/* * Copyright 2010 Tilera Corporation. All Rights Reserved. * * 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, version 2. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or * NON INFRINGEMENT. See the GNU General Public License for * more details. */ #include <linux/sched.h>#include <linux/preempt.h>#include <linux/module.h>#include <linux/fs.h>#include <linux/kprobes.h>#include <linux/elfcore.h>#include <linux/tick.h>#include <linux/init.h>#include <linux/mm.h>#include <linux/compat.h>#include <linux/nmi.h>#include <linux/syscalls.h>#include <linux/kernel.h>#include <linux/tracehook.h>#include <linux/signal.h>#include <linux/delay.h>#include <linux/context_tracking.h>#include <asm/stack.h>#include <asm/switch_to.h>#include <asm/homecache.h>#include <asm/syscalls.h>#include <asm/traps.h>#include <asm/setup.h>#include <asm/uaccess.h>#ifdef CONFIG_HARDWALL#include <asm/hardwall.h>#endif#include <arch/chip.h>#include <arch/abi.h>#include <arch/sim_def.h> /* * Use the (x86) "idle=poll" option to prefer low latency when leaving the * idle loop over low power while in the idle loop, e.g. if we have * one thread per core and we want to get threads out of futex waits fast. */static int __init idle_setup(char *str){ if (!str) return -EINVAL; if (!strcmp(str, "poll")) { pr_info("using polling idle threads\n"); cpu_idle_poll_ctrl(true); return 0; } else if (!strcmp(str, "halt")) { return 0; } return -1;}early_param("idle", idle_setup); void arch_cpu_idle(void){ __this_cpu_write(irq_stat.idle_timestamp, jiffies); _cpu_idle();} /* * Release a thread_info structure */void arch_release_thread_stack(unsigned long *stack){ struct thread_info *info = (void *)stack; struct single_step_state *step_state = info->step_state; if (step_state) { /* * FIXME: we don't munmap step_state->buffer * because the mm_struct for this process (info->task->mm) * has already been zeroed in exit_mm(). Keeping a * reference to it here seems like a bad move, so this * means we can't munmap() the buffer, and therefore if we * ptrace multiple threads in a process, we will slowly * leak user memory. (Note that as soon as the last * thread in a process dies, we will reclaim all user * memory including single-step buffers in the usual way.) * We should either assign a kernel VA to this buffer * somehow, or we should associate the buffer(s) with the * mm itself so we can clean them up that way. */ kfree(step_state); }} static void save_arch_state(struct thread_struct *t); int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg, struct task_struct *p){ struct pt_regs *childregs = task_pt_regs(p); unsigned long ksp; unsigned long *callee_regs; /* * Set up the stack and stack pointer appropriately for the * new child to find itself woken up in __switch_to(). * The callee-saved registers must be on the stack to be read; * the new task will then jump to assembly support to handle * calling schedule_tail(), etc., and (for userspace tasks) * returning to the context set up in the pt_regs. */ ksp = (unsigned long) childregs; ksp -= C_ABI_SAVE_AREA_SIZE; /* interrupt-entry save area */ ((long *)ksp)[0] = ((long *)ksp)[1] = 0; ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long); callee_regs = (unsigned long *)ksp; ksp -= C_ABI_SAVE_AREA_SIZE; /* __switch_to() save area */ ((long *)ksp)[0] = ((long *)ksp)[1] = 0; p->thread.ksp = ksp; /* Record the pid of the task that created this one. */ p->thread.creator_pid = current->pid; if (unlikely(p->flags & PF_KTHREAD)) { /* kernel thread */ memset(childregs, 0, sizeof(struct pt_regs)); memset(&callee_regs[2], 0, (CALLEE_SAVED_REGS_COUNT - 2) * sizeof(unsigned long)); callee_regs[0] = sp; /* r30 = function */ callee_regs[1] = arg; /* r31 = arg */ p->thread.pc = (unsigned long) ret_from_kernel_thread; return 0; } /* * Start new thread in ret_from_fork so it schedules properly * and then return from interrupt like the parent. */ p->thread.pc = (unsigned long) ret_from_fork; /* * Do not clone step state from the parent; each thread * must make its own lazily. */ task_thread_info(p)->step_state = NULL; #ifdef __tilegx__ /* * Do not clone unalign jit fixup from the parent; each thread * must allocate its own on demand. */ task_thread_info(p)->unalign_jit_base = NULL;#endif /* * Copy the registers onto the kernel stack so the * return-from-interrupt code will reload it into registers. */ *childregs = *current_pt_regs(); childregs->regs[0] = 0; /* return value is zero */ if (sp) childregs->sp = sp; /* override with new user stack pointer */ memcpy(callee_regs, &childregs->regs[CALLEE_SAVED_FIRST_REG], CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long)); /* Save user stack top pointer so we can ID the stack vm area later. */ p->thread.usp0 = childregs->sp; /* * If CLONE_SETTLS is set, set "tp" in the new task to "r4", * which is passed in as arg #5 to sys_clone(). */ if (clone_flags & CLONE_SETTLS) childregs->tp = childregs->regs[4]; #if CHIP_HAS_TILE_DMA() /* * No DMA in the new thread. We model this on the fact that * fork() clears the pending signals, alarms, and aio for the child. */ memset(&p->thread.tile_dma_state, 0, sizeof(struct tile_dma_state)); memset(&p->thread.dma_async_tlb, 0, sizeof(struct async_tlb));#endif /* New thread has its miscellaneous processor state bits clear. */ p->thread.proc_status = 0; #ifdef CONFIG_HARDWALL /* New thread does not own any networks. */ memset(&p->thread.hardwall[0], 0, sizeof(struct hardwall_task) * HARDWALL_TYPES);#endif /* * Start the new thread with the current architecture state * (user interrupt masks, etc.). */ save_arch_state(&p->thread); return 0;} int set_unalign_ctl(struct task_struct *tsk, unsigned int val){ task_thread_info(tsk)->align_ctl = val; return 0;} int get_unalign_ctl(struct task_struct *tsk, unsigned long adr){ return put_user(task_thread_info(tsk)->align_ctl, (unsigned int __user *)adr);} static struct task_struct corrupt_current = { .comm = "<corrupt>" }; /* * Return "current" if it looks plausible, or else a pointer to a dummy. * This can be helpful if we are just trying to emit a clean panic. */struct task_struct *validate_current(void){ struct task_struct *tsk = current; if (unlikely((unsigned long)tsk < PAGE_OFFSET || (high_memory && (void *)tsk > high_memory) || ((unsigned long)tsk & (__alignof__(*tsk) - 1)) != 0)) { pr_err("Corrupt 'current' %p (sp %#lx)\n", tsk, stack_pointer); tsk = &corrupt_current; } return tsk;} /* Take and return the pointer to the previous task, for schedule_tail(). */struct task_struct *sim_notify_fork(struct task_struct *prev){ struct task_struct *tsk = current; __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK_PARENT | (tsk->thread.creator_pid << _SIM_CONTROL_OPERATOR_BITS)); __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK | (tsk->pid << _SIM_CONTROL_OPERATOR_BITS)); return prev;} int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs){ struct pt_regs *ptregs = task_pt_regs(tsk); elf_core_copy_regs(regs, ptregs); return 1;} #if CHIP_HAS_TILE_DMA() /* Allow user processes to access the DMA SPRs */void grant_dma_mpls(void){#if CONFIG_KERNEL_PL == 2 __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1); __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);#else __insn_mtspr(SPR_MPL_DMA_CPL_SET_0, 1); __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_0, 1);#endif} /* Forbid user processes