1// SPDX-License-Identifier: GPL-2.0 2/* 3 * arch/sh/kernel/process.c 4 * 5 * This file handles the architecture-dependent parts of process handling.. 6 * 7 * Copyright (C) 1995 Linus Torvalds 8 * 9 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima 10 * Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC 11 * Copyright (C) 2002 - 2008 Paul Mundt 12 */ 13#include <linux/module.h> 14#include <linux/mm.h> 15#include <linux/sched/debug.h> 16#include <linux/sched/task.h> 17#include <linux/sched/task_stack.h> 18#include <linux/slab.h> 19#include <linux/elfcore.h> 20#include <linux/fs.h> 21#include <linux/ftrace.h> 22#include <linux/hw_breakpoint.h> 23#include <linux/prefetch.h> 24#include <linux/stackprotector.h> 25#include <linux/uaccess.h> 26#include <asm/mmu_context.h> 27#include <asm/fpu.h> 28#include <asm/syscalls.h> 29#include <asm/switch_to.h> 30 31void show_regs(struct pt_regs * regs) 32{ 33 pr_info("\n"); 34 show_regs_print_info(KERN_DEFAULT); 35 36 pr_info("PC is at %pS\n", (void *)instruction_pointer(regs)); 37 pr_info("PR is at %pS\n", (void *)regs->pr); 38 39 pr_info("PC : %08lx SP : %08lx SR : %08lx ", regs->pc, 40 regs->regs[15], regs->sr); 41#ifdef CONFIG_MMU 42 pr_cont("TEA : %08x\n", __raw_readl(MMU_TEA)); 43#else 44 pr_cont("\n"); 45#endif 46 47 pr_info("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 48 regs->regs[0], regs->regs[1], regs->regs[2], regs->regs[3]); 49 pr_info("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 50 regs->regs[4], regs->regs[5], regs->regs[6], regs->regs[7]); 51 pr_info("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 52 regs->regs[8], regs->regs[9], regs->regs[10], regs->regs[11]); 53 pr_info("R12 : %08lx R13 : %08lx R14 : %08lx\n", 54 regs->regs[12], regs->regs[13], regs->regs[14]); 55 pr_info("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 56 regs->mach, regs->macl, regs->gbr, regs->pr); 57 58 show_trace(NULL, (unsigned long *)regs->regs[15], regs, KERN_DEFAULT); 59 show_code(regs); 60} 61 62void start_thread(struct pt_regs *regs, unsigned long new_pc, 63 unsigned long new_sp) 64{ 65 regs->pr = 0; 66 regs->sr = SR_FD; 67 regs->pc = new_pc; 68 regs->regs[15] = new_sp; 69 70 free_thread_xstate(current); 71} 72EXPORT_SYMBOL(start_thread); 73 74void flush_thread(void) 75{ 76 struct task_struct *tsk = current; 77 78 flush_ptrace_hw_breakpoint(tsk); 79 80#if defined(CONFIG_SH_FPU) 81 /* Forget lazy FPU state */ 82 clear_fpu(tsk, task_pt_regs(tsk)); 83 clear_used_math(); 84#endif 85} 86 87asmlinkage void ret_from_fork(void); 88asmlinkage void ret_from_kernel_thread(void); 89 90int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 91{ 92 unsigned long clone_flags = args->flags; 93 unsigned long usp = args->stack; 94 unsigned long tls = args->tls; 95 struct thread_info *ti = task_thread_info(p); 96 struct pt_regs *childregs; 97 98#if defined(CONFIG_SH_DSP) 99 struct task_struct *tsk = current; 100 101 if (is_dsp_enabled(tsk)) { 102 /* We can use the __save_dsp or just copy the struct: 103 * __save_dsp(p); 104 * p->thread.dsp_status.status |= SR_DSP 105 */ 106 p->thread.dsp_status = tsk->thread.dsp_status; 107 } 108#endif 109 110 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 111 112 childregs = task_pt_regs(p); 113 p->thread.sp = (unsigned long) childregs; 114 if (unlikely(args->fn)) { 115 memset(childregs, 0, sizeof(struct pt_regs)); 116 p->thread.pc = (unsigned long) ret_from_kernel_thread; 117 childregs->regs[4] = (unsigned long) args->fn_arg; 118 childregs->regs[5] = (unsigned long) args->fn; 119 childregs->sr = SR_MD; 120#if defined(CONFIG_SH_FPU) 121 childregs->sr |= SR_FD; 122#endif 123 ti->status &= ~TS_USEDFPU; 124 p->thread.fpu_counter = 0; 125 return 0; 126 } 127 *childregs = *current_pt_regs(); 128 129 if (usp) 130 childregs->regs[15] = usp; 131 132 if (clone_flags & CLONE_SETTLS) 133 childregs->gbr = tls; 134 135 childregs->regs[0] = 0; /* Set return value for child */ 136 p->thread.pc = (unsigned long) ret_from_fork; 137 return 0; 138} 139 140/* 141 * switch_to(x,y) should switch tasks from x to y. 142 * 143 */ 144__notrace_funcgraph struct task_struct * 145__switch_to(struct task_struct *prev, struct task_struct *next) 146{ 147 struct thread_struct *next_t = &next->thread; 148 149#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP) 150 __stack_chk_guard = next->stack_canary; 151#endif 152 153 unlazy_fpu(prev, task_pt_regs(prev)); 154 155 /* we're going to use this soon, after a few expensive things */ 156 if (next->thread.fpu_counter > 5) 157 prefetch(next_t->xstate); 158 159#ifdef CONFIG_MMU 160 /* 161 * Restore the kernel mode register 162 * k7 (r7_bank1) 163 */ 164 asm volatile("ldc %0, r7_bank" 165 : /* no output */ 166 : "r" (task_thread_info(next))); 167#endif 168 169 /* 170 * If the task has used fpu the last 5 timeslices, just do a full 171 * restore of the math state immediately to avoid the trap; the 172 * chances of needing FPU soon are obviously high now 173 */ 174 if (next->thread.fpu_counter > 5) 175 __fpu_state_restore(); 176 177 return prev; 178} 179 180unsigned long __get_wchan(struct task_struct *p) 181{ 182 unsigned long pc; 183 184 /* 185 * The same comment as on the Alpha applies here, too ... 186 */ 187 pc = thread_saved_pc(p); 188 189#ifdef CONFIG_FRAME_POINTER 190 if (in_sched_functions(pc)) { 191 unsigned long schedule_frame = (unsigned long)p->thread.sp; 192 return ((unsigned long *)schedule_frame)[21]; 193 } 194#endif 195 196 return pc; 197} 198