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 30 void show_regs(struct pt_regs * regs) 31 { 32 printk("\n"); 33 printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm); 34 printk("CPU : %d \t\t%s (%s %.*s)\n\n", 35 smp_processor_id(), print_tainted(), init_utsname()->release, 36 (int)strcspn(init_utsname()->version, " "), 37 init_utsname()->version); 38 39 print_symbol("PC is at %s\n", instruction_pointer(regs)); 40 print_symbol("PR is at %s\n", 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 /* 70 * Create a kernel thread 71 */ 72 __noreturn void kernel_thread_helper(void *arg, int (*fn)(void *)) 73 { 74 do_exit(fn(arg)); 75 } 76 77 /* Don't use this in BL=1(cli). Or else, CPU resets! */ 78 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 79 { 80 struct pt_regs regs; 81 int pid; 82 83 memset(®s, 0, sizeof(regs)); 84 regs.regs[4] = (unsigned long)arg; 85 regs.regs[5] = (unsigned long)fn; 86 87 regs.pc = (unsigned long)kernel_thread_helper; 88 regs.sr = SR_MD; 89 #if defined(CONFIG_SH_FPU) 90 regs.sr |= SR_FD; 91 #endif 92 93 /* Ok, create the new process.. */ 94 pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, 95 ®s, 0, NULL, NULL); 96 97 return pid; 98 } 99 EXPORT_SYMBOL(kernel_thread); 100 101 void start_thread(struct pt_regs *regs, unsigned long new_pc, 102 unsigned long new_sp) 103 { 104 regs->pr = 0; 105 regs->sr = SR_FD; 106 regs->pc = new_pc; 107 regs->regs[15] = new_sp; 108 109 free_thread_xstate(current); 110 } 111 EXPORT_SYMBOL(start_thread); 112 113 /* 114 * Free current thread data structures etc.. 115 */ 116 void exit_thread(void) 117 { 118 } 119 120 void flush_thread(void) 121 { 122 struct task_struct *tsk = current; 123 124 flush_ptrace_hw_breakpoint(tsk); 125 126 #if defined(CONFIG_SH_FPU) 127 /* Forget lazy FPU state */ 128 clear_fpu(tsk, task_pt_regs(tsk)); 129 clear_used_math(); 130 #endif 131 } 132 133 void release_thread(struct task_struct *dead_task) 134 { 135 /* do nothing */ 136 } 137 138 /* Fill in the fpu structure for a core dump.. */ 139 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 140 { 141 int fpvalid = 0; 142 143 #if defined(CONFIG_SH_FPU) 144 struct task_struct *tsk = current; 145 146 fpvalid = !!tsk_used_math(tsk); 147 if (fpvalid) 148 fpvalid = !fpregs_get(tsk, NULL, 0, 149 sizeof(struct user_fpu_struct), 150 fpu, NULL); 151 #endif 152 153 return fpvalid; 154 } 155 EXPORT_SYMBOL(dump_fpu); 156 157 /* 158 * This gets called before we allocate a new thread and copy 159 * the current task into it. 160 */ 161 void prepare_to_copy(struct task_struct *tsk) 162 { 163 unlazy_fpu(tsk, task_pt_regs(tsk)); 164 } 165 166 asmlinkage void ret_from_fork(void); 167 168 int copy_thread(unsigned long clone_flags, unsigned long usp, 169 unsigned long unused, 170 struct task_struct *p, struct pt_regs *regs) 171 { 172 struct thread_info *ti = task_thread_info(p); 173 struct pt_regs *childregs; 174 175 #if defined(CONFIG_SH_DSP) 176 struct task_struct *tsk = current; 177 178 if (is_dsp_enabled(tsk)) { 179 /* We can use the __save_dsp or just copy the struct: 180 * __save_dsp(p); 181 * p->thread.dsp_status.status |= SR_DSP 182 */ 183 p->thread.dsp_status = tsk->thread.dsp_status; 184 } 185 #endif 186 187 childregs = task_pt_regs(p); 188 *childregs = *regs; 189 190 if (user_mode(regs)) { 191 childregs->regs[15] = usp; 192 ti->addr_limit = USER_DS; 193 } else { 194 childregs->regs[15] = (unsigned long)childregs; 195 ti->addr_limit = KERNEL_DS; 196 ti->status &= ~TS_USEDFPU; 197 p->fpu_counter = 0; 198 } 199 200 if (clone_flags & CLONE_SETTLS) 201 childregs->gbr = childregs->regs[0]; 202 203 childregs->regs[0] = 0; /* Set return value for child */ 204 205 p->thread.sp = (unsigned long) childregs; 206 p->thread.pc = (unsigned long) ret_from_fork; 207 208 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 209 210 return 0; 211 } 212 213 /* 214 * switch_to(x,y) should switch tasks from x to y. 215 * 216 */ 217 __notrace_funcgraph struct task_struct * 218 __switch_to(struct task_struct *prev, struct task_struct *next) 219 { 220 struct thread_struct *next_t = &next->thread; 221 222 unlazy_fpu(prev, task_pt_regs(prev)); 223 224 /* we're going to use this soon, after a few expensive things */ 225 if (next->fpu_counter > 5) 226 prefetch(next_t->xstate); 227 228 #ifdef CONFIG_MMU 229 /* 230 * Restore the kernel mode register 231 * k7 (r7_bank1) 232 */ 233 asm volatile("ldc %0, r7_bank" 234 : /* no output */ 235 : "r" (task_thread_info(next))); 236 #endif 237 238 /* 239 * If the task has used fpu the last 5 timeslices, just do a full 240 * restore of the math state immediately to avoid the trap; the 241 * chances of needing FPU soon are obviously high now 242 */ 243 if (next->fpu_counter > 5) 244 __fpu_state_restore(); 245 246 return prev; 247 } 248 249 asmlinkage int sys_fork(unsigned long r4, unsigned long r5, 250 unsigned long r6, unsigned long r7, 251 struct pt_regs __regs) 252 { 253 #ifdef CONFIG_MMU 254 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 255 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL); 256 #else 257 /* fork almost works, enough to trick you into looking elsewhere :-( */ 258 return -EINVAL; 259 #endif 260 } 261 262 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp, 263 unsigned long parent_tidptr, 264 unsigned long child_tidptr, 265 struct pt_regs __regs) 266 { 267 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 268 if (!newsp) 269 newsp = regs->regs[15]; 270 return do_fork(clone_flags, newsp, regs, 0, 271 (int __user *)parent_tidptr, 272 (int __user *)child_tidptr); 273 } 274 275 /* 276 * This is trivial, and on the face of it looks like it 277 * could equally well be done in user mode. 278 * 279 * Not so, for quite unobvious reasons - register pressure. 280 * In user mode vfork() cannot have a stack frame, and if 281 * done by calling the "clone()" system call directly, you 282 * do not have enough call-clobbered registers to hold all 283 * the information you need. 284 */ 285 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5, 286 unsigned long r6, unsigned long r7, 287 struct pt_regs __regs) 288 { 289 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 290 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs, 291 0, NULL, NULL); 292 } 293 294 /* 295 * sys_execve() executes a new program. 296 */ 297 asmlinkage int sys_execve(const char __user *ufilename, 298 const char __user *const __user *uargv, 299 const char __user *const __user *uenvp, 300 unsigned long r7, struct pt_regs __regs) 301 { 302 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 303 int error; 304 char *filename; 305 306 filename = getname(ufilename); 307 error = PTR_ERR(filename); 308 if (IS_ERR(filename)) 309 goto out; 310 311 error = do_execve(filename, uargv, uenvp, regs); 312 putname(filename); 313 out: 314 return error; 315 } 316 317 unsigned long get_wchan(struct task_struct *p) 318 { 319 unsigned long pc; 320 321 if (!p || p == current || p->state == TASK_RUNNING) 322 return 0; 323 324 /* 325 * The same comment as on the Alpha applies here, too ... 326 */ 327 pc = thread_saved_pc(p); 328 329 #ifdef CONFIG_FRAME_POINTER 330 if (in_sched_functions(pc)) { 331 unsigned long schedule_frame = (unsigned long)p->thread.sp; 332 return ((unsigned long *)schedule_frame)[21]; 333 } 334 #endif 335 336 return pc; 337 } 338