/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * 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 * 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. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "head_32.h" /* * Align to 4k in order to ensure that all functions modyfing srr0/srr1 * fit into one page in order to not encounter a TLB miss between the * modification of srr0/srr1 and the associated rfi. */ .align 12 #ifdef CONFIG_BOOKE .globl mcheck_transfer_to_handler mcheck_transfer_to_handler: mfspr r0,SPRN_DSRR0 stw r0,_DSRR0(r11) mfspr r0,SPRN_DSRR1 stw r0,_DSRR1(r11) /* fall through */ .globl debug_transfer_to_handler debug_transfer_to_handler: mfspr r0,SPRN_CSRR0 stw r0,_CSRR0(r11) mfspr r0,SPRN_CSRR1 stw r0,_CSRR1(r11) /* fall through */ .globl crit_transfer_to_handler crit_transfer_to_handler: #ifdef CONFIG_PPC_BOOK3E_MMU mfspr r0,SPRN_MAS0 stw r0,MAS0(r11) mfspr r0,SPRN_MAS1 stw r0,MAS1(r11) mfspr r0,SPRN_MAS2 stw r0,MAS2(r11) mfspr r0,SPRN_MAS3 stw r0,MAS3(r11) mfspr r0,SPRN_MAS6 stw r0,MAS6(r11) #ifdef CONFIG_PHYS_64BIT mfspr r0,SPRN_MAS7 stw r0,MAS7(r11) #endif /* CONFIG_PHYS_64BIT */ #endif /* CONFIG_PPC_BOOK3E_MMU */ #ifdef CONFIG_44x mfspr r0,SPRN_MMUCR stw r0,MMUCR(r11) #endif mfspr r0,SPRN_SRR0 stw r0,_SRR0(r11) mfspr r0,SPRN_SRR1 stw r0,_SRR1(r11) /* set the stack limit to the current stack */ mfspr r8,SPRN_SPRG_THREAD lwz r0,KSP_LIMIT(r8) stw r0,SAVED_KSP_LIMIT(r11) rlwinm r0,r1,0,0,(31 - THREAD_SHIFT) stw r0,KSP_LIMIT(r8) /* 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) mfspr r0,SPRN_SRR0 stw r0,crit_srr0@l(0) mfspr r0,SPRN_SRR1 stw r0,crit_srr1@l(0) /* set the stack limit to the current stack */ mfspr r8,SPRN_SPRG_THREAD lwz r0,KSP_LIMIT(r8) stw r0,saved_ksp_limit@l(0) rlwinm r0,r1,0,0,(31 - THREAD_SHIFT) stw r0,KSP_LIMIT(r8) /* 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_SPRG_THREAD beq 2f /* if from user, fix up THREAD.regs */ addi r2, r12, -THREAD 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 internal debug mode bit to do this. */ lwz r12,THREAD_DBCR0(r12) andis. r12,r12,DBCR0_IDM@h #endif ACCOUNT_CPU_USER_ENTRY(r2, r11, r12) #ifdef CONFIG_PPC_BOOK3S_32 kuep_lock r11, r12 #endif #if defined(CONFIG_40x) || defined(CONFIG_BOOKE) 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 #ifdef CONFIG_SMP lwz r9,TASK_CPU(r2) slwi r9,r9,3 add r11,r11,r9 #endif 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 */ kuap_save_and_lock r11, r12, r9, r2, r6 addi r2, r12, -THREAD lwz r9,KSP_LIMIT(r12) cmplw r1,r9 /* if r1 <= ksp_limit */ ble- stack_ovf /* then the kernel stack overflowed */ 5: #if defined(CONFIG_PPC_BOOK3S_32) || defined(CONFIG_E500) lwz r12,TI_LOCAL_FLAGS(r2) mtcrf 0x01,r12 bt- 31-TLF_NAPPING,4f bt- 31-TLF_SLEEPING,7f #endif /* CONFIG_PPC_BOOK3S_32 || CONFIG_E500 */ .globl transfer_to_handler_cont transfer_to_handler_cont: 3: mflr r9 tovirt(r2, r2) /* set r2 to current */ lwz r11,0(r9) /* virtual address of handler */ lwz r9,4(r9) /* where to go when done */ #if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) mtspr SPRN_NRI, r0 #endif #ifdef CONFIG_TRACE_IRQFLAGS /* * When tracing IRQ state (lockdep) we enable the MMU before we call * the IRQ tracing functions as they might access vmalloc space or * perform IOs for console output. * * To speed up the syscall path where interrupts stay on, let's check * first if we are changing the MSR value at all. */ tophys(r12, r1) lwz