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Diffstat (limited to 'arch/powerpc/kernel/entry_64.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 1343 |
1 files changed, 1343 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S new file mode 100644 index 000000000..58b50967b --- /dev/null +++ b/arch/powerpc/kernel/entry_64.S @@ -0,0 +1,1343 @@ +/* + * PowerPC version + * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) + * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP + * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu> + * 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/errno.h> +#include <linux/err.h> +#include <asm/unistd.h> +#include <asm/processor.h> +#include <asm/page.h> +#include <asm/mmu.h> +#include <asm/thread_info.h> +#include <asm/code-patching-asm.h> +#include <asm/ppc_asm.h> +#include <asm/asm-offsets.h> +#include <asm/cputable.h> +#include <asm/firmware.h> +#include <asm/bug.h> +#include <asm/ptrace.h> +#include <asm/irqflags.h> +#include <asm/hw_irq.h> +#include <asm/context_tracking.h> +#include <asm/tm.h> +#include <asm/ppc-opcode.h> +#include <asm/barrier.h> +#include <asm/export.h> +#include <asm/asm-compat.h> +#ifdef CONFIG_PPC_BOOK3S +#include <asm/exception-64s.h> +#else +#include <asm/exception-64e.h> +#endif +#include <asm/feature-fixups.h> + +/* + * System calls. + */ + .section ".toc","aw" +SYS_CALL_TABLE: + .tc sys_call_table[TC],sys_call_table + +/* This value is used to mark exception frames on the stack. */ +exception_marker: + .tc ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER + + .section ".text" + .align 7 + + .globl system_call_common +system_call_common: +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM +BEGIN_FTR_SECTION + extrdi. r10, r12, 1, (63-MSR_TS_T_LG) /* transaction active? */ + bne .Ltabort_syscall +END_FTR_SECTION_IFSET(CPU_FTR_TM) +#endif + andi. r10,r12,MSR_PR + mr r10,r1 + addi r1,r1,-INT_FRAME_SIZE + beq- 1f + ld r1,PACAKSAVE(r13) +1: std r10,0(r1) + std r11,_NIP(r1) + std r12,_MSR(r1) + std r0,GPR0(r1) + std r10,GPR1(r1) + beq 2f /* if from kernel mode */ +#ifdef CONFIG_PPC_FSL_BOOK3E +START_BTB_FLUSH_SECTION + BTB_FLUSH(r10) +END_BTB_FLUSH_SECTION +#endif + ACCOUNT_CPU_USER_ENTRY(r13, r10, r11) +2: std r2,GPR2(r1) + std r3,GPR3(r1) + mfcr r2 + std r4,GPR4(r1) + std r5,GPR5(r1) + std r6,GPR6(r1) + std r7,GPR7(r1) + std r8,GPR8(r1) + li r11,0 + std r11,GPR9(r1) + std r11,GPR10(r1) + std r11,GPR11(r1) + std r11,GPR12(r1) + std r11,_XER(r1) + std r11,_CTR(r1) + std r9,GPR13(r1) + mflr r10 + /* + * This clears CR0.SO (bit 28), which is the error indication on + * return from this system call. + */ + rldimi r2,r11,28,(63-28) + li r11,0xc01 + std r10,_LINK(r1) + std r11,_TRAP(r1) + std r3,ORIG_GPR3(r1) + std r2,_CCR(r1) + ld r2,PACATOC(r13) + addi r9,r1,STACK_FRAME_OVERHEAD + ld r11,exception_marker@toc(r2) + std r11,-16(r9) /* "regshere" marker */ +#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC_SPLPAR) +BEGIN_FW_FTR_SECTION + beq 33f + /* if from user, see if there are any DTL entries to process */ + ld r10,PACALPPACAPTR(r13) /* get ptr to VPA */ + ld r11,PACA_DTL_RIDX(r13) /* get log read index */ + addi r10,r10,LPPACA_DTLIDX + LDX_BE r10,0,r10 /* get log write index */ + cmpd cr1,r11,r10 + beq+ cr1,33f + bl accumulate_stolen_time + REST_GPR(0,r1) + REST_4GPRS(3,r1) + REST_2GPRS(7,r1) + addi r9,r1,STACK_FRAME_OVERHEAD +33: +END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR) +#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE && CONFIG_PPC_SPLPAR */ + + /* + * A syscall should always be called with interrupts enabled + * so we just unconditionally hard-enable here. When some kind + * of irq tracing is used, we additionally check that condition + * is correct + */ +#if defined(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG) && defined(CONFIG_BUG) + lbz r10,PACAIRQSOFTMASK(r13) +1: tdnei r10,IRQS_ENABLED + EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING +#endif + +#ifdef CONFIG_PPC_BOOK3E + wrteei 1 +#else + li r11,MSR_RI + ori