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/slab.h> 19 #include <linux/elfcore.h> 20 #include <linux/kallsyms.h> 21 #include <linux/fs.h> 22 #include <linux/ftrace.h> 23 #include <linux/hw_breakpoint.h> 24 #include <linux/prefetch.h> 25 #include <linux/stackprotector.h> 26 #include <asm/uaccess.h> 27 #include <asm/mmu_context.h> 28 #include <asm/fpu.h> 29 #include <asm/syscalls.h> 30 #include <asm/switch_to.h> 31 32 void show_regs(struct pt_regs * regs) 33 { 34 printk("\n"); 35 printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm); 36 printk("CPU : %d \t\t%s (%s %.*s)\n\n", 37 smp_processor_id(), print_tainted(), init_utsname()->release, 38 (int)strcspn(init_utsname()->version, " "), 39 init_utsname()->version); 40 41 print_symbol("PC is at %s\n", instruction_pointer(regs)); 42 print_symbol("PR is at %s\n", regs->pr); 43 44 printk("PC : %08lx SP : %08lx SR : %08lx ", 45 regs->pc, regs->regs[15], regs->sr); 46 #ifdef CONFIG_MMU 47 printk("TEA : %08x\n", __raw_readl(MMU_TEA)); 48 #else 49 printk("\n"); 50 #endif 51 52 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 53 regs->regs[0],regs->regs[1], 54 regs->regs[2],regs->regs[3]); 55 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 56 regs->regs[4],regs->regs[5], 57 regs->regs[6],regs->regs[7]); 58 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 59 regs->regs[8],regs->regs[9], 60 regs->regs[10],regs->regs[11]); 61 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n", 62 regs->regs[12],regs->regs[13], 63 regs->regs[14]); 64 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 65 regs->mach, regs->macl, regs->gbr, regs->pr); 66 67 show_trace(NULL, (unsigned long *)regs->regs[15], regs); 68 show_code(regs); 69 } 70 71 void start_thread(struct pt_regs *regs, unsigned long new_pc, 72 unsigned long new_sp) 73 { 74 regs->pr = 0; 75 regs->sr = SR_FD; 76 regs->pc = new_pc; 77 regs->regs[15] = new_sp; 78 79 free_thread_xstate(current); 80 } 81 EXPORT_SYMBOL(start_thread); 82 83 /* 84 * Free current thread data structures etc.. 85 */ 86 void exit_thread(void) 87 { 88 } 89 90 void flush_thread(void) 91 { 92 struct task_struct *tsk = current; 93 94 flush_ptrace_hw_breakpoint(tsk); 95 96 #if defined(CONFIG_SH_FPU) 97 /* Forget lazy FPU state */ 98 clear_fpu(tsk, task_pt_regs(tsk)); 99 clear_used_math(); 100 #endif 101 } 102 103 void release_thread(struct task_struct *dead_task) 104 { 105 /* do nothing */ 106 } 107 108 /* Fill in the fpu structure for a core dump.. */ 109 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 110 { 111 int fpvalid = 0; 112 113 #if defined(CONFIG_SH_FPU) 114 struct task_struct *tsk = current; 115 116 fpvalid = !!tsk_used_math(tsk); 117 if (fpvalid) 118 fpvalid = !fpregs_get(tsk, NULL, 0, 119 sizeof(struct user_fpu_struct), 120 fpu, NULL); 121 #endif 122 123 return fpvalid; 124 } 125 EXPORT_SYMBOL(dump_fpu); 126 127 asmlinkage void ret_from_fork(void); 128 asmlinkage void ret_from_kernel_thread(void); 129 130 int copy_thread(unsigned long clone_flags, unsigned long usp, 131 unsigned long arg, struct task_struct *p) 132 { 133 struct thread_info *ti = task_thread_info(p); 134 struct pt_regs *childregs; 135 136 #if defined(CONFIG_SH_DSP) 137 struct task_struct *tsk = current; 138 139 if (is_dsp_enabled(tsk)) { 140 /* We can use the __save_dsp or just copy the struct: 141 * __save_dsp(p); 142 * p->thread.dsp_status.status |= SR_DSP 143 */ 144 p->thread.dsp_status = tsk->thread.dsp_status; 145 } 146 #endif 147 148 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 149 150 childregs = task_pt_regs(p); 151 p->thread.sp = (unsigned long) childregs; 152 if (unlikely(p->flags & PF_KTHREAD)) { 153 memset(childregs, 0, sizeof(struct pt_regs)); 154 p->thread.pc = (unsigned long) ret_from_kernel_thread; 155 childregs->regs[4] = arg; 156 childregs->regs[5] = usp; 157 childregs->sr = SR_MD; 158 #if defined(CONFIG_SH_FPU) 159 childregs->sr |= SR_FD; 160 #endif 161 ti->addr_limit = KERNEL_DS; 162 ti->status &= ~TS_USEDFPU; 163 p->fpu_counter = 0; 164 return 0; 165 } 166 *childregs = *current_pt_regs(); 167 168 if (usp) 169 childregs->regs[15] = usp; 170 ti->addr_limit = USER_DS; 171 172 if (clone_flags & CLONE_SETTLS) 173 childregs->gbr = childregs->regs[0]; 174 175 childregs->regs[0] = 0; /* Set return value for child */ 176 p->thread.pc = (unsigned long) ret_from_fork; 177 return 0; 178 } 179 180 /* 181 * switch_to(x,y) should switch tasks from x to y. 182 * 183 */ 184 __notrace_funcgraph struct task_struct * 185 __switch_to(struct task_struct *prev, struct task_struct *next) 186 { 187 struct thread_struct *next_t = &next->thread; 188 189 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) 190 __stack_chk_guard = next->stack_canary; 191 #endif 192 193 unlazy_fpu(prev, task_pt_regs(prev)); 194 195 /* we're going to use this soon, after a few expensive things */ 196 if (next->fpu_counter > 5) 197 prefetch(next_t->xstate); 198 199 #ifdef CONFIG_MMU 200 /* 201 * Restore the kernel mode register 202 * k7 (r7_bank1) 203 */ 204 asm volatile("ldc %0, r7_bank" 205 : /* no output */ 206 : "r" (task_thread_info(next))); 207 #endif 208 209 /* 210 * If the task has used fpu the last 5 timeslices, just do a full 211 * restore of the math state immediately to avoid the trap; the 212 * chances of needing FPU soon are obviously high now 213 */ 214 if (next->fpu_counter > 5) 215 __fpu_state_restore(); 216 217 return prev; 218 } 219 220 unsigned long get_wchan(struct task_struct *p) 221 { 222 unsigned long pc; 223 224 if (!p || p == current || p->state == TASK_RUNNING) 225 return 0; 226 227 /* 228 * The same comment as on the Alpha applies here, too ... 229 */ 230 pc = thread_saved_pc(p); 231 232 #ifdef CONFIG_FRAME_POINTER 233 if (in_sched_functions(pc)) { 234 unsigned long schedule_frame = (unsigned long)p->thread.sp; 235 return ((unsigned long *)schedule_frame)[21]; 236 } 237 #endif 238 239 return pc; 240 } 241