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 <asm/uaccess.h> 26 #include <asm/mmu_context.h> 27 #include <asm/system.h> 28 #include <asm/fpu.h> 29 #include <asm/syscalls.h> 30 31 void show_regs(struct pt_regs * regs) 32 { 33 printk("\n"); 34 printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm); 35 printk("CPU : %d \t\t%s (%s %.*s)\n\n", 36 smp_processor_id(), print_tainted(), init_utsname()->release, 37 (int)strcspn(init_utsname()->version, " "), 38 init_utsname()->version); 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 /* 71 * Create a kernel thread 72 */ 73 ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *)) 74 { 75 do_exit(fn(arg)); 76 } 77 78 /* Don't use this in BL=1(cli). Or else, CPU resets! */ 79 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 80 { 81 struct pt_regs regs; 82 int pid; 83 84 memset(®s, 0, sizeof(regs)); 85 regs.regs[4] = (unsigned long)arg; 86 regs.regs[5] = (unsigned long)fn; 87 88 regs.pc = (unsigned long)kernel_thread_helper; 89 regs.sr = SR_MD; 90 #if defined(CONFIG_SH_FPU) 91 regs.sr |= SR_FD; 92 #endif 93 94 /* Ok, create the new process.. */ 95 pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, 96 ®s, 0, NULL, NULL); 97 98 return pid; 99 } 100 EXPORT_SYMBOL(kernel_thread); 101 102 void start_thread(struct pt_regs *regs, unsigned long new_pc, 103 unsigned long new_sp) 104 { 105 set_fs(USER_DS); 106 107 regs->pr = 0; 108 regs->sr = SR_FD; 109 regs->pc = new_pc; 110 regs->regs[15] = new_sp; 111 112 free_thread_xstate(current); 113 } 114 EXPORT_SYMBOL(start_thread); 115 116 /* 117 * Free current thread data structures etc.. 118 */ 119 void exit_thread(void) 120 { 121 } 122 123 void flush_thread(void) 124 { 125 struct task_struct *tsk = current; 126 127 flush_ptrace_hw_breakpoint(tsk); 128 129 #if defined(CONFIG_SH_FPU) 130 /* Forget lazy FPU state */ 131 clear_fpu(tsk, task_pt_regs(tsk)); 132 clear_used_math(); 133 #endif 134 } 135 136 void release_thread(struct task_struct *dead_task) 137 { 138 /* do nothing */ 139 } 140 141 /* Fill in the fpu structure for a core dump.. */ 142 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 143 { 144 int fpvalid = 0; 145 146 #if defined(CONFIG_SH_FPU) 147 struct task_struct *tsk = current; 148 149 fpvalid = !!tsk_used_math(tsk); 150 if (fpvalid) 151 fpvalid = !fpregs_get(tsk, NULL, 0, 152 sizeof(struct user_fpu_struct), 153 fpu, NULL); 154 #endif 155 156 return fpvalid; 157 } 158 EXPORT_SYMBOL(dump_fpu); 159 160 /* 161 * This gets called before we allocate a new thread and copy 162 * the current task into it. 163 */ 164 void prepare_to_copy(struct task_struct *tsk) 165 { 166 unlazy_fpu(tsk, task_pt_regs(tsk)); 167 } 168 169 asmlinkage void ret_from_fork(void); 170 171 int copy_thread(unsigned long clone_flags, unsigned long usp, 172 unsigned long unused, 173 struct task_struct *p, struct pt_regs *regs) 174 { 175 struct thread_info *ti = task_thread_info(p); 176 struct pt_regs *childregs; 177 178 #if defined(CONFIG_SH_DSP) 179 struct task_struct *tsk = current; 180 181 if (is_dsp_enabled(tsk)) { 182 /* We can use the __save_dsp or just copy the struct: 183 * __save_dsp(p); 184 * p->thread.dsp_status.status |= SR_DSP 185 */ 186 p->thread.dsp_status = tsk->thread.dsp_status; 187 } 188 #endif 189 190 childregs = task_pt_regs(p); 191 *childregs = *regs; 192 193 if (user_mode(regs)) { 194 childregs->regs[15] = usp; 195 ti->addr_limit = USER_DS; 196 } else { 197 childregs->regs[15] = (unsigned long)childregs; 198 ti->addr_limit = KERNEL_DS; 199 ti->status &= ~TS_USEDFPU; 200 p->fpu_counter = 0; 201 } 202 203 if (clone_flags & CLONE_SETTLS) 204 childregs->gbr = childregs->regs[0]; 205 206 childregs->regs[0] = 0; /* Set