1 /* 2 * Access to user system call parameters and results 3 * 4 * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. 5 * 6 * This copyrighted material is made available to anyone wishing to use, 7 * modify, copy, or redistribute it subject to the terms and conditions 8 * of the GNU General Public License v.2. 9 * 10 * See asm-generic/syscall.h for descriptions of what we must do here. 11 */ 12 13 #ifndef _ASM_X86_SYSCALL_H 14 #define _ASM_X86_SYSCALL_H 15 16 #include <linux/sched.h> 17 #include <linux/err.h> 18 19 extern const unsigned long sys_call_table[]; 20 21 /* 22 * Only the low 32 bits of orig_ax are meaningful, so we return int. 23 * This importantly ignores the high bits on 64-bit, so comparisons 24 * sign-extend the low 32 bits. 25 */ 26 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) 27 { 28 return regs->orig_ax; 29 } 30 31 static inline void syscall_rollback(struct task_struct *task, 32 struct pt_regs *regs) 33 { 34 regs->ax = regs->orig_ax; 35 } 36 37 static inline long syscall_get_error(struct task_struct *task, 38 struct pt_regs *regs) 39 { 40 unsigned long error = regs->ax; 41 #ifdef CONFIG_IA32_EMULATION 42 /* 43 * TS_COMPAT is set for 32-bit syscall entries and then 44 * remains set until we return to user mode. 45 */ 46 if (task_thread_info(task)->status & TS_COMPAT) 47 /* 48 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO 49 * and will match correctly in comparisons. 50 */ 51 error = (long) (int) error; 52 #endif 53 return IS_ERR_VALUE(error) ? error : 0; 54 } 55 56 static inline long syscall_get_return_value(struct task_struct *task, 57 struct pt_regs *regs) 58 { 59 return regs->ax; 60 } 61 62 static inline void syscall_set_return_value(struct task_struct *task, 63 struct pt_regs *regs, 64 int error, long val) 65 { 66 regs->ax = (long) error ?: val; 67 } 68 69 #ifdef CONFIG_X86_32 70 71 static inline void syscall_get_arguments(struct task_struct *task, 72 struct pt_regs *regs, 73 unsigned int i, unsigned int n, 74 unsigned long *args) 75 { 76 BUG_ON(i + n > 6); 77 memcpy(args, ®s->bx + i, n * sizeof(args[0])); 78 } 79 80 static inline void syscall_set_arguments(struct task_struct *task, 81 struct pt_regs *regs, 82 unsigned int i, unsigned int n, 83 const unsigned long *args) 84 { 85 BUG_ON(i + n > 6); 86 memcpy(®s->bx + i, args, n * sizeof(args[0])); 87 } 88 89 #else /* CONFIG_X86_64 */ 90 91 static inline void syscall_get_arguments(struct task_struct *task, 92 struct pt_regs *regs, 93 unsigned int i, unsigned int n, 94 unsigned long *args) 95 { 96 # ifdef CONFIG_IA32_EMULATION 97 if (task_thread_info(task)->status & TS_COMPAT) 98 switch (i) { 99 case 0: 100 if (!n--) break; 101 *args++ = regs->bx; 102 case 1: 103 if (!n--) break; 104 *args++ = regs->cx; 105 case 2: 106 if (!n--) break; 107 *args++ = regs->dx; 108 case 3: 109 if (!n--) break; 110 *args++ = regs->si; 111 case 4: 112 if (!n--) break; 113 *args++ = regs->di; 114 case 5: 115 if (!n--) break; 116 *args++ = regs->bp; 117 case 6: 118 if (!n--) break; 119 default: 120 BUG(); 121 break; 122 } 123 else 124 # endif 125 switch (i) { 126 case 0: 127 if (!n--) break; 128 *args++ = regs->di; 129 case 1: 130 if (!n--) break; 131 *args++ = regs->si; 132 case 2: 133 if (!n--) break; 134 *args++ = regs->dx; 135 case 3: 136 if (!n--) break; 137 *args++ = regs->r10; 138 case 4: 139 if (!n--) break; 140 *args++ = regs->r8; 141 case 5: 142 if (!n--) break; 143 *args++ = regs->r9; 144 case 6: 145 if (!n--) break; 146 default: 147 BUG(); 148 break; 149 } 150 } 151 152 static inline void syscall_set_arguments(struct task_struct *task, 153 struct pt_regs *regs, 154 unsigned int i, unsigned int n, 155 const unsigned long *args) 156 { 157 # ifdef CONFIG_IA32_EMULATION 158 if (task_thread_info(task)->status & TS_COMPAT) 159 switch (i) { 160 case 0: 161 if (!n--) break; 162 regs->bx = *args++; 163 case 1: 164 if (!n--) break; 165 regs->cx = *args++; 166 case 2: 167 if (!n--) break; 168 regs->dx = *args++; 169 case 3: 170 if (!n--) break; 171 regs->si = *args++; 172 case 4: 173 if (!n--) break; 174 regs->di = *args++; 175 case 5: 176 if (!n--) break; 177 regs->bp = *args++; 178 case 6: 179 if (!n--) break; 180 default: 181 BUG(); 182 break; 183 } 184 else 185 # endif 186 switch (i) { 187 case 0: 188 if (!n--) break; 189 regs->di = *args++; 190 case 1: 191 if (!n--) break; 192 regs->si = *args++; 193 case 2: 194 if (!n--) break; 195 regs->dx = *args++; 196 case 3: 197 if (!n--) break; 198 regs->r10 = *args++; 199 case 4: 200 if (!n--) break; 201 regs->r8 = *args++; 202 case 5: 203 if (!n--) break; 204 regs->r9 = *args++; 205 case 6: 206 if (!n--) break; 207 default: 208 BUG(); 209 break; 210 } 211 } 212 213 #endif /* CONFIG_X86_32 */ 214 215 #endif /* _ASM_X86_SYSCALL_H */ 216