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 extern const unsigned long sys_call_table[]; 22 extern const unsigned long compat_sys_call_table[]; 23 24 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) 25 { 26 /* 27 * Note that we are returning an int here. That means 0xffffffff, ie. 28 * 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel. 29 * This is important for seccomp so that compat tasks can set r0 = -1 30 * to reject the syscall. 31 */ 32 return TRAP(regs) == 0xc00 ? regs->gpr[0] : -1; 33 } 34 35 static inline void syscall_rollback(struct task_struct *task, 36 struct pt_regs *regs) 37 { 38 regs->gpr[3] = regs->orig_gpr3; 39 } 40 41 static inline long syscall_get_return_value(struct task_struct *task, 42 struct pt_regs *regs) 43 { 44 return regs->gpr[3]; 45 } 46 47 static inline void syscall_set_return_value(struct task_struct *task, 48 struct pt_regs *regs, 49 int error, long val) 50 { 51 /* 52 * In the general case it's not obvious that we must deal with CCR 53 * here, as the syscall exit path will also do that for us. However 54 * there are some places, eg. the signal code, which check ccr to 55 * decide if the value in r3 is actually an error. 56 */ 57 if (error) { 58 regs->ccr |= 0x10000000L; 59 regs->gpr[3] = error; 60 } else { 61 regs->ccr &= ~0x10000000L; 62 regs->gpr[3] = val; 63 } 64 } 65 66 static inline void syscall_get_arguments(struct task_struct *task, 67 struct pt_regs *regs, 68 unsigned long *args) 69 { 70 unsigned long val, mask = -1UL; 71 unsigned int n = 6; 72 73 #ifdef CONFIG_COMPAT 74 if (test_tsk_thread_flag(task, TIF_32BIT)) 75 mask = 0xffffffff; 76 #endif 77 while (n--) { 78 if (n == 0) 79 val = regs->orig_gpr3; 80 else 81 val = regs->gpr[3 + n]; 82 83 args[n] = val & mask; 84 } 85 } 86 87 static inline void syscall_set_arguments(struct task_struct *task, 88 struct pt_regs *regs, 89 const unsigned long *args) 90 { 91 memcpy(®s->gpr[3], args, 6 * sizeof(args[0])); 92 93 /* Also copy the first argument into orig_gpr3 */ 94 regs->orig_gpr3 = args[0]; 95 } 96 97 static inline int syscall_get_arch(void) 98 { 99 int arch = is_32bit_task() ? AUDIT_ARCH_PPC : AUDIT_ARCH_PPC64; 100 #ifdef __LITTLE_ENDIAN__ 101 arch |= __AUDIT_ARCH_LE; 102 #endif 103 return arch; 104 } 105 #endif /* _ASM_SYSCALL_H */ 106