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/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 void (*sys_call_ptr_t)(void);
  24 extern const sys_call_ptr_t sys_call_table[];
  25
  26 /*
  27  * Only the low 32 bits of orig_ax are meaningful, so we return int.
  28  * This importantly ignores the high bits on 64-bit, so comparisons
  29  * sign-extend the low 32 bits.
  30  */
  31 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  32 {
  33         return regs->orig_ax;
  34 }
  35
  36 static inline void syscall_rollback(struct task_struct *task,
  37                                     struct pt_regs *regs)
  38 {
  39         regs->ax = regs->orig_ax;
  40 }
  41
  42 static inline long syscall_get_error(struct task_struct *task,
  43                                      struct pt_regs *regs)
  44 {
  45         unsigned long error = regs->ax;
  46 #ifdef CONFIG_IA32_EMULATION
  47         /*
  48          * TS_COMPAT is set for 32-bit syscall entries and then
  49          * remains set until we return to user mode.
  50          */
  51         if (task_thread_info(task)->status & TS_COMPAT)
  52                 /*
  53                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  54                  * and will match correctly in comparisons.
  55                  */
  56                 error = (long) (int) error;
  57 #endif
  58         return IS_ERR_VALUE(error) ? error : 0;
  59 }
  60
  61 static inline long syscall_get_return_value(struct task_struct *task,
  62                                             struct pt_regs *regs)
  63 {
  64         return regs->ax;
  65 }
  66
  67 static inline void syscall_set_return_value(struct task_struct *task,
  68                                             struct pt_regs *regs,
  69                                             int error, long val)
  70 {
  71         regs->ax = (long) error ?: val;
  72 }
  73
  74 #ifdef CONFIG_X86_32
  75
  76 static inline void syscall_get_arguments(struct task_struct *task,
  77                                          struct pt_regs *regs,
  78                                          unsigned int i, unsigned int n,
  79                                          unsigned long *args)
  80 {
  81         BUG_ON(i + n > 6);
  82         memcpy(args, &regs->bx + i, n * sizeof(args[0]));
  83 }
  84
  85 static inline void syscall_set_arguments(struct task_struct *task,
  86                                          struct pt_regs *regs,
  87                                          unsigned int i, unsigned int n,
  88                                          const unsigned long *args)
  89 {
  90         BUG_ON(i + n > 6);
  91         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  92 }
  93
  94 static inline int syscall_get_arch(struct task_struct *task,
  95                                    struct pt_regs *regs)
  96 {
  97         return AUDIT_ARCH_I386;
  98 }
  99
 100 #else    /* CONFIG_X86_64 */
 101
 102 static inline void syscall_get_arguments(struct task_struct *task,
 103                                          struct pt_regs *regs,
 104                                          unsigned int i, unsigned int n,
 105                                          unsigned long *args)
 106 {
 107 # ifdef CONFIG_IA32_EMULATION
 108         if (task_thread_info(task)->status & TS_COMPAT)
 109                 switch (i) {
 110                 case 0:
 111                         if (!n--) break;
 112                         *args++ = regs->bx;
 113                 case 1:
 114                         if (!n--) break;
 115                         *args++ = regs->cx;
 116                 case 2:
 117                         if (!n--) break;
 118                         *args++ = regs->dx;
 119                 case 3:
 120                         if (!n--) break;
 121                         *args++ = regs->si;
 122                 case 4:
 123                         if (!n--) break;
 124                         *args++ = regs->di;
 125                 case 5:
 126                         if (!n--) break;
 127                         *args++ = regs->bp;
 128                 case 6:
 129                         if (!n--) break;
 130                 default:
 131                         BUG();
 132                         break;
 133                 }
 134         else
 135 # endif
 136                 switch (i) {
 137                 case 0:
 138                         if (!n--) break;
 139                         *args++ = regs->di;
 140                 case 1:
 141                         if (!n--) break;
 142                         *args++ = regs->si;
 143                 case 2:
 144                         if (!n--) break;
 145                         *args++ = regs->dx;
 146                 case 3:
 147                         if (!n--) break;
 148                         *args++ = regs->r10;
 149                 case 4:
 150                         if (!n--) break;
 151                         *args++ = regs->r8;
 152                 case 5:
 153                         if (!n--) break;
 154                         *args++ = regs->r9;
 155                 case 6:
 156                         if (!n--) break;
 157                 default:
 158                         BUG();
 159                         break;
 160                 }
 161 }
 162
 163 static inline void syscall_set_arguments(struct task_struct *task,
 164                                          struct pt_regs *regs,
 165                                          unsigned int i, unsigned int n,
 166                                          const unsigned long *args)
 167 {
 168 # ifdef CONFIG_IA32_EMULATION
 169         if (task_thread_info(task)->status & TS_COMPAT)
 170                 switch (i) {
 171                 case 0:
 172                         if (!n--) break;
 173                         regs->bx = *args++;
 174                 case 1:
 175                         if (!n--) break;
 176                         regs->cx = *args++;
 177                 case 2:
 178                         if (!n--) break;
 179                         regs->dx = *args++;
 180                 case 3:
 181                         if (!n--) break;
 182                         regs->si = *args++;
 183                 case 4:
 184                         if (!n--) break;
 185                         regs->di = *args++;
 186                 case 5:
 187                         if (!n--) break;
 188                         regs->bp = *args++;
 189                 case 6:
 190                         if (!n--) break;
 191                 default:
 192                         BUG();
 193                         break;
 194                 }
 195         else
 196 # endif
 197                 switch (i) {
 198                 case 0:
 199                         if (!n--) break;
 200                         regs->di = *args++;
 201                 case 1:
 202                         if (!n--) break;
 203                         regs->si = *args++;
 204                 case 2:
 205                         if (!n--) break;
 206                         regs->dx = *args++;
 207                 case 3:
 208                         if (!n--) break;
 209                         regs->r10 = *args++;
 210                 case 4:
 211                         if (!n--) break;
 212                         regs->r8 = *args++;
 213                 case 5:
 214                         if (!n--) break;
 215                         regs->r9 = *args++;
 216                 case 6:
 217                         if (!n--) break;
 218                 default:
 219                         BUG();
 220                         break;
 221                 }
 222 }
 223
 224 static inline int syscall_get_arch(struct task_struct *task,
 225                                    struct pt_regs *regs)
 226 {
 227 #ifdef CONFIG_IA32_EMULATION
 228         /*
 229          * TS_COMPAT is set for 32-bit syscall entry and then
 230          * remains set until we return to user mode.
 231          *
 232          * TIF_IA32 tasks should always have TS_COMPAT set at
 233          * system call time.
 234          *
 235          * x32 tasks should be considered AUDIT_ARCH_X86_64.
 236          */
 237         if (task_thread_info(task)->status & TS_COMPAT)
 238                 return AUDIT_ARCH_I386;
 239 #endif
 240         /* Both x32 and x86_64 are considered "64-bit". */
 241         return AUDIT_ARCH_X86_64;
 242 }
 243 #endif  /* CONFIG_X86_32 */
 244
 245 #endif  /* _ASM_X86_SYSCALL_H */