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 <uapi/linux/audit.h> 17 #include <linux/sched.h> 18 #include <linux/err.h> 19 #include <asm/asm-offsets.h> /* For NR_syscalls */ 20 #include <asm/thread_info.h> /* for TS_COMPAT */ 21 #include <asm/unistd.h> 22 23 #ifdef CONFIG_X86_64 24 typedef asmlinkage long (*sys_call_ptr_t)(const struct pt_regs *); 25 #else 26 typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long, 27 unsigned long, unsigned long, 28 unsigned long, unsigned long); 29 #endif /* CONFIG_X86_64 */ 30 extern const sys_call_ptr_t sys_call_table[]; 31 32 #if defined(CONFIG_X86_32) 33 #define ia32_sys_call_table sys_call_table 34 #define __NR_syscall_compat_max __NR_syscall_max 35 #define IA32_NR_syscalls NR_syscalls 36 #endif 37 38 #if defined(CONFIG_IA32_EMULATION) 39 extern const sys_call_ptr_t ia32_sys_call_table[]; 40 #endif 41 42 /* 43 * Only the low 32 bits of orig_ax are meaningful, so we return int. 44 * This importantly ignores the high bits on 64-bit, so comparisons 45 * sign-extend the low 32 bits. 46 */ 47 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) 48 { 49 return regs->orig_ax; 50 } 51 52 static inline void syscall_rollback(struct task_struct *task, 53 struct pt_regs *regs) 54 { 55 regs->ax = regs->orig_ax; 56 } 57 58 static inline long syscall_get_error(struct task_struct *task, 59 struct pt_regs *regs) 60 { 61 unsigned long error = regs->ax; 62 #ifdef CONFIG_IA32_EMULATION 63 /* 64 * TS_COMPAT is set for 32-bit syscall entries and then 65 * remains set until we return to user mode. 66 */ 67 if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED)) 68 /* 69 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO 70 * and will match correctly in comparisons. 71 */ 72 error = (long) (int) error; 73 #endif 74 return IS_ERR_VALUE(error) ? error : 0; 75 } 76 77 static inline long syscall_get_return_value(struct task_struct *task, 78 struct pt_regs *regs) 79 { 80 return regs->ax; 81 } 82 83 static inline void syscall_set_return_value(struct task_struct *task, 84 struct pt_regs *regs, 85 int error, long val) 86 { 87 regs->ax = (long) error ?: val; 88 } 89 90 #ifdef CONFIG_X86_32 91 92 static inline void syscall_get_arguments(struct task_struct *task, 93 struct pt_regs *regs, 94 unsigned long *args) 95 { 96 memcpy(args, ®s->bx, 6 * sizeof(args[0])); 97 } 98 99 static inline void syscall_set_arguments(struct task_struct *task, 100 struct pt_regs *regs, 101 unsigned int i, unsigned int n, 102 const unsigned long *args) 103 { 104 BUG_ON(i + n > 6); 105 memcpy(®s->bx + i, args, n * sizeof(args[0])); 106 } 107 108 static inline int syscall_get_arch(struct task_struct *task) 109 { 110 return AUDIT_ARCH_I386; 111 } 112 113 #else /* CONFIG_X86_64 */ 114 115 static inline void syscall_get_arguments(struct task_struct *task, 116 struct pt_regs *regs, 117 unsigned long *args) 118 { 119 # ifdef CONFIG_IA32_EMULATION 120 if (task->thread_info.status & TS_COMPAT) { 121 *args++ = regs->bx; 122 *args++ = regs->cx; 123 *args++ = regs->dx; 124 *args++ = regs->si; 125 *args++ = regs->di; 126 *args = regs->bp; 127 } else 128 # endif 129 { 130 *args++ = regs->di; 131 *args++ = regs->si; 132 *args++ = regs->dx; 133 *args++ = regs->r10; 134 *args++ = regs->r8; 135 *args = regs->r9; 136 } 137 } 138 139 static inline void syscall_set_arguments(struct task_struct *task, 140 struct pt_regs *regs, 141 const unsigned long *args) 142 { 143 # ifdef CONFIG_IA32_EMULATION 144 if (task->thread_info.status & TS_COMPAT) { 145 regs->bx = *args++; 146 regs->cx = *args++; 147 regs->dx = *args++; 148 regs->si = *args++; 149 regs->di = *args++; 150 regs->bp = *args; 151 } else 152 # endif 153 { 154 regs->di = *args++; 155 regs->si = *args++; 156 regs->dx = *args++; 157 regs->r10 = *args++; 158 regs->r8 = *args++; 159 regs->r9 = *args; 160 } 161 } 162 163 static inline int syscall_get_arch(struct task_struct *task) 164 { 165 /* x32 tasks should be considered AUDIT_ARCH_X86_64. */ 166 return (IS_ENABLED(CONFIG_IA32_EMULATION) && 167 task->thread_info.status & TS_COMPAT) 168 ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64; 169 } 170 #endif /* CONFIG_X86_32 */ 171 172 #endif /* _ASM_X86_SYSCALL_H */ 173