| /* |
| * 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 <linux/errno.h> |
| #include <linux/sched.h> |
| #include <linux/tick.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/stddef.h> |
| #include <linux/unistd.h> |
| #include <linux/export.h> |
| #include <linux/ptrace.h> |
| #include <linux/mman.h> |
| #include <linux/personality.h> |
| #include <linux/sys.h> |
| #include <linux/init.h> |
| #include <linux/completion.h> |
| #include <linux/kallsyms.h> |
| #include <linux/random.h> |
| #include <linux/prctl.h> |
| |
| #include <asm/asm.h> |
| #include <asm/bootinfo.h> |
| #include <asm/cpu.h> |
| #include <asm/dsp.h> |
| #include <asm/fpu.h> |
| #include <asm/msa.h> |
| #include <asm/pgtable.h> |
| #include <asm/mipsregs.h> |
| #include <asm/processor.h> |
| #include <asm/reg.h> |
| #include <asm/uaccess.h> |
| #include <asm/io.h> |
| #include <asm/elf.h> |
| #include <asm/isadep.h> |
| #include <asm/inst.h> |
| #include <asm/stacktrace.h> |
| #include <asm/irq_regs.h> |
| |
| #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; |
| lose_fpu(0); |
| clear_thread_flag(TIF_MSA_CTX_LIVE); |
| clear_used_math(); |
| init_dsp(); |
| 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 <linux/stackprotector.h> |
| 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 occurring. 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; |
| } |