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 <uapi/linux/audit.h>
  17 #include <linux/sched.h>
  18 #include <linux/err.h>
  19 #include <asm/asm-offsets.h>    /* For NR_syscalls */
  20 #include <asm/thread_info.h>    /* for TS_COMPAT */
  21 #include <asm/unistd.h>
  22
  23 typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long,
  24                                           unsigned long, unsigned long,
  25                                           unsigned long, unsigned long);
  26 extern const sys_call_ptr_t sys_call_table[];
  27
  28 #if defined(CONFIG_X86_32)
  29 #define ia32_sys_call_table sys_call_table
  30 #define __NR_syscall_compat_max __NR_syscall_max
  31 #define IA32_NR_syscalls NR_syscalls
  32 #endif
  33
  34 #if defined(CONFIG_IA32_EMULATION)
  35 extern const sys_call_ptr_t ia32_sys_call_table[];
  36 #endif
  37
  38 /*
  39  * Only the low 32 bits of orig_ax are meaningful, so we return int.
  40  * This importantly ignores the high bits on 64-bit, so comparisons
  41  * sign-extend the low 32 bits.
  42  */
  43 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  44 {
  45         return regs->orig_ax;
  46 }
  47
  48 static inline void syscall_rollback(struct task_struct *task,
  49                                     struct pt_regs *regs)
  50 {
  51         regs->ax = regs->orig_ax;
  52 }
  53
  54 static inline long syscall_get_error(struct task_struct *task,
  55                                      struct pt_regs *regs)
  56 {
  57         unsigned long error = regs->ax;
  58 #ifdef CONFIG_IA32_EMULATION
  59         /*
  60          * TS_COMPAT is set for 32-bit syscall entries and then
  61          * remains set until we return to user mode.
  62          */
  63         if (task_thread_info(task)->status & TS_COMPAT)
  64                 /*
  65                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  66                  * and will match correctly in comparisons.
  67                  */
  68                 error = (long) (int) error;
  69 #endif
  70         return IS_ERR_VALUE(error) ? error : 0;
  71 }
  72
  73 static inline long syscall_get_return_value(struct task_struct *task,
  74                                             struct pt_regs *regs)
  75 {
  76         return regs->ax;
  77 }
  78
  79 static inline void syscall_set_return_value(struct task_struct *task,
  80                                             struct pt_regs *regs,
  81                                             int error, long val)
  82 {
  83         regs->ax = (long) error ?: val;
  84 }
  85
  86 #ifdef CONFIG_X86_32
  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         BUG_ON(i + n > 6);
  94         memcpy(args, &regs->bx + i, n * sizeof(args[0]));
  95 }
  96
  97 static inline void syscall_set_arguments(struct task_struct *task,
  98                                          struct pt_regs *regs,
  99                                          unsigned int i, unsigned int n,
 100                                          const unsigned long *args)
 101 {
 102         BUG_ON(i + n > 6);
 103         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
 104 }
 105
 106 static inline int syscall_get_arch(void)
 107 {
 108         return AUDIT_ARCH_I386;
 109 }
 110
 111 #else    /* CONFIG_X86_64 */
 112
 113 static inline void syscall_get_arguments(struct task_struct *task,
 114                                          struct pt_regs *regs,
 115                                          unsigned int i, unsigned int n,
 116                                          unsigned long *args)
 117 {
 118 # ifdef CONFIG_IA32_EMULATION
 119         if (task_thread_info(task)->status & TS_COMPAT)
 120                 switch (i) {
 121                 case 0:
 122                         if (!n--) break;
 123                         *args++ = regs->bx;
 124                 case 1:
 125                         if (!n--) break;
 126                         *args++ = regs->cx;
 127                 case 2:
 128                         if (!n--) break;
 129                         *args++ = regs->dx;
 130                 case 3:
 131                         if (!n--) break;
 132                         *args++ = regs->si;
 133                 case 4:
 134                         if (!n--) break;
 135                         *args++ = regs->di;
 136                 case 5:
 137                         if (!n--) break;
 138                         *args++ = regs->bp;
 139                 case 6:
 140                         if (!n--) break;
 141                 default:
 142                         BUG();
 143                         break;
 144                 }
 145         else
 146 # endif
 147                 switch (i) {
 148                 case 0:
 149                         if (!n--) break;
 150                         *args++ = regs->di;
 151                 case 1:
 152                         if (!n--) break;
 153                         *args++ = regs->si;
 154                 case 2:
 155                         if (!n--) break;
 156                         *args++ = regs->dx;
 157                 case 3:
 158                         if (!n--) break;
 159                         *args++ = regs->r10;
 160                 case 4:
 161                         if (!n--) break;
 162                         *args++ = regs->r8;
 163                 case 5:
 164                         if (!n--) break;
 165                         *args++ = regs->r9;
 166                 case 6:
 167                         if (!n--) break;
 168                 default:
 169                         BUG();
 170                         break;
 171                 }
 172 }
 173
 174 static inline void syscall_set_arguments(struct task_struct *task,
 175                                          struct pt_regs *regs,
 176                                          unsigned int i, unsigned int n,
 177                                          const unsigned long *args)
 178 {
 179 # ifdef CONFIG_IA32_EMULATION
 180         if (task_thread_info(task)->status & TS_COMPAT)
 181                 switch (i) {
 182                 case 0:
 183                         if (!n--) break;
 184                         regs->bx = *args++;
 185                 case 1:
 186                         if (!n--) break;
 187                         regs->cx = *args++;
 188                 case 2:
 189                         if (!n--) break;
 190                         regs->dx = *args++;
 191                 case 3:
 192                         if (!n--) break;
 193                         regs->si = *args++;
 194                 case 4:
 195                         if (!n--) break;
 196                         regs->di = *args++;
 197                 case 5:
 198                         if (!n--) break;
 199                         regs->bp = *args++;
 200                 case 6:
 201                         if (!n--) break;
 202                 default:
 203                         BUG();
 204                         break;
 205                 }
 206         else
 207 # endif
 208                 switch (i) {
 209                 case 0:
 210                         if (!n--) break;
 211                         regs->di = *args++;
 212                 case 1:
 213                         if (!n--) break;
 214                         regs->si = *args++;
 215                 case 2:
 216                         if (!n--) break;
 217                         regs->dx = *args++;
 218                 case 3:
 219                         if (!n--) break;
 220                         regs->r10 = *args++;
 221                 case 4:
 222                         if (!n--) break;
 223                         regs->r8 = *args++;
 224                 case 5:
 225                         if (!n--) break;
 226                         regs->r9 = *args++;
 227                 case 6:
 228                         if (!n--) break;
 229                 default:
 230                         BUG();
 231                         break;
 232                 }
 233 }
 234
 235 static inline int syscall_get_arch(void)
 236 {
 237 #ifdef CONFIG_IA32_EMULATION
 238         /*
 239          * TS_COMPAT is set for 32-bit syscall entry and then
 240          * remains set until we return to user mode.
 241          *
 242          * TIF_IA32 tasks should always have TS_COMPAT set at
 243          * system call time.
 244          *
 245          * x32 tasks should be considered AUDIT_ARCH_X86_64.
 246          */
 247         if (task_thread_info(current)->status & TS_COMPAT)
 248                 return AUDIT_ARCH_I386;
 249 #endif
 250         /* Both x32 and x86_64 are considered "64-bit". */
 251         return AUDIT_ARCH_X86_64;
 252 }
 253 #endif  /* CONFIG_X86_32 */
 254
 255 #endif  /* _ASM_X86_SYSCALL_H */