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 #include <asm/asm-offsets.h> /* For NR_syscalls */ 19 20 extern const unsigned long sys_call_table[]; 21 22 /* 23 * Only the low 32 bits of orig_ax are meaningful, so we return int. 24 * This importantly ignores the high bits on 64-bit, so comparisons 25 * sign-extend the low 32 bits. 26 */ 27 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) 28 { 29 return regs->orig_ax; 30 } 31 32 static inline void syscall_rollback(struct task_struct *task, 33 struct pt_regs *regs) 34 { 35 regs->ax = regs->orig_ax; 36 } 37 38 static inline long syscall_get_error(struct task_struct *task, 39 struct pt_regs *regs) 40 { 41 unsigned long error = regs->ax; 42 #ifdef CONFIG_IA32_EMULATION 43 /* 44 * TS_COMPAT is set for 32-bit syscall entries and then 45 * remains set until we return to user mode. 46 */ 47 if (task_thread_info(task)->status & TS_COMPAT) 48 /* 49 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO 50 * and will match correctly in comparisons. 51 */ 52 error = (long) (int) error; 53 #endif 54 return IS_ERR_VALUE(error) ? error : 0; 55 } 56 57 static inline long syscall_get_return_value(struct task_struct *task, 58 struct pt_regs *regs) 59 { 60 return regs->ax; 61 } 62 63 static inline void syscall_set_return_value(struct task_struct *task, 64 struct pt_regs *regs, 65 int error, long val) 66 { 67 regs->ax = (long) error ?: val; 68 } 69 70 #ifdef CONFIG_X86_32 71 72 static inline void syscall_get_arguments(struct task_struct *task, 73 struct pt_regs *regs, 74 unsigned int i, unsigned int n, 75 unsigned long *args) 76 { 77 BUG_ON(i + n > 6); 78 memcpy(args, ®s->bx + i, n * sizeof(args[0])); 79 } 80 81 static inline void syscall_set_arguments(struct task_struct *task, 82 struct pt_regs *regs, 83 unsigned int i, unsigned int n, 84 const unsigned long *args) 85 { 86 BUG_ON(i + n > 6); 87 memcpy(®s->bx + i, args, n * sizeof(args[0])); 88 } 89 90 #else /* CONFIG_X86_64 */ 91 92 static inline void syscall_get_arguments(struct task_struct *task, 93 struct pt_regs *regs, 94 unsigned int i, unsigned int n, 95 unsigned long *args) 96 { 97 # ifdef CONFIG_IA32_EMULATION 98 if (task_thread_info(task)->status & TS_COMPAT) 99 switch (i) { 100 case 0: 101 if (!n--) break; 102 *args++ = regs->bx; 103 case 1: 104 if (!n--) break; 105 *args++ = regs->cx; 106 case 2: 107 if (!n--) break; 108 *args++ = regs->dx; 109 case 3: 110 if (!n--) break; 111 *args++ = regs->si; 112 case 4: 113 if (!n--) break; 114 *args++ = regs->di; 115 case 5: 116 if (!n--) break; 117 *args++ = regs->bp; 118 case 6: 119 if (!n--) break; 120 default: 121 BUG(); 122 break; 123 } 124 else 125 # endif 126 switch (i) { 127 case 0: 128 if (!n--) break; 129 *args++ = regs->di; 130 case 1: 131 if (!n--) break; 132 *args++ = regs->si; 133 case 2: 134 if (!n--) break; 135 *args++ = regs->dx; 136 case 3: 137 if (!n--) break; 138 *args++ = regs->r10; 139 case 4: 140 if (!n--) break; 141 *args++ = regs->r8; 142 case 5: 143 if (!n--) break; 144 *args++ = regs->r9; 145 case 6: 146 if (!n--) break; 147 default: 148 BUG(); 149 break; 150 } 151 } 152 153 static inline void syscall_set_arguments(struct task_struct *task, 154 struct pt_regs *regs, 155 unsigned int i, unsigned int n, 156 const unsigned long *args) 157 { 158 # ifdef CONFIG_IA32_EMULATION 159 if (task_thread_info(task)->status & TS_COMPAT) 160 switch (i) { 161 case 0: 162 if (!n--) break; 163 regs->bx = *args++; 164 case 1: 165 if (!n--) break; 166 regs->cx = *args++; 167 case 2: 168 if (!n--) break; 169 regs->dx = *args++; 170 case 3: 171 if (!n--) break; 172 regs->si = *args++; 173 case 4: 174 if (!n--) break; 175 regs->di = *args++; 176 case 5: 177 if (!n--) break; 178 regs->bp = *args++; 179 case 6: 180 if (!n--) break; 181 default: 182 BUG(); 183 break; 184 } 185 else 186 # endif 187 switch (i) { 188 case 0: 189 if (!n--) break; 190 regs->di = *args++; 191 case 1: 192 if (!n--) break; 193 regs->si = *args++; 194 case 2: 195 if (!n--) break; 196 regs->dx = *args++; 197 case 3: 198 if (!n--) break; 199 regs->r10 = *args++; 200 case 4: 201 if (!n--) break; 202 regs->r8 = *args++; 203 case 5: 204 if (!n--) break; 205 regs->r9 = *args++; 206 case 6: 207 if (!n--) break; 208 default: 209 BUG(); 210 break; 211 } 212 } 213 214 #endif /* CONFIG_X86_32 */ 215 216 #endif /* _ASM_X86_SYSCALL_H */ 217