r12,_MSR(r12) andi. r12,r12,MSR_EE bne 1f /* MSR isn't changing, just transition directly */ #endif mtspr SPRN_SRR0,r11 mtspr SPRN_SRR1,r10 mtlr r9 SYNC RFI /* jump to handler, enable MMU */ #ifdef CONFIG_TRACE_IRQFLAGS 1: /* MSR is changing, re-enable MMU so we can notify lockdep. We need to * keep interrupts disabled at this point otherwise we might risk * taking an interrupt before we tell lockdep they are enabled. */ lis r12,reenable_mmu@h ori r12,r12,reenable_mmu@l LOAD_REG_IMMEDIATE(r0, MSR_KERNEL) mtspr SPRN_SRR0,r12 mtspr SPRN_SRR1,r0 SYNC RFI reenable_mmu: /* * We save a bunch of GPRs, * r3 can be different from GPR3(r1) at this point, r9 and r11 * contains the old MSR and handler address respectively, * r4 & r5 can contain page fault arguments that need to be passed * along as well. r12, CCR, CTR, XER etc... are left clobbered as * they aren't useful past this point (aren't syscall arguments), * the rest is restored from the exception frame. */ stwu r1,-32(r1) stw r9,8(r1) stw r11,12(r1) stw r3,16(r1) stw r4,20(r1) stw r5,24(r1) /* If we are disabling interrupts (normal case), simply log it with * lockdep */ 1: bl trace_hardirqs_off 2: lwz r5,24(r1) lwz r4,20(r1) lwz r3,16(r1) lwz r11,12(r1) lwz r9,8(r1) addi r1,r1,32 lwz r0,GPR0(r1) lwz r6,GPR6(r1) lwz r7,GPR7(r1) lwz r8,GPR8(r1) mtctr r11 mtlr r9 bctr /* jump to handler */ #endif /* CONFIG_TRACE_IRQFLAGS */ #if defined (CONFIG_PPC_BOOK3S_32) || defined(CONFIG_E500) 4: rlwinm r12,r12,0,~_TLF_NAPPING stw r12,TI_LOCAL_FLAGS(r2) b power_save_ppc32_restore 7: rlwinm r12,r12,0,~_TLF_SLEEPING stw r12,TI_LOCAL_FLAGS(r2) lwz r9,_MSR(r11) /* if sleeping, clear MSR.EE */ rlwinm r9,r9,0,~MSR_EE lwz r12,_LINK(r11) /* and return to address in LR */ kuap_restore r11, r2, r3, r4, r5 lwz r2, GPR2(r11) b fast_exception_return #endif /* * 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 r12,_end@h ori r12,r12,_end@l cmplw r1,r12 ble 5b /* 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_REG_IMMEDIATE(r10,MSR_KERNEL) #if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) mtspr SPRN_NRI, r0 #endif mtspr SPRN_SRR0,r9 mtspr SPRN_SRR1,r10 SYNC RFI #ifdef CONFIG_TRACE_IRQFLAGS trace_syscall_entry_irq_off: /* * Syscall shouldn't happen while interrupts are disabled, * so let's do a warning here. */ 0: trap EMIT_BUG_ENTRY 0b,__FILE__,__LINE__, BUGFLAG_WARNING bl trace_hardirqs_on /* Now enable for real */ LOAD_REG_IMMEDIATE(r10, MSR_KERNEL | MSR_EE) mtmsr r10 REST_GPR(0, r1) REST_4GPRS(3, r1) REST_2GPRS(7, r1) b DoSyscall #endif /* CONFIG_TRACE_IRQFLAGS */ .globl transfer_to_syscall transfer_to_syscall: #ifdef CONFIG_TRACE_IRQFLAGS andi. r12,r9,MSR_EE beq- trace_syscall_entry_irq_off #endif /* CONFIG_TRACE_IRQFLAGS */ /* * 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 r3,ORIG_GPR3(r1) li r12,0 stw r12,RESULT(r1) #ifdef CONFIG_TRACE_IRQFLAGS /* Make sure interrupts are enabled */ mfmsr r11 andi. r12,r11,MSR_EE /* We came in with interrupts disabled, we WARN and mark them enabled * for lockdep now */ 0: tweqi r12, 0 EMIT_BUG_ENTRY 0b,__FILE__,__LINE__, BUGFLAG_WARNING #endif /* CONFIG_TRACE_IRQFLAGS */ lwz r11,TI_FLAGS(r2) andi. r11,r11,_TIF_SYSCALL_DOTRACE 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 barrier_nospec_asm /* * Prevent the load of the handler below (based on the user-passed * system call number) being speculatively executed until the test * against NR_syscalls and branch to .66f above has * committed. */ 