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