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 task_thread_info(task)->syscall; 42 } 43 44 static inline void syscall_set_nr(struct task_struct *task, 45 struct pt_regs *regs, 46 int nr) 47 { 48 /* 49 * New syscall number has to be assigned to regs[2] because 50 * it is loaded from there unconditionally after return from 51 * syscall_trace_enter() invocation. 52 * 53 * Consequently, if the syscall was indirect and nr != __NR_syscall, 54 * then after this assignment the syscall will cease to be indirect. 55 */ 56 task_thread_info(task)->syscall = regs->regs[2] = nr; 57 } 58 59 static inline void mips_syscall_update_nr(struct task_struct *task, 60 struct pt_regs *regs) 61 { 62 /* 63 * v0 is the system call number, except for O32 ABI syscall(), where it 64 * ends up in a0. 65 */ 66 if (mips_syscall_is_indirect(task, regs)) 67 task_thread_info(task)->syscall = regs->regs[4]; 68 else 69 task_thread_info(task)->syscall = regs->regs[2]; 70 } 71 72 static inline void mips_get_syscall_arg(unsigned long *arg, 73 struct task_struct *task, struct pt_regs *regs, unsigned int n) 74 { 75 #ifdef CONFIG_32BIT 76 switch (n) { 77 case 0: case 1: case 2: case 3: 78 *arg = regs->regs[4 + n]; 79 return; 80 case 4: case 5: case 6: case 7: 81 *arg = regs->args[n]; 82 return; 83 } 84 #else 85 *arg = regs->regs[4 + n]; 86 if ((IS_ENABLED(CONFIG_MIPS32_O32) && 87 test_tsk_thread_flag(task, TIF_32BIT_REGS))) 88 *arg = (unsigned int)*arg; 89 #endif 90 } 91 92 static inline void mips_set_syscall_arg(unsigned long *arg, 93 struct task_struct *task, struct pt_regs *regs, unsigned int n) 94 { 95 #ifdef CONFIG_32BIT 96 switch (n) { 97 case 0: case 1: case 2: case 3: 98 regs->regs[4 + n] = *arg; 99 return; 100 case 4: case 5: case 6: case 7: 101 *arg = regs->args[n] = *arg; 102 return; 103 } 104 #else 105 regs->regs[4 + n] = *arg; 106 #endif 107 } 108 109 static inline long syscall_get_error(struct task_struct *task, 110 struct pt_regs *regs) 111 { 112 return regs->regs[7] ? -regs->regs[2] : 0; 113 } 114 115 static inline long syscall_get_return_value(struct task_struct *task, 116 struct pt_regs *regs) 117 { 118 return regs->regs[2]; 119 } 120 121 static inline void syscall_rollback(struct task_struct *task, 122 struct pt_regs *regs) 123 { 124 /* Do nothing */ 125 } 126 127 static inline void syscall_set_return_value(struct task_struct *task, 128 struct pt_regs *regs, 129 int error, long val) 130 { 131 if (error) { 132 regs->regs[2] = -error; 133 regs->regs[7] = 1; 134 } else { 135 regs->regs[2] = val; 136 regs->regs[7] = 0; 137 } 138 } 139 140 static inline void syscall_get_arguments(struct task_struct *task, 141 struct pt_regs *regs, 142 unsigned long *args) 143 { 144 unsigned int i = 0; 145 unsigned int n = 6; 146 147 /* O32 ABI syscall() */ 148 if (mips_syscall_is_indirect(task, regs)) 149 i++; 150 151 while (n--) 152 mips_get_syscall_arg(args++, task, regs, i++); 153 } 154 155 static inline void syscall_set_arguments(struct task_struct *task, 156 struct pt_regs *regs, 157 unsigned long *args) 158 { 159 unsigned int i = 0; 160 unsigned int n = 6; 161 162 while (n--) 163 mips_set_syscall_arg(args++, task, regs, i++); 164 } 165 166 extern const unsigned long sys_call_table[]; 167 extern const unsigned long sys32_call_table[]; 168 extern const unsigned long sysn32_call_table[]; 169 170 static inline int syscall_get_arch(struct task_struct *task) 171 { 172 int arch = AUDIT_ARCH_MIPS; 173 #ifdef CONFIG_64BIT 174 if (!test_tsk_thread_flag(task, TIF_32BIT_REGS)) { 175 arch |= __AUDIT_ARCH_64BIT; 176 /* N32 sets only TIF_32BIT_ADDR */ 177 if (test_tsk_thread_flag(task, TIF_32BIT_ADDR)) 178 arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32; 179 } 180 #endif 181 #if defined(__LITTLE_ENDIAN) 182 arch |= __AUDIT_ARCH_LE; 183 #endif 184 return arch; 185 } 186 187 #endif /* __ASM_MIPS_SYSCALL_H */ 188