return value for child */ 207 208 p->thread.sp = (unsigned long) childregs; 209 p->thread.pc = (unsigned long) ret_from_fork; 210 211 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 212 213 return 0; 214 } 215 216 /* 217 * switch_to(x,y) should switch tasks from x to y. 218 * 219 */ 220 __notrace_funcgraph struct task_struct * 221 __switch_to(struct task_struct *prev, struct task_struct *next) 222 { 223 struct thread_struct *next_t = &next->thread; 224 225 unlazy_fpu(prev, task_pt_regs(prev)); 226 227 /* we're going to use this soon, after a few expensive things */ 228 if (next->fpu_counter > 5) 229 prefetch(next_t->xstate); 230 231 #ifdef CONFIG_MMU 232 /* 233 * Restore the kernel mode register 234 * k7 (r7_bank1) 235 */ 236 asm volatile("ldc %0, r7_bank" 237 : /* no output */ 238 : "r" (task_thread_info(next))); 239 #endif 240 241 /* 242 * If the task has used fpu the last 5 timeslices, just do a full 243 * restore of the math state immediately to avoid the trap; the 244 * chances of needing FPU soon are obviously high now 245 */ 246 if (next->fpu_counter > 5) 247 __fpu_state_restore(); 248 249 return prev; 250 } 251 252 asmlinkage int sys_fork(unsigned long r4, unsigned long r5, 253 unsigned long r6, unsigned long r7, 254 struct pt_regs __regs) 255 { 256 #ifdef CONFIG_MMU 257 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 258 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL); 259 #else 260 /* fork almost works, enough to trick you into looking elsewhere :-( */ 261 return -EINVAL; 262 #endif 263 } 264 265 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp, 266 unsigned long parent_tidptr, 267 unsigned long child_tidptr, 268 struct pt_regs __regs) 269 { 270 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 271 if (!newsp) 272 newsp = regs->regs[15]; 273 return do_fork(clone_flags, newsp, regs, 0, 274 (int __user *)parent_tidptr, 275 (int __user *)child_tidptr); 276 } 277 278 /* 279 * This is trivial, and on the face of it looks like it 280 * could equally well be done in user mode. 281 * 282 * Not so, for quite unobvious reasons - register pressure. 283 * In user mode vfork() cannot have a stack frame, and if 284 * done by calling the "clone()" system call directly, you 285 * do not have enough call-clobbered registers to hold all 286 * the information you need. 287 */ 288 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5, 289 unsigned long r6, unsigned long r7, 290 struct pt_regs __regs) 291 { 292 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 293 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs, 294 0, NULL, NULL); 295 } 296 297 /* 298 * sys_execve() executes a new program. 299 */ 300 asmlinkage int sys_execve(const char __user *ufilename, 301 const char __user *const __user *uargv, 302 const char __user *const __user *uenvp, 303 unsigned long r7, struct pt_regs __regs) 304 { 305 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 306 int error; 307 char *filename; 308 309 filename = getname(ufilename); 310 error = PTR_ERR(filename); 311 if (IS_ERR(filename)) 312 goto out; 313 314 error = do_execve(filename, uargv, uenvp, regs); 315 putname(filename); 316 out: 317 return error; 318 } 319 320 unsigned long get_wchan(struct task_struct *p) 321 { 322 unsigned long pc; 323 324 if (!p || p == current || p->state == TASK_RUNNING) 325 return 0; 326 327 /* 328 * The same comment as on the Alpha applies here, too ... 329 */ 330 pc = thread_saved_pc(p); 331 332 #ifdef CONFIG_FRAME_POINTER 333 if (in_sched_functions(pc)) { 334 unsigned long schedule_frame = (unsigned long)p->thread.sp; 335 return ((unsigned long *)schedule_frame)[21]; 336 } 337 #endif 338 339 return pc; 340 } 341