vma-coverage.c

/*
 * Compile as:
 * 	powerpc64-linux-gnu-gcc -o vma-coverage	-g -O0		\
 * 				-mcpu=powerpc64	-mno-altivec	\
 * 				-mno-vsx -nostdlib -static	\
 * 				vma-coverage.c
 */

#ifndef __powerpc64__
#error "unsupported architecture"
#endif

#include <sys/mman.h>
#include <sys/types.h>

#define SYS_exit	1
#define SYS_fork	2
#define SYS_mmap	90
#define SYS_munmap	91
#define SYS_mlock	150

#define	EPERM		1
#define	ENOENT		2
#define	ESRCH		3
#define	EINTR		4
#define	EIO		5
#define	ENXIO		6
#define	E2BIG		7
#define	ENOEXEC		8
#define	EBADF		9
#define	ECHILD		10
#define	EAGAIN		11
#define	ENOMEM		12
#define	EACCES		13
#define	EFAULT		14
#define	ENOTBLK		15
#define	EBUSY		16
#define	EEXIST		17
#define	EXDEV		18
#define	ENODEV		19
#define	ENOTDIR		20
#define	EISDIR		21
#define	EINVAL		22
#define	ENFILE		23
#define	EMFILE		24
#define	ENOTTY		25
#define	ETXTBSY		26
#define	EFBIG		27
#define	ENOSPC		28
#define	ESPIPE		29
#define	EROFS		30
#define	EMLINK		31
#define	EPIPE		32
#define	EDOM		33
#define	ERANGE		34

#define PAGE_SIZE	(1UL << 16)
#define TASK_SIZE	(1UL << 52)

int errno;

long syscall(long syscall, long arg1, long arg2, long arg3, long arg4,
	     long arg5, long arg6, long arg7)
{
	long ret;
	int err;

	asm volatile("mr	0, 3	\n\t"	\
		     "mr	3, 4	\n\t"	\
		     "mr	4, 5	\n\t"	\
		     "mr	5, 6	\n\t"	\
		     "mr	6, 7	\n\t"	\
		     "mr	7, 8	\n\t"	\
		     "mr	8, 9	\n\t"	\
		     "mr	9, 10	\n\t"	\
		     "sc		\n\t"	\
		     "mr	%0, 3	\n\t"	\
		     "mfcr	%1"
		     : "=r"(ret), "=r"(err)
		     :
		     : "cr0", "r0", "r3", "r4", "r5", "r6", "r7", "r8", "r9");

	if (err & 0x10000000) {
		errno = ret;
		ret = -1L;
	}

	return ret;
}

__attribute__ ((noreturn))
void exit(int status)
{
	syscall(SYS_exit, (long) status, 0, 0, 0, 0, 0, 0);
	while (1);
}

pid_t fork(void)
{
	return (pid_t) syscall(SYS_fork, 0, 0, 0, 0, 0, 0, 0);
}

void *mmap(void *addr, size_t length, int prot, int flags, int fd,
	   off_t offset)
{
	return (void *) syscall(SYS_mmap, (long) addr, (long) length,
				(long) prot, (long) flags, (long) fd,
				(long) offset, 0);
}

int munmap(void *addr, size_t length)
{
	return (int) syscall(SYS_munmap, (long) addr, (long) length,
			     0, 0, 0, 0, 0);
}

int mlock(const void *addr, size_t length)
{
	return (int) syscall(SYS_mlock, (long) addr, (long) length,
			     0, 0, 0, 0, 0);
}

void _start()
{
	unsigned long addr;
	void *region;

#ifdef __STRESS
	if (!fork())
		goto begin;
	if (!fork())
		goto begin;
	if (!fork())
		goto begin;
	if (!fork())
		goto begin;

begin:
#endif
	for (addr = 0; addr < TASK_SIZE; addr += 8 * PAGE_SIZE) {
		region = mmap((void *) addr, 8 * PAGE_SIZE, PROT_READ | PROT_WRITE,
			      MAP_FIXED_NOREPLACE | MAP_PRIVATE | MAP_ANONYMOUS,
			      -1, 0);
		if (region == MAP_FAILED) {
			if (errno == EEXIST || errno == EPERM)
				continue;
			break;
		}

		if (mlock(region, 8 * PAGE_SIZE))
			break;

		/* try to generate a page fault */
		*((unsigned int *) (region + 0 * PAGE_SIZE)) = 0xdeadbeef;
		*((unsigned int *) (region + 1 * PAGE_SIZE)) = 0xdeadbeef;
		*((unsigned int *) (region + 2 * PAGE_SIZE)) = 0xdeadbeef;
		*((unsigned int *) (region + 3 * PAGE_SIZE)) = 0xdeadbeef;
		*((unsigned int *) (region + 4 * PAGE_SIZE)) = 0xdeadbeef;
		*((unsigned int *) (region + 5 * PAGE_SIZE)) = 0xdeadbeef;
		*((unsigned int *) (region + 6 * PAGE_SIZE)) = 0xdeadbeef;
		*((unsigned int *) (region + 7 * PAGE_SIZE)) = 0xdeadbeef;

		if (munmap(region, 8 * PAGE_SIZE))
			break;
	}

	if (addr < TASK_SIZE)
		asm volatile("trap");

	exit(0);
}