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