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/asm-offsets.h>    /* For NR_syscalls */
  17 #include <asm/thread_info.h>    /* for TS_COMPAT */
  18 #include <asm/unistd.h>
  19
  20 #ifdef CONFIG_X86_64
  21 typedef asmlinkage long (*sys_call_ptr_t)(const struct pt_regs *);
  22 #else
  23 typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long,
  24                                           unsigned long, unsigned long,
  25                                           unsigned long, unsigned long);
  26 #endif /* CONFIG_X86_64 */
  27 extern const sys_call_ptr_t sys_call_table[];
  28
  29 #if defined(CONFIG_X86_32)
  30 #define ia32_sys_call_table sys_call_table
  31 #define __NR_syscall_compat_max __NR_syscall_max
  32 #define IA32_NR_syscalls NR_syscalls
  33 #endif
  34
  35 #if defined(CONFIG_IA32_EMULATION)
  36 extern const sys_call_ptr_t ia32_sys_call_table[];
  37 #endif
  38
  39 /*
  40  * Only the low 32 bits of orig_ax are meaningful, so we return int.
  41  * This importantly ignores the high bits on 64-bit, so comparisons
  42  * sign-extend the low 32 bits.
  43  */
  44 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  45 {
  46         return regs->orig_ax;
  47 }
  48
  49 static inline void syscall_rollback(struct task_struct *task,
  50                                     struct pt_regs *regs)
  51 {
  52         regs->ax = regs->orig_ax;
  53 }
  54
  55 static inline long syscall_get_error(struct task_struct *task,
  56                                      struct pt_regs *regs)
  57 {
  58         unsigned long error = regs->ax;
  59 #ifdef CONFIG_IA32_EMULATION
  60         /*
  61          * TS_COMPAT is set for 32-bit syscall entries and then
  62          * remains set until we return to user mode.
  63          */
  64         if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
  65                 /*
  66                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  67                  * and will match correctly in comparisons.
  68                  */
  69                 error = (long) (int) error;
  70 #endif
  71         return IS_ERR_VALUE(error) ? error : 0;
  72 }
  73
  74 static inline long syscall_get_return_value(struct task_struct *task,
  75                                             struct pt_regs *regs)
  76 {
  77         return regs->ax;
  78 }
  79
  80 static inline void syscall_set_return_value(struct task_struct *task,
  81                                             struct pt_regs *regs,
  82                                             int error, long val)
  83 {
  84         regs->ax = (long) error ?: val;
  85 }
  86
  87 #ifdef CONFIG_X86_32
  88
  89 static inline void syscall_get_arguments(struct task_struct *task,
  90                                          struct pt_regs *regs,
  91                                          unsigned long *args)
  92 {
  93         memcpy(args, &regs->bx, 6 * sizeof(args[0]));
  94 }
  95
  96 static inline void syscall_set_arguments(struct task_struct *task,
  97                                          struct pt_regs *regs,
  98                                          unsigned int i, unsigned int n,
  99                                          const unsigned long *args)
 100 {
 101         BUG_ON(i + n > 6);
 102         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
 103 }
 104
 105 static inline int syscall_get_arch(struct task_struct *task)
 106 {
 107         return AUDIT_ARCH_I386;
 108 }
 109
 110 #else    /* CONFIG_X86_64 */
 111
 112 static inline void syscall_get_arguments(struct task_struct *task,
 113                                          struct pt_regs *regs,
 114                                          unsigned long *args)
 115 {
 116 # ifdef CONFIG_IA32_EMULATION
 117         if (task->thread_info.status & TS_COMPAT) {
 118                 *args++ = regs->bx;
 119                 *args++ = regs->cx;
 120                 *args++ = regs->dx;
 121                 *args++ = regs->si;
 122                 *args++ = regs->di;
 123                 *args   = regs->bp;
 124         } else
 125 # endif
 126         {
 127                 *args++ = regs->di;
 128                 *args++ = regs->si;
 129                 *args++ = regs->dx;
 130                 *args++ = regs->r10;
 131                 *args++ = regs->r8;
 132                 *args   = regs->r9;
 133         }
 134 }
 135
 136 static inline void syscall_set_arguments(struct task_struct *task,
 137                                          struct pt_regs *regs,
 138                                          const unsigned long *args)
 139 {
 140 # ifdef CONFIG_IA32_EMULATION
 141         if (task->thread_info.status & TS_COMPAT) {
 142                 regs->bx = *args++;
 143                 regs->cx = *args++;
 144                 regs->dx = *args++;
 145                 regs->si = *args++;
 146                 regs->di = *args++;
 147                 regs->bp = *args;
 148         } else
 149 # endif
 150         {
 151                 regs->di = *args++;
 152                 regs->si = *args++;
 153                 regs->dx = *args++;
 154                 regs->r10 = *args++;
 155                 regs->r8 = *args++;
 156                 regs->r9 = *args;
 157         }
 158 }
 159
 160 static inline int syscall_get_arch(struct task_struct *task)
 161 {
 162         /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
 163         return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
 164                 task->thread_info.status & TS_COMPAT)
 165                 ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
 166 }
 167 #endif  /* CONFIG_X86_32 */
 168
 169 #endif  /* _ASM_X86_SYSCALL_H */