r11,r11,MSR_EE + mtmsrd r11,1 +#endif /* CONFIG_PPC_BOOK3E */ + +system_call: /* label this so stack traces look sane */ + /* We do need to set SOFTE in the stack frame or the return + * from interrupt will be painful + */ + li r10,IRQS_ENABLED + std r10,SOFTE(r1) + + CURRENT_THREAD_INFO(r11, r1) + ld r10,TI_FLAGS(r11) + andi. r11,r10,_TIF_SYSCALL_DOTRACE + bne .Lsyscall_dotrace /* does not return */ + cmpldi 0,r0,NR_syscalls + bge- .Lsyscall_enosys + +.Lsyscall: +/* + * Need to vector to 32 Bit or default sys_call_table here, + * based on caller's run-mode / personality. + */ + ld r11,SYS_CALL_TABLE@toc(2) + andi. r10,r10,_TIF_32BIT + beq 15f + addi r11,r11,8 /* use 32-bit syscall entries */ + clrldi r3,r3,32 + clrldi r4,r4,32 + clrldi r5,r5,32 + clrldi r6,r6,32 + clrldi r7,r7,32 + clrldi r8,r8,32 +15: + slwi r0,r0,4 + + 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 .Lsyscall_enosys above has + * committed. + */ + + ldx r12,r11,r0 /* Fetch system call handler [ptr] */ + mtctr r12 + bctrl /* Call handler */ + +.Lsyscall_exit: + std r3,RESULT(r1) + +#ifdef CONFIG_DEBUG_RSEQ + /* Check whether the syscall is issued inside a restartable sequence */ + addi r3,r1,STACK_FRAME_OVERHEAD + bl rseq_syscall + ld r3,RESULT(r1) +#endif + + CURRENT_THREAD_INFO(r12, r1) + + ld r8,_MSR(r1) +#ifdef CONFIG_PPC_BOOK3S + /* No MSR:RI on BookE */ + andi. r10,r8,MSR_RI + beq- .Lunrecov_restore +#endif + +/* + * This is a few instructions into the actual syscall exit path (which actually + * starts at .Lsyscall_exit) to cater to kprobe blacklisting and to reduce the + * number of visible symbols for profiling purposes. + * + * We can probe from system_call until this point as MSR_RI is set. But once it + * is cleared below, we won't be able to take a trap. + * + * This is blacklisted from kprobes further below with _ASM_NOKPROBE_SYMBOL(). + */ +system_call_exit: + /* + * Disable interrupts so current_thread_info()->flags can't change, + * and so that we don't get interrupted after loading SRR0/1. + */ +#ifdef CONFIG_PPC_BOOK3E + wrteei 0 +#else + /* + * For performance reasons we clear RI the same time that we + * clear EE. We only need to clear RI just before we restore r13 + * below, but batching it with EE saves us one expensive mtmsrd call. + * We have to be careful to restore RI if we branch anywhere from + * here (eg syscall_exit_work). + */ + li r11,0 + mtmsrd r11,1 +#endif /* CONFIG_PPC_BOOK3E */ + + ld r9,TI_FLAGS(r12) + li r11,-MAX_ERRNO + andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK) + bne- .Lsyscall_exit_work + + andi. r0,r8,MSR_FP + beq 2f +#ifdef CONFIG_ALTIVEC + andis. r0,r8,MSR_VEC@h + bne 3f +#endif +2: addi r3,r1,STACK_FRAME_OVERHEAD +#ifdef CONFIG_PPC_BOOK3S + li r10,MSR_RI + mtmsrd r10,1 /* Restore RI */ +#endif + bl restore_math +#ifdef CONFIG_PPC_BOOK3S + li r11,0 + mtmsrd r11,1 +#endif + ld r8,_MSR(r1) + ld r3,RESULT(r1) + li r11,-MAX_ERRNO + +3: cmpld r3,r11 + ld r5,_CCR(r1) + bge- .Lsyscall_error +.Lsyscall_error_cont: + ld r7,_NIP(r1) +BEGIN_FTR_SECTION + stdcx. r0,0,r1 /* to clear the reservation */ +END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) + andi. r6,r8,MSR_PR + ld r4,_LINK(r1) + + beq- 1f + ACCOUNT_CPU_USER_EXIT(r13, r11, r12) + +BEGIN_FTR_SECTION + HMT_MEDIUM_LOW +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + + ld r13,GPR13(r1) /* only restore r13 if returning to usermode */ + ld r2,GPR2(r1) + ld r1,GPR1(r1) + mtlr r4 + mtcr r5 + mtspr SPRN_SRR0,r7 + mtspr SPRN_SRR1,r8 + RFI_TO_USER + b . /* prevent speculative execution */ + + /* exit to kernel */ +1: ld r2,GPR2(r1) + ld r1,GPR1(r1) + mtlr r4 + mtcr r5 + mtspr SPRN_SRR0,r7 + mtspr SPRN_SRR1,r8 + RFI_TO_KERNEL + b . /* prevent speculative execution */ + +.Lsyscall_error: + oris r5,r5,0x1000 /* Set SO bit in CR */ + neg r3,r3 + std r5,_CCR(r1) + b .Lsyscall_error_cont + +/* Traced system call support */ +.Lsyscall_dotrace: + bl save_nvgprs + addi r3,r1,STACK_FRAME_OVERHEAD + bl do_syscall_trace_enter + + /* + * We use the return value of do_syscall_trace_enter() as the