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 #else
  25 /*
  26  * These may not exist, but still put the prototypes in so we
  27  * can use IS_ENABLED().
  28  */
  29 extern const sys_call_ptr_t ia32_sys_call_table[];
  30 extern const sys_call_ptr_t x32_sys_call_table[];
  31 #endif
  32
  33 /*
  34  * Only the low 32 bits of orig_ax are meaningful, so we return int.
  35  * This importantly ignores the high bits on 64-bit, so comparisons
  36  * sign-extend the low 32 bits.
  37  */
  38 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  39 {
  40         return regs->orig_ax;
  41 }
  42
  43 static inline void syscall_rollback(struct task_struct *task,
  44                                     struct pt_regs *regs)
  45 {
  46         regs->ax = regs->orig_ax;
  47 }
  48
  49 static inline long syscall_get_error(struct task_struct *task,
  50                                      struct pt_regs *regs)
  51 {
  52         unsigned long error = regs->ax;
  53 #ifdef CONFIG_IA32_EMULATION
  54         /*
  55          * TS_COMPAT is set for 32-bit syscall entries and then
  56          * remains set until we return to user mode.
  57          */
  58         if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
  59                 /*
  60                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  61                  * and will match correctly in comparisons.
  62                  */
  63                 error = (long) (int) error;
  64 #endif
  65         return IS_ERR_VALUE(error) ? error : 0;
  66 }
  67
  68 static inline long syscall_get_return_value(struct task_struct *task,
  69                                             struct pt_regs *regs)
  70 {
  71         return regs->ax;
  72 }
  73
  74 static inline void syscall_set_return_value(struct task_struct *task,
  75                                             struct pt_regs *regs,
  76                                             int error, long val)
  77 {
  78         regs->ax = (long) error ?: val;
  79 }
  80
  81 #ifdef CONFIG_X86_32
  82
  83 static inline void syscall_get_arguments(struct task_struct *task,
  84                                          struct pt_regs *regs,
  85                                          unsigned long *args)
  86 {
  87         memcpy(args, &regs->bx, 6 * sizeof(args[0]));
  88 }
  89
  90 static inline void syscall_set_arguments(struct task_struct *task,
  91                                          struct pt_regs *regs,
  92                                          unsigned int i, unsigned int n,
  93                                          const unsigned long *args)
  94 {
  95         BUG_ON(i + n > 6);
  96         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  97 }
  98
  99 static inline int syscall_get_arch(struct task_struct *task)
 100 {
 101         return AUDIT_ARCH_I386;
 102 }
 103
 104 #else    /* CONFIG_X86_64 */
 105
 106 static inline void syscall_get_arguments(struct task_struct *task,
 107                                          struct pt_regs *regs,
 108                                          unsigned long *args)
 109 {
 110 # ifdef CONFIG_IA32_EMULATION
 111         if (task->thread_info.status & TS_COMPAT) {
 112                 *args++ = regs->bx;
 113                 *args++ = regs->cx;
 114                 *args++ = regs->dx;
 115                 *args++ = regs->si;
 116                 *args++ = regs->di;
 117                 *args   = regs->bp;
 118         } else
 119 # endif
 120         {
 121                 *args++ = regs->di;
 122                 *args++ = regs->si;
 123                 *args++ = regs->dx;
 124                 *args++ = regs->r10;
 125                 *args++ = regs->r8;
 126                 *args   = regs->r9;
 127         }
 128 }
 129
 130 static inline void syscall_set_arguments(struct task_struct *task,
 131                                          struct pt_regs *regs,
 132                                          const unsigned long *args)
 133 {
 134 # ifdef CONFIG_IA32_EMULATION
 135         if (task->thread_info.status & TS_COMPAT) {
 136                 regs->bx = *args++;
 137                 regs->cx = *args++;
 138                 regs->dx = *args++;
 139                 regs->si = *args++;
 140                 regs->di = *args++;
 141                 regs->bp = *args;
 142         } else
 143 # endif
 144         {
 145                 regs->di = *args++;
 146                 regs->si = *args++;
 147                 regs->dx = *args++;
 148                 regs->r10 = *args++;
 149                 regs->r8 = *args++;
 150                 regs->r9 = *args;
 151         }
 152 }
 153
 154 static inline int syscall_get_arch(struct task_struct *task)
 155 {
 156         /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
 157         return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
 158                 task->thread_info.status & TS_COMPAT)
 159                 ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
 160 }
 161
 162 void do_syscall_64(struct pt_regs *regs, int nr);
 163 void do_int80_syscall_32(struct pt_regs *regs);
 164 long do_fast_syscall_32(struct pt_regs *regs);
 165
 166 #endif  /* CONFIG_X86_32 */
 167
 168 #endif  /* _ASM_X86_SYSCALL_H */