stub_32.h

  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 <asm/ptrace.h>
 11#include <generated/asm-offsets.h>
 12
 13#define STUB_MMAP_NR __NR_mmap2
 14#define MMAP_OFFSET(o) ((o) >> UM_KERN_PAGE_SHIFT)
 15
 16static __always_inline long stub_syscall0(long syscall)
 17{
 18	long ret;
 19
 20	__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall)
 21			: "memory");
 22
 23	return ret;
 24}
 25
 26static __always_inline long stub_syscall1(long syscall, long arg1)
 27{
 28	long ret;
 29
 30	__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1)
 31			: "memory");
 32
 33	return ret;
 34}
 35
 36static __always_inline long stub_syscall2(long syscall, long arg1, long arg2)
 37{
 38	long ret;
 39
 40	__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
 41			"c" (arg2)
 42			: "memory");
 43
 44	return ret;
 45}
 46
 47static __always_inline long stub_syscall3(long syscall, long arg1, long arg2,
 48					  long arg3)
 49{
 50	long ret;
 51
 52	__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
 53			"c" (arg2), "d" (arg3)
 54			: "memory");
 55
 56	return ret;
 57}
 58
 59static __always_inline long stub_syscall4(long syscall, long arg1, long arg2,
 60					  long arg3, long arg4)
 61{
 62	long ret;
 63
 64	__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
 65			"c" (arg2), "d" (arg3), "S" (arg4)
 66			: "memory");
 67
 68	return ret;
 69}
 70
 71static __always_inline long stub_syscall5(long syscall, long arg1, long arg2,
 72					  long arg3, long arg4, long arg5)
 73{
 74	long ret;
 75
 76	__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
 77			"c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
 78			: "memory");
 79
 80	return ret;
 81}
 82
 83static __always_inline long stub_syscall6(long syscall, long arg1, long arg2,
 84					  long arg3, long arg4, long arg5,
 85					  long arg6)
 86{
 87	struct syscall_args {
 88		int ebx, ebp;
 89	} args = { arg1, arg6 };
 90	long ret;
 91
 92	__asm__ volatile ("pushl %%ebp;"
 93			"movl 0x4(%%ebx),%%ebp;"
 94			"movl (%%ebx),%%ebx;"
 95			"int $0x80;"
 96			"popl %%ebp"
 97			: "=a" (ret)
 98			: "0" (syscall), "b" (&args),
 99			"c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
100			: "memory");
101
102	return ret;
103}
104
105static __always_inline void trap_myself(void)
106{
107	__asm("int3");
108}
109
110static __always_inline void *get_stub_data(void)
111{
112	unsigned long ret;
113
114	asm volatile (
115		"call _here_%=;"
116		"_here_%=:"
117		"popl %0;"
118		"andl %1, %0 ;"
119		"addl %2, %0 ;"
120		: "=a" (ret)
121		: "g" (~(UM_KERN_PAGE_SIZE - 1)),
122		  "g" (UM_KERN_PAGE_SIZE));
123
124	return (void *)ret;
125}
126
127#define stub_start(fn)							\
128	asm volatile (							\
129		"subl %0,%%esp ;"					\
130		"movl %1, %%eax ; "					\
131		"call *%%eax ;"						\
132		:: "i" (STUB_SIZE),					\
133		   "i" (&fn))
134
135static __always_inline void
136stub_seccomp_restore_state(struct stub_data_arch *arch)
137{
138	for (int i = 0; i < sizeof(arch->tls) / sizeof(arch->tls[0]); i++) {
139		if (arch->sync & (1 << i))
140			stub_syscall1(__NR_set_thread_area,
141				      (unsigned long) &arch->tls[i]);
142	}
143
144	arch->sync = 0;
145}
146
147#endif