arch/x86/include/asm/syscall.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Access to user system call parameters and results
   4  *
   5  * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
   6  *
   7  * See asm-generic/syscall.h for descriptions of what we must do here.
   8  */
   9
  10 #ifndef _ASM_X86_SYSCALL_H
  11 #define _ASM_X86_SYSCALL_H
  12
  13 #include <uapi/linux/audit.h>
  14 #include <linux/sched.h>
  15 #include <linux/err.h>
  16 #include <asm/thread_info.h>    /* for TS_COMPAT */
  17 #include <asm/unistd.h>
  18
  19 typedef long (*sys_call_ptr_t)(const struct pt_regs *);
  20 extern const sys_call_ptr_t sys_call_table[];
  21
  22 #if defined(CONFIG_X86_32)
  23 #define ia32_sys_call_table sys_call_table
  24 #endif
  25
  26 #if defined(CONFIG_IA32_EMULATION)
  27 extern const sys_call_ptr_t ia32_sys_call_table[];
  28 #endif
  29
  30 #ifdef CONFIG_X86_X32_ABI
  31 extern const sys_call_ptr_t x32_sys_call_table[];
  32 #endif
  33
  34 /*
  35  * Only the low 32 bits of orig_ax are meaningful, so we return int.
  36  * This importantly ignores the high bits on 64-bit, so comparisons
  37  * sign-extend the low 32 bits.
  38  */
  39 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  40 {
  41         return regs->orig_ax;
  42 }
  43
  44 static inline void syscall_rollback(struct task_struct *task,
  45                                     struct pt_regs *regs)
  46 {
  47         regs->ax = regs->orig_ax;
  48 }
  49
  50 static inline long syscall_get_error(struct task_struct *task,
  51                                      struct pt_regs *regs)
  52 {
  53         unsigned long error = regs->ax;
  54 #ifdef CONFIG_IA32_EMULATION
  55         /*
  56          * TS_COMPAT is set for 32-bit syscall entries and then
  57          * remains set until we return to user mode.
  58          */
  59         if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
  60                 /*
  61                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  62                  * and will match correctly in comparisons.
  63                  */
  64                 error = (long) (int) error;
  65 #endif
  66         return IS_ERR_VALUE(error) ? error : 0;
  67 }
  68
  69 static inline long syscall_get_return_value(struct task_struct *task,
  70                                             struct pt_regs *regs)
  71 {
  72         return regs->ax;
  73 }
  74
  75 static inline void syscall_set_return_value(struct task_struct *task,
  76                                             struct pt_regs *regs,
  77                                             int error, long val)
  78 {
  79         regs->ax = (long) error ?: val;
  80 }
  81
  82 #ifdef CONFIG_X86_32
  83
  84 static inline void syscall_get_arguments(struct task_struct *task,
  85                                          struct pt_regs *regs,
  86                                          unsigned long *args)
  87 {
  88         memcpy(args, &regs->bx, 6 * sizeof(args[0]));
  89 }
  90
  91 static inline void syscall_set_arguments(struct task_struct *task,
  92                                          struct pt_regs *regs,
  93                                          unsigned int i, unsigned int n,
  94                                          const unsigned long *args)
  95 {
  96         BUG_ON(i + n > 6);
  97         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  98 }
  99
 100 static inline int syscall_get_arch(struct task_struct *task)
 101 {
 102         return AUDIT_ARCH_I386;
 103 }
 104
 105 #else    /* CONFIG_X86_64 */
 106
 107 static inline void syscall_get_arguments(struct task_struct *task,
 108                                          struct pt_regs *regs,
 109                                          unsigned long *args)
 110 {
 111 # ifdef CONFIG_IA32_EMULATION
 112         if (task->thread_info.status & TS_COMPAT) {
 113                 *args++ = regs->bx;
 114                 *args++ = regs->cx;
 115                 *args++ = regs->dx;
 116                 *args++ = regs->si;
 117                 *args++ = regs->di;
 118                 *args   = regs->bp;
 119         } else
 120 # endif
 121         {
 122                 *args++ = regs->di;
 123                 *args++ = regs->si;
 124                 *args++ = regs->dx;
 125                 *args++ = regs->r10;
 126                 *args++ = regs->r8;
 127                 *args   = regs->r9;
 128         }
 129 }
 130
 131 static inline void syscall_set_arguments(struct task_struct *task,
 132                                          struct pt_regs *regs,
 133                                          const unsigned long *args)
 134 {
 135 # ifdef CONFIG_IA32_EMULATION
 136         if (task->thread_info.status & TS_COMPAT) {
 137                 regs->bx = *args++;
 138                 regs->cx = *args++;
 139                 regs->dx = *args++;
 140                 regs->si = *args++;
 141                 regs->di = *args++;
 142                 regs->bp = *args;
 143         } else
 144 # endif
 145         {
 146                 regs->di = *args++;
 147                 regs->si = *args++;
 148                 regs->dx = *args++;
 149                 regs->r10 = *args++;
 150                 regs->r8 = *args++;
 151                 regs->r9 = *args;
 152         }
 153 }
 154
 155 static inline int syscall_get_arch(struct task_struct *task)
 156 {
 157         /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
 158         return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
 159                 task->thread_info.status & TS_COMPAT)
 160                 ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
 161 }
 162
 163 void do_syscall_64(unsigned long nr, struct pt_regs *regs);
 164 void do_int80_syscall_32(struct pt_regs *regs);
 165 long do_fast_syscall_32(struct pt_regs *regs);
 166
 167 #endif  /* CONFIG_X86_32 */
 168
 169 #endif  /* _ASM_X86_SYSCALL_H */