arch/x86/include/asm/syscall.h

   1 /*
   2  * Access to user system call parameters and results
   3  *
   4  * Copyright (C) 2008-2009 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_X86_SYSCALL_H
  14 #define _ASM_X86_SYSCALL_H
  15
  16 #include <linux/sched.h>
  17 #include <linux/err.h>
  18
  19 extern const unsigned long sys_call_table[];
  20
  21 /*
  22  * Only the low 32 bits of orig_ax are meaningful, so we return int.
  23  * This importantly ignores the high bits on 64-bit, so comparisons
  24  * sign-extend the low 32 bits.
  25  */
  26 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  27 {
  28         return regs->orig_ax;
  29 }
  30
  31 static inline void syscall_rollback(struct task_struct *task,
  32                                     struct pt_regs *regs)
  33 {
  34         regs->ax = regs->orig_ax;
  35 }
  36
  37 static inline long syscall_get_error(struct task_struct *task,
  38                                      struct pt_regs *regs)
  39 {
  40         unsigned long error = regs->ax;
  41 #ifdef CONFIG_IA32_EMULATION
  42         /*
  43          * TS_COMPAT is set for 32-bit syscall entries and then
  44          * remains set until we return to user mode.
  45          */
  46         if (task_thread_info(task)->status & TS_COMPAT)
  47                 /*
  48                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  49                  * and will match correctly in comparisons.
  50                  */
  51                 error = (long) (int) error;
  52 #endif
  53         return IS_ERR_VALUE(error) ? error : 0;
  54 }
  55
  56 static inline long syscall_get_return_value(struct task_struct *task,
  57                                             struct pt_regs *regs)
  58 {
  59         return regs->ax;
  60 }
  61
  62 static inline void syscall_set_return_value(struct task_struct *task,
  63                                             struct pt_regs *regs,
  64                                             int error, long val)
  65 {
  66         regs->ax = (long) error ?: val;
  67 }
  68
  69 #ifdef CONFIG_X86_32
  70
  71 static inline void syscall_get_arguments(struct task_struct *task,
  72                                          struct pt_regs *regs,
  73                                          unsigned int i, unsigned int n,
  74                                          unsigned long *args)
  75 {
  76         BUG_ON(i + n > 6);
  77         memcpy(args, &regs->bx + i, n * sizeof(args[0]));
  78 }
  79
  80 static inline void syscall_set_arguments(struct task_struct *task,
  81                                          struct pt_regs *regs,
  82                                          unsigned int i, unsigned int n,
  83                                          const unsigned long *args)
  84 {
  85         BUG_ON(i + n > 6);
  86         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  87 }
  88
  89 #else    /* CONFIG_X86_64 */
  90
  91 static inline void syscall_get_arguments(struct task_struct *task,
  92                                          struct pt_regs *regs,
  93                                          unsigned int i, unsigned int n,
  94                                          unsigned long *args)
  95 {
  96 # ifdef CONFIG_IA32_EMULATION
  97         if (task_thread_info(task)->status & TS_COMPAT)
  98                 switch (i) {
  99                 case 0:
 100                         if (!n--) break;
 101                         *args++ = regs->bx;
 102                 case 1:
 103                         if (!n--) break;
 104                         *args++ = regs->cx;
 105                 case 2:
 106                         if (!n--) break;
 107                         *args++ = regs->dx;
 108                 case 3:
 109                         if (!n--) break;
 110                         *args++ = regs->si;
 111                 case 4:
 112                         if (!n--) break;
 113                         *args++ = regs->di;
 114                 case 5:
 115                         if (!n--) break;
 116                         *args++ = regs->bp;
 117                 case 6:
 118                         if (!n--) break;
 119                 default:
 120                         BUG();
 121                         break;
 122                 }
 123         else
 124 # endif
 125                 switch (i) {
 126                 case 0:
 127                         if (!n--) break;
 128                         *args++ = regs->di;
 129                 case 1:
 130                         if (!n--) break;
 131                         *args++ = regs->si;
 132                 case 2:
 133                         if (!n--) break;
 134                         *args++ = regs->dx;
 135                 case 3:
 136                         if (!n--) break;
 137                         *args++ = regs->r10;
 138                 case 4:
 139                         if (!n--) break;
 140                         *args++ = regs->r8;
 141                 case 5:
 142                         if (!n--) break;
 143                         *args++ = regs->r9;
 144                 case 6:
 145                         if (!n--) break;
 146                 default:
 147                         BUG();
 148                         break;
 149                 }
 150 }
 151
 152 static inline void syscall_set_arguments(struct task_struct *task,
 153                                          struct pt_regs *regs,
 154                                          unsigned int i, unsigned int n,
 155                                          const unsigned long *args)
 156 {
 157 # ifdef CONFIG_IA32_EMULATION
 158         if (task_thread_info(task)->status & TS_COMPAT)
 159                 switch (i) {
 160                 case 0:
 161                         if (!n--) break;
 162                         regs->bx = *args++;
 163                 case 1:
 164                         if (!n--) break;
 165                         regs->cx = *args++;
 166                 case 2:
 167                         if (!n--) break;
 168                         regs->dx = *args++;
 169                 case 3:
 170                         if (!n--) break;
 171                         regs->si = *args++;
 172                 case 4:
 173                         if (!n--) break;
 174                         regs->di = *args++;
 175                 case 5:
 176                         if (!n--) break;
 177                         regs->bp = *args++;
 178                 case 6:
 179                         if (!n--) break;
 180                 default:
 181                         BUG();
 182                         break;
 183                 }
 184         else
 185 # endif
 186                 switch (i) {
 187                 case 0:
 188                         if (!n--) break;
 189                         regs->di = *args++;
 190                 case 1:
 191                         if (!n--) break;
 192                         regs->si = *args++;
 193                 case 2:
 194                         if (!n--) break;
 195                         regs->dx = *args++;
 196                 case 3:
 197                         if (!n--) break;
 198                         regs->r10 = *args++;
 199                 case 4:
 200                         if (!n--) break;
 201                         regs->r8 = *args++;
 202                 case 5:
 203                         if (!n--) break;
 204                         regs->r9 = *args++;
 205                 case 6:
 206                         if (!n--) break;
 207                 default:
 208                         BUG();
 209                         break;
 210                 }
 211 }
 212
 213 #endif  /* CONFIG_X86_32 */
 214
 215 #endif  /* _ASM_X86_SYSCALL_H */