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 printk("\n"); 34 show_regs_print_info(KERN_DEFAULT); 35 36 printk("PC is at %pS\n", (void *)instruction_pointer(regs)); 37 printk("PR is at %pS\n", (void *)regs->pr); 38 39 printk("PC : %08lx SP : %08lx SR : %08lx ", 40 regs->pc, regs->regs[15], regs->sr); 41 #ifdef CONFIG_MMU 42 printk("TEA : %08x\n", __raw_readl(MMU_TEA)); 43 #else 44 printk("\n"); 45 #endif 46 47 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 48 regs->regs[0],regs->regs[1], 49 regs->regs[2],regs->regs[3]); 50 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 51 regs->regs[4],regs->regs[5], 52 regs->regs[6],regs->regs[7]); 53 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 54 regs->regs[8],regs->regs[9], 55 regs->regs[10],regs->regs[11]); 56 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n", 57 regs->regs[12],regs->regs[13], 58 regs->regs[14]); 59 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 60 regs->mach, regs->macl, regs->gbr, regs->pr); 61 62 show_trace(NULL, (unsigned long *)regs->regs[15], regs); 63 show_code(regs); 64 } 65 66 void start_thread(struct pt_regs *regs, unsigned long new_pc, 67 unsigned long new_sp) 68 { 69 regs->pr = 0; 70 regs->sr = SR_FD; 71 regs->pc = new_pc; 72 regs->regs[15] = new_sp; 73 74 free_thread_xstate(current); 75 } 76 EXPORT_SYMBOL(start_thread); 77 78 void flush_thread(void) 79 { 80 struct task_struct *tsk = current; 81 82 flush_ptrace_hw_breakpoint(tsk); 83 84 #if defined(CONFIG_SH_FPU) 85 /* Forget lazy FPU state */ 86 clear_fpu(tsk, task_pt_regs(tsk)); 87 clear_used_math(); 88 #endif 89 } 90 91 void release_thread(struct task_struct *dead_task) 92 { 93 /* do nothing */ 94 } 95 96 /* Fill in the fpu structure for a core dump.. */ 97 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 98 { 99 int fpvalid = 0; 100 101 #if defined(CONFIG_SH_FPU) 102 struct task_struct *tsk = current; 103 104 fpvalid = !!tsk_used_math(tsk); 105 if (fpvalid) 106 fpvalid = !fpregs_get(tsk, NULL, 0, 107 sizeof(struct user_fpu_struct), 108 fpu, NULL); 109 #endif 110 111 return fpvalid; 112 } 113 EXPORT_SYMBOL(dump_fpu); 114 115 asmlinkage void ret_from_fork(void); 116 asmlinkage void ret_from_kernel_thread(void); 117 118 int copy_thread(unsigned long clone_flags, unsigned long usp, 119 unsigned long arg, struct task_struct *p) 120 { 121 struct thread_info *ti = task_thread_info(p); 122 struct pt_regs *childregs; 123 124 #if defined(CONFIG_SH_DSP) 125 struct task_struct *tsk = current; 126 127 if (is_dsp_enabled(tsk)) { 128 /* We can use the __save_dsp or just copy the struct: 129 * __save_dsp(p); 130 * p->thread.dsp_status.status |= SR_DSP 131 */ 132 p->thread.dsp_status = tsk->thread.dsp_status; 133 } 134 #endif 135 136 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 137 138 childregs = task_pt_regs(p); 139 p->thread.sp = (unsigned long) childregs; 140 if (unlikely(p->flags & PF_KTHREAD)) { 141 memset(childregs, 0, sizeof(struct pt_regs)); 142 p->thread.pc = (unsigned long) ret_from_kernel_thread; 143 childregs->regs[4] = arg; 144 childregs->regs[5] = usp; 145 childregs->sr = SR_MD; 146 #if defined(CONFIG_SH_FPU) 147 childregs->sr |= SR_FD; 148 #endif 149 ti->addr_limit = KERNEL_DS; 150 ti->status &= ~TS_USEDFPU; 151 p->thread.fpu_counter = 0; 152 return 0; 153 } 154 *childregs = *current_pt_regs(); 155 156 if (usp) 157 childregs->regs[15] = usp; 158 ti->addr_limit = USER_DS; 159 160 if (clone_flags & CLONE_SETTLS) 161 childregs->gbr = childregs->regs[0]; 162 163 childregs->regs[0] = 0; /* Set return value for child */ 164 p->thread.pc = (unsigned long) ret_from_fork; 165 return 0; 166 } 167 168 /* 169 * switch_to(x,y) should switch tasks from x to y. 170 * 171 */ 172 __notrace_funcgraph struct task_struct * 173 __switch_to(struct task_struct *prev, struct task_struct *next) 174 { 175 struct thread_struct *next_t = &next->thread; 176 177 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP) 178 __stack_chk_guard = next->stack_canary; 179 #endif 180 181 unlazy_fpu(prev, task_pt_regs(prev)); 182 183 /* we're going to use this soon, after a few expensive things */ 184 if (next->thread.fpu_counter > 5) 185 prefetch(next_t->xstate); 186 187 #ifdef CONFIG_MMU 188 /* 189 * Restore the kernel mode register 190 * k7 (r7_bank1) 191 */ 192 asm volatile("ldc %0, r7_bank" 193 : /* no output */ 194 : "r" (task_thread_info(next))); 195 #endif 196 197 /* 198 * If the task has used fpu the last 5 timeslices, just do a full 199 * restore of the math state immediately to avoid the trap; the 200 * chances of needing FPU soon are obviously high now 201 */ 202 if (next->thread.fpu_counter > 5) 203 __fpu_state_restore(); 204 205 return prev; 206 } 207 208 unsigned long get_wchan(struct task_struct *p) 209 { 210 unsigned long pc; 211 212 if (!p || p == current || p->state == TASK_RUNNING) 213 return 0; 214 215 /* 216 * The same comment as on the Alpha applies here, too ... 217 */ 218 pc = thread_saved_pc(p); 219 220 #ifdef CONFIG_FRAME_POINTER 221 if (in_sched_functions(pc)) { 222 unsigned long schedule_frame = (unsigned long)p->thread.sp; 223 return ((unsigned long *)schedule_frame)[21]; 224 } 225 #endif 226 227 return pc; 228 } 229