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From: Larry McVoy <lm@bitmover.com>
To: linux-kernel@vger.kernel.org
Subject: Re: help with next generation bkbits please
Date: Mon, 20 Sep 2004 18:25:36 -0700	[thread overview]
Message-ID: <20040921012536.GA17088@work.bitmover.com> (raw)
In-Reply-To: <20040921012208.GA16008@work.bitmover.com>

Forgot memory scrubber, here it is.

#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>

#define	unless(x)	if (!(x))
#define	u32		unsigned int
#define	status(s)	write(1, s, 1); newline = 1;

int	newline;
void	doit(u32 bs);

int
main(int ac, char **av)
{
	if (ac != 2) {
		printf("Usage: %s amount_in_MB\n", av[0]);
		exit(0);
	}
	doit(atoi(av[1])<<20);
	return (0);
}

void
bad(u32 *start, u32 *p, u32 want)
{
	u32	off = (char*)p - (char*)start;
	u32	got = *p;

	if (newline) printf("\n");
	newline = 0;
	printf("WANT=0x%08x GOT=0x%08x DIFF=0x%08x OFF=0x%08x ADDR=%p\n",
	    want, got, want - got, off, (void*)p);
}

void
doit(u32 bs)
{
	u32	*buf = malloc(bs);
	u32	*end;
	u32	*p;
	u32	off;

	fprintf(stderr, "Scrub %u bytes\n", bs);
	unless (buf) {
		perror("malloc");
		exit(1);
	}
	end = (u32*)((char*)buf + bs);
	bzero(buf, bs);
	unless (sizeof(int) == 4) {
		fprintf(stderr, "Expected 4 byte ints\n");
		exit(1);
	}
	for (off = 0, p = buf; p < end; *p++ = off, off += 4);
	for (;;) {
		for (off = 0, p = buf; p < end; off += 4) {
			if (*p != off) bad(buf, p, off);
			*p++ = 0xdeadbeef;
		}
		status("d");
		for (off = 0, p = buf; p < end; off += 4) {
			if (*p != 0xdeadbeef) bad(buf, p, 0xdeadbeef);
			*p++ = 0x50505050;
		}
		status("5");
		for (off = 0, p = buf; p < end; off += 4) {
			if (*p != 0x50505050) bad(buf, p, 0x50505050);
			*p++ = 0x0a0a0a0a;
		}
		status("a");
		for (off = 0, p = buf; p < end; off += 4) {
			if (*p != 0x0a0a0a0a) bad(buf, p, 0x0a0a0a0a);
			*p++ = 0x55555555;
		}
		status("-");
		for (off = 0, p = buf; p < end; off += 4) {
			if (*p != 0x55555555) bad(buf, p, 0x55555555);
			*p++ = 0xaaaaaaaa;
		}
		status("A");
		for (off = 0, p = buf; p < end; off += 4) {
			if (*p != 0xaaaaaaaa) bad(buf, p, 0xaaaaaaaa);
			*p++ = 0x0;
		}
		status("0");
		for (off = 0, p = buf; p < end; off += 4) {
			if (*p != 0x0) bad(buf, p, 0);
			*p++ = 0xffffffff;
		}
		status("f");
		for (off = 0, p = buf; p < end; off += 4) {
			if (*p != 0xffffffff) bad(buf, p, 0xffffffff);
			*p++ = off;
		}
		status("o");
	}
}

  reply	other threads:[~2004-09-21  1:25 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-21  1:22 help with next generation bkbits please Larry McVoy
2004-09-21  1:25 ` Larry McVoy [this message]
2004-09-21  8:13 ` Denis Vlasenko

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