syscall + * number. If the syscall was rejected for any reason do_syscall_trace_enter() + * returns an invalid syscall number and the test below against + * NR_syscalls will fail. + */ + mr r0,r3 + + /* Restore argument registers just clobbered and/or possibly changed. */ + ld r3,GPR3(r1) + ld r4,GPR4(r1) + ld r5,GPR5(r1) + ld r6,GPR6(r1) + ld r7,GPR7(r1) + ld r8,GPR8(r1) + + /* Repopulate r9 and r10 for the syscall path */ + addi r9,r1,STACK_FRAME_OVERHEAD + CURRENT_THREAD_INFO(r10, r1) + ld r10,TI_FLAGS(r10) + + cmpldi r0,NR_syscalls + blt+ .Lsyscall + + /* Return code is already in r3 thanks to do_syscall_trace_enter() */ + b .Lsyscall_exit + + +.Lsyscall_enosys: + li r3,-ENOSYS + b .Lsyscall_exit + +.Lsyscall_exit_work: +#ifdef CONFIG_PPC_BOOK3S + li r10,MSR_RI + mtmsrd r10,1 /* Restore RI */ +#endif + /* If TIF_RESTOREALL is set, don't scribble on either r3 or ccr. + If TIF_NOERROR is set, just save r3 as it is. */ + + andi. r0,r9,_TIF_RESTOREALL + beq+ 0f + REST_NVGPRS(r1) + b 2f +0: cmpld r3,r11 /* r11 is -MAX_ERRNO */ + blt+ 1f + andi. r0,r9,_TIF_NOERROR + bne- 1f + ld r5,_CCR(r1) + neg r3,r3 + oris r5,r5,0x1000 /* Set SO bit in CR */ + std r5,_CCR(r1) +1: std r3,GPR3(r1) +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,r12,TI_FLAGS +3: ldarx r10,0,r12 + andc r10,r10,r11 + stdcx. r10,0,r12 + bne- 3b + subi r12,r12,TI_FLAGS + +4: /* Anything else left to do? */ +BEGIN_FTR_SECTION + lis r3,INIT_PPR@highest /* Set thread.ppr = 3 */ + ld r10,PACACURRENT(r13) + sldi r3,r3,32 /* bits 11-13 are used for ppr */ + std r3,TASKTHREADPPR(r10) +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + + andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP) + beq ret_from_except_lite + + /* Re-enable interrupts */ +#ifdef CONFIG_PPC_BOOK3E + wrteei 1 +#else + li r10,MSR_RI + ori r10,r10,MSR_EE + mtmsrd r10,1 +#endif /* CONFIG_PPC_BOOK3E */ + + bl save_nvgprs + addi r3,r1,STACK_FRAME_OVERHEAD + bl do_syscall_trace_leave + b ret_from_except + +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM +.Ltabort_syscall: + /* Firstly we need to enable TM in the kernel */ + mfmsr r10 + li r9, 1 + rldimi r10, r9, MSR_TM_LG, 63-MSR_TM_LG + mtmsrd r10, 0 + + /* tabort, this dooms the transaction, nothing else */ + li r9, (TM_CAUSE_SYSCALL|TM_CAUSE_PERSISTENT) + TABORT(R9) + + /* + * Return directly to userspace. We have corrupted user register state, + * but userspace will never see that register state. Execution will + * resume after the tbegin of the aborted transaction with the + * checkpointed register state. + */ + li r9, MSR_RI + andc r10, r10, r9 + mtmsrd r10, 1 + mtspr SPRN_SRR0, r11 + mtspr SPRN_SRR1, r12 + RFI_TO_USER + b . /* prevent speculative execution */ +#endif +_ASM_NOKPROBE_SYMBOL(system_call_common); +_ASM_NOKPROBE_SYMBOL(system_call_exit); + +/* Save non-volatile GPRs, if not already saved. */ +_GLOBAL(save_nvgprs) + ld r11,_TRAP(r1) + andi. r0,r11,1 + beqlr- + SAVE_NVGPRS(r1) + clrrdi r0,r11,1 + std r0,_TRAP(r1) + blr +_ASM_NOKPROBE_SYMBOL(save_nvgprs); + + +/* + * 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 (r14 - r31) before calling + * the C code. Similarly, fork, vfork and clone need the full + * register state on the stack so that it can be copied to the child. + */ + +_GLOBAL(ppc_fork) + bl save_nvgprs + bl sys_fork + b .Lsyscall_exit + +_GLOBAL(ppc_vfork) + bl save_nvgprs + bl sys_vfork + b .Lsyscall_exit + +_GLOBAL(ppc_clone) + bl save_nvgprs + bl sys_clone + b .Lsyscall_exit + +_GLOBAL(ppc32_swapcontext) + bl save_nvgprs + bl compat_sys_swapcontext + b .Lsyscall_exit + +_GLOBAL(ppc64_swapcontext) + bl save_nvgprs + bl sys_swapcontext + b .Lsyscall_exit + +_GLOBAL(ppc_switch_endian) + bl save_nvgprs + bl sys_switch_endian + b .Lsyscall_exit + +_GLOBAL(ret_from_fork) + bl schedule_tail + REST_NVGPRS(r1) + li r3,0 + b .Lsyscall_exit + +_GLOBAL(ret_from_kernel_thread) + bl schedule_tail + REST_NVGPRS(r1) + mtlr r14 + mr r3,r15 +#ifdef PPC64_ELF_ABI_v2 + mr r12,r14 +#endif + blrl + li r3,0 + b .Lsyscall_exit + +#ifdef CONFIG_PPC_BOOK3S_64 + +#define FLUSH_COUNT_CACHE \ +1: nop; \ + patch_site 1b, patch__call_flush_count_cache + + +#define BCCTR_FLUSH .long 0x4c400420 + +.macro nops number + .rept \number + nop + .endr +.endm + +.balign 32 +.global flush_count_cache +flush_count_cache: + /* Save LR into r9 */ + mflr r9 + + // Flush the link stack + .rept 64 + bl .