2 * 'traps.c' handles hardware traps and faults after we have saved some
5 * SuperH version: Copyright (C) 1999 Niibe Yutaka
6 * Copyright (C) 2000 Philipp Rumpf
7 * Copyright (C) 2000 David Howells
8 * Copyright (C) 2002 - 2007 Paul Mundt
10 * This file is subject to the terms and conditions of the GNU General Public
11 * License. See the file "COPYING" in the main directory of this archive
14 #include <linux/kernel.h>
15 #include <linux/ptrace.h>
16 #include <linux/hardirq.h>
17 #include <linux/init.h>
18 #include <linux/spinlock.h>
19 #include <linux/module.h>
20 #include <linux/kallsyms.h>
22 #include <linux/bug.h>
23 #include <linux/debug_locks.h>
24 #include <linux/kdebug.h>
25 #include <linux/kexec.h>
26 #include <linux/limits.h>
27 #include <linux/proc_fs.h>
28 #include <asm/system.h>
29 #include <asm/uaccess.h>
31 #include <asm/kprobes.h>
34 # define TRAP_RESERVED_INST 4
35 # define TRAP_ILLEGAL_SLOT_INST 6
36 # define TRAP_ADDRESS_ERROR 9
37 # ifdef CONFIG_CPU_SH2A
39 # define TRAP_FPU_ERROR 13
40 # define TRAP_DIVZERO_ERROR 17
41 # define TRAP_DIVOVF_ERROR 18
44 #define TRAP_RESERVED_INST 12
45 #define TRAP_ILLEGAL_SLOT_INST 13
48 static unsigned long se_user;
49 static unsigned long se_sys;
50 static unsigned long se_half;
51 static unsigned long se_word;
52 static unsigned long se_dword;
53 static unsigned long se_multi;
54 /* bitfield: 1: warn 2: fixup 4: signal -> combinations 2|4 && 1|2|4 are not
56 static int se_usermode = 3;
57 /* 0: no warning 1: print a warning message */
58 static int se_kernmode_warn = 1;
61 static const char *se_usermode_action[] = {
71 proc_alignment_read(char *page, char **start, off_t off, int count, int *eof,
77 p += sprintf(p, "User:\t\t%lu\n", se_user);
78 p += sprintf(p, "System:\t\t%lu\n", se_sys);
79 p += sprintf(p, "Half:\t\t%lu\n", se_half);
80 p += sprintf(p, "Word:\t\t%lu\n", se_word);
81 p += sprintf(p, "DWord:\t\t%lu\n", se_dword);
82 p += sprintf(p, "Multi:\t\t%lu\n", se_multi);
83 p += sprintf(p, "User faults:\t%i (%s)\n", se_usermode,
84 se_usermode_action[se_usermode]);
85 p += sprintf(p, "Kernel faults:\t%i (fixup%s)\n", se_kernmode_warn,
86 se_kernmode_warn ? "+warn" : "");
88 len = (p - page) - off;
92 *eof = (len <= count) ? 1 : 0;
98 static int proc_alignment_write(struct file *file, const char __user *buffer,
99 unsigned long count, void *data)
104 if (get_user(mode, buffer))
106 if (mode >= '0' && mode <= '5')
107 se_usermode = mode - '0';
112 static int proc_alignment_kern_write(struct file *file, const char __user *buffer,
113 unsigned long count, void *data)
118 if (get_user(mode, buffer))
120 if (mode >= '0' && mode <= '1')
121 se_kernmode_warn = mode - '0';
127 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
132 printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
134 for (p = bottom & ~31; p < top; ) {
135 printk("%04lx: ", p & 0xffff);
137 for (i = 0; i < 8; i++, p += 4) {
140 if (p < bottom || p >= top)
143 if (__get_user(val, (unsigned int __user *)p)) {
147 printk("%08x ", val);
154 static DEFINE_SPINLOCK(die_lock);
156 void die(const char * str, struct pt_regs * regs, long err)
158 static int die_counter;
163 spin_lock_irq(&die_lock);
166 printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
171 printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
172 task_pid_nr(current), task_stack_page(current) + 1);
174 if (!user_mode(regs) || in_interrupt())
175 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
176 (unsigned long)task_stack_page(current));
178 notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
181 add_taint(TAINT_DIE);
182 spin_unlock_irq(&die_lock);
184 if (kexec_should_crash(current))
188 panic("Fatal exception in interrupt");
