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