+4 + .endr + b 1f + nops 6 + + .balign 32 + /* Restore LR */ +1: mtlr r9 + + // If we're just flushing the link stack, return here +3: nop + patch_site 3b patch__flush_link_stack_return + + li r9,0x7fff + mtctr r9 + + BCCTR_FLUSH + +2: nop + patch_site 2b patch__flush_count_cache_return + + nops 3 + + .rept 278 + .balign 32 + BCCTR_FLUSH + nops 7 + .endr + + blr +#else +#define FLUSH_COUNT_CACHE +#endif /* CONFIG_PPC_BOOK3S_64 */ + +/* + * 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, via ret_from_except. + * On entry, r3 points to the THREAD for the current task, r4 + * points to the THREAD for the new task. + * + * 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/powerpc/kernel/process.c + */ + .align 7 +_GLOBAL(_switch) + mflr r0 + std r0,16(r1) + stdu r1,-SWITCH_FRAME_SIZE(r1) + /* r3-r13 are caller saved -- Cort */ + SAVE_8GPRS(14, r1) + SAVE_10GPRS(22, r1) + std r0,_NIP(r1) /* Return to switch caller */ + mfcr r23 + std r23,_CCR(r1) + std r1,KSP(r3) /* Set old stack pointer */ + + FLUSH_COUNT_CACHE + + /* + * On SMP kernels, care must be taken because a task may be + * scheduled off CPUx and on to CPUy. Memory ordering must be + * considered. + * + * Cacheable stores on CPUx will be visible when the task is + * scheduled on CPUy by virtue of the core scheduler barriers + * (see "Notes on Program-Order guarantees on SMP systems." in + * kernel/sched/core.c). + * + * Uncacheable stores in the case of involuntary preemption must + * be taken care of. The smp_mb__before_spin_lock() in __schedule() + * is implemented as hwsync on powerpc, which orders MMIO too. So + * long as there is an hwsync in the context switch path, it will + * be executed on the source CPU after the task has performed + * all MMIO ops on that CPU, and on the destination CPU before the + * task performs any MMIO ops there. + */ + + /* + * The kernel context switch path must contain a spin_lock, + * which contains larx/stcx, which will clear any reservation + * of the task being switched. + */ +#ifdef CONFIG_PPC_BOOK3S +/* Cancel all explict user streams as they will have no use after context + * switch and will stop the HW from creating streams itself + */ + DCBT_BOOK3S_STOP_ALL_STREAM_IDS(r6) +#endif + + addi r6,r4,-THREAD /* Convert THREAD to 'current' */ + std r6,PACACURRENT(r13) /* Set new 'current' */ + + ld r8,KSP(r4) /* new stack pointer */ +#ifdef CONFIG_PPC_BOOK3S_64 +BEGIN_MMU_FTR_SECTION + b 2f +END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX) +BEGIN_FTR_SECTION + clrrdi r6,r8,28 /* get its ESID */ + clrrdi r9,r1,28 /* get current sp ESID */ +FTR_SECTION_ELSE + clrrdi r6,r8,40 /* get its 1T ESID */ + clrrdi r9,r1,40 /* get current sp 1T ESID */ +ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_1T_SEGMENT) + clrldi. r0,r6,2 /* is new ESID c00000000? */ + cmpd cr1,r6,r9 /* or is new ESID the same as current ESID? */ + cror eq,4*cr1+eq,eq + beq 2f /* if yes, don't slbie it */ + + /* Bolt in the new stack SLB entry */ + ld r7,KSP_VSID(r4) /* Get new stack's VSID */ + oris r0,r6,(SLB_ESID_V)@h + ori r0,r0,(SLB_NUM_BOLTED-1)@l +BEGIN_FTR_SECTION + li r9,MMU_SEGSIZE_1T /* insert B field */ + oris r6,r6,(MMU_SEGSIZE_1T << SLBIE_SSIZE_SHIFT)@h + rldimi r7,r9,SLB_VSID_SSIZE_SHIFT,0 +END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT) + + /* Update the last bolted SLB. No write barriers are needed + * here, provided we only update the current CPU's SLB shadow + * buffer. + */ + ld r9,PACA_SLBSHADOWPTR(r13) + li r12,0 + std r12,SLBSHADOW_STACKESID(r9) /* Clear ESID */ + li r12,SLBSHADOW_STACKVSID + STDX_BE r7,r12,r9 /* Save VSID */ + li r12,SLBSHADOW_STACKESID + STDX_BE r0,r12,r9 /* Save ESID */ + + /* No need to check for MMU_FTR_NO_SLBIE_B