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 #ifdef CONFIG_X86_64
  24 typedef asmlinkage long (*sys_call_ptr_t)(const struct pt_regs *);
  25 #else
  26 typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long,
  27                                           unsigned long, unsigned long,
  28                                           unsigned long, unsigned long);
  29 #endif /* CONFIG_X86_64 */
  30 extern const sys_call_ptr_t sys_call_table[];
  31
  32 #if defined(CONFIG_X86_32)
  33 #define ia32_sys_call_table sys_call_table
  34 #define __NR_syscall_compat_max __NR_syscall_max
  35 #define IA32_NR_syscalls NR_syscalls
  36 #endif
  37
  38 #if defined(CONFIG_IA32_EMULATION)
  39 extern const sys_call_ptr_t ia32_sys_call_table[];
  40 #endif
  41
  42 /*
  43  * Only the low 32 bits of orig_ax are meaningful, so we return int.
  44  * This importantly ignores the high bits on 64-bit, so comparisons
  45  * sign-extend the low 32 bits.
  46  */
  47 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  48 {
  49         return regs->orig_ax;
  50 }
  51
  52 static inline void syscall_rollback(struct task_struct *task,
  53                                     struct pt_regs *regs)
  54 {
  55         regs->ax = regs->orig_ax;
  56 }
  57
  58 static inline long syscall_get_error(struct task_struct *task,
  59                                      struct pt_regs *regs)
  60 {
  61         unsigned long error = regs->ax;
  62 #ifdef CONFIG_IA32_EMULATION
  63         /*
  64          * TS_COMPAT is set for 32-bit syscall entries and then
  65          * remains set until we return to user mode.
  66          */
  67         if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
  68                 /*
  69                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  70                  * and will match correctly in comparisons.
  71                  */
  72                 error = (long) (int) error;
  73 #endif
  74         return IS_ERR_VALUE(error) ? error : 0;
  75 }
  76
  77 static inline long syscall_get_return_value(struct task_struct *task,
  78                                             struct pt_regs *regs)
  79 {
  80         return regs->ax;
  81 }
  82
  83 static inline void syscall_set_return_value(struct task_struct *task,
  84                                             struct pt_regs *regs,
  85                                             int error, long val)
  86 {
  87         regs->ax = (long) error ?: val;
  88 }
  89
  90 #ifdef CONFIG_X86_32
  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         BUG_ON(i + n > 6);
  98         memcpy(args, &regs->bx + i, n * sizeof(args[0]));
  99 }
 100
 101 static inline void syscall_set_arguments(struct task_struct *task,
 102                                          struct pt_regs *regs,
 103                                          unsigned int i, unsigned int n,
 104                                          const unsigned long *args)
 105 {
 106         BUG_ON(i + n > 6);
 107         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
 108 }
 109
 110 static inline int syscall_get_arch(void)
 111 {
 112         return AUDIT_ARCH_I386;
 113 }
 114
 115 #else    /* CONFIG_X86_64 */
 116
 117 static inline void syscall_get_arguments(struct task_struct *task,
 118                                          struct pt_regs *regs,
 119                                          unsigned int i, unsigned int n,
 120                                          unsigned long *args)
 121 {
 122 # ifdef CONFIG_IA32_EMULATION
 123         if (task->thread_info.status & TS_COMPAT)
 124                 switch (i) {
 125                 case 0:
 126                         if (!n--) break;
 127                         *args++ = regs->bx;
 128                 case 1:
 129                         if (!n--) break;
 130                         *args++ = regs->cx;
 131                 case 2:
 132                         if (!n--) break;
 133                         *args++ = regs->dx;
 134                 case 3:
 135                         if (!n--) break;
 136                         *args++ = regs->si;
 137                 case 4:
 138                         if (!n--) break;
 139                         *args++ = regs->di;
 140                 case 5:
 141                         if (!n--) break;
 142                         *args++ = regs->bp;
 143                 case 6:
 144                         if (!n--) break;
 145                 default:
 146                         BUG();
 147                         break;
 148                 }
 149         else
 150 # endif
 151                 switch (i) {
 152                 case 0:
 153                         if (!n--) break;
 154                         *args++ = regs->di;
 155                 case 1:
 156                         if (!n--) break;
 157                         *args++ = regs->si;
 158                 case 2:
 159                         if (!n--) break;
 160                         *args++ = regs->dx;
 161                 case 3:
 162                         if (!n--) break;
 163                         *args++ = regs->r10;
 164                 case 4:
 165                         if (!n--) break;
 166                         *args++ = regs->r8;
 167                 case 5:
 168                         if (!n--) break;
 169                         *args++ = regs->r9;
 170                 case 6:
 171                         if (!n--) break;
 172                 default:
 173                         BUG();
 174                         break;
 175                 }
 176 }
 177
 178 static inline void syscall_set_arguments(struct task_struct *task,
 179                                          struct pt_regs *regs,
 180                                          unsigned int i, unsigned int n,
 181                                          const unsigned long *args)
 182 {
 183 # ifdef CONFIG_IA32_EMULATION
 184         if (task->thread_info.status & TS_COMPAT)
 185                 switch (i) {
 186                 case 0:
 187                         if (!n--) break;
 188                         regs->bx = *args++;
 189                 case 1:
 190                         if (!n--) break;
 191                         regs->cx = *args++;
 192                 case 2:
 193                         if (!n--) break;
 194                         regs->dx = *args++;
 195                 case 3:
 196                         if (!n--) break;
 197                         regs->si = *args++;
 198                 case 4:
 199                         if (!n--) break;
 200                         regs->di = *args++;
 201                 case 5:
 202                         if (!n--) break;
 203                         regs->bp = *args++;
 204                 case 6:
 205                         if (!n--) break;
 206                 default:
 207                         BUG();
 208                         break;
 209                 }
 210         else
 211 # endif
 212                 switch (i) {
 213                 case 0:
 214                         if (!n--) break;
 215                         regs->di = *args++;
 216                 case 1:
 217                         if (!n--) break;
 218                         regs->si = *args++;
 219                 case 2:
 220                         if (!n--) break;
 221                         regs->dx = *args++;
 222                 case 3:
 223                         if (!n--) break;
 224                         regs->r10 = *args++;
 225                 case 4:
 226                         if (!n--) break;
 227                         regs->r8 = *args++;
 228                 case 5:
 229                         if (!n--) break;
 230                         regs->r9 = *args++;
 231                 case 6:
 232                         if (!n--) break;
 233                 default:
 234                         BUG();
 235                         break;
 236                 }
 237 }
 238
 239 static inline int syscall_get_arch(void)
 240 {
 241         /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
 242         return in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
 243 }
 244 #endif  /* CONFIG_X86_32 */
 245
 246 #endif  /* _ASM_X86_SYSCALL_H */