stub_64.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 <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
 21static __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
 32static __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
 43static __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
 54static __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
 67static __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
 81static __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
 95static __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
111static __always_inline void trap_myself(void)
112{
113	__asm("int3");
114}
115
116static __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" (STUB_SIZE),					\
137		   "i" (&fn))
138
139static __always_inline void
140stub_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