here, since when + * we have 1TB segments, the only CPUs known to have the errata + * only support less than 1TB of system memory and we'll never + * actually hit this code path. + */ + + isync + slbie r6 + slbie r6 /* Workaround POWER5 < DD2.1 issue */ + slbmte r7,r0 + isync +2: +#endif /* CONFIG_PPC_BOOK3S_64 */ + + CURRENT_THREAD_INFO(r7, r8) /* base of new stack */ + /* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE + because we don't need to leave the 288-byte ABI gap at the + top of the kernel stack. */ + addi r7,r7,THREAD_SIZE-SWITCH_FRAME_SIZE + + /* + * PMU interrupts in radix may come in here. They will use r1, not + * PACAKSAVE, so this stack switch will not cause a problem. They + * will store to the process stack, which may then be migrated to + * another CPU. However the rq lock release on this CPU paired with + * the rq lock acquire on the new CPU before the stack becomes + * active on the new CPU, will order those stores. + */ + mr r1,r8 /* start using new stack pointer */ + std r7,PACAKSAVE(r13) + + ld r6,_CCR(r1) + mtcrf 0xFF,r6 + + /* r3-r13 are destroyed -- Cort */ + REST_8GPRS(14, r1) + REST_10GPRS(22, r1) + + /* convert old thread to its task_struct for return value */ + addi r3,r3,-THREAD + ld r7,_NIP(r1) /* Return to _switch caller in new task */ + mtlr r7 + addi r1,r1,SWITCH_FRAME_SIZE + blr + + .align 7 +_GLOBAL(ret_from_except) + ld r11,_TRAP(r1) + andi. r0,r11,1 + bne ret_from_except_lite + REST_NVGPRS(r1) + +_GLOBAL(ret_from_except_lite) + /* + * Disable interrupts so that current_thread_info()->flags + * can't change between when we test it and when we return + * from the interrupt. + */ +#ifdef CONFIG_PPC_BOOK3E + wrteei 0 +#else + li r10,MSR_RI + mtmsrd r10,1 /* Update machine state */ +#endif /* CONFIG_PPC_BOOK3E */ + + CURRENT_THREAD_INFO(r9, r1) + ld r3,_MSR(r1) +#ifdef CONFIG_PPC_BOOK3E + ld r10,PACACURRENT(r13) +#endif /* CONFIG_PPC_BOOK3E */ + ld r4,TI_FLAGS(r9) + andi. r3,r3,MSR_PR + beq resume_kernel +#ifdef CONFIG_PPC_BOOK3E + lwz r3,(THREAD+THREAD_DBCR0)(r10) +#endif /* CONFIG_PPC_BOOK3E */ + + /* Check current_thread_info()->flags */ + andi. r0,r4,_TIF_USER_WORK_MASK + bne 1f +#ifdef CONFIG_PPC_BOOK3E + /* + * Check to see if the dbcr0 register is set up to debug. + * Use the internal debug mode bit to do this. + */ + andis. r0,r3,DBCR0_IDM@h + beq restore + mfmsr r0 + rlwinm r0,r0,0,~MSR_DE /* Clear MSR.DE */ + mtmsr r0 + mtspr SPRN_DBCR0,r3 + li r10, -1 + mtspr SPRN_DBSR,r10 + b restore +#else + addi r3,r1,STACK_FRAME_OVERHEAD + bl restore_math + b restore +#endif +1: andi. r0,r4,_TIF_NEED_RESCHED + beq 2f + bl restore_interrupts + SCHEDULE_USER + b ret_from_except_lite +2: +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM + andi. r0,r4,_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM + bne 3f /* only restore TM if nothing else to do */ + addi r3,r1,STACK_FRAME_OVERHEAD + bl restore_tm_state + b restore +3: +#endif + bl save_nvgprs + /* + * Use a non volatile GPR to save and restore our thread_info flags + * across the call to restore_interrupts. + */ + mr r30,r4 + bl restore_interrupts + mr r4,r30 + addi r3,r1,STACK_FRAME_OVERHEAD + bl do_notify_resume + b ret_from_except + +resume_kernel: + /* check current_thread_info, _TIF_EMULATE_STACK_STORE */ + andis. r8,r4,_TIF_EMULATE_STACK_STORE@h + beq+ 1f + + addi r8,r1,INT_FRAME_SIZE /* Get the kprobed function entry */ + + ld 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/8 /* size: INT_FRAME_SIZE */ + li r6,0 /* start offset: 0 */ + mtctr r5 +2: ldx r0,r6,r4 + stdx r0,r6,r3 + addi r6,r6,8 + bdnz 2b + + /* Do real store operation to complete stdu */ + ld r5,GPR1(r1) + std r8,0(r5) + + /* Clear _TIF_EMULATE_STACK_STORE flag */ + lis r11,_TIF_EMULATE_STACK_STORE@h + addi r5,r9,TI_FLAGS +0: ldarx r4,0,r5 + andc r4,r4,r11 + stdcx. r4,0,r5 + bne- 0b +1: + +#ifdef CONFIG_PREEMPT + /* Check if we need to preempt */ + andi. r0,r4,_TIF_NEED_RESCHED + beq+ restore + /* Check that preempt_count() == 0 and interrupts are enabled */ + lwz r8,TI_PREEMPT(r9) + cmpwi