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 long *args)
  95 {
  96         memcpy(args, &regs->bx, 6 * sizeof(args[0]));
  97 }
  98
  99 static inline void syscall_set_arguments(struct task_struct *task,
 100                                          struct pt_regs *regs,
 101                                          unsigned int i, unsigned int n,
 102                                          const unsigned long *args)
 103 {
 104         BUG_ON(i + n > 6);
 105         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
 106 }
 107
 108 static inline int syscall_get_arch(struct task_struct *task)
 109 {
 110         return AUDIT_ARCH_I386;
 111 }
 112
 113 #else    /* CONFIG_X86_64 */
 114
 115 static inline void syscall_get_arguments(struct task_struct *task,
 116                                          struct pt_regs *regs,
 117                                          unsigned long *args)
 118 {
 119 # ifdef CONFIG_IA32_EMULATION
 120         if (task->thread_info.status & TS_COMPAT) {
 121                 *args++ = regs->bx;
 122                 *args++ = regs->cx;
 123                 *args++ = regs->dx;
 124                 *args++ = regs->si;
 125                 *args++ = regs->di;
 126                 *args   = regs->bp;
 127         } else
 128 # endif
 129         {
 130                 *args++ = regs->di;
 131                 *args++ = regs->si;
 132                 *args++ = regs->dx;
 133                 *args++ = regs->r10;
 134                 *args++ = regs->r8;
 135                 *args   = regs->r9;
 136         }
 137 }
 138
 139 static inline void syscall_set_arguments(struct task_struct *task,
 140                                          struct pt_regs *regs,
 141                                          const unsigned long *args)
 142 {
 143 # ifdef CONFIG_IA32_EMULATION
 144         if (task->thread_info.status & TS_COMPAT) {
 145                 regs->bx = *args++;
 146                 regs->cx = *args++;
 147                 regs->dx = *args++;
 148                 regs->si = *args++;
 149                 regs->di = *args++;
 150                 regs->bp = *args;
 151         } else
 152 # endif
 153         {
 154                 regs->di = *args++;
 155                 regs->si = *args++;
 156                 regs->dx = *args++;
 157                 regs->r10 = *args++;
 158                 regs->r8 = *args++;
 159                 regs->r9 = *args;
 160         }
 161 }
 162
 163 static inline int syscall_get_arch(struct task_struct *task)
 164 {
 165         /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
 166         return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
 167                 task->thread_info.status & TS_COMPAT)
 168                 ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
 169 }
 170 #endif  /* CONFIG_X86_32 */
 171
 172 #endif  /* _ASM_X86_SYSCALL_H */