191 panic("Fatal exception");
197 static inline void die_if_kernel(const char *str, struct pt_regs *regs,
200 if (!user_mode(regs))
205 * try and fix up kernelspace address errors
206 * - userspace errors just cause EFAULT to be returned, resulting in SEGV
207 * - kernel/userspace interfaces cause a jump to an appropriate handler
208 * - other kernel errors are bad
210 static void die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
212 if (!user_mode(regs)) {
213 const struct exception_table_entry *fixup;
214 fixup = search_exception_tables(regs->pc);
216 regs->pc = fixup->fixup;
224 static inline void sign_extend(unsigned int count, unsigned char *dst)
226 #ifdef __LITTLE_ENDIAN__
227 if ((count == 1) && dst[0] & 0x80) {
232 if ((count == 2) && dst[1] & 0x80) {
237 if ((count == 1) && dst[3] & 0x80) {
242 if ((count == 2) && dst[2] & 0x80) {
249 static struct mem_access user_mem_access = {
255 * handle an instruction that does an unaligned memory access by emulating the
257 * - note that PC _may not_ point to the faulting instruction
258 * (if that instruction is in a branch delay slot)
259 * - return 0 if emulation okay, -EFAULT on existential error
261 static int handle_unaligned_ins(insn_size_t instruction, struct pt_regs *regs,
262 struct mem_access *ma)
264 int ret, index, count;
265 unsigned long *rm, *rn;
266 unsigned char *src, *dst;
267 unsigned char __user *srcu, *dstu;
269 index = (instruction>>8)&15; /* 0x0F00 */
270 rn = ®s->regs[index];
272 index = (instruction>>4)&15; /* 0x00F0 */
273 rm = ®s->regs[index];
275 count = 1<<(instruction&3);
278 case 1: se_half += 1; break;
279 case 2: se_word += 1; break;
280 case 4: se_dword += 1; break;
281 case 8: se_multi += 1; break; /* ??? */
285 switch (instruction>>12) {
286 case 0: /* mov.[bwl] to/from memory via r0+rn */
287 if (instruction & 8) {
289 srcu = (unsigned char __user *)*rm;
290 srcu += regs->regs[0];
291 dst = (unsigned char *)rn;
292 *(unsigned long *)dst = 0;
294 #if !defined(__LITTLE_ENDIAN__)
297 if (ma->from(dst, srcu, count))
300 sign_extend(count, dst);
303 src = (unsigned char *)rm;
304 #if !defined(__LITTLE_ENDIAN__)
307 dstu = (unsigned char __user *)*rn;
308 dstu += regs->regs[0];
310 if (ma->to(dstu, src, count))
316 case 1: /* mov.l Rm,@(disp,Rn) */
317 src = (unsigned char*) rm;
318 dstu = (unsigned char __user *)*rn;
319 dstu += (instruction&0x000F)<<2;
321 if (ma->to(dstu, src, 4))
326 case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
329 src = (unsigned char*) rm;
330 dstu = (unsigned char __user *)*rn;
331 #if !defined(__LITTLE_ENDIAN__)
334 if (ma->to(dstu, src, count))
339 case 5: /* mov.l @(disp,Rm),Rn */
340 srcu = (unsigned char __user *)*rm;
341 srcu += (instruction & 0x000F) << 2;
342 dst = (unsigned char *)rn;
343 *(unsigned long *)dst = 0;
345 if (ma->from(dst, srcu, 4))
350 case 6: /* mov.[bwl] from memory, possibly with post-increment */
351 srcu = (unsigned char __user *)*rm;
354 dst = (unsigned char*) rn;
355 *(unsigned long*)dst = 0;
357 #if !defined(__LITTLE_ENDIAN__)
360 if (ma->from(dst, srcu, count))
362 sign_extend(count, dst);
367 switch ((instruction&0xFF00)>>8) {
368 case 0x81: /* mov.w R0,@(disp,Rn) */
369 src = (unsigned char *) ®s->regs[0];
370 #if !defined(__LITTLE_ENDIAN__)
373 dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
374 dstu += (instruction & 0x000F) << 1;
376 if (ma->to(dstu, src, 2))
381 case 0x85: /* mov.w @(disp,Rm),R0 */
382 srcu = (unsigned char __user *)*rm;
383 srcu += (instruction & 0x000F) << 1;
384 dst = (unsigned char *) ®s->regs[0];
385 *(unsigned long *)dst = 0;
387 #if !defined(__LITTLE_ENDIAN__)
390 if (ma->from(dst, srcu, 2))
401 /* Argh. Address not only misaligned but also non-existent.
