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