From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/mips/kernel/process.c | 666 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 666 insertions(+) create mode 100644 arch/mips/kernel/process.c (limited to 'arch/mips/kernel/process.c') diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c new file mode 100644 index 000000000..f2975d4d1 --- /dev/null +++ b/arch/mips/kernel/process.c @@ -0,0 +1,666 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others. + * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org) + * Copyright (C) 1999, 2000 Silicon Graphics, Inc. + * Copyright (C) 2004 Thiemo Seufer + * Copyright (C) 2013 Imagination Technologies Ltd. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifdef CONFIG_HOTPLUG_CPU +void arch_cpu_idle_dead(void) +{ + /* What the heck is this check doing ? */ + if (!cpumask_test_cpu(smp_processor_id(), &cpu_callin_map)) + play_dead(); +} +#endif + +asmlinkage void ret_from_fork(void); +asmlinkage void ret_from_kernel_thread(void); + +void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) +{ + unsigned long status; + + /* New thread loses kernel privileges. */ + status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK); + status |= KU_USER; + regs->cp0_status = status; + clear_used_math(); + clear_fpu_owner(); + init_dsp(); + clear_thread_flag(TIF_USEDMSA); + clear_thread_flag(TIF_MSA_CTX_LIVE); + disable_msa(); + regs->cp0_epc = pc; + regs->regs[29] = sp; +} + +void exit_thread(void) +{ +} + +void flush_thread(void) +{ +} + +int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) +{ + /* + * Save any process state which is live in hardware registers to the + * parent context prior to duplication. This prevents the new child + * state becoming stale if the parent is preempted before copy_thread() + * gets a chance to save the parent's live hardware registers to the + * child context. + */ + preempt_disable(); + + if (is_msa_enabled()) + save_msa(current); + else if (is_fpu_owner()) + _save_fp(current); + + save_dsp(current); + + preempt_enable(); + + *dst = *src; + return 0; +} + +/* + * Copy architecture-specific thread state + */ +int copy_thread(unsigned long clone_flags, unsigned long usp, + unsigned long kthread_arg, struct task_struct *p) +{ + struct thread_info *ti = task_thread_info(p); + struct pt_regs *childregs, *regs = current_pt_regs(); + unsigned long childksp; + p->set_child_tid = p->clear_child_tid = NULL; + + childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; + + /* set up new TSS. */ + childregs = (struct pt_regs *) childksp - 1; + /* Put the stack after the struct pt_regs. */ + childksp = (unsigned long) childregs; + p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); + if (unlikely(p->flags & PF_KTHREAD)) { + /* kernel thread */ + unsigned long status = p->thread.cp0_status; + memset(childregs, 0, sizeof(struct pt_regs)); + ti->addr_limit = KERNEL_DS; + p->thread.reg16 = usp; /* fn */ + p->thread.reg17 = kthread_arg; + p->thread.reg29 = childksp; + p->thread.reg31 = (unsigned long) ret_from_kernel_thread; +#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) + status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | + ((status & (ST0_KUC | ST0_IEC)) << 2); +#else + status |= ST0_EXL; +#endif + childregs->cp0_status = status; + return 0; + } + + /* user thread */ + *childregs = *regs; + childregs->regs[7] = 0; /* Clear error flag */ + childregs->regs[2] = 0; /* Child gets zero as return value */ + if (usp) + childregs->regs[29] = usp; + ti->addr_limit = USER_DS; + + p->thread.reg29 = (unsigned long) childregs; + p->thread.reg31 = (unsigned long) ret_from_fork; + + /* + * New tasks lose permission to use the fpu. This accelerates context + * switching for most programs since they don't use the fpu. + */ + childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); + + clear_tsk_thread_flag(p, TIF_USEDFPU); + clear_tsk_thread_flag(p, TIF_USEDMSA); + clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE); + +#ifdef CONFIG_MIPS_MT_FPAFF + clear_tsk_thread_flag(p, TIF_FPUBOUND); +#endif /* CONFIG_MIPS_MT_FPAFF */ + + if (clone_flags & CLONE_SETTLS) + ti->tp_value = regs->regs[7]; + + return 0; +} + +#ifdef CONFIG_CC_STACKPROTECTOR +#include +unsigned long __stack_chk_guard __read_mostly; +EXPORT_SYMBOL(__stack_chk_guard); +#endif + +struct mips_frame_info { + void *func; + unsigned long func_size; + int frame_size; + int pc_offset; +}; + +#define J_TARGET(pc,target) \ + (((unsigned long)(pc) & 0xf0000000) | ((target) << 2)) + +static inline int is_ra_save_ins(union mips_instruction *ip) +{ +#ifdef CONFIG_CPU_MICROMIPS + union mips_instruction mmi; + + /* + * swsp ra,offset + * swm16 reglist,offset(sp) + * swm32 reglist,offset(sp) + * sw32 ra,offset(sp) + * jradiussp - NOT SUPPORTED + * + * microMIPS is way more fun... + */ + if (mm_insn_16bit(ip->halfword[0])) { + mmi.word = (ip->halfword[0] << 16); + return (mmi.mm16_r5_format.opcode == mm_swsp16_op && + mmi.mm16_r5_format.rt == 31) || + (mmi.mm16_m_format.opcode == mm_pool16c_op && + mmi.mm16_m_format.func == mm_swm16_op); + } + else { + mmi.halfword[0] = ip->halfword[1]; + mmi.halfword[1] = ip->halfword[0]; + return (mmi.mm_m_format.opcode == mm_pool32b_op && + mmi.mm_m_format.rd > 9 && + mmi.mm_m_format.base == 29 && + mmi.mm_m_format.func == mm_swm32_func) || + (mmi.i_format.opcode == mm_sw32_op && + mmi.i_format.rs == 29 && + mmi.i_format.rt == 31); + } +#else + /* sw / sd $ra, offset($sp) */ + return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && + ip->i_format.rs == 29 && + ip->i_format.rt == 31; +#endif +} + +static inline int is_jump_ins(union mips_instruction *ip) +{ +#ifdef CONFIG_CPU_MICROMIPS + /* + * jr16,jrc,jalr16,jalr16 + * jal + * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb + * jraddiusp - NOT SUPPORTED + * + * microMIPS is kind of more fun... + */ + union mips_instruction mmi; + + mmi.word = (ip->halfword[0] << 16); + + if ((mmi.mm16_r5_format.opcode == mm_pool16c_op && + (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) || + ip->j_format.opcode == mm_jal32_op) + return 1; + if (ip->r_format.opcode != mm_pool32a_op || + ip->r_format.func != mm_pool32axf_op) + return 0; + return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op; +#else + if (ip->j_format.opcode == j_op) + return 1; + if (ip->j_format.opcode == jal_op) + return 1; + if (ip->r_format.opcode != spec_op) + return 0; + return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; +#endif +} + +static inline int is_sp_move_ins(union mips_instruction *ip) +{ +#ifdef CONFIG_CPU_MICROMIPS + /* + * addiusp -imm + * addius5 sp,-imm + * addiu32 sp,sp,-imm + * jradiussp - NOT SUPPORTED + * + * microMIPS is not more fun... + */ + if (mm_insn_16bit(ip->halfword[0])) { + union mips_instruction mmi; + + mmi.word = (ip->halfword[0] << 16); + return (mmi.mm16_r3_format.opcode == mm_pool16d_op && + mmi.mm16_r3_format.simmediate && mm_addiusp_func) || + (mmi.mm16_r5_format.opcode == mm_pool16d_op && + mmi.mm16_r5_format.rt == 29); + } + return ip->mm_i_format.opcode == mm_addiu32_op && + ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29; +#else + /* addiu/daddiu sp,sp,-imm */ + if (ip->i_format.rs != 29 || ip->i_format.rt != 29) + return 0; + if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) + return 1; +#endif + return 0; +} + +static int get_frame_info(struct mips_frame_info *info) +{ +#ifdef CONFIG_CPU_MICROMIPS + union mips_instruction *ip = (void *) (((char *) info->func) - 1); +#else + union mips_instruction *ip = info->func; +#endif + unsigned max_insns = info->func_size / sizeof(union mips_instruction); + unsigned i; + + info->pc_offset = -1; + info->frame_size = 0; + + if (!ip) + goto err; + + if (max_insns == 0) + max_insns = 128U; /* unknown function size */ + max_insns = min(128U, max_insns); + + for (i = 0; i < max_insns; i++, ip++) { + + if (is_jump_ins(ip)) + break; + if (!info->frame_size) { + if (is_sp_move_ins(ip)) + { +#ifdef CONFIG_CPU_MICROMIPS + if (mm_insn_16bit(ip->halfword[0])) + { + unsigned short tmp; + + if (ip->halfword[0] & mm_addiusp_func) + { + tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2); + info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0)); + } else { + tmp = (ip->halfword[0] >> 1); + info->frame_size = -(signed short)(tmp & 0xf); + } + ip = (void *) &ip->halfword[1]; + ip--; + } else +#endif + info->frame_size = - ip->i_format.simmediate; + } + continue; + } + if (info->pc_offset == -1 && is_ra_save_ins(ip)) { + info->pc_offset = + ip->i_format.simmediate / sizeof(long); + break; + } + } + if (info->frame_size && info->pc_offset >= 0) /* nested */ + return 0; + if (info->pc_offset < 0) /* leaf */ + return 1; + /* prologue seems boggus... */ +err: + return -1; +} + +static struct mips_frame_info schedule_mfi __read_mostly; + +#ifdef CONFIG_KALLSYMS +static unsigned long get___schedule_addr(void) +{ + return kallsyms_lookup_name("__schedule"); +} +#else +static unsigned long get___schedule_addr(void) +{ + union mips_instruction *ip = (void *)schedule; + int max_insns = 8; + int i; + + for (i = 0; i < max_insns; i++, ip++) { + if (ip->j_format.opcode == j_op) + return J_TARGET(ip, ip->j_format.target); + } + return 0; +} +#endif + +static int __init frame_info_init(void) +{ + unsigned long size = 0; +#ifdef CONFIG_KALLSYMS + unsigned long ofs; +#endif + unsigned long addr; + + addr = get___schedule_addr(); + if (!addr) + addr = (unsigned long)schedule; + +#ifdef CONFIG_KALLSYMS + kallsyms_lookup_size_offset(addr, &size, &ofs); +#endif + schedule_mfi.func = (void *)addr; + schedule_mfi.func_size = size; + + get_frame_info(&schedule_mfi); + + /* + * Without schedule() frame info, result given by + * thread_saved_pc() and get_wchan() are not reliable. + */ + if (schedule_mfi.pc_offset < 0) + printk("Can't analyze schedule() prologue at %p\n", schedule); + + return 0; +} + +arch_initcall(frame_info_init); + +/* + * Return saved PC of a blocked thread. + */ +unsigned long thread_saved_pc(struct task_struct *tsk) +{ + struct thread_struct *t = &tsk->thread; + + /* New born processes are a special case */ + if (t->reg31 == (unsigned long) ret_from_fork) + return t->reg31; + if (schedule_mfi.pc_offset < 0) + return 0; + return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; +} + + +#ifdef CONFIG_KALLSYMS +/* generic stack unwinding function */ +unsigned long notrace unwind_stack_by_address(unsigned long stack_page, + unsigned long *sp, + unsigned long pc, + unsigned long *ra) +{ + struct mips_frame_info info; + unsigned long size, ofs; + int leaf; + extern void ret_from_irq(void); + extern void ret_from_exception(void); + + if (!stack_page) + return 0; + + /* + * If we reached the bottom of interrupt context, + * return saved pc in pt_regs. + */ + if (pc == (unsigned long)ret_from_irq || + pc == (unsigned long)ret_from_exception) { + struct pt_regs *regs; + if (*sp >= stack_page && + *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) { + regs = (struct pt_regs *)*sp; + pc = regs->cp0_epc; + if (__kernel_text_address(pc)) { + *sp = regs->regs[29]; + *ra = regs->regs[31]; + return pc; + } + } + return 0; + } + if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) + return 0; + /* + * Return ra if an exception occurred at the first instruction + */ + if (unlikely(ofs == 0)) { + pc = *ra; + *ra = 0; + return pc; + } + + info.func = (void *)(pc - ofs); + info.func_size = ofs; /* analyze from start to ofs */ + leaf = get_frame_info(&info); + if (leaf < 0) + return 0; + + if (*sp < stack_page || + *sp + info.frame_size > stack_page + THREAD_SIZE - 32) + return 0; + + if (leaf) + /* + * For some extreme cases, get_frame_info() can + * consider wrongly a nested function as a leaf + * one. In that cases avoid to return always the + * same value. + */ + pc = pc != *ra ? *ra : 0; + else + pc = ((unsigned long *)(*sp))[info.pc_offset]; + + *sp += info.frame_size; + *ra = 0; + return __kernel_text_address(pc) ? pc : 0; +} +EXPORT_SYMBOL(unwind_stack_by_address); + +/* used by show_backtrace() */ +unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, + unsigned long pc, unsigned long *ra) +{ + unsigned long stack_page = (unsigned