402 * Raise an EFAULT and see if it's trapped
404 die_if_no_fixup("Fault in unaligned fixup", regs, 0);
409 * emulate the instruction in the delay slot
410 * - fetches the instruction from PC+2
412 static inline int handle_delayslot(struct pt_regs *regs,
413 insn_size_t old_instruction,
414 struct mem_access *ma)
416 insn_size_t instruction;
417 void __user *addr = (void __user *)(regs->pc +
418 instruction_size(old_instruction));
420 if (copy_from_user(&instruction, addr, sizeof(instruction))) {
421 /* the instruction-fetch faulted */
426 die("delay-slot-insn faulting in handle_unaligned_delayslot",
430 return handle_unaligned_ins(instruction, regs, ma);
434 * handle an instruction that does an unaligned memory access
435 * - have to be careful of branch delay-slot instructions that fault
437 * - if the branch would be taken PC points to the branch
438 * - if the branch would not be taken, PC points to delay-slot
440 * - PC always points to delayed branch
441 * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
444 /* Macros to determine offset from current PC for branch instructions */
445 /* Explicit type coercion is used to force sign extension where needed */
446 #define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
447 #define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
449 int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
450 struct mem_access *ma, int expected)
455 index = (instruction>>8)&15; /* 0x0F00 */
456 rm = regs->regs[index];
458 /* shout about fixups */
459 if (!expected && printk_ratelimit())
460 printk(KERN_NOTICE "Fixing up unaligned %s access "
461 "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
462 user_mode(regs) ? "userspace" : "kernel",
463 current->comm, task_pid_nr(current),
464 (void *)regs->pc, instruction);
467 switch (instruction&0xF000) {
469 if (instruction==0x000B) {
471 ret = handle_delayslot(regs, instruction, ma);
475 else if ((instruction&0x00FF)==0x0023) {
477 ret = handle_delayslot(regs, instruction, ma);
481 else if ((instruction&0x00FF)==0x0003) {
483 ret = handle_delayslot(regs, instruction, ma);
485 regs->pr = regs->pc + 4;
490 /* mov.[bwl] to/from memory via r0+rn */
495 case 0x1000: /* mov.l Rm,@(disp,Rn) */
498 case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
502 if ((instruction&0x00FF)==0x002B) {
504 ret = handle_delayslot(regs, instruction, ma);
508 else if ((instruction&0x00FF)==0x000B) {
510 ret = handle_delayslot(regs, instruction, ma);
512 regs->pr = regs->pc + 4;
517 /* mov.[bwl] to/from memory via r0+rn */
522 case 0x5000: /* mov.l @(disp,Rm),Rn */
525 case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
528 case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
529 switch (instruction&0x0F00) {
530 case 0x0100: /* mov.w R0,@(disp,Rm) */
532 case 0x0500: /* mov.w @(disp,Rm),R0 */
534 case 0x0B00: /* bf lab - no delayslot*/
536 case 0x0F00: /* bf/s lab */
537 ret = handle_delayslot(regs, instruction, ma);
539 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
540 if ((regs->sr & 0x00000001) != 0)
541 regs->pc += 4; /* next after slot */
544 regs->pc += SH_PC_8BIT_OFFSET(instruction);
547 case 0x0900: /* bt lab - no delayslot */
549 case 0x0D00: /* bt/s lab */
550 ret = handle_delayslot(regs, instruction, ma);
552 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
553 if ((regs->sr & 0x00000001) == 0)
554 regs->pc += 4; /* next after slot */
557 regs->pc += SH_PC_8BIT_OFFSET(instruction);
563 case 0xA000: /* bra label */
564 ret = handle_delayslot(regs, instruction, ma);
566 regs->pc += SH_PC_12BIT_OFFSET(instruction);
569 case 0xB000: /* bsr label */
570 ret = handle_delayslot(regs, instruction, ma);
572 regs->pr = regs->pc + 4;
573 regs->pc += SH_PC_12BIT_OFFSET(instruction);
579 /* handle non-delay-slot instruction */
581 ret = handle_unaligned_ins(instruction, regs, ma);
583 regs->pc += instruction_size(instruction);
588 * Handle various address error exceptions:
589 * - instruction address error:
591 * PC >= 0x80000000 in user mode
592 * - data address error (read and write)
593 * misaligned data access
594 * access to >= 0x80000000 is user mode
595 * Unfortuntaly we can't distinguish between instruction address error
596 * and data address errors caused by read accesses.
