include/asm-x86/syscall.h

   1 /*
   2  * Access to user system call parameters and results
   3  *
   4  * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
   5  *
   6  * This copyrighted material is made available to anyone wishing to use,
   7  * modify, copy, or redistribute it subject to the terms and conditions
   8  * of the GNU General Public License v.2.
   9  *
  10  * See asm-generic/syscall.h for descriptions of what we must do here.
  11  */
  12
  13 #ifndef _ASM_SYSCALL_H
  14 #define _ASM_SYSCALL_H  1
  15
  16 #include <linux/sched.h>
  17
  18 static inline long syscall_get_nr(struct task_struct *task,
  19                                   struct pt_regs *regs)
  20 {
  21         /*
  22          * We always sign-extend a -1 value being set here,
  23          * so this is always either -1L or a syscall number.
  24          */
  25         return regs->orig_ax;
  26 }
  27
  28 static inline void syscall_rollback(struct task_struct *task,
  29                                     struct pt_regs *regs)
  30 {
  31         regs->ax = regs->orig_ax;
  32 }
  33
  34 static inline long syscall_get_error(struct task_struct *task,
  35                                      struct pt_regs *regs)
  36 {
  37         unsigned long error = regs->ax;
  38 #ifdef CONFIG_IA32_EMULATION
  39         /*
  40          * TS_COMPAT is set for 32-bit syscall entries and then
  41          * remains set until we return to user mode.
  42          */
  43         if (task_thread_info(task)->status & TS_COMPAT)
  44                 /*
  45                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  46                  * and will match correctly in comparisons.
  47                  */
  48                 error = (long) (int) error;
  49 #endif
  50         return error >= -4095L ? error : 0;
  51 }
  52
  53 static inline long syscall_get_return_value(struct task_struct *task,
  54                                             struct pt_regs *regs)
  55 {
  56         return regs->ax;
  57 }
  58
  59 static inline void syscall_set_return_value(struct task_struct *task,
  60                                             struct pt_regs *regs,
  61                                             int error, long val)
  62 {
  63         regs->ax = (long) error ?: val;
  64 }
  65
  66 #ifdef CONFIG_X86_32
  67
  68 static inline void syscall_get_arguments(struct task_struct *task,
  69                                          struct pt_regs *regs,
  70                                          unsigned int i, unsigned int n,
  71                                          unsigned long *args)
  72 {
  73         BUG_ON(i + n > 6);
  74         memcpy(args, &regs->bx + i, n * sizeof(args[0]));
  75 }
  76
  77 static inline void syscall_set_arguments(struct task_struct *task,
  78                                          struct pt_regs *regs,
  79                                          unsigned int i, unsigned int n,
  80                                          const unsigned long *args)
  81 {
  82         BUG_ON(i + n > 6);
  83         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  84 }
  85
  86 #else    /* CONFIG_X86_64 */
  87
  88 static inline void syscall_get_arguments(struct task_struct *task,
  89                                          struct pt_regs *regs,
  90                                          unsigned int i, unsigned int n,
  91                                          unsigned long *args)
  92 {
  93 # ifdef CONFIG_IA32_EMULATION
  94         if (task_thread_info(task)->status & TS_COMPAT)
  95                 switch (i + n) {
  96                 case 6:
  97                         if (!n--) break;
  98                         *args++ = regs->bp;
  99                 case 5:
 100                         if (!n--) break;
 101                         *args++ = regs->di;
 102                 case 4:
 103                         if (!n--) break;
 104                         *args++ = regs->si;
 105                 case 3:
 106                         if (!n--) break;
 107                         *args++ = regs->dx;
 108                 case 2:
 109                         if (!n--) break;
 110                         *args++ = regs->cx;
 111                 case 1:
 112                         if (!n--) break;
 113                         *args++ = regs->bx;
 114                 case 0:
 115                         if (!n--) break;
 116                 default:
 117                         BUG();
 118                         break;
 119                 }
 120         else
 121 # endif
 122                 switch (i + n) {
 123                 case 6:
 124                         if (!n--) break;
 125                         *args++ = regs->r9;
 126                 case 5:
 127                         if (!n--) break;
 128                         *args++ = regs->r8;
 129                 case 4:
 130                         if (!n--) break;
 131                         *args++ = regs->r10;
 132                 case 3:
 133                         if (!n--) break;
 134                         *args++ = regs->dx;
 135                 case 2:
 136                         if (!n--) break;
 137                         *args++ = regs->si;
 138                 case 1:
 139                         if (!n--) break;
 140                         *args++ = regs->di;
 141                 case 0:
 142                         if (!n--) break;
 143                 default:
 144                         BUG();
 145                         break;
 146                 }
 147 }
 148
 149 static inline void syscall_set_arguments(struct task_struct *task,
 150                                          struct pt_regs *regs,
 151                                          unsigned int i, unsigned int n,
 152                                          const unsigned long *args)
 153 {
 154 # ifdef CONFIG_IA32_EMULATION
 155         if (task_thread_info(task)->status & TS_COMPAT)
 156                 switch (i + n) {
 157                 case 6:
 158                         if (!n--) break;
 159                         regs->bp = *args++;
 160                 case 5:
 161                         if (!n--) break;
 162                         regs->di = *args++;
 163                 case 4:
 164                         if (!n--) break;
 165                         regs->si = *args++;
 166                 case 3:
 167                         if (!n--) break;
 168                         regs->dx = *args++;
 169                 case 2:
 170                         if (!n--) break;
 171                         regs->cx = *args++;
 172                 case 1:
 173                         if (!n--) break;
 174                         regs->bx = *args++;
 175                 case 0:
 176                         if (!n--) break;
 177                 default:
 178                         BUG();
 179                 }
 180         else
 181 # endif
 182                 switch (i + n) {
 183                 case 6:
 184                         if (!n--) break;
 185                         regs->r9 = *args++;
 186                 case 5:
 187                         if (!n--) break;
 188                         regs->r8 = *args++;
 189                 case 4:
 190                         if (!n--) break;
 191                         regs->r10 = *args++;
 192                 case 3:
 193                         if (!n--) break;
 194                         regs->dx = *args++;
 195                 case 2:
 196                         if (!n--) break;
 197                         regs->si = *args++;
 198                 case 1:
 199                         if (!n--) break;
 200                         regs->di = *args++;
 201                 case 0:
 202                         if (!n--) break;
 203                 default:
 204                         BUG();
 205                 }
 206 }
 207
 208 #endif  /* CONFIG_X86_32 */
 209
 210 #endif  /* _ASM_SYSCALL_H */