_SECTION_IFSET(CPU_FTR_601) + li r10,-1 + stw r10,_TRAP(r11) + addi r3,r1,STACK_FRAME_OVERHEAD + lis r10,MSR_KERNEL@h + ori r10,r10,MSR_KERNEL@l + bl transfer_to_handler_full + .long nonrecoverable_exception + .long ret_from_except +#endif + + .globl sigreturn_exit +sigreturn_exit: + subi r1,r3,STACK_FRAME_OVERHEAD + rlwinm r12,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */ + lwz r9,TI_FLAGS(r12) + andi. r0,r9,_TIF_SYSCALL_T_OR_A + beq+ ret_from_except_full + bl do_syscall_trace_leave + /* fall through */ + + .globl ret_from_except_full +ret_from_except_full: + REST_NVGPRS(r1) + /* fall through */ + + .globl ret_from_except +ret_from_except: + /* Hard-disable interrupts so that current_thread_info()->flags + * can't change between when we test it and when we return + * from the interrupt. */ + LOAD_MSR_KERNEL(r10,MSR_KERNEL) + SYNC /* Some chip revs have problems here... */ + MTMSRD(r10) /* disable interrupts */ + + lwz r3,_MSR(r1) /* Returning to user mode? */ + andi. r0,r3,MSR_PR + beq resume_kernel + +user_exc_return: /* r10 contains MSR_KERNEL here */ + /* Check current_thread_info()->flags */ + rlwinm r9,r1,0,0,(31-THREAD_SHIFT) + lwz r9,TI_FLAGS(r9) + andi. r0,r9,(_TIF_SIGPENDING|_TIF_NEED_RESCHED) + bne do_work + +restore_user: +#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) + /* Check whether this process has its own DBCR0 value. The single + step bit tells us that dbcr0 should be loaded. */ + lwz r0,THREAD+THREAD_DBCR0(r2) + andis. r10,r0,DBCR0_IC@h + bnel- load_dbcr0 +#endif + +#ifdef CONFIG_PREEMPT + b restore + +/* N.B. the only way to get here is from the beq following ret_from_except. */ +resume_kernel: + /* check current_thread_info->preempt_count */ + rlwinm r9,r1,0,0,(31-THREAD_SHIFT) + lwz r0,TI_PREEMPT(r9) + cmpwi 0,r0,0 /* if non-zero, just restore regs and return */ + bne restore + lwz r0,TI_FLAGS(r9) + andi. r0,r0,_TIF_NEED_RESCHED + beq+ restore + andi. r0,r3,MSR_EE /* interrupts off? */ + beq restore /* don't schedule if so */ +1: bl preempt_schedule_irq + rlwinm r9,r1,0,0,(31-THREAD_SHIFT) + lwz r3,TI_FLAGS(r9) + andi. r0,r3,_TIF_NEED_RESCHED + bne- 1b +#else +resume_kernel: +#endif /* CONFIG_PREEMPT */ + + /* interrupts are hard-disabled at this point */ +restore: + lwz r0,GPR0(r1) + lwz r2,GPR2(r1) + REST_4GPRS(3, r1) + REST_2GPRS(7, r1) + + lwz r10,_XER(r1) + lwz r11,_CTR(r1) + mtspr SPRN_XER,r10 + mtctr r11 + + PPC405_ERR77(0,r1) + stwcx. r0,0,r1 /* to clear the reservation */ + +#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) + lwz r9,_MSR(r1) + andi. r10,r9,MSR_RI /* check if this exception occurred */ + beql nonrecoverable /* at a bad place (MSR:RI = 0) */ + + lwz r10,_CCR(r1) + lwz r11,_LINK(r1) + mtcrf 0xFF,r10 + mtlr r11 + + /* + * Once we put values in SRR0 and SRR1, we are in a state + * where exceptions are not recoverable, since taking an + * exception will trash SRR0 and SRR1. Therefore we clear the + * MSR:RI bit to indicate this. If we do take an exception, + * we can't return to the point of the exception but we + * can restart the exception exit path at the label + * exc_exit_restart below. -- paulus + */ + LOAD_MSR_KERNEL(r10,MSR_KERNEL & ~MSR_RI) + SYNC + MTMSRD(r10) /* clear the RI bit */ + .globl exc_exit_restart +exc_exit_restart: + lwz r9,_MSR(r1) + lwz r12,_NIP(r1) + FIX_SRR1(r9,r10) + mtspr SPRN_SRR0,r12 + mtspr SPRN_SRR1,r9 + REST_4GPRS(9, r1) + lwz r1,GPR1(r1) + .globl exc_exit_restart_end +exc_exit_restart_end: + SYNC + RFI + +#else /* !