598 asmlinkage void do_address_error(struct pt_regs *regs,
599 unsigned long writeaccess,
600 unsigned long address)
602 unsigned long error_code = 0;
605 insn_size_t instruction;
608 /* Intentional ifdef */
609 #ifdef CONFIG_CPU_HAS_SR_RB
610 error_code = lookup_exception_vector();
615 if (user_mode(regs)) {
616 int si_code = BUS_ADRERR;
622 #ifndef CONFIG_CPU_SH2A
624 if (copy_from_user(&instruction, (u16 *)(regs->pc & ~1), 2)) {
630 /* shout about userspace fixups */
632 printk(KERN_NOTICE "Unaligned userspace access "
633 "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
634 current->comm, current->pid, (void *)regs->pc,
645 regs->pc += instruction_size(instruction);
650 /* bad PC is not something we can fix */
652 si_code = BUS_ADRALN;
657 tmp = handle_unaligned_access(instruction, regs,
658 &user_mem_access, 0);
664 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
665 "access (PC %lx PR %lx)\n", current->comm, regs->pc,
668 info.si_signo = SIGBUS;
670 info.si_code = si_code;
671 info.si_addr = (void __user *)address;
672 force_sig_info(SIGBUS, &info, current);
676 if (se_kernmode_warn)
677 printk(KERN_NOTICE "Unaligned kernel access "
678 "on behalf of \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
679 current->comm, current->pid, (void *)regs->pc,
683 die("unaligned program counter", regs, error_code);
686 if (copy_from_user(&instruction, (void __user *)(regs->pc),
687 sizeof(instruction))) {
688 /* Argh. Fault on the instruction itself.
689 This should never happen non-SMP
692 die("insn faulting in do_address_error", regs, 0);
695 handle_unaligned_access(instruction, regs,
696 &user_mem_access, 0);
703 * SH-DSP support gerg@snapgear.com.
705 int is_dsp_inst(struct pt_regs *regs)
707 unsigned short inst = 0;
710 * Safe guard if DSP mode is already enabled or we're lacking
711 * the DSP altogether.
713 if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
716 get_user(inst, ((unsigned short *) regs->pc));
720 /* Check for any type of DSP or support instruction */
721 if ((inst == 0xf000) || (inst == 0x4000))
727 #define is_dsp_inst(regs) (0)
728 #endif /* CONFIG_SH_DSP */
730 #ifdef CONFIG_CPU_SH2A
731 asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
732 unsigned long r6, unsigned long r7,
733 struct pt_regs __regs)
738 case TRAP_DIVZERO_ERROR:
739 info.si_code = FPE_INTDIV;
741 case TRAP_DIVOVF_ERROR:
742 info.si_code = FPE_INTOVF;
746 force_sig_info(SIGFPE, &info, current);
750 asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
751 unsigned long r6, unsigned long r7,
752 struct pt_regs __regs)
754 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
755 unsigned long error_code;
756 struct task_struct *tsk = current;
758 #ifdef CONFIG_SH_FPU_EMU
759 unsigned short inst = 0;
762 get_user(inst, (unsigned short*)regs->pc);
764 err = do_fpu_inst(inst, regs);
766 regs->pc += instruction_size(inst);
769 /* not a FPU inst. */
773 /* Check if it's a DSP instruction */
774 if (is_dsp_inst(regs)) {
775 /* Enable DSP mode, and restart instruction. */
778 tsk->thread.dsp_status.status |= SR_DSP;
783 error_code = lookup_exception_vector();
786 force_sig(SIGILL, tsk);
787 die_if_no_fixup("reserved instruction", regs, error_code);
790 #ifdef CONFIG_SH_FPU_EMU
791 static int emulate_branch(unsigned short inst, struct pt_regs *regs)
794 * bfs: 8fxx: PC+=d*2+4;
795 * bts: 8dxx: PC+=d*2+4;
796 * bra: axxx: PC+=D*2+4;
797 * bsr: bxxx: PC+=D*2+4 after PR=PC+4;
798 * braf:0x23: PC+=Rn*2+4;
799 * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
801 * jsr: 4x0b: PC=Rn after PR=PC+4;
804 if (((inst & 0xf000) == 0xb000) || /* bsr */
805 ((inst & 0xf0ff) == 0x0003) || /* bsrf */
806 ((inst & 0xf0ff) == 0x400b)) /* jsr */
807 regs->pr = regs->pc + 4;
809 if ((inst & 0xfd00) == 0x8d00) { /* bfs, bts */
810 regs->pc += SH_PC_8BIT_OFFSET(inst);
814 if ((inst & 0xe000) == 0xa000) { /* bra, bsr */
815 regs->pc += SH_PC_12BIT_OFFSET(inst);
819 if ((inst & 0xf0df) == 0x0003) { /* braf, bsrf */
820 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
824 if ((inst & 0xf0df) == 0x400b) { /* jmp, jsr */
825 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
829 if ((inst & 0xffff) == 0x000b) { /* rts */
838 asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
839 unsigned long r6, unsigned long r7,
840 struct pt_regs __regs)
842 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
844 struct task_struct *tsk = current;
846 if (kprobe_handle_illslot(regs->pc) == 0)
849 #ifdef CONFIG_SH_FPU_EMU
850 get_user(inst, (unsigned short *)regs->pc + 1);
851 if (!do_fpu_inst(inst, regs)) {
852 get_user(inst, (unsigned short *)regs->pc);
853 if (!emulate_branch(inst, regs))
855 /* fault in branch.*/
857 /* not a FPU inst. */
860 inst = lookup_exception_vector();
863 force_sig(SIGILL, tsk);
864 die_if_no_fixup("illegal slot instruction", regs, inst);
867 asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
868 unsigned long r6, unsigned long r7,
869 struct pt_regs __regs)
871 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
874 ex = lookup_exception_vector();
875 die_if_kernel("exception", regs, ex);
878 #if defined(CONFIG_SH_STANDARD_BIOS)
879 void *gdb_vbr_vector;
881 static inline void __init gdb_vbr_init(void)
883 register unsigned long vbr;
886 * Read the old value of the VBR register to initialise
887 * the vector through which debug and BIOS traps are
888 * delegated by the Linux trap handler.