from accessing the DMA SPRs */void restrict_dma_mpls(void){#if CONFIG_KERNEL_PL == 2 __insn_mtspr(SPR_MPL_DMA_CPL_SET_2, 1); __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_2, 1);#else __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1); __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);#endif} /* Pause the DMA engine, then save off its state registers. */static void save_tile_dma_state(struct tile_dma_state *dma){ unsigned long state = __insn_mfspr(SPR_DMA_USER_STATUS); unsigned long post_suspend_state; /* If we're running, suspend the engine. */ if ((state & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK); /* * Wait for the engine to idle, then save regs. Note that we * want to record the "running" bit from before suspension, * and the "done" bit from after, so that we can properly * distinguish a case where the user suspended the engine from * the case where the kernel suspended as part of the context * swap. */ do { post_suspend_state = __insn_mfspr(SPR_DMA_USER_STATUS); } while (post_suspend_state & SPR_DMA_STATUS__BUSY_MASK); dma->src = __insn_mfspr(SPR_DMA_SRC_ADDR); dma->src_chunk = __insn_mfspr(SPR_DMA_SRC_CHUNK_ADDR); dma->dest = __insn_mfspr(SPR_DMA_DST_ADDR); dma->dest_chunk = __insn_mfspr(SPR_DMA_DST_CHUNK_ADDR); dma->strides = __insn_mfspr(SPR_DMA_STRIDE); dma->chunk_size = __insn_mfspr(SPR_DMA_CHUNK_SIZE); dma->byte = __insn_mfspr(SPR_DMA_BYTE); dma->status = (state & SPR_DMA_STATUS__RUNNING_MASK) | (post_suspend_state & SPR_DMA_STATUS__DONE_MASK);} /* Restart a DMA that was running before we were context-switched out. */static void restore_tile_dma_state(struct thread_struct *t){ const struct tile_dma_state *dma = &t->tile_dma_state; /* * The only way to restore the done bit is to run a zero * length transaction. */ if ((dma->status & SPR_DMA_STATUS__DONE_MASK) && !(__insn_mfspr(SPR_DMA_USER_STATUS) & SPR_DMA_STATUS__DONE_MASK)) { __insn_mtspr(SPR_DMA_BYTE, 0); __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK); while (__insn_mfspr(SPR_DMA_USER_STATUS) & SPR_DMA_STATUS__BUSY_MASK) ; } __insn_mtspr(SPR_DMA_SRC_ADDR, dma->src); __insn_mtspr(SPR_DMA_SRC_CHUNK_ADDR, dma->src_chunk); __insn_mtspr(SPR_DMA_DST_ADDR, dma->dest); __insn_mtspr(SPR_DMA_DST_CHUNK_ADDR, dma->dest_chunk); __insn_mtspr(SPR_DMA_STRIDE, dma->strides); __insn_mtspr(SPR_DMA_CHUNK_SIZE, dma->chunk_size); __insn_mtspr(SPR_DMA_BYTE, dma->byte); /* * Restart the engine if we were running and not done. * Clear a pending async DMA fault that we were waiting on return * to user space to execute, since we expect the DMA engine * to regenerate those faults for us now. Note that we don't * try to clear the TIF_ASYNC_TLB flag, since it's relatively * harmless if set, and it covers both DMA and the SN processor. */ if ((dma->status & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) { t->dma_async_tlb.fault_num = 0; __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK); }} #endif static void save_arch_state(struct thread_struct *t){#if CHIP_HAS_SPLIT_INTR_MASK() t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0_0) | ((u64)__insn_mfspr(SPR_INTERRUPT_MASK_0_1) << 32);#else t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0);#endif t->ex_context[0] = __insn_mfspr(SPR_EX_CONTEXT_0_0); t->ex_context[1] = __insn_mfspr(SPR_EX_CONTEXT_0_1); t->system_save[0] = __insn_mfspr(SPR_SYSTEM_SAVE_0_0); t->system_save[1] = __insn_mfspr(SPR_SYSTEM_SAVE_0_1); t->system_save[2] = __insn_mfspr(SPR_SYSTEM_SAVE_0_2); t->system_save[3] = __insn_mfspr(SPR_SYSTEM_SAVE_0_3); t->intctrl_0 = __insn_mfspr(SPR_INTCTRL_0_STATUS); t->proc_status = __insn_mfspr(SPR_PROC_STATUS);#if !CHIP_HAS_FIXED_INTVEC_BASE() t->interrupt_vector_base = __insn_mfspr(SPR_INTERRUPT_VECTOR_BASE_0);#endif t->tile_rtf_hwm = __insn_mfspr(SPR_TILE_RTF_HWM);#if CHIP_HAS_DSTREAM_PF() t->dstream_pf = __insn_mfspr(SPR_DSTREAM_PF);#endif} static void restore_arch_state(const struct thread_struct *t){#if CHIP_HAS_SPLIT_INTR_MASK() __insn_mtspr(SPR_INTERRUPT_MASK_0_0, (u32) t->interrupt_mask); __insn_mtspr(SPR_INTERRUPT_MASK_0_1, t->interrupt_mask >> 32);#else __insn_mtspr(SPR_INTERRUPT_MASK_0, t->interrupt_mask);#endif __insn_mtspr(SPR_EX_CONTEXT_0_0, t->ex_context[0]); __insn_mtspr(SPR_EX_CONTEXT_0_1, t->ex_context[1]); __insn_mtspr(SPR_SYSTEM_SAVE_0_0, t->system_save[0]); __insn_mtspr(SPR_SYSTEM_SAVE_0_1, t->system_save[1]); __insn_mtspr(SPR_SYSTEM_SAVE_0_2, t->system_save[2]); __insn_mtspr(SPR_SYSTEM_SAVE_0_3, t->system_save[3]); __insn_mtspr(SPR_INTCTRL_0_STATUS, t->intctrl_0); __insn_mtspr(SPR_PROC_STATUS, t->proc_status);#if !CHIP_HAS_FIXED_INTVEC_BASE() __insn_mtspr(SPR_INTERRUPT_VECTOR_BASE_0, t->interrupt_vector_base);#endif __insn_mtspr(SPR_TILE_RTF_HWM, t->tile_rtf_hwm);#if CHIP_HAS_DSTREAM_PF() __insn_mtspr(SPR_DSTREAM_PF, t->dstream_pf);#endif} void _prepare_arch_switch(struct task_struct *next){#if CHIP_HAS_TILE_DMA() struct tile_dma_state *dma = ¤t->thread.tile_dma_state; if (dma->enabled) save_tile_dma_state(dma);#endif} struct task_struct *__sched _switch_to(struct task_struct *prev, struct task_struct *next){ /* DMA state is already saved; save off other arch state. */ save_arch_state(&prev->thread); #if CHIP_HAS_TILE_DMA() /* * Restore DMA in new task if desired. * Note that it is only safe to restart here since interrupts * are disabled, so we can't take any DMATLB miss or access * interrupts before we have finished switching stacks. */ if (next->thread.tile_dma_state.enabled) { restore_tile_dma_state(&next->thread); grant_dma_mpls(); } else { restrict_dma_mpls(); }#endif /* Restore other arch state. */ restore_arch_state(&next->thread); #ifdef CONFIG_HARDWALL /* Enable or disable access to the network registers appropriately. */ hardwall_switch_tasks(prev, next);#endif /* Notify the simulator of task exit. */ if (unlikely(prev->state == TASK_DEAD)) __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_EXIT | (prev->pid << _SIM_CONTROL_OPERATOR_BITS)); /* * Switch kernel SP, PC, and callee-saved registers. * In the context of the new task, return the old task pointer * (i.e. the task that actually called __switch_to). * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp. */ return __switch_to(prev, next, next_current_ksp0(next));} /* * This routine is called on return from interrupt if any of the * TIF_ALLWORK_MASK flags are set in thread_info->flags. It is * entered with interrupts disabled so we don't miss an event that * modified the thread_info flags. We loop until all the tested flags * are clear. Note that the function is called on certain conditions * that are not listed in the loop condition here (e.g. SINGLESTEP) * which guarantees we will do those things once, and redo them if any * of the other work items is re-done, but won't continue looping if * all the other work is done. */void prepare_exit_to_usermode(struct pt_regs *regs, u32 thread_info_flags){ if (WARN_ON(!user_mode(regs))) return; do { local_irq_enable(); if (thread_info_flags & _TIF_NEED_RESCHED) schedule(); #if CHIP_HAS_TILE_DMA() if (thread_info_flags & _TIF_ASYNC_TLB) do_async_page_fault(regs);#endif if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); if (thread_info_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); } local_irq_disable(); thread_info_flags = READ_ONCE(current_thread_info()->flags);Lines 1–500 of 656. Load more
