1 /* 2 * Access to user system call parameters and results 3 * 4 * This file is subject to the terms and conditions of the GNU General Public 5 * License. See the file "COPYING" in the main directory of this archive 6 * for more details. 7 * 8 * See asm-generic/syscall.h for descriptions of what we must do here. 9 * 10 * Copyright (C) 2012 Ralf Baechle <ralf@linux-mips.org> 11 */ 12 13 #ifndef __ASM_MIPS_SYSCALL_H 14 #define __ASM_MIPS_SYSCALL_H 15 16 #include <linux/compiler.h> 17 #include <uapi/linux/audit.h> 18 #include <linux/elf-em.h> 19 #include <linux/kernel.h> 20 #include <linux/sched.h> 21 #include <linux/uaccess.h> 22 #include <asm/ptrace.h> 23 #include <asm/unistd.h> 24 25 #ifndef __NR_syscall /* Only defined if _MIPS_SIM == _MIPS_SIM_ABI32 */ 26 #define __NR_syscall 4000 27 #endif 28 29 static inline bool mips_syscall_is_indirect(struct task_struct *task, 30 struct pt_regs *regs) 31 { 32 /* O32 ABI syscall() - Either 64-bit with O32 or 32-bit */ 33 return (IS_ENABLED(CONFIG_32BIT) || 34 test_tsk_thread_flag(task, TIF_32BIT_REGS)) && 35 (regs->regs[2] == __NR_syscall); 36 } 37 38 static inline long syscall_get_nr(struct task_struct *task, 39 struct pt_regs *regs) 40 { 41 return current_thread_info()->syscall; 42 } 43 44 static inline void mips_syscall_update_nr(struct task_struct *task, 45 struct pt_regs *regs) 46 { 47 /* 48 * v0 is the system call number, except for O32 ABI syscall(), where it 49 * ends up in a0. 50 */ 51 if (mips_syscall_is_indirect(task, regs)) 52 task_thread_info(task)->syscall = regs->regs[4]; 53 else 54 task_thread_info(task)->syscall = regs->regs[2]; 55 } 56 57 static inline unsigned long mips_get_syscall_arg(unsigned long *arg, 58 struct task_struct *task, struct pt_regs *regs, unsigned int n) 59 { 60 unsigned long usp __maybe_unused = regs->regs[29]; 61 62 switch (n) { 63 case 0: case 1: case 2: case 3: 64 *arg = regs->regs[4 + n]; 65 66 return 0; 67 68 #ifdef CONFIG_32BIT 69 case 4: case 5: case 6: case 7: 70 return get_user(*arg, (int *)usp + n); 71 #endif 72 73 #ifdef CONFIG_64BIT 74 case 4: case 5: case 6: case 7: 75 #ifdef CONFIG_MIPS32_O32 76 if (test_tsk_thread_flag(task, TIF_32BIT_REGS)) 77 return get_user(*arg, (int *)usp + n); 78 else 79 #endif 80 *arg = regs->regs[4 + n]; 81 82 return 0; 83 #endif 84 85 default: 86 BUG(); 87 } 88 89 unreachable(); 90 } 91 92 static inline long syscall_get_error(struct task_struct *task, 93 struct pt_regs *regs) 94 { 95 return regs->regs[7] ? -regs->regs[2] : 0; 96 } 97 98 static inline long syscall_get_return_value(struct task_struct *task, 99 struct pt_regs *regs) 100 { 101 return regs->regs[2]; 102 } 103 104 static inline void syscall_rollback(struct task_struct *task, 105 struct pt_regs *regs) 106 { 107 /* Do nothing */ 108 } 109 110 static inline void syscall_set_return_value(struct task_struct *task, 111 struct pt_regs *regs, 112 int error, long val) 113 { 114 if (error) { 115 regs->regs[2] = -error; 116 regs->regs[7] = 1; 117 } else { 118 regs->regs[2] = val; 119 regs->regs[7] = 0; 120 } 121 } 122 123 static inline void syscall_get_arguments(struct task_struct *task, 124 struct pt_regs *regs, 125 unsigned long *args) 126 { 127 unsigned int i = 0; 128 unsigned int n = 6; 129 int ret; 130 131 /* O32 ABI syscall() */ 132 if (mips_syscall_is_indirect(task, regs)) 133 i++; 134 135 while (n--) 136 ret |= mips_get_syscall_arg(args++, task, regs, i++); 137 138 /* 139 * No way to communicate an error because this is a void function. 140 */ 141 #if 0 142 return ret; 143 #endif 144 } 145 146 extern const unsigned long sys_call_table[]; 147 extern const unsigned long sys32_call_table[]; 148 extern const unsigned long sysn32_call_table[]; 149 150 static inline int syscall_get_arch(struct task_struct *task) 151 { 152 int arch = AUDIT_ARCH_MIPS; 153 #ifdef CONFIG_64BIT 154 if (!test_tsk_thread_flag(task, TIF_32BIT_REGS)) { 155 arch |= __AUDIT_ARCH_64BIT; 156 /* N32 sets only TIF_32BIT_ADDR */ 157 if (test_tsk_thread_flag(task, TIF_32BIT_ADDR)) 158 arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32; 159 } 160 #endif 161 #if defined(__LITTLE_ENDIAN) 162 arch |= __AUDIT_ARCH_LE; 163 #endif 164 return arch; 165 } 166 167 #endif /* __ASM_MIPS_SYSCALL_H */ 168