/* * 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 #ifdef CONFIG_HOTPLUG_CPU void arch_cpu_idle_dead(void) { /* What the heck is this check doing ? */ if (!cpu_isset(smp_processor_id(), cpu_callin_map)) play_dead(); } #endif void arch_cpu_idle(void) { #ifdef CONFIG_MIPS_MT_SMTC extern void smtc_idle_loop_hook(void); smtc_idle_loop_hook(); #endif if (cpu_wait) (*cpu_wait)(); else local_irq_enable(); } 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); #ifdef CONFIG_64BIT status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR; #endif status |= KU_USER; regs->cp0_status = status; clear_used_math(); clear_fpu_owner(); if (cpu_has_dsp) __init_dsp(); regs->cp0_epc = pc; regs->regs[29] = sp; } void exit_thread(void) { } void flush_thread(void) { } int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long 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; preempt_disable(); if (is_fpu_owner()) save_fp(p); if (cpu_has_dsp) save_dsp(p); preempt_enable(); /* 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)) { 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 = 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; } *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); #ifdef CONFIG_MIPS_MT_SMTC /* * SMTC restores TCStatus after Status, and the CU bits * are aliased there. */ childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1); #endif clear_tsk_thread_flag(p, TIF_USEDFPU); #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; } /* Fill in the fpu structure for a core dump.. */ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) { memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu)); return 1; } void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs) { int i; for (i = 0; i < EF_R0; i++) gp[i] = 0; gp[EF_R0] = 0; for (i = 1; i <= 31; i++) gp[EF_R0 + i] = regs->regs[i]; gp[EF_R26] = 0; gp[EF_R27] = 0; gp[EF_LO] = regs->lo; gp[EF_HI] = regs->hi; gp[EF_CP0_EPC] = regs->cp0_epc; gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; gp[EF_CP0_STATUS] = regs->cp0_status; gp[EF_CP0_CAUSE] = regs->cp0_cause; #ifdef EF_UNUSED0 gp[EF_UNUSED0] = 0; #endif } int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) { elf_dump_regs(*regs, task_pt_regs(tsk)); return 1; } int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) { memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu)); return 1; } /* * */ 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; }