base, _, errno := syscall.Syscall6(syscall.SYS_MMAP,
		0xa0<<32, 3<<30, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_PRIVATE|syscall.MAP_ANONYMOUS, ^uintptr(0), 0)
	if errno != 0 {
		t.Skipf("could not create memory mapping: %s", errno)
	}
	syscall.Syscall(syscall.SYS_MUNMAP, base, 3<<30, 0)

	for off := uintptr(0); off < 3<<30; off += 65536 {
		_, _, errno := syscall.Syscall6(syscall.SYS_MMAP,

	SYS_READAHEAD               = 213
	SYS_BRK                     = 214
	SYS_MUNMAP                  = 215
	SYS_MREMAP                  = 216
	SYS_ADD_KEY                 = 217
	SYS_REQUEST_KEY             = 218
	SYS_KEYCTL                  = 219
	SYS_CLONE                   = 220
	SYS_EXECVE                  = 221
	SYS_MMAP                    = 222
	SYS_FADVISE64               = 223
	SYS_SWAPON                  = 224

	SYS_READAHEAD               = 213
	SYS_BRK                     = 214
	SYS_MUNMAP                  = 215
	SYS_MREMAP                  = 216
	SYS_ADD_KEY                 = 217
	SYS_REQUEST_KEY             = 218
	SYS_KEYCTL                  = 219
	SYS_CLONE                   = 220
	SYS_EXECVE                  = 221
	SYS_MMAP                    = 222
	SYS_FADVISE64               = 223
	SYS_SWAPON                  = 224

	SYS_READAHEAD               = 213
	SYS_BRK                     = 214
	SYS_MUNMAP                  = 215
	SYS_MREMAP                  = 216
	SYS_ADD_KEY                 = 217
	SYS_REQUEST_KEY             = 218
	SYS_KEYCTL                  = 219
	SYS_CLONE                   = 220
	SYS_EXECVE                  = 221
	SYS_MMAP                    = 222
	SYS_FADVISE64               = 223
	SYS_SWAPON                  = 224

	SYS_STAT                    = 5004
	SYS_FSTAT                   = 5005
	SYS_LSTAT                   = 5006
	SYS_POLL                    = 5007
	SYS_LSEEK                   = 5008
	SYS_MMAP                    = 5009
	SYS_MPROTECT                = 5010
	SYS_MUNMAP                  = 5011
	SYS_BRK                     = 5012
	SYS_RT_SIGACTION            = 5013
	SYS_RT_SIGPROCMASK          = 5014
	SYS_IOCTL                   = 5015

	MOVSL
	MOVSL
	MOVSL
	MOVSL
	MOVSL
	MOVL	$0, AX	// top 32 bits of file offset
	STOSL
	MOVL	$SYS_mmap, AX
	INT	$0x80
	JAE	ok
	MOVL	$0, p+24(FP)
	MOVL	AX, err+28(FP)
	RET
ok:
	MOVL	AX, p+24(FP)
	MOVL	$0, err+28(FP)
	RET

TEXT runtime·munmap(SB),NOSPLIT,$-4
	MOVL	$SYS_munmap, AX
	INT	$0x80
	JAE	2(PC)
	MOVL	$0xf1, 0xf1  // crash
	RET

TEXT runtime·madvise(SB),NOSPLIT,$-4

#define SYS_exit			1
#define SYS_read			3
#define SYS_write			4
#define SYS_open			5
#define SYS_close			6
#define SYS_getpid			20
#define SYS_kill			37
#define SYS_munmap			73
#define SYS_madvise			75
#define SYS_fcntl			92
#define SYS_mmap			197
#define SYS___sysctl			202
#define SYS___sigaltstack14		281
#define SYS___sigprocmask14		293
#define SYS_issetugid			305
#define SYS_getcontext			307

	SYS_STAT                    = 5004
	SYS_FSTAT                   = 5005
	SYS_LSTAT                   = 5006
	SYS_POLL                    = 5007
	SYS_LSEEK                   = 5008
	SYS_MMAP                    = 5009
	SYS_MPROTECT                = 5010
	SYS_MUNMAP                  = 5011
	SYS_BRK                     = 5012
	SYS_RT_SIGACTION            = 5013
	SYS_RT_SIGPROCMASK          = 5014
	SYS_IOCTL                   = 5015

	SYS_GETPAGESIZE             = 64
	SYS_MSYNC                   = 65
	SYS_VFORK                   = 66
	SYS_PREAD64                 = 67
	SYS_PWRITE64                = 68
	SYS_MMAP                    = 71
	SYS_MUNMAP                  = 73
	SYS_MPROTECT                = 74
	SYS_MADVISE                 = 75
	SYS_VHANGUP                 = 76
	SYS_MINCORE                 = 78
	SYS_GETGROUPS               = 79

	SYS_READLINK                = 85
	SYS_USELIB                  = 86
	SYS_SWAPON                  = 87
	SYS_REBOOT                  = 88
	SYS_READDIR                 = 89
	SYS_MMAP                    = 90
	SYS_MUNMAP                  = 91
	SYS_TRUNCATE                = 92
	SYS_FTRUNCATE               = 93
	SYS_FCHMOD                  = 94
	SYS_GETPRIORITY             = 96
	SYS_SETPRIORITY             = 97