diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 1cc40533021b..48a987579e4f 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -50,6 +50,7 @@ #include #include #include +#include #include #ifdef CONFIG_PPC64 #include @@ -467,6 +468,117 @@ static inline bool hw_brk_match(struct arch_hw_breakpoint *a, return false; return true; } +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM +static inline void tm_reclaim_task(struct task_struct *tsk) +{ + /* We have to work out if we're switching from/to a task that's in the + * middle of a transaction. + * + * In switching we need to maintain a 2nd register state as + * oldtask->thread.ckpt_regs. We tm_reclaim(oldproc); this saves the + * checkpointed (tbegin) state in ckpt_regs and saves the transactional + * (current) FPRs into oldtask->thread.transact_fpr[]. + * + * We also context switch (save) TFHAR/TEXASR/TFIAR in here. + */ + struct thread_struct *thr = &tsk->thread; + + if (!thr->regs) + return; + + if (!MSR_TM_ACTIVE(thr->regs->msr)) + goto out_and_saveregs; + + /* Stash the original thread MSR, as giveup_fpu et al will + * modify it. We hold onto it to see whether the task used + * FP & vector regs. + */ + thr->tm_orig_msr = thr->regs->msr; + + TM_DEBUG("--- tm_reclaim on pid %d (NIP=%lx, " + "ccr=%lx, msr=%lx, trap=%lx)\n", + tsk->pid, thr->regs->nip, + thr->regs->ccr, thr->regs->msr, + thr->regs->trap); + + tm_reclaim(thr, thr->regs->msr, TM_CAUSE_RESCHED); + + TM_DEBUG("--- tm_reclaim on pid %d complete\n", + tsk->pid); + +out_and_saveregs: + /* Always save the regs here, even if a transaction's not active. + * This context-switches a thread's TM info SPRs. We do it here to + * be consistent with the restore path (in recheckpoint) which + * cannot happen later in _switch(). + */ + tm_save_sprs(thr); +} + +static inline void __maybe_unused tm_recheckpoint_new_task(struct task_struct *new) +{ + unsigned long msr; + + if (!cpu_has_feature(CPU_FTR_TM)) + return; + + /* Recheckpoint the registers of the thread we're about to switch to. + * + * If the task was using FP, we non-lazily reload both the original and + * the speculative FP register states. This is because the kernel + * doesn't see if/when a TM rollback occurs, so if we take an FP + * unavoidable later, we are unable to determine which set of FP regs + * need to be restored. + */ + if (!new->thread.regs) + return; + + /* The TM SPRs are restored here, so that TEXASR.FS can be set + * before the trecheckpoint and no explosion occurs. + */ + tm_restore_sprs(&new->thread); + + if (!MSR_TM_ACTIVE(new->thread.regs->msr)) + return; + msr = new->thread.tm_orig_msr; + /* Recheckpoint to restore original checkpointed register state. */ + TM_DEBUG("*** tm_recheckpoint of pid %d " + "(new->msr 0x%lx, new->origmsr 0x%lx)\n", + new->pid, new->thread.regs->msr, msr); + + /* This loads the checkpointed FP/VEC state, if used */ + tm_recheckpoint(&new->thread, msr); + + /* This loads the speculative FP/VEC state, if used */ + if (msr & MSR_FP) { + do_load_up_transact_fpu(&new->thread); + new->thread.regs->msr |= + (MSR_FP | new->thread.fpexc_mode); + } + if (msr & MSR_VEC) { + do_load_up_transact_altivec(&new->thread); + new->thread.regs->msr |= MSR_VEC; + } + /* We may as well turn on VSX too since all the state is restored now */ + if (msr & MSR_VSX) + new->thread.regs->msr |= MSR_VSX; + + TM_DEBUG("*** tm_recheckpoint of pid %d complete " + "(kernel msr 0x%lx)\n", + new->pid, mfmsr()); +} + +static inline void __switch_to_tm(struct task_struct *prev) +{ + if (cpu_has_feature(CPU_FTR_TM)) { + tm_enable(); + tm_reclaim_task(prev); + } +} +#else +#define tm_recheckpoint_new_task(new) +#define __switch_to_tm(prev) +#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *new)