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 #ifdef CONFIG_32BIT 61 switch (n) { 62 case 0: case 1: case 2: case 3: 63 *arg = regs->regs[4 + n]; 64 return; 65 case 4: case 5: case 6: case 7: 66 *arg = regs->args[n]; 67 return; 68 } 69 #else 70 *arg = regs->regs[4 + n]; 71 if ((IS_ENABLED(CONFIG_MIPS32_O32) && 72 test_tsk_thread_flag(task, TIF_32BIT_REGS))) 73 *arg = (unsigned int)*arg; 74 #endif 75 } 76 77 static inline long syscall_get_error(struct task_struct *task, 78 struct pt_regs *regs) 79 { 80 return regs->regs[7] ? -regs->regs[2] : 0; 81 } 82 83 static inline long syscall_get_return_value(struct task_struct *task, 84 struct pt_regs *regs) 85 { 86 return regs->regs[2]; 87 } 88 89 static inline void syscall_rollback(struct task_struct *task, 90 struct pt_regs *regs) 91 { 92 /* Do nothing */ 93 } 94 95 static inline void syscall_set_return_value(struct task_struct *task, 96 struct pt_regs *regs, 97 int error, long val) 98 { 99 if (error) { 100 regs->regs[2] = -error; 101 regs->regs[7] = 1; 102 } else { 103 regs->regs[2] = val; 104 regs->regs[7] = 0; 105 } 106 } 107 108 static inline void syscall_get_arguments(struct task_struct *task, 109 struct pt_regs *regs, 110 unsigned long *args) 111 { 112 unsigned int i = 0; 113 unsigned int n = 6; 114 115 /* O32 ABI syscall() */ 116 if (mips_syscall_is_indirect(task, regs)) 117 i++; 118 119 while (n--) 120 mips_get_syscall_arg(args++, task, regs, i++); 121 } 122 123 extern const unsigned long sys_call_table[]; 124 extern const unsigned long sys32_call_table[]; 125 extern const unsigned long sysn32_call_table[]; 126 127 static inline int syscall_get_arch(struct task_struct *task) 128 { 129 int arch = AUDIT_ARCH_MIPS; 130 #ifdef CONFIG_64BIT 131 if (!test_tsk_thread_flag(task, TIF_32BIT_REGS)) { 132 arch |= __AUDIT_ARCH_64BIT; 133 /* N32 sets only TIF_32BIT_ADDR */ 134 if (test_tsk_thread_flag(task, TIF_32BIT_ADDR)) 135 arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32; 136 } 137 #endif 138 #if defined(__LITTLE_ENDIAN) 139 arch |= __AUDIT_ARCH_LE; 140 #endif 141 return arch; 142 } 143 144 #endif /* __ASM_MIPS_SYSCALL_H */ 145