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 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 void 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; 67 68 #ifdef CONFIG_32BIT 69 case 4: case 5: case 6: case 7: 70 get_user(*arg, (int *)usp + n); 71 return; 72 #endif 73 74 #ifdef CONFIG_64BIT 75 case 4: case 5: case 6: case 7: 76 #ifdef CONFIG_MIPS32_O32 77 if (test_tsk_thread_flag(task, TIF_32BIT_REGS)) 78 get_user(*arg, (int *)usp + n); 79 else 80 #endif 81 *arg = regs->regs[4 + n]; 82 83 return; 84 #endif 85 86 default: 87 BUG(); 88 } 89 90 unreachable(); 91 } 92 93 static inline long syscall_get_error(struct task_struct *task, 94 struct pt_regs *regs) 95 { 96 return regs->regs[7] ? -regs->regs[2] : 0; 97 } 98 99 static inline long syscall_get_return_value(struct task_struct *task, 100 struct pt_regs *regs) 101 { 102 return regs->regs[2]; 103 } 104 105 static inline void syscall_rollback(struct task_struct *task, 106 struct pt_regs *regs) 107 { 108 /* Do nothing */ 109 } 110 111 static inline void syscall_set_return_value(struct task_struct *task, 112 struct pt_regs *regs, 113 int error, long val) 114 { 115 if (error) { 116 regs->regs[2] = -error; 117 regs->regs[7] = 1; 118 } else { 119 regs->regs[2] = val; 120 regs->regs[7] = 0; 121 } 122 } 123 124 static inline void syscall_get_arguments(struct task_struct *task, 125 struct pt_regs *regs, 126 unsigned long *args) 127 { 128 unsigned int i = 0; 129 unsigned int n = 6; 130 131 /* O32 ABI syscall() */ 132 if (mips_syscall_is_indirect(task, regs)) 133 i++; 134 135 while (n--) 136 mips_get_syscall_arg(args++, task, regs, i++); 137 } 138 139 extern const unsigned long sys_call_table[]; 140 extern const unsigned long sys32_call_table[]; 141 extern const unsigned long sysn32_call_table[]; 142 143 static inline int syscall_get_arch(struct task_struct *task) 144 { 145 int arch = AUDIT_ARCH_MIPS; 146 #ifdef CONFIG_64BIT 147 if (!test_tsk_thread_flag(task, TIF_32BIT_REGS)) { 148 arch |= __AUDIT_ARCH_64BIT; 149 /* N32 sets only TIF_32BIT_ADDR */ 150 if (test_tsk_thread_flag(task, TIF_32BIT_ADDR)) 151 arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32; 152 } 153 #endif 154 #if defined(__LITTLE_ENDIAN) 155 arch |= __AUDIT_ARCH_LE; 156 #endif 157 return arch; 158 } 159 160 #endif /* __ASM_MIPS_SYSCALL_H */ 161