/* * Copyright 2010 Tilera Corporation. All Rights Reserved. * * 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, version 2. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or * NON INFRINGEMENT. See the GNU General Public License for * more details. */ #include <linux/sched.h> #include <linux/preempt.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/kprobes.h> #include <linux/elfcore.h> #include <linux/tick.h> #include <linux/init.h> #include <linux/mm.h> #include <linux/compat.h> #include <linux/nmi.h> #include <linux/syscalls.h> #include <linux/kernel.h> #include <linux/tracehook.h> #include <linux/signal.h> #include <linux/delay.h> #include <linux/context_tracking.h> #include <asm/stack.h> #include <asm/switch_to.h> #include <asm/homecache.h> #include <asm/syscalls.h> #include <asm/traps.h> #include <asm/setup.h> #include <asm/uaccess.h> #ifdef CONFIG_HARDWALL #include <asm/hardwall.h> #endif #include <arch/chip.h> #include <arch/abi.h> #include <arch/sim_def.h> /* * Use the (x86) "idle=poll" option to prefer low latency when leaving the * idle loop over low power while in the idle loop, e.g. if we have * one thread per core and we want to get threads out of futex waits fast. */ static int __init idle_setup(char *str) { if (!str) return -EINVAL; if (!strcmp(str, "poll")) { pr_info("using polling idle threads\n"); cpu_idle_poll_ctrl(true); return 0; } else if (!strcmp(str, "halt")) { return 0; } return -1; } early_param("idle", idle_setup); void arch_cpu_idle(void) { __this_cpu_write(irq_stat.idle_timestamp, jiffies); _cpu_idle(); } /* * Release a thread_info structure */ void arch_release_thread_stack(unsigned long *stack) { struct thread_info *info = (void *)stack; struct single_step_state *step_state = info->step_state; if (step_state) { /* * FIXME: we don't munmap step_state->buffer * because the mm_struct for this process (info->task->mm) * has already been zeroed in exit_mm(). Keeping a * reference to it here seems like a bad move, so this * means we can't munmap() the buffer, and therefore if we * ptrace multiple threads in a process, we will slowly * leak user memory. (Note that as soon as the last * thread in a process dies, we will reclaim all user * memory including single-step buffers in the usual way.) * We should either assign a kernel VA to this buffer * somehow, or we should associate the buffer(s) with the * mm itself so we can clean them up that way. */ kfree(step_state); } } static void save_arch_state(struct thread_struct *t); int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg, struct task_struct *p) { struct pt_regs *childregs = task_pt_regs(p); unsigned long ksp; unsigned long *callee_regs; /* * Set up the stack and stack pointer appropriately for the * new child to find itself woken up in __switch_to(). * The callee-saved registers must be on the stack to be read; * the new task will then jump to assembly support to handle * calling schedule_tail(), etc., and (for userspace tasks) * returning to the context set up in the pt_regs. */ ksp = (unsigned long) childregs; ksp -= C_ABI_SAVE_AREA_SIZE; /* interrupt-entry save area */ ((long *)ksp)[0] = ((long *)ksp)[1] = 0; ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long); callee_regs = (unsigned long *)ksp; ksp -= C_ABI_SAVE_AREA_SIZE; /* __switch_to() save area */ ((long *)ksp)[0] = ((long *)ksp)[1] = 0; p->thread.ksp = ksp; /* Record the pid of the task that created this one. */ p->thread.creator_pid = current->pid; if (unlikely(p->flags & PF_KTHREAD)) { /* kernel thread */ memset(childregs, 0, sizeof(struct pt_regs)); memset(&callee_regs[2], 0, (CALLEE_SAVED_REGS_COUNT - 2) * sizeof(unsigned long)); callee_regs[0] = sp; /* r30 = function */ callee_regs[1] = arg; /* r31 = arg */ p->thread.pc = (unsigned long) ret_from_kernel_thread; return 0; } /* * Start new thread in ret_from_fork so it schedules properly * and then return from interrupt like the parent. */ p->thread.pc = (unsigned long) ret_from_fork; /* * Do not clone step state from the parent; each thread * must make its own lazily. */ task_thread_info(p)->step_state = NULL; #ifdef __tilegx__ /* * Do not clone unalign jit fixup from the parent; each thread * must allocate its own on demand. */ task_thread_info(p)->unalign_jit_base = NULL; #endif /* * Copy the registers onto the kernel stack so the * return-from-interrupt code will reload it into registers. */ *childregs = *current_pt_regs(); childregs->regs[0] = 0; /* return value is zero */ if (sp) childregs->sp = sp; /* override with new user stack pointer */ memcpy(callee_regs, &childregs->regs[CALLEE_SAVED_FIRST_REG], CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long)); /* Save user stack top pointer so we can ID the stack vm area later. */ p->thread.usp0 = childregs->sp; /* * If CLONE_SETTLS is set, set "tp" in the new task to "r4", * which is passed in as arg #5 to sys_clone(). */ if (clone_flags & CLONE_SETTLS) childregs->tp = childregs->regs[4]; #if CHIP_HAS_TILE_DMA() /* * No DMA in the new thread. We model this on the fact that * fork() clears the pending signals, alarms, and aio for the child. */ memset(&p->thread.tile_dma_state, 0, sizeof(struct tile_dma_state)); memset(&p->thread.dma_async_tlb, 0, sizeof(struct async_tlb)); #endif /* New thread has its miscellaneous processor state bits clear. */ p->thread.proc_status = 0; #ifdef CONFIG_HARDWALL /* New thread does not own any networks. */ memset(&p->thread.hardwall[0], 0, sizeof(struct hardwall_task) * HARDWALL_TYPES); #endif /* * Start the new thread with the current architecture state * (user interrupt masks, etc.). */ save_arch_state(&p->thread); return 0; } int set_unalign_ctl(struct task_struct *tsk, unsigned int val) { task_thread_info(tsk)->align_ctl = val; return 0; } int get_unalign_ctl(struct task_struct *tsk, unsigned long adr) { return put_user(task_thread_info(tsk)->align_ctl, (unsigned int __user *)adr); } static struct task_struct corrupt_current = { .comm = "<corrupt>" }; /* * Return "current" if it looks plausible, or else a pointer to a dummy. * This can be helpful if we are just trying to emit a clean panic. */ struct task_struct *validate_current(void) { struct task_struct *tsk = current; if (unlikely((unsigned long)tsk < PAGE_OFFSET || (high_memory && (void *)tsk > high_memory) || ((unsigned long)tsk & (__alignof__(*tsk) - 1)) != 0)) { pr_err("Corrupt 'current' %p (sp %#lx)\n", tsk, stack_pointer); tsk = &corrupt_current; } return tsk; } /* Take and return the pointer to the previous task, for schedule_tail(). */ struct task_struct *sim_notify_fork(struct task_struct *prev) { struct task_struct *tsk = current; __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK_PARENT | (tsk->thread.creator_pid << _SIM_CONTROL_OPERATOR_BITS)); __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK | (tsk->pid << _SIM_CONTROL_OPERATOR_BITS)); return prev; } int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) { struct pt_regs *ptregs = task_pt_regs(tsk); elf_core_copy_regs(regs, ptregs); return 1; } #if CHIP_HAS_TILE_DMA() /* Allow user processes to access the DMA SPRs */ void grant_dma_mpls(void) { #if CONFIG_KERNEL_PL == 2 __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1); __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1); #else __insn_mtspr(SPR_MPL_DMA_CPL_SET_0, 1); __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_0, 1); #endif } /* Forbid