(CONFIG_4xx || CONFIG_BOOKE) */ + /* + * This is a bit different on 4xx/Book-E because it doesn't have + * the RI bit in the MSR. + * The TLB miss handler checks if we have interrupted + * the exception exit path and restarts it if so + * (well maybe one day it will... :). + */ + lwz r11,_LINK(r1) + mtlr r11 + lwz r10,_CCR(r1) + mtcrf 0xff,r10 + REST_2GPRS(9, r1) + .globl exc_exit_restart +exc_exit_restart: + lwz r11,_NIP(r1) + lwz r12,_MSR(r1) +exc_exit_start: + mtspr SPRN_SRR0,r11 + mtspr SPRN_SRR1,r12 + REST_2GPRS(11, r1) + lwz r1,GPR1(r1) + .globl exc_exit_restart_end +exc_exit_restart_end: + PPC405_ERR77_SYNC + rfi + b . /* prevent prefetch past rfi */ + +/* + * Returning from a critical interrupt in user mode doesn't need + * to be any different from a normal exception. For a critical + * interrupt in the kernel, we just return (without checking for + * preemption) since the interrupt may have happened at some crucial + * place (e.g. inside the TLB miss handler), and because we will be + * running with r1 pointing into critical_stack, not the current + * process's kernel stack (and therefore current_thread_info() will + * give the wrong answer). + * We have to restore various SPRs that may have been in use at the + * time of the critical interrupt. + * + */ +#ifdef CONFIG_40x +#define PPC_40x_TURN_OFF_MSR_DR \ + /* avoid any possible TLB misses here by turning off MSR.DR, we \ + * assume the instructions here are mapped by a pinned TLB entry */ \ + li r10,MSR_IR; \ + mtmsr r10; \ + isync; \ + tophys(r1, r1); +#else +#define PPC_40x_TURN_OFF_MSR_DR +#endif + +#define RET_FROM_EXC_LEVEL(exc_lvl_srr0, exc_lvl_srr1, exc_lvl_rfi) \ + REST_NVGPRS(r1); \ + lwz r3,_MSR(r1); \ + andi. r3,r3,MSR_PR; \ + LOAD_MSR_KERNEL(r10,MSR_KERNEL); \ + bne user_exc_return; \ + lwz r0,GPR0(r1); \ + lwz r2,GPR2(r1); \ + REST_4GPRS(3, r1); \ + REST_2GPRS(7, r1); \ + lwz r10,_XER(r1); \ + lwz r11,_CTR(r1); \ + mtspr SPRN_XER,r10; \ + mtctr r11; \ + PPC405_ERR77(0,r1); \ + stwcx. r0,0,r1; /* to clear the reservation */ \ + lwz r11,_LINK(r1); \ + mtlr r11; \ + lwz r10,_CCR(r1); \ + mtcrf 0xff,r10; \ + PPC_40x_TURN_OFF_MSR_DR; \ + lwz r9,_DEAR(r1); \ + lwz r10,_ESR(r1); \ + mtspr SPRN_DEAR,r9; \ + mtspr SPRN_ESR,r10; \ + lwz r11,_NIP(r1); \ + lwz r12,_MSR(r1); \ + mtspr exc_lvl_srr0,r11; \ + mtspr exc_lvl_srr1,r12; \ + lwz r9,GPR9(r1); \ + lwz r12,GPR12(r1); \ + lwz r10,GPR10(r1); \ + lwz r11,GPR11(r1); \ + lwz r1,GPR1(r1); \ + PPC405_ERR77_SYNC; \ + exc_lvl_rfi; \ + b .; /* prevent prefetch past exc_lvl_rfi */ + + .globl ret_from_crit_exc +ret_from_crit_exc: + RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, RFCI) + +#ifdef CONFIG_BOOKE + .globl ret_from_debug_exc +ret_from_debug_exc: + RET_FROM_EXC_LEVEL(SPRN_DSRR0, SPRN_DSRR1, RFDI) + + .globl ret_from_mcheck_exc +ret_from_mcheck_exc: + RET_FROM_EXC_LEVEL(SPRN_MCSRR0, SPRN_MCSRR1, RFMCI) +#endif /* CONFIG_BOOKE */ + +/* + * Load the DBCR0 value for a task that is being ptraced, + * having first saved away the global DBCR0. Note that r0 + * has the dbcr0 value to set upon entry to this. + */ +load_dbcr0: + mfmsr r10 /* first disable debug exceptions */ + rlwinm r10,r10,0,~MSR_DE + mtmsr r10 + isync + mfspr r10,SPRN_DBCR0 + lis r11,global_dbcr0@ha + addi r11,r11,global_dbcr0@l + stw r10,0(r11) + mtspr SPRN_DBCR0,r0 + lwz r10,4(r11) + addi r10,r10,1 + stw r10,4(r11) + li r11,-1 + mtspr SPRN_DBSR,r11 /* clear all pending debug events */ + blr + + .comm global_dbcr0,8 +#endif /* !