890 asm volatile("stc vbr, %0" : "=r" (vbr));
892 gdb_vbr_vector = (void *)(vbr + 0x100);
893 printk("Setting GDB trap vector to 0x%08lx\n",
894 (unsigned long)gdb_vbr_vector);
898 void __cpuinit per_cpu_trap_init(void)
900 extern void *vbr_base;
902 #ifdef CONFIG_SH_STANDARD_BIOS
903 if (raw_smp_processor_id() == 0)
907 /* NOTE: The VBR value should be at P1
908 (or P2, virtural "fixed" address space).
909 It's definitely should not in physical address. */
911 asm volatile("ldc %0, vbr"
917 void *set_exception_table_vec(unsigned int vec, void *handler)
919 extern void *exception_handling_table[];
922 old_handler = exception_handling_table[vec];
923 exception_handling_table[vec] = handler;
927 void __init trap_init(void)
929 set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
930 set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
932 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
933 defined(CONFIG_SH_FPU_EMU)
935 * For SH-4 lacking an FPU, treat floating point instructions as
936 * reserved. They'll be handled in the math-emu case, or faulted on
939 set_exception_table_evt(0x800, do_reserved_inst);
940 set_exception_table_evt(0x820, do_illegal_slot_inst);
941 #elif defined(CONFIG_SH_FPU)
942 #ifdef CONFIG_CPU_SUBTYPE_SHX3
943 set_exception_table_evt(0xd80, fpu_state_restore_trap_handler);
944 set_exception_table_evt(0xda0, fpu_state_restore_trap_handler);
946 set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
947 set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
951 #ifdef CONFIG_CPU_SH2
952 set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
954 #ifdef CONFIG_CPU_SH2A
955 set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
956 set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
958 set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
963 set_exception_table_vec(TRAP_UBC, break_point_trap);
966 /* Setup VBR for boot cpu */
970 void show_stack(struct task_struct *tsk, unsigned long *sp)
977 sp = (unsigned long *)current_stack_pointer;
979 sp = (unsigned long *)tsk->thread.sp;
981 stack = (unsigned long)sp;
982 dump_mem("Stack: ", stack, THREAD_SIZE +
983 (unsigned long)task_stack_page(tsk));
984 show_trace(tsk, sp, NULL);
987 void dump_stack(void)
989 show_stack(NULL, NULL);
991 EXPORT_SYMBOL(dump_stack);
993 #ifdef CONFIG_PROC_FS
995 * This needs to be done after sysctl_init, otherwise sys/ will be
996 * overwritten. Actually, this shouldn't be in sys/ at all since
997 * it isn't a sysctl, and it doesn't contain sysctl information.
998 * We now locate it in /proc/cpu/alignment instead.
1000 static int __init alignment_init(void)
1002 struct proc_dir_entry *dir, *res;
1004 dir = proc_mkdir("cpu", NULL);
1008 res = create_proc_entry("alignment", S_IWUSR | S_IRUGO, dir);
1012 res->read_proc = proc_alignment_read;
1013 res->write_proc = proc_alignment_write;
1015 res = create_proc_entry("kernel_alignment", S_IWUSR | S_IRUGO, dir);
1019 res->read_proc = proc_alignment_read;
1020 res->write_proc = proc_alignment_kern_write;
1025 fs_initcall(alignment_init);