1 /*
2 * Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
3 * Licensed under the GPL
4 */
5
6 #ifndef __SYSDEP_STUB_H
7 #define __SYSDEP_STUB_H
8
9 #include <stddef.h>
10 #include <sysdep/ptrace_user.h>
11 #include <generated/asm-offsets.h>
12 #include <linux/stddef.h>
13 #include <asm/prctl.h>
14
15 #define STUB_MMAP_NR __NR_mmap
16 #define MMAP_OFFSET(o) (o)
17
18 #define __syscall_clobber "r11","rcx","memory"
19 #define __syscall "syscall"
20
stub_syscall0(long syscall)21 static __always_inline long stub_syscall0(long syscall)
22 {
23 long ret;
24
25 __asm__ volatile (__syscall
26 : "=a" (ret)
27 : "0" (syscall) : __syscall_clobber );
28
29 return ret;
30 }
31
stub_syscall1(long syscall,long arg1)32 static __always_inline long stub_syscall1(long syscall, long arg1)
33 {
34 long ret;
35
36 __asm__ volatile (__syscall
37 : "=a" (ret)
38 : "0" (syscall), "D" (arg1) : __syscall_clobber );
39
40 return ret;
41 }
42
stub_syscall2(long syscall,long arg1,long arg2)43 static __always_inline long stub_syscall2(long syscall, long arg1, long arg2)
44 {
45 long ret;
46
47 __asm__ volatile (__syscall
48 : "=a" (ret)
49 : "0" (syscall), "D" (arg1), "S" (arg2) : __syscall_clobber );
50
51 return ret;
52 }
53
stub_syscall3(long syscall,long arg1,long arg2,long arg3)54 static __always_inline long stub_syscall3(long syscall, long arg1, long arg2,
55 long arg3)
56 {
57 long ret;
58
59 __asm__ volatile (__syscall
60 : "=a" (ret)
61 : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3)
62 : __syscall_clobber );
63
64 return ret;
65 }
66
stub_syscall4(long syscall,long arg1,long arg2,long arg3,long arg4)67 static __always_inline long stub_syscall4(long syscall, long arg1, long arg2, long arg3,
68 long arg4)
69 {
70 long ret;
71
72 __asm__ volatile ("movq %5,%%r10 ; " __syscall
73 : "=a" (ret)
74 : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3),
75 "g" (arg4)
76 : __syscall_clobber, "r10" );
77
78 return ret;
79 }
80
stub_syscall5(long syscall,long arg1,long arg2,long arg3,long arg4,long arg5)81 static __always_inline long stub_syscall5(long syscall, long arg1, long arg2,
82 long arg3, long arg4, long arg5)
83 {
84 long ret;
85
86 __asm__ volatile ("movq %5,%%r10 ; movq %6,%%r8 ; " __syscall
87 : "=a" (ret)
88 : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3),
89 "g" (arg4), "g" (arg5)
90 : __syscall_clobber, "r10", "r8" );
91
92 return ret;
93 }
94
stub_syscall6(long syscall,long arg1,long arg2,long arg3,long arg4,long arg5,long arg6)95 static __always_inline long stub_syscall6(long syscall, long arg1, long arg2,
96 long arg3, long arg4, long arg5,
97 long arg6)
98 {
99 long ret;
100
101 __asm__ volatile ("movq %5,%%r10 ; movq %6,%%r8 ; movq %7,%%r9 ; "
102 __syscall
103 : "=a" (ret)
104 : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3),
105 "g" (arg4), "g" (arg5), "g" (arg6)
106 : __syscall_clobber, "r10", "r8", "r9");
107
108 return ret;
109 }
110
trap_myself(void)111 static __always_inline void trap_myself(void)
112 {
113 __asm("int3");
114 }
115
get_stub_data(void)116 static __always_inline void *get_stub_data(void)
117 {
118 unsigned long ret;
119
120 asm volatile (
121 "lea 0(%%rip), %0;"
122 "andq %1, %0 ;"
123 "addq %2, %0 ;"
124 : "=a" (ret)
125 : "g" (~(UM_KERN_PAGE_SIZE - 1)),
126 "g" (UM_KERN_PAGE_SIZE));
127
128 return (void *)ret;
129 }
130
131 #define stub_start(fn) \
132 asm volatile ( \
133 "subq %0,%%rsp ;" \
134 "movq %1,%%rax ;" \
135 "call *%%rax ;" \
136 :: "i" ((1 + STUB_DATA_PAGES) * UM_KERN_PAGE_SIZE), \
137 "i" (&fn))
138
139 static __always_inline void
stub_seccomp_restore_state(struct stub_data_arch * arch)140 stub_seccomp_restore_state(struct stub_data_arch *arch)
141 {
142 /*
143 * We could use _writefsbase_u64/_writegsbase_u64 if the host reports
144 * support in the hwcaps (HWCAP2_FSGSBASE).
145 */
146 if (arch->sync & STUB_SYNC_FS_BASE)
147 stub_syscall2(__NR_arch_prctl, ARCH_SET_FS, arch->fs_base);
148 if (arch->sync & STUB_SYNC_GS_BASE)
149 stub_syscall2(__NR_arch_prctl, ARCH_SET_GS, arch->gs_base);
150
151 arch->sync = 0;
152 }
153
154 #endif
155