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_return_value(struct task_struct *task, 93 struct pt_regs *regs) 94 { 95 return regs->regs[2]; 96 } 97 98 static inline void syscall_rollback(struct task_struct *task, 99 struct pt_regs *regs) 100 { 101 /* Do nothing */ 102 } 103 104 static inline void syscall_set_return_value(struct task_struct *task, 105 struct pt_regs *regs, 106 int error, long val) 107 { 108 if (error) { 109 regs->regs[2] = -error; 110 regs->regs[7] = 1; 111 } else { 112 regs->regs[2] = val; 113 regs->regs[7] = 0; 114 } 115 } 116 117 static inline void syscall_get_arguments(struct task_struct *task, 118 struct pt_regs *regs, 119 unsigned long *args) 120 { 121 unsigned int i = 0; 122 unsigned int n = 6; 123 int ret; 124 125 /* O32 ABI syscall() */ 126 if (mips_syscall_is_indirect(task, regs)) 127 i++; 128 129 while (n--) 130 ret |= mips_get_syscall_arg(args++, task, regs, i++); 131 132 /* 133 * No way to communicate an error because this is a void function. 134 */ 135 #if 0 136 return ret; 137 #endif 138 } 139 140 extern const unsigned long sys_call_table[]; 141 extern const unsigned long sys32_call_table[]; 142 extern const unsigned long sysn32_call_table[]; 143 144 static inline int syscall_get_arch(struct task_struct *task) 145 { 146 int arch = AUDIT_ARCH_MIPS; 147 #ifdef CONFIG_64BIT 148 if (!test_tsk_thread_flag(task, TIF_32BIT_REGS)) { 149 arch |= __AUDIT_ARCH_64BIT; 150 /* N32 sets only TIF_32BIT_ADDR */ 151 if (test_tsk_thread_flag(task, TIF_32BIT_ADDR)) 152 arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32; 153 } 154 #endif 155 #if defined(__LITTLE_ENDIAN) 156 arch |= __AUDIT_ARCH_LE; 157 #endif 158 return arch; 159 } 160 161 #endif /* __ASM_MIPS_SYSCALL_H */ 162