cr0,r8,0 + bne restore + ld r0,SOFTE(r1) + andi. r0,r0,IRQS_DISABLED + bne restore + + /* + * Here we are preempting the current task. We want to make + * sure we are soft-disabled first and reconcile irq state. + */ + RECONCILE_IRQ_STATE(r3,r4) +1: bl preempt_schedule_irq + + /* Re-test flags and eventually loop */ + CURRENT_THREAD_INFO(r9, r1) + ld r4,TI_FLAGS(r9) + andi. r0,r4,_TIF_NEED_RESCHED + bne 1b + + /* + * arch_local_irq_restore() from preempt_schedule_irq above may + * enable hard interrupt but we really should disable interrupts + * when we return from the interrupt, and so that we don't get + * interrupted after loading SRR0/1. + */ +#ifdef CONFIG_PPC_BOOK3E + wrteei 0 +#else + li r10,MSR_RI + mtmsrd r10,1 /* Update machine state */ +#endif /* CONFIG_PPC_BOOK3E */ +#endif /* CONFIG_PREEMPT */ + + .globl fast_exc_return_irq +fast_exc_return_irq: +restore: + /* + * This is the main kernel exit path. First we check if we + * are about to re-enable interrupts + */ + ld r5,SOFTE(r1) + lbz r6,PACAIRQSOFTMASK(r13) + andi. r5,r5,IRQS_DISABLED + bne .Lrestore_irq_off + + /* We are enabling, were we already enabled ? Yes, just return */ + andi. r6,r6,IRQS_DISABLED + beq cr0,.Ldo_restore + + /* + * We are about to soft-enable interrupts (we are hard disabled + * at this point). We check if there's anything that needs to + * be replayed first. + */ + lbz r0,PACAIRQHAPPENED(r13) + cmpwi cr0,r0,0 + bne- .Lrestore_check_irq_replay + + /* + * Get here when nothing happened while soft-disabled, just + * soft-enable and move-on. We will hard-enable as a side + * effect of rfi + */ +.Lrestore_no_replay: + TRACE_ENABLE_INTS + li r0,IRQS_ENABLED + stb r0,PACAIRQSOFTMASK(r13); + + /* + * Final return path. BookE is handled in a different file + */ +.Ldo_restore: +#ifdef CONFIG_PPC_BOOK3E + b exception_return_book3e +#else + /* + * Clear the reservation. If we know the CPU tracks the address of + * the reservation then we can potentially save some cycles and use + * a larx. On POWER6 and POWER7 this is significantly faster. + */ +BEGIN_FTR_SECTION + stdcx. r0,0,r1 /* to clear the reservation */ +FTR_SECTION_ELSE + ldarx r4,0,r1 +ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) + + /* + * Some code path such as load_up_fpu or altivec return directly + * here. They run entirely hard disabled and do not alter the + * interrupt state. They also don't use lwarx/stwcx. and thus + * are known not to leave dangling reservations. + */ + .globl fast_exception_return +fast_exception_return: + ld r3,_MSR(r1) + ld r4,_CTR(r1) + ld r0,_LINK(r1) + mtctr r4 + mtlr r0 + ld r4,_XER(r1) + mtspr SPRN_XER,r4 + + REST_8GPRS(5, r1) + + andi. r0,r3,MSR_RI + beq- .Lunrecov_restore + + /* Load PPR from thread struct before we clear MSR:RI */ +BEGIN_FTR_SECTION + ld r2,PACACURRENT(r13) + ld r2,TASKTHREADPPR(r2) +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + + /* + * Clear RI before restoring r13. If we are returning to + * userspace and we take an exception after restoring r13, + * we end up corrupting the userspace r13 value. + */ + li r4,0 + mtmsrd r4,1 + +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM + /* TM debug */ + std r3, PACATMSCRATCH(r13) /* Stash returned-to MSR */ +#endif + /* + * r13 is our per cpu area, only restore it if we are returning to + * userspace the value stored in the stack frame may belong to + * another CPU. + */ + andi. r0,r3,MSR_PR + beq 1f +BEGIN_FTR_SECTION + mtspr SPRN_PPR,r2 /* Restore PPR */ +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + ACCOUNT_CPU_USER_EXIT(r13, r2, r4) + REST_GPR(13, r1) + + mtspr SPRN_SRR1,r3 + + ld r2,_CCR(r1) + mtcrf 0xFF,r2 + ld r2,_NIP(r1) + mtspr SPRN_SRR0,r2 + + ld r0,GPR0(r1) + ld r2,GPR2(r1) + ld r3,GPR3(r1) + ld r4,GPR4(r1) + ld r1,GPR1(r1) + RFI_TO_USER + b . /* prevent speculative execution */ + +1: mtspr SPRN_SRR1,r3 + + ld r2,_CCR(r1) + mtcrf 0xFF,r2 + ld r2,_NIP(r1) + mtspr SPRN_SRR0,r2 + + /* + * Leaving a stale exception_marker on the stack can confuse + * the reliable stack unwinder later on. Clear