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 CONFIG_DEBUG_RSEQ /* Check whether the syscall is issued inside a restartable sequence */ stw r3,GPR3(r1) addi r3,r1,STACK_FRAME_OVERHEAD bl rseq_syscall lwz r3,GPR3(r1) #endif mr r6,r3 /* disable interrupts so current_thread_info()->flags can't change */ LOAD_REG_IMMEDIATE(r10,MSR_KERNEL) /* doesn't include MSR_EE */ /* Note: We don't bother telling lockdep about it */ SYNC MTMSRD(r10) lwz r9,TI_FLAGS(r2) li r8,-MAX_ERRNO andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK) bne- syscall_exit_work cmplw 0,r3,r8 blt+ syscall_exit_cont lwz r11,_CCR(r1) /* Load CR */ neg r3,r3 oris r11,r11,0x1000 /* Set SO bit in CR */ stw r11,_CCR(r1) syscall_exit_cont: lwz r8,_MSR(r1) #ifdef CONFIG_TRACE_IRQFLAGS /* If we are going to return from the syscall with interrupts * off, we trace that here. It shouldn't normally happen. */ andi. r10,r8,MSR_EE bne+ 1f stw r3,GPR3(r1) bl trace_hardirqs_off lwz r3,GPR3(r1) 1: #endif /* CONFIG_TRACE_IRQFLAGS */ #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) /* If the process has its own DBCR0 value, load it up. The internal debug mode bit tells us that dbcr0 should be loaded. */ lwz r0,THREAD+THREAD_DBCR0(r2) andis. r10,r0,DBCR0_IDM@h bnel- load_dbcr0 #endif #ifdef CONFIG_44x BEGIN_MMU_FTR_SECTION lis r4,icache_44x_need_flush@ha lwz r5,icache_44x_need_flush@l(r4) cmplwi cr0,r5,0 bne- 2f 1: END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_47x) #endif /* CONFIG_44x */ BEGIN_FTR_SECTION lwarx r7,0,r1 END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) stwcx. r0,0,r1 /* to clear the reservation */ ACCOUNT_CPU_USER_EXIT(r2, r5, r7) #ifdef CONFIG_PPC_BOOK3S_32 kuep_unlock r5, r7 #endif kuap_check r2, r4 lwz r4,_LINK(r1) lwz r5,_CCR(r1) mtlr r4 mtcr r5 lwz r7,_NIP(r1) lwz r2,GPR2(r1) lwz r1,GPR1(r1) #if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) mtspr SPRN_NRI, r0 #endif mtspr SPRN_SRR0,r7 mtspr SPRN_SRR1,r8 SYNC RFI #ifdef CONFIG_44x 2: li r7,0 iccci r0,r0 stw r7,icache_44x_need_flush@l(r4) b 1b #endif /* CONFIG_44x */ 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 .globl ret_from_kernel_thread ret_from_kernel_thread: REST_NVGPRS(r1) bl schedule_tail mtlr r14 mr r3,r15 PPC440EP_ERR42 blrl 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 /* * Restore argument registers possibly just changed. * We use the return value of do_syscall_trace_enter * for call number to look up in the table (r0). */ mr r0,r3 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) cmplwi r0,NR_syscalls /* Return code is already in r3 thanks to do_syscall_trace_enter() */ bge- ret_from_syscall b syscall_dotrace_cont syscall_exit_work: andi. r0,r9,_TIF_RESTOREALL beq+ 0f REST_NVGPRS(r1) b 2f 0: cmplw 0,r3,r8 blt+ 1f andi. r0,r9,_TIF_NOERROR bne- 1f lwz r11,_CCR(r1) /* Load CR */ neg r3,r3 oris r11,r11,0x1000 /* Set SO bit in CR */ stw r11,_CCR(r1) 1: stw r6,RESULT(r1) /* Save result */ stw r3,GPR3(r1) /* Update return value */ 2: andi. r0,r9,(_TIF_PERSYSCALL_MASK) beq 4f /* Clear per-syscall TIF flags if any are set. */ li r11,_TIF_PERSYSCALL_MASK addi r12,r2,TI_FLAGS 3: lwarx r8,0,r12 andc r8,r8,r11 #ifdef CONFIG_IBM405_ERR77 dcbt 0,r12 #endif stwcx. r8,0,r12 bne- 3b 4: /* Anything which requires enabling interrupts? */ andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP) beq ret_from_except /* Re-enable interrupts. There is no need to trace that with * lockdep as we are supposed to have IRQs on at this point */ ori r10,r10,MSR_EE SYNC MTMSRD(r10) /* Save NVGPRS if they're not saved already */ lwz r4,_TRAP(r1) andi. r4,r4,1 beq 5f SAVE_NVGPRS(r1) li r4,0xc00 stw r4,_TRAP(r1) 5: addi r3,r1,STACK_FRAME_OVERHEAD bl do_syscall_trace_leave b ret_from_except_full /* * The fork/clone functions need to copy the full register set into * the child process. Therefore we need to save all the nonvolatile * registers (r13 - r31) before calling the C code. */ .