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 31 void 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 62 void 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 } 72 EXPORT_SYMBOL(start_thread); 73 74 void 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 87 void release_thread(struct task_struct *dead_task) 88 { 89 /* do nothing */ 90 } 91 92 asmlinkage void ret_from_fork(void); 93 asmlinkage void ret_from_kernel_thread(void); 94 95 int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg, 96 struct task_struct *p, unsigned long tls) 97 { 98 struct thread_info *ti = task_thread_info(p); 99 struct pt_regs *childregs; 100 101 #if defined(CONFIG_SH_DSP) 102 struct task_struct *tsk = current; 103 104 if (is_dsp_enabled(tsk)) { 105 /* We can use the __save_dsp or just copy the struct: 106 * __save_dsp(p); 107 * p->thread.dsp_status.status |= SR_DSP 108 */ 109 p->thread.dsp_status = tsk->thread.dsp_status; 110 } 111 #endif 112 113 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 114 115 childregs = task_pt_regs(p); 116 p->thread.sp = (unsigned long) childregs; 117 if (unlikely(p->flags & PF_KTHREAD)) { 118 memset(childregs, 0, sizeof(struct pt_regs)); 119 p->thread.pc = (unsigned long) ret_from_kernel_thread; 120 childregs->regs[4] = arg; 121 childregs->regs[5] = usp; 122 childregs->sr = SR_MD; 123 #if defined(CONFIG_SH_FPU) 124 childregs->sr |= SR_FD; 125 #endif 126 ti->addr_limit = KERNEL_DS; 127 ti->status &= ~TS_USEDFPU; 128 p->thread.fpu_counter = 0; 129 return 0; 130 } 131 *childregs = *current_pt_regs(); 132 133 if (usp) 134 childregs->regs[15] = usp; 135 ti->addr_limit = USER_DS; 136 137 if (clone_flags & CLONE_SETTLS) 138 childregs->gbr = tls; 139 140 childregs->regs[0] = 0; /* Set return value for child */ 141 p->thread.pc = (unsigned long) ret_from_fork; 142 return 0; 143 } 144 145 /* 146 * switch_to(x,y) should switch tasks from x to y. 147 * 148 */ 149 __notrace_funcgraph struct task_struct * 150 __switch_to(struct task_struct *prev, struct task_struct *next) 151 { 152 struct thread_struct *next_t = &next->thread; 153 154 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP) 155 __stack_chk_guard = next->stack_canary; 156 #endif 157 158 unlazy_fpu(prev, task_pt_regs(prev)); 159 160 /* we're going to use this soon, after a few expensive things */ 161 if (next->thread.fpu_counter > 5) 162 prefetch(next_t->xstate); 163 164 #ifdef CONFIG_MMU 165 /* 166 * Restore the kernel mode register 167 * k7 (r7_bank1) 168 */ 169 asm volatile("ldc %0, r7_bank" 170 : /* no output */ 171 : "r" (task_thread_info(next))); 172 #endif 173 174 /* 175 * If the task has used fpu the last 5 timeslices, just do a full 176 * restore of the math state immediately to avoid the trap; the 177 * chances of needing FPU soon are obviously high now 178 */ 179 if (next->thread.fpu_counter > 5) 180 __fpu_state_restore(); 181 182 return prev; 183 } 184 185 unsigned long get_wchan(struct task_struct *p) 186 { 187 unsigned long pc; 188 189 if (!p || p == current || p->state == TASK_RUNNING) 190 return 0; 191 192 /* 193 * The same comment as on the Alpha applies here, too ... 194 */ 195 pc = thread_saved_pc(p); 196 197 #ifdef CONFIG_FRAME_POINTER 198 if (in_sched_functions(pc)) { 199 unsigned long schedule_frame = (unsigned long)p->thread.sp; 200 return ((unsigned long *)schedule_frame)[21]; 201 } 202 #endif 203 204 return pc; 205 } 206