it. + */ + li r2,0 + std r2,STACK_FRAME_OVERHEAD-16(r1) + + ld r0,GPR0(r1) + ld r2,GPR2(r1) + ld r3,GPR3(r1) + ld r4,GPR4(r1) + ld r1,GPR1(r1) + RFI_TO_KERNEL + b . /* prevent speculative execution */ + +#endif /* CONFIG_PPC_BOOK3E */ + + /* + * We are returning to a context with interrupts soft disabled. + * + * However, we may also about to hard enable, so we need to + * make sure that in this case, we also clear PACA_IRQ_HARD_DIS + * or that bit can get out of sync and bad things will happen + */ +.Lrestore_irq_off: + ld r3,_MSR(r1) + lbz r7,PACAIRQHAPPENED(r13) + andi. r0,r3,MSR_EE + beq 1f + rlwinm r7,r7,0,~PACA_IRQ_HARD_DIS + stb r7,PACAIRQHAPPENED(r13) +1: +#if defined(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG) && defined(CONFIG_BUG) + /* The interrupt should not have soft enabled. */ + lbz r7,PACAIRQSOFTMASK(r13) +1: tdeqi r7,IRQS_ENABLED + EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING +#endif + b .Ldo_restore + + /* + * Something did happen, check if a re-emit is needed + * (this also clears paca->irq_happened) + */ +.Lrestore_check_irq_replay: + /* XXX: We could implement a fast path here where we check + * for irq_happened being just 0x01, in which case we can + * clear it and return. That means that we would potentially + * miss a decrementer having wrapped all the way around. + * + * Still, this might be useful for things like hash_page + */ + bl __check_irq_replay + cmpwi cr0,r3,0 + beq .Lrestore_no_replay + + /* + * We need to re-emit an interrupt. We do so by re-using our + * existing exception frame. We first change the trap value, + * but we need to ensure we preserve the low nibble of it + */ + ld r4,_TRAP(r1) + clrldi r4,r4,60 + or r4,r4,r3 + std r4,_TRAP(r1) + + /* + * PACA_IRQ_HARD_DIS won't always be set here, so set it now + * to reconcile the IRQ state. Tracing is already accounted for. + */ + lbz r4,PACAIRQHAPPENED(r13) + ori r4,r4,PACA_IRQ_HARD_DIS + stb r4,PACAIRQHAPPENED(r13) + + /* + * Then find the right handler and call it. Interrupts are + * still soft-disabled and we keep them that way. + */ + cmpwi cr0,r3,0x500 + bne 1f + addi r3,r1,STACK_FRAME_OVERHEAD; + bl do_IRQ + b ret_from_except +1: cmpwi cr0,r3,0xf00 + bne 1f + addi r3,r1,STACK_FRAME_OVERHEAD; + bl performance_monitor_exception + b ret_from_except +1: cmpwi cr0,r3,0xe60 + bne 1f + addi r3,r1,STACK_FRAME_OVERHEAD; + bl handle_hmi_exception + b ret_from_except +1: cmpwi cr0,r3,0x900 + bne 1f + addi r3,r1,STACK_FRAME_OVERHEAD; + bl timer_interrupt + b ret_from_except +#ifdef CONFIG_PPC_DOORBELL +1: +#ifdef CONFIG_PPC_BOOK3E + cmpwi cr0,r3,0x280 +#else + cmpwi cr0,r3,0xa00 +#endif /* CONFIG_PPC_BOOK3E */ + bne 1f + addi r3,r1,STACK_FRAME_OVERHEAD; + bl doorbell_exception +#endif /* CONFIG_PPC_DOORBELL */ +1: b ret_from_except /* What else to do here ? */ + +.Lunrecov_restore: + addi r3,r1,STACK_FRAME_OVERHEAD + bl unrecoverable_exception + b .Lunrecov_restore + +_ASM_NOKPROBE_SYMBOL(ret_from_except); +_ASM_NOKPROBE_SYMBOL(ret_from_except_lite); +_ASM_NOKPROBE_SYMBOL(resume_kernel); +_ASM_NOKPROBE_SYMBOL(fast_exc_return_irq); +_ASM_NOKPROBE_SYMBOL(restore); +_ASM_NOKPROBE_SYMBOL(fast_exception_return); + + +#ifdef CONFIG_PPC_RTAS +/* + * On CHRP, the Run-Time Abstraction Services (RTAS) have to be + * called with the MMU off. + * + * In addition, we need to be in 32b mode, at least for now. + * + * Note: r3 is an input parameter to rtas, so don't trash it... + */ +_GLOBAL(enter_rtas) + mflr r0 + std r0,16(r1) + stdu r1,-RTAS_FRAME_SIZE(r1) /* Save SP and create stack space. */ + + /* Because RTAS is running in 32b mode, it clobbers the high order half + * of all registers that it saves. We therefore save those registers + * RTAS might touch to the stack. (r0, r3-r13 are caller saved) + */ + SAVE_GPR(2, r1) /* Save the TOC */ + SAVE_GPR(13, r1) /* Save paca */ + SAVE_8GPRS(14, r1) /* Save the non-volatiles */ + SAVE_10GPRS(22, r1) /* ditto */ + + mfcr r4 + std r4,_CCR(r1) + mfctr r5 + std r5,_CTR(r1) + mfspr r6,SPRN_XER + std r6,_XER(r1) + mfdar r7 + std