long)task_stack_page(task); + return unwind_stack_by_address(stack_page, sp, pc, ra); +} +#endif + +/* + * get_wchan - a maintenance nightmare^W^Wpain in the ass ... + */ +unsigned long get_wchan(struct task_struct *task) +{ + unsigned long pc = 0; +#ifdef CONFIG_KALLSYMS + unsigned long sp; + unsigned long ra = 0; +#endif + + if (!task || task == current || task->state == TASK_RUNNING) + goto out; + if (!task_stack_page(task)) + goto out; + + pc = thread_saved_pc(task); + +#ifdef CONFIG_KALLSYMS + sp = task->thread.reg29 + schedule_mfi.frame_size; + + while (in_sched_functions(pc)) + pc = unwind_stack(task, &sp, pc, &ra); +#endif + +out: + return pc; +} + +/* + * Don't forget that the stack pointer must be aligned on a 8 bytes + * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. + */ +unsigned long arch_align_stack(unsigned long sp) +{ + if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) + sp -= get_random_int() & ~PAGE_MASK; + + return sp & ALMASK; +} + +static void arch_dump_stack(void *info) +{ + struct pt_regs *regs; + + regs = get_irq_regs(); + + if (regs) + show_regs(regs); + + dump_stack(); +} + +void arch_trigger_all_cpu_backtrace(bool include_self) +{ + smp_call_function(arch_dump_stack, NULL, 1); +} + +int mips_get_process_fp_mode(struct task_struct *task) +{ + int value = 0; + + if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS)) + value |= PR_FP_MODE_FR; + if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS)) + value |= PR_FP_MODE_FRE; + + return value; +} + +int mips_set_process_fp_mode(struct task_struct *task, unsigned int value) +{ + const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE; + unsigned long switch_count; + struct task_struct *t; + + /* Check the value is valid */ + if (value & ~known_bits) + return -EOPNOTSUPP; + + /* Avoid inadvertently triggering emulation */ + if ((value & PR_FP_MODE_FR) && cpu_has_fpu && + !(current_cpu_data.fpu_id & MIPS_FPIR_F64)) + return -EOPNOTSUPP; + if ((value & PR_FP_MODE_FRE) && cpu_has_fpu && !cpu_has_fre) + return -EOPNOTSUPP; + + /* FR = 0 not supported in MIPS R6 */ + if (!(value & PR_FP_MODE_FR) && cpu_has_fpu && cpu_has_mips_r6) + return -EOPNOTSUPP; + + /* Save FP & vector context, then disable FPU & MSA */ + if (task->signal == current->signal) + lose_fpu(1); + + /* Prevent any threads from obtaining live FP context */ + atomic_set(&task->mm->context.fp_mode_switching, 1); + smp_mb__after_atomic(); + + /* + * If there are multiple online CPUs then wait until all threads whose + * FP mode is about to change have been context switched. This approach + * allows us to only worry about whether an FP mode switch is in + * progress when FP is first used in a tasks time slice. Pretty much all + * of the mode switch overhead can thus be confined to cases where mode + * switches are actually occuring. That is, to here. However for the + * thread performing the mode switch it may take a while... + */ + if (num_online_cpus() > 1) { + spin_lock_irq(&task->sighand->siglock); + + for_each_thread(task, t) { + if (t == current) + continue; + + switch_count = t->nvcsw + t->nivcsw; + + do { + spin_unlock_irq(&task->sighand->siglock); + cond_resched(); + spin_lock_irq(&task->sighand->siglock); + } while ((t->nvcsw + t->nivcsw) == switch_count); + } + + spin_unlock_irq(&task->sighand->siglock); + } + + /* + * There are now no threads of the process with live FP context, so it + * is safe to proceed with the FP mode switch. + */ + for_each_thread(task, t) { + /* Update desired FP register width */ + if (value & PR_FP_MODE_FR) { + clear_tsk_thread_flag(t, TIF_32BIT_FPREGS); + } else { + set_tsk_thread_flag(t, TIF_32BIT_FPREGS); + clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE); + } + + /* Update desired FP single layout */ + if (value & PR_FP_MODE_FRE) + set_tsk_thread_flag(t, TIF_HYBRID_FPREGS); + else + clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS); + } + + /* Allow threads to use FP again */ + atomic_set(&task->mm->context.fp_mode_switching, 0); + + return 0; +} -- cgit v1.2.3-54-g00ecf