user processes from accessing the DMA SPRs */ void restrict_dma_mpls(void) { #if CONFIG_KERNEL_PL == 2 __insn_mtspr(SPR_MPL_DMA_CPL_SET_2, 1); __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_2, 1); #else __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1); __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1); #endif } /* Pause the DMA engine, then save off its state registers. */ static void save_tile_dma_state(struct tile_dma_state *dma) { unsigned long state = __insn_mfspr(SPR_DMA_USER_STATUS); unsigned long post_suspend_state; /* If we're running, suspend the engine. */ if ((state & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK); /* * Wait for the engine to idle, then save regs. Note that we * want to record the "running" bit from before suspension, * and the "done" bit from after, so that we can properly * distinguish a case where the user suspended the engine from * the case where the kernel suspended as part of the context * swap. */ do { post_suspend_state = __insn_mfspr(SPR_DMA_USER_STATUS); } while (post_suspend_state & SPR_DMA_STATUS__BUSY_MASK); dma->src = __insn_mfspr(SPR_DMA_SRC_ADDR); dma->src_chunk = __insn_mfspr(SPR_DMA_SRC_CHUNK_ADDR); dma->dest = __insn_mfspr(SPR_DMA_DST_ADDR); dma->dest_chunk = __insn_mfspr(SPR_DMA_DST_CHUNK_ADDR); dma->strides = __insn_mfspr(SPR_DMA_STRIDE); dma->chunk_size = __insn_mfspr(SPR_DMA_CHUNK_SIZE); dma->byte = __insn_mfspr(SPR_DMA_BYTE); dma->status = (state & SPR_DMA_STATUS__RUNNING_MASK) | (post_suspend_state & SPR_DMA_STATUS__DONE_MASK); } /* Restart a DMA that was running before we were context-switched out. */ static void restore_tile_dma_state(struct thread_struct *t) { const struct tile_dma_state *dma = &t->tile_dma_state; /* * The only way to restore the done bit is to run a zero * length transaction. */ if ((dma->status & SPR_DMA_STATUS__DONE_MASK) && !(__insn_mfspr(SPR_DMA_USER_STATUS) & SPR_DMA_STATUS__DONE_MASK)) { __insn_mtspr(SPR_DMA_BYTE, 0); __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK); while (__insn_mfspr(SPR_DMA_USER_STATUS) & SPR_DMA_STATUS__BUSY_MASK) ; } __insn_mtspr(SPR_DMA_SRC_ADDR, dma->src); __insn_mtspr(SPR_DMA_SRC_CHUNK_ADDR, dma->src_chunk); __insn_mtspr(SPR_DMA_DST_ADDR, dma->dest); __insn_mtspr(SPR_DMA_DST_CHUNK_ADDR, dma->dest_chunk); __insn_mtspr(SPR_DMA_STRIDE, dma->strides); __insn_mtspr(SPR_DMA_CHUNK_SIZE, dma->chunk_size); __insn_mtspr(SPR_DMA_BYTE, dma->byte); /* * Restart the engine if we were running and not done. * Clear a pending async DMA fault that we were waiting on return * to user space to execute, since we expect the DMA engine * to regenerate those faults for us now. Note that we don't * try to clear the TIF_ASYNC_TLB flag, since it's relatively * harmless if set, and it covers both DMA and the SN processor. */ if ((dma->status & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) { t->dma_async_tlb.fault_num = 0; __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK); } } #endif static void save_arch_state(struct thread_struct *t) { #if CHIP_HAS_SPLIT_INTR_MASK() t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0_0) | ((u64)__insn_mfspr(SPR_INTERRUPT_MASK_0_1) << 32); #else t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0); #endif t->ex_context[0] = __insn_mfspr(SPR_EX_CONTEXT_0_0); t->ex_context[1] = __insn_mfspr(SPR_EX_CONTEXT_0_1); t->system_save[0] = __insn_mfspr(SPR_SYSTEM_SAVE_0_0); t->system_save[1] = __insn_mfspr(SPR_SYSTEM_SAVE_0_1); t->system_save[2] = __insn_mfspr(SPR_SYSTEM_SAVE_0_2); t->system_save[3] = __insn_mfspr(SPR_SYSTEM_SAVE_0_3); t->intctrl_0 = __insn_mfspr(SPR_INTCTRL_0_STATUS); t->proc_status = __insn_mfspr(SPR_PROC_STATUS); #if !CHIP_HAS_FIXED_INTVEC_BASE() t->interrupt_vector_base = __insn_mfspr(SPR_INTERRUPT_VECTOR_BASE_0); #endif t->tile_rtf_hwm = __insn_mfspr(SPR_TILE_RTF_HWM); #if CHIP_HAS_DSTREAM_PF() t->dstream_pf = __insn_mfspr(SPR_DSTREAM_PF); #endif } static void restore_arch_state(const struct thread_struct *t) { #if CHIP_HAS_SPLIT_INTR_MASK() __insn_mtspr(SPR_INTERRUPT_MASK_0_0, (u32) t->interrupt_mask); __insn_mtspr(SPR_INTERRUPT_MASK_0_1, t->interrupt_mask >> 32); #else __insn_mtspr(SPR_INTERRUPT_MASK_0, t->interrupt_mask); #endif __insn_mtspr(SPR_EX_CONTEXT_0_0, t->ex_context[0]); __insn_mtspr(SPR_EX_CONTEXT_0_1, t->ex_context[1]); __insn_mtspr(SPR_SYSTEM_SAVE_0_0, t->system_save[0]); __insn_mtspr(SPR_SYSTEM_SAVE_0_1, t->system_save[1]); __insn_mtspr(SPR_SYSTEM_SAVE_0_2, t->system_save[2]); __insn_mtspr(SPR_SYSTEM_SAVE_0_3, t->system_save[3]); __insn_mtspr(SPR_INTCTRL_0_STATUS, t->intctrl_0); __insn_mtspr(SPR_PROC_STATUS, t->proc_status); #if !CHIP_HAS_FIXED_INTVEC_BASE() __insn_mtspr(SPR_INTERRUPT_VECTOR_BASE_0, t->interrupt_vector_base); #endif __insn_mtspr(SPR_TILE_RTF_HWM, t->tile_rtf_hwm); #if CHIP_HAS_DSTREAM_PF() __insn_mtspr(SPR_DSTREAM_PF, t->dstream_pf); #endif } void _prepare_arch_switch(struct task_struct *next) { #if CHIP_HAS_TILE_DMA() struct tile_dma_state *dma = ¤t->thread.tile_dma_state; if (dma->enabled) save_tile_dma_state(dma); #endif } struct task_struct *__sched _switch_to(struct task_struct *prev, struct task_struct *next) { /* DMA state is already saved; save off other arch state. */ save_arch_state(&prev->thread); #if CHIP_HAS_TILE_DMA() /* * Restore DMA in new task if desired. * Note that it is only safe to restart here since interrupts * are disabled, so we can't take any DMATLB miss or access * interrupts before we have finished switching stacks. */ if (next->thread.tile_dma_state.enabled) { restore_tile_dma_state(&next->thread); grant_dma_mpls(); } else { restrict_dma_mpls(); } #endif /* Restore other arch state. */ restore_arch_state(&next->thread); #ifdef CONFIG_HARDWALL /* Enable or disable access to the network registers appropriately. */ hardwall_switch_tasks(prev, next); #endif /* Notify the simulator of task exit. */ if (unlikely(prev->state == TASK_DEAD)) __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_EXIT | (prev->pid << _SIM_CONTROL_OPERATOR_BITS)); /* * Switch kernel SP, PC, and callee-saved registers. * In the context of the new task, return the old task pointer * (i.e. the task that actually called __switch_to). * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp. */ return __switch_to(prev, next, next_current_ksp0(next)); } /* * This routine is called on return from interrupt if any of the * TIF_ALLWORK_MASK flags are set in thread_info->flags. It is * entered with interrupts disabled so we don't miss an event that * modified the thread_info flags. We loop until all the tested flags * are clear. Note that the function is called on certain conditions * that are not listed in the loop condition here (e.g. SINGLESTEP) * which guarantees we will do those things once, and redo them if any * of the other work items is re-done, but won't continue looping if * all the other work is done. */ void prepare_exit_to_usermode(struct pt_regs *regs, u32 thread_info_flags) { if (WARN_ON(!user_mode(regs))) return; do { local_irq_enable(); if (thread_info_flags & _TIF_NEED_RESCHED) schedule(); #if CHIP_HAS_TILE_DMA() if (thread_info_flags & _TIF_ASYNC_TLB) do_async_page_fault(regs); #endif if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); if (thread_info_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); } local_irq_disable(); thread_info_flags = READ_ONCE(current_thread_info()->flags);