(CONFIG_4xx || CONFIG_BOOKE) */ + +do_work: /* r10 contains MSR_KERNEL here */ + andi. r0,r9,_TIF_NEED_RESCHED + beq do_user_signal + +do_resched: /* r10 contains MSR_KERNEL here */ + ori r10,r10,MSR_EE + SYNC + MTMSRD(r10) /* hard-enable interrupts */ + bl schedule +recheck: + LOAD_MSR_KERNEL(r10,MSR_KERNEL) + SYNC + MTMSRD(r10) /* disable interrupts */ + rlwinm r9,r1,0,0,(31-THREAD_SHIFT) + lwz r9,TI_FLAGS(r9) + andi. r0,r9,_TIF_NEED_RESCHED + bne- do_resched + andi. r0,r9,_TIF_SIGPENDING + beq restore_user +do_user_signal: /* r10 contains MSR_KERNEL here */ + ori r10,r10,MSR_EE + SYNC + MTMSRD(r10) /* hard-enable interrupts */ + /* save r13-r31 in the exception frame, if not already done */ + lwz r3,_TRAP(r1) + andi. r0,r3,1 + beq 2f + SAVE_NVGPRS(r1) + rlwinm r3,r3,0,0,30 + stw r3,_TRAP(r1) +2: li r3,0 + addi r4,r1,STACK_FRAME_OVERHEAD + bl do_signal + REST_NVGPRS(r1) + b recheck + +/* + * We come here when we are at the end of handling an exception + * that occurred at a place where taking an exception will lose + * state information, such as the contents of SRR0 and SRR1. + */ +nonrecoverable: + lis r10,exc_exit_restart_end@ha + addi r10,r10,exc_exit_restart_end@l + cmplw r12,r10 + bge 3f + lis r11,exc_exit_restart@ha + addi r11,r11,exc_exit_restart@l + cmplw r12,r11 + blt 3f + lis r10,ee_restarts@ha + lwz r12,ee_restarts@l(r10) + addi r12,r12,1 + stw r12,ee_restarts@l(r10) + mr r12,r11 /* restart at exc_exit_restart */ + blr +3: /* OK, we can't recover, kill this process */ + /* but the 601 doesn't implement the RI bit, so assume it's OK */ +BEGIN_FTR_SECTION + blr +END_FTR_SECTION_IFSET(CPU_FTR_601) + lwz r3,_TRAP(r1) + andi. r0,r3,1 + beq 4f + SAVE_NVGPRS(r1) + rlwinm r3,r3,0,0,30 + stw r3,_TRAP(r1) +4: addi r3,r1,STACK_FRAME_OVERHEAD + bl nonrecoverable_exception + /* shouldn't return */ + b 4b + + .comm ee_restarts,4 + +/* + * PROM code for specific machines follows. Put it + * here so it's easy to add arch-specific sections later. + * -- Cort + */ +#ifdef CONFIG_PPC_RTAS +/* + * On CHRP, the Run-Time Abstraction Services (RTAS) have to be + * called with the MMU off. + */ +_GLOBAL(enter_rtas) + stwu r1,-INT_FRAME_SIZE(r1) + mflr r0 + stw r0,INT_FRAME_SIZE+4(r1) + LOADADDR(r4, rtas) + lis r6,1f@ha /* physical return address for rtas */ + addi r6,r6,1f@l + tophys(r6,r6) + tophys(r7,r1) + lwz r8,RTASENTRY(r4) + lwz r4,RTASBASE(r4) + mfmsr r9 + stw r9,8(r1) + LOAD_MSR_KERNEL(r0,MSR_KERNEL) + SYNC /* disable interrupts so SRR0/1 */ + MTMSRD(r0) /* don't get trashed */ + li r9,MSR_KERNEL & ~(MSR_IR|MSR_DR) + mtlr r6 + mtspr SPRN_SPRG2,r7 + mtspr SPRN_SRR0,r8 + mtspr SPRN_SRR1,r9 + RFI +1: tophys(r9,r1) + lwz r8,INT_FRAME_SIZE+4(r9) /* get return address */ + lwz r9,8(r9) /* original msr value */ + FIX_SRR1(r9,r0) + addi r1,r1,INT_FRAME_SIZE + li r0,0 + mtspr SPRN_SPRG2,r0 + mtspr SPRN_SRR0,r8 + mtspr SPRN_SRR1,r9 + RFI /* return to caller */ + + .globl machine_check_in_rtas +machine_check_in_rtas: + twi 31,0,0 + /* XXX load up BATs and panic */ + +#endif /* CONFIG_PPC_RTAS */ |