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_clone3 ppc_clone3: 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_clone3 .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 #ifdef CONFIG_PPC_BOOK3S_32 andis. r0,r5,DSISR_DABRMATCH@h bne- handle_dabr_fault #endif 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 #ifdef CONFIG_PPC_BOOK3S_32 /* We have a data breakpoint exception - handle it */ handle_dabr_fault: SAVE_NVGPRS(r1) lwz r0,_TRAP(r1) clrrwi r0,r0,1 stw r0,_TRAP(r1) bl do_break b ret_from_except_full #endif /* * 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 BEGIN_FTR_SECTION oris r0,r0,MSR_SPE@h /* Disable SPE */ mfspr r12,SPRN_SPEFSCR /* save spefscr register value */ stw r12,THREAD+THREAD_SPEFSCR(r2) END_FTR_SECTION_IFSET(CPU_FTR_SPE) #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 */ kuap_check r2, r4 #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) mtspr SPRN_SPRG_THREAD,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 BEGIN_FTR_SECTION lwz r0,THREAD+THREAD_SPEFSCR(r2) mtspr SPRN_SPEFSCR,r0 /* restore SPEFSCR reg */ END_FTR_SECTION_IFSET(CPU_FTR_SPE) #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 /* Clear the exception_marker on the stack to avoid confusing stacktrace */ li r10, 0 stw r10, 8(r11) REST_GPR(10, r11) #if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) mtspr SPRN_NRI, r0 #endif 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 #ifdef CONFIG_PPC_BOOK3S_601 bge 2b #else bge 3f #endif lis r4,exc_exit_restart@ha addi r4,r4,exc_exit_restart@l cmplw r12,r4 #ifdef CONFIG_PPC_BOOK3S_601 blt 2b #else blt 3f #endif 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 .section .bss .align 2 fee_restarts: .space 4 .previous /* 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: 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 unrecoverable_exception .long ret_from_except #endif .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. */ /* Note: We don't bother telling lockdep about it */ LOAD_REG_IMMEDIATE(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 */ lwz r9,TI_FLAGS(r2) andi. r0,r9,_TIF_USER_WORK_MASK bne do_work restore_user: #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) /* Check whether this process has its own DBCR0 value. The internal debug mode bit tells us that dbcr0 should be loaded. */ lwz r0,THREAD+THREAD_DBCR0(r2) andis. r10,r0,DBCR0_IDM@h bnel- load_dbcr0 #endif ACCOUNT_CPU_USER_EXIT(r2, r10, r11) #ifdef CONFIG_PPC_BOOK3S_32 kuep_unlock r10, r11 #endif b restore /* N.B. the only way to get here is from the beq following ret_from_except. */ resume_kernel: /* check current_thread_info, _TIF_EMULATE_STACK_STORE */ lwz r8,TI_FLAGS(r2) andis. r0,r8,_TIF_EMULATE_STACK_STORE@h beq+ 1f addi r8,r1,INT_FRAME_SIZE /* Get the kprobed function entry */ lwz r3,GPR1(r1) subi r3,r3,INT_FRAME_SIZE /* dst: Allocate a trampoline exception frame */ mr r4,r1 /* src: current exception frame */ mr r1,r3 /* Reroute the trampoline frame to r1 */ /* Copy from the original to the trampoline. */ li r5,INT_FRAME_SIZE/4 /* size: INT_FRAME_SIZE */ li r6,0 /* start offset: 0 */ mtctr r5 2: lwzx r0,r6,r4 stwx r0,r6,r3 addi r6,r6,4 bdnz 2b /* Do real store operation to complete stwu */ lwz r5,GPR1(r1) stw r8,0(r5) /* Clear _TIF_EMULATE_STACK_STORE flag */ lis r11,_TIF_EMULATE_STACK_STORE@h addi r5,r2,TI_FLAGS 0: lwarx r8,0,r5 andc r8,r8,r11 #ifdef CONFIG_IBM405_ERR77 dcbt 0,r5 #endif stwcx. r8,0,r5 bne- 0b 1: #ifdef CONFIG_PREEMPT /* check current_thread_info->preempt_count */ lwz r0,TI_PREEMPT(r2) cmpwi 0,r0,0 /* if non-zero, just restore regs and return */ bne restore_kuap andi. r8,r8,_TIF_NEED_RESCHED beq+ restore_kuap lwz r3,_MSR(r1) andi. r0,r3,MSR_EE /* interrupts off? */ beq restore_kuap /* don't schedule if so */ #ifdef CONFIG_TRACE_IRQFLAGS /* Lockdep thinks irqs are enabled, we need to call * preempt_schedule_irq with IRQs off, so we inform lockdep * now that we -did- turn them off already */ bl trace_hardirqs_off #endif bl preempt_schedule_irq #ifdef CONFIG_TRACE_IRQFLAGS /* And now, to properly rebalance the above, we tell lockdep they * are being turned back on, which will happen when we return */ bl trace_hardirqs_on #endif #endif /* CONFIG_PREEMPT */ restore_kuap: kuap_restore r1, r2, r9, r10, r0 /* interrupts are hard-disabled at this point */ restore: #ifdef CONFIG_44x BEGIN_MMU_FTR_SECTION b 1f END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_47x) lis r4,icache_44x_need_flush@ha lwz r5,icache_44x_need_flush@l(r4) cmplwi cr0,r5,0 beq+ 1f li r6,0 iccci r0,r0 stw r6,icache_44x_need_flush@l(r4) 1: #endif /* CONFIG_44x */ lwz r9,_MSR(r1) #ifdef CONFIG_TRACE_IRQFLAGS /* Lockdep doesn't know about the fact that IRQs are temporarily turned * off in this assembly code while peeking at TI_FLAGS() and such. However * we need to inform it if the exception turned interrupts off, and we * are about to trun them back on. */ andi. r10,r9,MSR_EE beq 1f stwu r1,-32(r1) mflr r0 stw r0,4(r1) bl trace_hardirqs_on addi r1, r1, 32 lwz r9,_MSR(r1) 1: #endif /* CONFIG_TRACE_IRQFLAGS */ 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) BEGIN_FTR_SECTION lwarx r11,0,r1 END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) stwcx. r0,0,r1 /* to clear the reservation */ #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) 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 /* Clear the exception_marker on the stack to avoid confusing stacktrace */ li r10, 0 stw r10, 8(r1) /* * 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_REG_IMMEDIATE(r10,MSR_KERNEL & ~MSR_RI) SYNC MTMSRD(r10) /* clear the RI bit */ .globl exc_exit_restart exc_exit_restart: lwz r12,_NIP(r1) 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 /* Clear the exception_marker on the stack to avoid confusing stacktrace */ li r10, 0 stw r10, 8(r1) 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_REG_IMMEDIATE(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 */ #define RESTORE_xSRR(exc_lvl_srr0, exc_lvl_srr1) \ lwz r9,_##exc_lvl_srr0(r1); \ lwz r10,_##exc_lvl_srr1(r1); \ mtspr SPRN_##exc_lvl_srr0,r9; \ mtspr SPRN_##exc_lvl_srr1,r10; #if defined(CONFIG_PPC_BOOK3E_MMU) #ifdef CONFIG_PHYS_64BIT #define RESTORE_MAS7 \ lwz r11,MAS7(r1); \ mtspr SPRN_MAS7,r11; #else #define RESTORE_MAS7 #endif /* CONFIG_PHYS_64BIT */ #define RESTORE_MMU_REGS \ lwz r9,MAS0(r1); \ lwz r10,MAS1(r1); \ lwz