1 /* 2 * arch/sh/kernel/process.c 3 * 4 * This file handles the architecture-dependent parts of process handling.. 5 * 6 * Copyright (C) 1995 Linus Torvalds 7 * 8 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima 9 * Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC 10 * Copyright (C) 2002 - 2008 Paul Mundt 11 * 12 * This file is subject to the terms and conditions of the GNU General Public 13 * License. See the file "COPYING" in the main directory of this archive 14 * for more details. 15 */ 16 #include <linux/module.h> 17 #include <linux/mm.h> 18 #include <linux/sched/debug.h> 19 #include <linux/sched/task.h> 20 #include <linux/sched/task_stack.h> 21 #include <linux/slab.h> 22 #include <linux/elfcore.h> 23 #include <linux/kallsyms.h> 24 #include <linux/fs.h> 25 #include <linux/ftrace.h> 26 #include <linux/hw_breakpoint.h> 27 #include <linux/prefetch.h> 28 #include <linux/stackprotector.h> 29 #include <linux/uaccess.h> 30 #include <asm/mmu_context.h> 31 #include <asm/fpu.h> 32 #include <asm/syscalls.h> 33 #include <asm/switch_to.h> 34 35 void show_regs(struct pt_regs * regs) 36 { 37 printk("\n"); 38 show_regs_print_info(KERN_DEFAULT); 39 40 print_symbol("PC is at %s\n", instruction_pointer(regs)); 41 print_symbol("PR is at %s\n", regs->pr); 42 43 printk("PC : %08lx SP : %08lx SR : %08lx ", 44 regs->pc, regs->regs[15], regs->sr); 45 #ifdef CONFIG_MMU 46 printk("TEA : %08x\n", __raw_readl(MMU_TEA)); 47 #else 48 printk("\n"); 49 #endif 50 51 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 52 regs->regs[0],regs->regs[1], 53 regs->regs[2],regs->regs[3]); 54 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 55 regs->regs[4],regs->regs[5], 56 regs->regs[6],regs->regs[7]); 57 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 58 regs->regs[8],regs->regs[9], 59 regs->regs[10],regs->regs[11]); 60 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n", 61 regs->regs[12],regs->regs[13], 62 regs->regs[14]); 63 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 64 regs->mach, regs->macl, regs->gbr, regs->pr); 65 66 show_trace(NULL, (unsigned long *)regs->regs[15], regs); 67 show_code(regs); 68 } 69 70 void start_thread(struct pt_regs *regs, unsigned long new_pc, 71 unsigned long new_sp) 72 { 73 regs->pr = 0; 74 regs->sr = SR_FD; 75 regs->pc = new_pc; 76 regs->regs[15] = new_sp; 77 78 free_thread_xstate(current); 79 } 80 EXPORT_SYMBOL(start_thread); 81 82 void flush_thread(void) 83 { 84 struct task_struct *tsk = current; 85 86 flush_ptrace_hw_breakpoint(tsk); 87 88 #if defined(CONFIG_SH_FPU) 89 /* Forget lazy FPU state */ 90 clear_fpu(tsk, task_pt_regs(tsk)); 91 clear_used_math(); 92 #endif 93 } 94 95 void release_thread(struct task_struct *dead_task) 96 { 97 /* do nothing */ 98 } 99 100 /* Fill in the fpu structure for a core dump.. */ 101 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 102 { 103 int fpvalid = 0; 104 105 #if defined(CONFIG_SH_FPU) 106 struct task_struct *tsk = current; 107 108 fpvalid = !!tsk_used_math(tsk); 109 if (fpvalid) 110 fpvalid = !fpregs_get(tsk, NULL, 0, 111 sizeof(struct user_fpu_struct), 112 fpu, NULL); 113 #endif 114 115 return fpvalid; 116 } 117 EXPORT_SYMBOL(dump_fpu); 118 119 asmlinkage void ret_from_fork(void); 120 asmlinkage void ret_from_kernel_thread(void); 121 122 int copy_thread(unsigned long clone_flags, unsigned long usp, 123 unsigned long arg, struct task_struct *p) 124 { 125 struct thread_info *ti = task_thread_info(p); 126 struct pt_regs *childregs; 127 128 #if defined(CONFIG_SH_DSP) 129 struct task_struct *tsk = current; 130 131 if (is_dsp_enabled(tsk)) { 132 /* We can use the __save_dsp or just copy the struct: 133 * __save_dsp(p); 134 * p->thread.dsp_status.status |= SR_DSP 135 */ 136 p->thread.dsp_status = tsk->thread.dsp_status; 137 } 138 #endif 139 140 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 141 142 childregs = task_pt_regs(p); 143 p->thread.sp = (unsigned long) childregs; 144 if (unlikely(p->flags & PF_KTHREAD)) { 145 memset(childregs, 0, sizeof(struct pt_regs)); 146 p->thread.pc = (unsigned long) ret_from_kernel_thread; 147 childregs->regs[4] = arg; 148 childregs->regs[5] = usp; 149 childregs->sr = SR_MD; 150 #if defined(CONFIG_SH_FPU) 151 childregs->sr |= SR_FD; 152 #endif 153 ti->addr_limit = KERNEL_DS; 154 ti->status &= ~TS_USEDFPU; 155 p->thread.fpu_counter = 0; 156 return 0; 157 } 158 *childregs = *current_pt_regs(); 159 160 if (usp) 161 childregs->regs[15] = usp; 162 ti->addr_limit = USER_DS; 163 164 if (clone_flags & CLONE_SETTLS) 165 childregs->gbr = childregs->regs[0]; 166 167 childregs->regs[0] = 0; /* Set return value for child */ 168 p->thread.pc = (unsigned long) ret_from_fork; 169 return 0; 170 } 171 172 /* 173 * switch_to(x,y) should switch tasks from x to y. 174 * 175 */ 176 __notrace_funcgraph struct task_struct * 177 __switch_to(struct task_struct *prev, struct task_struct *next) 178 { 179 struct thread_struct *next_t = &next->thread; 180 181 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) 182 __stack_chk_guard = next->stack_canary; 183 #endif 184 185 unlazy_fpu(prev, task_pt_regs(prev)); 186 187 /* we're going to use this soon, after a few expensive things */ 188 if (next->thread.fpu_counter > 5) 189 prefetch(next_t->xstate); 190 191 #ifdef CONFIG_MMU 192 /* 193 * Restore the kernel mode register 194 * k7 (r7_bank1) 195 */ 196 asm volatile("ldc %0, r7_bank" 197 : /* no output */ 198 : "r" (task_thread_info(next))); 199 #endif 200 201 /* 202 * If the task has used fpu the last 5 timeslices, just do a full 203 * restore of the math state immediately to avoid the trap; the 204 * chances of needing FPU soon are obviously high now 205 */ 206 if (next->thread.fpu_counter > 5) 207 __fpu_state_restore(); 208 209 return prev; 210 } 211 212 unsigned long get_wchan(struct task_struct *p) 213 { 214 unsigned long pc; 215 216 if (!p || p == current || p->state == TASK_RUNNING) 217 return 0; 218 219 /* 220 * The same comment as on the Alpha applies here, too ... 221 */ 222 pc = thread_saved_pc(p); 223 224 #ifdef CONFIG_FRAME_POINTER 225 if (in_sched_functions(pc)) { 226 unsigned long schedule_frame = (unsigned long)p->thread.sp; 227 return ((unsigned long *)schedule_frame)[21]; 228 } 229 #endif 230 231 return pc; 232 } 233