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(void)
  95 {
  96         return AUDIT_ARCH_I386;
  97 }
  98
  99 #else    /* CONFIG_X86_64 */
 100
 101 static inline void syscall_get_arguments(struct task_struct *task,
 102                                          struct pt_regs *regs,
 103                                          unsigned int i, unsigned int n,
 104                                          unsigned long *args)
 105 {
 106 # ifdef CONFIG_IA32_EMULATION
 107         if (task_thread_info(task)->status & TS_COMPAT)
 108                 switch (i) {
 109                 case 0:
 110                         if (!n--) break;
 111                         *args++ = regs->bx;
 112                 case 1:
 113                         if (!n--) break;
 114                         *args++ = regs->cx;
 115                 case 2:
 116                         if (!n--) break;
 117                         *args++ = regs->dx;
 118                 case 3:
 119                         if (!n--) break;
 120                         *args++ = regs->si;
 121                 case 4:
 122                         if (!n--) break;
 123                         *args++ = regs->di;
 124                 case 5:
 125                         if (!n--) break;
 126                         *args++ = regs->bp;
 127                 case 6:
 128                         if (!n--) break;
 129                 default:
 130                         BUG();
 131                         break;
 132                 }
 133         else
 134 # endif
 135                 switch (i) {
 136                 case 0:
 137                         if (!n--) break;
 138                         *args++ = regs->di;
 139                 case 1:
 140                         if (!n--) break;
 141                         *args++ = regs->si;
 142                 case 2:
 143                         if (!n--) break;
 144                         *args++ = regs->dx;
 145                 case 3:
 146                         if (!n--) break;
 147                         *args++ = regs->r10;
 148                 case 4:
 149                         if (!n--) break;
 150                         *args++ = regs->r8;
 151                 case 5:
 152                         if (!n--) break;
 153                         *args++ = regs->r9;
 154                 case 6:
 155                         if (!n--) break;
 156                 default:
 157                         BUG();
 158                         break;
 159                 }
 160 }
 161
 162 static inline void syscall_set_arguments(struct task_struct *task,
 163                                          struct pt_regs *regs,
 164                                          unsigned int i, unsigned int n,
 165                                          const unsigned long *args)
 166 {
 167 # ifdef CONFIG_IA32_EMULATION
 168         if (task_thread_info(task)->status & TS_COMPAT)
 169                 switch (i) {
 170                 case 0:
 171                         if (!n--) break;
 172                         regs->bx = *args++;
 173                 case 1:
 174                         if (!n--) break;
 175                         regs->cx = *args++;
 176                 case 2:
 177                         if (!n--) break;
 178                         regs->dx = *args++;
 179                 case 3:
 180                         if (!n--) break;
 181                         regs->si = *args++;
 182                 case 4:
 183                         if (!n--) break;
 184                         regs->di = *args++;
 185                 case 5:
 186                         if (!n--) break;
 187                         regs->bp = *args++;
 188                 case 6:
 189                         if (!n--) break;
 190                 default:
 191                         BUG();
 192                         break;
 193                 }
 194         else
 195 # endif
 196                 switch (i) {
 197                 case 0:
 198                         if (!n--) break;
 199                         regs->di = *args++;
 200                 case 1:
 201                         if (!n--) break;
 202                         regs->si = *args++;
 203                 case 2:
 204                         if (!n--) break;
 205                         regs->dx = *args++;
 206                 case 3:
 207                         if (!n--) break;
 208                         regs->r10 = *args++;
 209                 case 4:
 210                         if (!n--) break;
 211                         regs->r8 = *args++;
 212                 case 5:
 213                         if (!n--) break;
 214                         regs->r9 = *args++;
 215                 case 6:
 216                         if (!n--) break;
 217                 default:
 218                         BUG();
 219                         break;
 220                 }
 221 }
 222
 223 static inline int syscall_get_arch(void)
 224 {
 225 #ifdef CONFIG_IA32_EMULATION
 226         /*
 227          * TS_COMPAT is set for 32-bit syscall entry and then
 228          * remains set until we return to user mode.
 229          *
 230          * TIF_IA32 tasks should always have TS_COMPAT set at
 231          * system call time.
 232          *
 233          * x32 tasks should be considered AUDIT_ARCH_X86_64.
 234          */
 235         if (task_thread_info(current)->status & TS_COMPAT)
 236                 return AUDIT_ARCH_I386;
 237 #endif
 238         /* Both x32 and x86_64 are considered "64-bit". */
 239         return AUDIT_ARCH_X86_64;
 240 }
 241 #endif  /* CONFIG_X86_32 */
 242
 243 #endif  /* _ASM_X86_SYSCALL_H */