1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Access to user system call parameters and results 4 * 5 * Copyright IBM Corp. 2008 6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) 7 */ 8 9 #ifndef _ASM_SYSCALL_H 10 #define _ASM_SYSCALL_H 1 11 12 #include <uapi/linux/audit.h> 13 #include <linux/sched.h> 14 #include <linux/err.h> 15 #include <asm/ptrace.h> 16 17 extern const sys_call_ptr_t sys_call_table[]; 18 extern const sys_call_ptr_t sys_call_table_emu[]; 19 20 static inline long syscall_get_nr(struct task_struct *task, 21 struct pt_regs *regs) 22 { 23 return test_pt_regs_flag(regs, PIF_SYSCALL) ? 24 (regs->int_code & 0xffff) : -1; 25 } 26 27 static inline void syscall_set_nr(struct task_struct *task, 28 struct pt_regs *regs, 29 int nr) 30 { 31 /* 32 * Unlike syscall_get_nr(), syscall_set_nr() can be called only when 33 * the target task is stopped for tracing on entering syscall, so 34 * there is no need to have the same check syscall_get_nr() has. 35 */ 36 regs->int_code = (regs->int_code & ~0xffff) | (nr & 0xffff); 37 } 38 39 static inline void syscall_rollback(struct task_struct *task, 40 struct pt_regs *regs) 41 { 42 regs->gprs[2] = regs->orig_gpr2; 43 } 44 45 static inline long syscall_get_error(struct task_struct *task, 46 struct pt_regs *regs) 47 { 48 unsigned long error = regs->gprs[2]; 49 #ifdef CONFIG_COMPAT 50 if (test_tsk_thread_flag(task, TIF_31BIT)) { 51 /* 52 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO 53 * and will match correctly in comparisons. 54 */ 55 error = (long)(int)error; 56 } 57 #endif 58 return IS_ERR_VALUE(error) ? error : 0; 59 } 60 61 static inline long syscall_get_return_value(struct task_struct *task, 62 struct pt_regs *regs) 63 { 64 return regs->gprs[2]; 65 } 66 67 static inline void syscall_set_return_value(struct task_struct *task, 68 struct pt_regs *regs, 69 int error, long val) 70 { 71 set_pt_regs_flag(regs, PIF_SYSCALL_RET_SET); 72 regs->gprs[2] = error ? error : val; 73 } 74 75 static inline void syscall_get_arguments(struct task_struct *task, 76 struct pt_regs *regs, 77 unsigned long *args) 78 { 79 unsigned long mask = -1UL; 80 81 #ifdef CONFIG_COMPAT 82 if (test_tsk_thread_flag(task, TIF_31BIT)) 83 mask = 0xffffffff; 84 #endif 85 for (int i = 1; i < 6; i++) 86 args[i] = regs->gprs[2 + i] & mask; 87 88 args[0] = regs->orig_gpr2 & mask; 89 } 90 91 static inline void syscall_set_arguments(struct task_struct *task, 92 struct pt_regs *regs, 93 const unsigned long *args) 94 { 95 regs->orig_gpr2 = args[0]; 96 for (int n = 1; n < 6; n++) 97 regs->gprs[2 + n] = args[n]; 98 } 99 100 static inline int syscall_get_arch(struct task_struct *task) 101 { 102 #ifdef CONFIG_COMPAT 103 if (test_tsk_thread_flag(task, TIF_31BIT)) 104 return AUDIT_ARCH_S390; 105 #endif 106 return AUDIT_ARCH_S390X; 107 } 108 109 static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs) 110 { 111 return false; 112 } 113 114 #define SYSCALL_FMT_0 115 #define SYSCALL_FMT_1 , "0" (r2) 116 #define SYSCALL_FMT_2 , "d" (r3) SYSCALL_FMT_1 117 #define SYSCALL_FMT_3 , "d" (r4) SYSCALL_FMT_2 118 #define SYSCALL_FMT_4 , "d" (r5) SYSCALL_FMT_3 119 #define SYSCALL_FMT_5 , "d" (r6) SYSCALL_FMT_4 120 #define SYSCALL_FMT_6 , "d" (r7) SYSCALL_FMT_5 121 122 #define SYSCALL_PARM_0 123 #define SYSCALL_PARM_1 , long arg1 124 #define SYSCALL_PARM_2 SYSCALL_PARM_1, long arg2 125 #define SYSCALL_PARM_3 SYSCALL_PARM_2, long arg3 126 #define SYSCALL_PARM_4 SYSCALL_PARM_3, long arg4 127 #define SYSCALL_PARM_5 SYSCALL_PARM_4, long arg5 128 #define SYSCALL_PARM_6 SYSCALL_PARM_5, long arg6 129 130 #define SYSCALL_REGS_0 131 #define SYSCALL_REGS_1 \ 132 register long r2 asm("2") = arg1 133 #define SYSCALL_REGS_2 \ 134 SYSCALL_REGS_1; \ 135 register long r3 asm("3") = arg2 136 #define SYSCALL_REGS_3 \ 137 SYSCALL_REGS_2; \ 138 register long r4 asm("4") = arg3 139 #define SYSCALL_REGS_4 \ 140 SYSCALL_REGS_3; \ 141 register long r5 asm("5") = arg4 142 #define SYSCALL_REGS_5 \ 143 SYSCALL_REGS_4; \ 144 register long r6 asm("6") = arg5 145 #define SYSCALL_REGS_6 \ 146 SYSCALL_REGS_5; \ 147 register long r7 asm("7") = arg6 148 149 #define GENERATE_SYSCALL_FUNC(nr) \ 150 static __always_inline \ 151 long syscall##nr(unsigned long syscall SYSCALL_PARM_##nr) \ 152 { \ 153 register unsigned long r1 asm ("1") = syscall; \ 154 register long rc asm ("2"); \ 155 SYSCALL_REGS_##nr; \ 156 \ 157 asm volatile ( \ 158 " svc 0\n" \ 159 : "=d" (rc) \ 160 : "d" (r1) SYSCALL_FMT_##nr \ 161 : "memory"); \ 162 return rc; \ 163 } 164 165 GENERATE_SYSCALL_FUNC(0) 166 GENERATE_SYSCALL_FUNC(1) 167 GENERATE_SYSCALL_FUNC(2) 168 GENERATE_SYSCALL_FUNC(3) 169 GENERATE_SYSCALL_FUNC(4) 170 GENERATE_SYSCALL_FUNC(5) 171 GENERATE_SYSCALL_FUNC(6) 172 173 #endif /* _ASM_SYSCALL_H */ 174