r11,MAS2(r1); \ mtspr SPRN_MAS0,r9; \ lwz r9,MAS3(r1); \ mtspr SPRN_MAS1,r10; \ lwz r10,MAS6(r1); \ mtspr SPRN_MAS2,r11; \ mtspr SPRN_MAS3,r9; \ mtspr SPRN_MAS6,r10; \ RESTORE_MAS7; #elif defined(CONFIG_44x) #define RESTORE_MMU_REGS \ lwz r9,MMUCR(r1); \ mtspr SPRN_MMUCR,r9; #else #define RESTORE_MMU_REGS #endif #ifdef CONFIG_40x .globl ret_from_crit_exc ret_from_crit_exc: mfspr r9,SPRN_SPRG_THREAD lis r10,saved_ksp_limit@ha; lwz r10,saved_ksp_limit@l(r10); tovirt(r9,r9); stw r10,KSP_LIMIT(r9) lis r9,crit_srr0@ha; lwz r9,crit_srr0@l(r9); lis r10,crit_srr1@ha; lwz r10,crit_srr1@l(r10); mtspr SPRN_SRR0,r9; mtspr SPRN_SRR1,r10; RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, PPC_RFCI) #endif /* CONFIG_40x */ #ifdef CONFIG_BOOKE .globl ret_from_crit_exc ret_from_crit_exc: mfspr r9,SPRN_SPRG_THREAD lwz r10,SAVED_KSP_LIMIT(r1) stw r10,KSP_LIMIT(r9) RESTORE_xSRR(SRR0,SRR1); RESTORE_MMU_REGS; RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, PPC_RFCI) .globl ret_from_debug_exc ret_from_debug_exc: mfspr r9,SPRN_SPRG_THREAD lwz r10,SAVED_KSP_LIMIT(r1) stw r10,KSP_LIMIT(r9) RESTORE_xSRR(SRR0,SRR1); RESTORE_xSRR(CSRR0,CSRR1); RESTORE_MMU_REGS; RET_FROM_EXC_LEVEL(SPRN_DSRR0, SPRN_DSRR1, PPC_RFDI) .globl ret_from_mcheck_exc ret_from_mcheck_exc: mfspr r9,SPRN_SPRG_THREAD lwz r10,SAVED_KSP_LIMIT(r1) stw r10,KSP_LIMIT(r9) RESTORE_xSRR(SRR0,SRR1); RESTORE_xSRR(CSRR0,CSRR1); RESTORE_xSRR(DSRR0,DSRR1); RESTORE_MMU_REGS; RET_FROM_EXC_LEVEL(SPRN_MCSRR0, SPRN_MCSRR1, PPC_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 #ifdef CONFIG_SMP lwz r9,TASK_CPU(r2) slwi r9,r9,3 add r11,r11,r9 #endif 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 .section .bss .align 4 .global global_dbcr0 global_dbcr0: .space 8*NR_CPUS .previous #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 */ #ifdef CONFIG_TRACE_IRQFLAGS bl trace_hardirqs_on mfmsr r10 #endif ori r10,r10,MSR_EE SYNC MTMSRD(r10) /* hard-enable interrupts */ bl schedule recheck: /* Note: And we don't tell it we are disabling them again * neither. Those disable/enable cycles used to peek at * TI_FLAGS aren't advertised. */ LOAD_REG_IMMEDIATE(r10,MSR_KERNEL) SYNC MTMSRD(r10) /* disable interrupts */ lwz r9,TI_FLAGS(r2) andi. r0,r9,_TIF_NEED_RESCHED bne- do_resched andi. r0,r9,_TIF_USER_WORK_MASK 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: addi r3,r1,STACK_FRAME_OVERHEAD mr r4,r9 bl do_notify_resume 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 #ifdef CONFIG_PPC_BOOK3S_601 bgelr #else bge 3f #endif lis r11,exc_exit_restart@ha addi r11,r11,exc_exit_restart@l cmplw r12,r11 #ifdef CONFIG_PPC_BOOK3S_601 bltlr #else blt 3f #endif 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 */ lwz r3,_TRAP(r1) andi. r0,r3,1 beq 5f SAVE_NVGPRS(r1) rlwinm r3,r3,0,0,30 stw r3,_TRAP(r1) 5: mfspr r2,SPRN_SPRG_THREAD addi r2,r2,-THREAD tovirt(r2,r2) /* set back r2 to current */ 4: addi r3,r1,STACK_FRAME_OVERHEAD bl unrecoverable_exception /* shouldn't return */ b 4b .section .bss .align 2 ee_restarts: .space 4 .previous /* * 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) LOAD_REG_ADDR(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_REG_IMMEDIATE(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 stw r7, THREAD + RTAS_SP(r2) 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 */ addi r1,r1,INT_FRAME_SIZE li r0,0 tophys(r7, r2) stw r0, THREAD + RTAS_SP(r7) 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 */