r7,_DAR(r1) + mfdsisr r8 + std r8,_DSISR(r1) + + /* Temporary workaround to clear CR until RTAS can be modified to + * ignore all bits. + */ + li r0,0 + mtcr r0 + +#ifdef CONFIG_BUG + /* There is no way it is acceptable to get here with interrupts enabled, + * check it with the asm equivalent of WARN_ON + */ + lbz r0,PACAIRQSOFTMASK(r13) +1: tdeqi r0,IRQS_ENABLED + EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING +#endif + + /* Hard-disable interrupts */ + mfmsr r6 + rldicl r7,r6,48,1 + rotldi r7,r7,16 + mtmsrd r7,1 + + /* Unfortunately, the stack pointer and the MSR are also clobbered, + * so they are saved in the PACA which allows us to restore + * our original state after RTAS returns. + */ + std r1,PACAR1(r13) + std r6,PACASAVEDMSR(r13) + + /* Setup our real return addr */ + LOAD_REG_ADDR(r4,rtas_return_loc) + clrldi r4,r4,2 /* convert to realmode address */ + mtlr r4 + + li r0,0 + ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI + andc r0,r6,r0 + + li r9,1 + rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG) + ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI|MSR_LE + andc r6,r0,r9 + +__enter_rtas: + sync /* disable interrupts so SRR0/1 */ + mtmsrd r0 /* don't get trashed */ + + LOAD_REG_ADDR(r4, rtas) + ld r5,RTASENTRY(r4) /* get the rtas->entry value */ + ld r4,RTASBASE(r4) /* get the rtas->base value */ + + mtspr SPRN_SRR0,r5 + mtspr SPRN_SRR1,r6 + RFI_TO_KERNEL + b . /* prevent speculative execution */ + +rtas_return_loc: + FIXUP_ENDIAN + + /* + * Clear RI and set SF before anything. + */ + mfmsr r6 + li r0,MSR_RI + andc r6,r6,r0 + sldi r0,r0,(MSR_SF_LG - MSR_RI_LG) + or r6,r6,r0 + sync + mtmsrd r6 + + /* relocation is off at this point */ + GET_PACA(r4) + clrldi r4,r4,2 /* convert to realmode address */ + + bcl 20,31,$+4 +0: mflr r3 + ld r3,(1f-0b)(r3) /* get &rtas_restore_regs */ + + ld r1,PACAR1(r4) /* Restore our SP */ + ld r4,PACASAVEDMSR(r4) /* Restore our MSR */ + + mtspr SPRN_SRR0,r3 + mtspr SPRN_SRR1,r4 + RFI_TO_KERNEL + b . /* prevent speculative execution */ +_ASM_NOKPROBE_SYMBOL(__enter_rtas) +_ASM_NOKPROBE_SYMBOL(rtas_return_loc) + + .align 3 +1: .8byte rtas_restore_regs + +rtas_restore_regs: + /* relocation is on at this point */ + REST_GPR(2, r1) /* Restore the TOC */ + REST_GPR(13, r1) /* Restore paca */ + REST_8GPRS(14, r1) /* Restore the non-volatiles */ + REST_10GPRS(22, r1) /* ditto */ + + GET_PACA(r13) + + ld r4,_CCR(r1) + mtcr r4 + ld r5,_CTR(r1) + mtctr r5 + ld r6,_XER(r1) + mtspr SPRN_XER,r6 + ld r7,_DAR(r1) + mtdar r7 + ld r8,_DSISR(r1) + mtdsisr r8 + + addi r1,r1,RTAS_FRAME_SIZE /* Unstack our frame */ + ld r0,16(r1) /* get return address */ + + mtlr r0 + blr /* return to caller */ + +#endif /* CONFIG_PPC_RTAS */ + +_GLOBAL(enter_prom) + mflr r0 + std r0,16(r1) + stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */ + + /* Because PROM is running in 32b mode, it clobbers the high order half + * of all registers that it saves. We therefore save those registers + * PROM might touch to the stack. (r0, r3-r13 are caller saved) + */ + SAVE_GPR(2, r1) + SAVE_GPR(13, r1) + SAVE_8GPRS(14, r1) + SAVE_10GPRS(22, r1) + mfcr r10 + mfmsr r11 + std r10,_CCR(r1) + std r11,_MSR(r1) + + /* Put PROM address in SRR0 */ + mtsrr0 r4 + + /* Setup our trampoline return addr in LR */ + bcl 20,31,$+4 +0: mflr r4 + addi r4,r4,(1f - 0b) + mtlr r4 + + /* Prepare a 32-bit mode big endian MSR + */ +#ifdef CONFIG_PPC_BOOK3E + rlwinm r11,r11,0,1,31 + mtsrr1 r11 + rfi +#else /* CONFIG_PPC_BOOK3E */ + LOAD_REG_IMMEDIATE(r12, MSR_SF | MSR_ISF | MSR_LE) + andc r11,r11,r12 + mtsrr1 r11 + RFI_TO_KERNEL +#endif /* CONFIG_PPC_BOOK3E */ + +1: /* Return from OF */ + FIXUP_ENDIAN + + /* Just make sure that r1 top 32 bits didn't get + * corrupt by OF + */ + rldicl r1,r1,0,32 + + /* Restore the MSR (back to 64 bits) */ + ld r0,_MSR(r1) + MTMSRD(r0) + isync + + /* Restore other registers */ + REST_GPR(2, r1) + REST_GPR(13, r1) + REST_8GPRS(14, r1) + REST_10GPRS(22, r1) + ld r4,_CCR(r1) + mtcr r4 + + addi r1,r1,PROM_FRAME_SIZE + ld r0,16(r1) + mtlr r0 + blr |