arch/powerpc/include/asm/syscall.h

   1 /*
   2  * Access to user system call parameters and results
   3  *
   4  * Copyright (C) 2008 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_SYSCALL_H
  14 #define _ASM_SYSCALL_H  1
  15
  16 #include <uapi/linux/audit.h>
  17 #include <linux/sched.h>
  18 #include <linux/thread_info.h>
  19
  20 /* ftrace syscalls requires exporting the sys_call_table */
  21 #ifdef CONFIG_FTRACE_SYSCALLS
  22 extern const unsigned long sys_call_table[];
  23 #endif /* CONFIG_FTRACE_SYSCALLS */
  24
  25 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  26 {
  27         /*
  28          * Note that we are returning an int here. That means 0xffffffff, ie.
  29          * 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel.
  30          * This is important for seccomp so that compat tasks can set r0 = -1
  31          * to reject the syscall.
  32          */
  33         return TRAP(regs) == 0xc00 ? regs->gpr[0] : -1;
  34 }
  35
  36 static inline void syscall_rollback(struct task_struct *task,
  37                                     struct pt_regs *regs)
  38 {
  39         regs->gpr[3] = regs->orig_gpr3;
  40 }
  41
  42 static inline long syscall_get_return_value(struct task_struct *task,
  43                                             struct pt_regs *regs)
  44 {
  45         return regs->gpr[3];
  46 }
  47
  48 static inline void syscall_set_return_value(struct task_struct *task,
  49                                             struct pt_regs *regs,
  50                                             int error, long val)
  51 {
  52         /*
  53          * In the general case it's not obvious that we must deal with CCR
  54          * here, as the syscall exit path will also do that for us. However
  55          * there are some places, eg. the signal code, which check ccr to
  56          * decide if the value in r3 is actually an error.
  57          */
  58         if (error) {
  59                 regs->ccr |= 0x10000000L;
  60                 regs->gpr[3] = error;
  61         } else {
  62                 regs->ccr &= ~0x10000000L;
  63                 regs->gpr[3] = val;
  64         }
  65 }
  66
  67 static inline void syscall_get_arguments(struct task_struct *task,
  68                                          struct pt_regs *regs,
  69                                          unsigned int i, unsigned int n,
  70                                          unsigned long *args)
  71 {
  72         unsigned long val, mask = -1UL;
  73
  74         BUG_ON(i + n > 6);
  75
  76 #ifdef CONFIG_COMPAT
  77         if (test_tsk_thread_flag(task, TIF_32BIT))
  78                 mask = 0xffffffff;
  79 #endif
  80         while (n--) {
  81                 if (n == 0 && i == 0)
  82                         val = regs->orig_gpr3;
  83                 else
  84                         val = regs->gpr[3 + i + n];
  85
  86                 args[n] = val & mask;
  87         }
  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->gpr[3 + i], args, n * sizeof(args[0]));
  97
  98         /* Also copy the first argument into orig_gpr3 */
  99         if (i == 0 && n > 0)
 100                 regs->orig_gpr3 = args[0];
 101 }
 102
 103 static inline int syscall_get_arch(void)
 104 {
 105         int arch = is_32bit_task() ? AUDIT_ARCH_PPC : AUDIT_ARCH_PPC64;
 106 #ifdef __LITTLE_ENDIAN__
 107         arch |= __AUDIT_ARCH_LE;
 108 #endif
 109         return arch;
 110 }
 111 #endif  /* _ASM_SYSCALL_H */