/* -*- linux-c -*- ------------------------------------------------------- *
 *
 *   Copyright 2002 H. Peter Anvin - All Rights Reserved
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
 *   Boston MA 02111-1307, USA; either version 2 of the License, or
 *   (at your option) any later version; incorporated herein by reference.
 *
 * ----------------------------------------------------------------------- */

/*
 * raid6/recov.c
 *
 * RAID-6 data recovery in dual failure mode.  In single failure mode,
 * use the RAID-5 algorithm (or, in the case of Q failure, just reconstruct
 * the syndrome.)
 */

#include <linux/export.h>
#include <linux/raid/pq.h>

/* Recover two failed data blocks. */
static void raid6_2data_recov_intx1(int disks, size_t bytes, int faila,
		int failb, void **ptrs)
{
	u8 *p, *q, *dp, *dq;
	u8 px, qx, db;
	const u8 *pbmul;	/* P multiplier table for B data */
	const u8 *qmul;		/* Q multiplier table (for both) */

	p = (u8 *)ptrs[disks-2];
	q = (u8 *)ptrs[disks-1];

	/* Compute syndrome with zero for the missing data pages
	   Use the dead data pages as temporary storage for
	   delta p and delta q */
	dp = (u8 *)ptrs[faila];
	ptrs[faila] = (void *)raid6_empty_zero_page;
	ptrs[disks-2] = dp;
	dq = (u8 *)ptrs[failb];
	ptrs[failb] = (void *)raid6_empty_zero_page;
	ptrs[disks-1] = dq;

	raid6_call.gen_syndrome(disks, bytes, ptrs);

	/* Restore pointer table */
	ptrs[faila]   = dp;
	ptrs[failb]   = dq;
	ptrs[disks-2] = p;
	ptrs[disks-1] = q;

	/* Now, pick the proper data tables */
	pbmul = raid6_gfmul[raid6_gfexi[failb-faila]];
	qmul  = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]];

	/* Now do it... */
	while ( bytes-- ) {
		px    = *p ^ *dp;
		qx    = qmul[*q ^ *dq];
		*dq++ = db = pbmul[px] ^ qx; /* Reconstructed B */
		*dp++ = db ^ px; /* Reconstructed A */
		p++; q++;
	}
}

/* Recover failure of one data block plus the P block */
static void raid6_datap_recov_intx1(int disks, size_t bytes, int faila,
		void **ptrs)
{
	u8 *p, *q, *dq;
	const u8 *qmul;		/* Q multiplier table */

	p = (u8 *)ptrs[disks-2];
	q = (u8 *)ptrs[disks-1];

	/* Compute syndrome with zero for the missing data page
	   Use the dead data page as temporary storage for delta q */
	dq = (u8 *)ptrs[faila];
	ptrs[faila] = (void *)raid6_empty_zero_page;
	ptrs[disks-1] = dq;

	raid6_call.gen_syndrome(disks, bytes, ptrs);

	/* Restore pointer table */
	ptrs[faila]   = dq;
	ptrs[disks-1] = q;

	/* Now, pick the proper data tables */
	qmul  = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]]];

	/* Now do it... */
	while ( bytes-- ) {
		*p++ ^= *dq = qmul[*q ^ *dq];
		q++; dq++;
	}
}


const struct raid6_recov_calls raid6_recov_intx1 = {
	.data2 = raid6_2data_recov_intx1,
	.datap = raid6_datap_recov_intx1,
	.valid = NULL,
	.name = "intx1",
	.priority = 0,
};

#ifndef __KERNEL__
/* Testing only */

/* Recover two failed blocks. */
void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, void **ptrs)
{
	if ( faila > failb ) {
		int tmp = faila;
		faila = failb;
		failb = tmp;
	}

	if ( failb == disks-1 ) {
		if ( faila == disks-2 ) {
			/* P+Q failure.  Just rebuild the syndrome. */
			raid6_call.gen_syndrome(disks, bytes, ptrs);
		} else {
			/* data+Q failure.  Reconstruct data from P,
			   then rebuild syndrome. */
			/* NOT IMPLEMENTED - equivalent to RAID-5 */
		}
	} else {
		if ( failb == disks-2 ) {
			/* data+P failure. */
			raid6_datap_recov(disks, bytes, faila, ptrs);
		} else {
			/* data+data failure. */
			raid6_2data_recov(disks, bytes, faila, failb, ptrs);
		}
	}
}

#endif
143'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Bjorn Helgaas &lt;bhelgaas@google.com&gt;</td><td class='right'>2017-01-27 15:00:45 -0600</td></tr>
<tr><th>committer</th><td>Bjorn Helgaas &lt;bhelgaas@google.com&gt;</td><td class='right'>2017-01-27 15:00:45 -0600</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/math-emu/single.h?h=nds-private-remove&amp;id=030305d69fc6963c16003f50d7e8d74b02d0a143'>030305d69fc6963c16003f50d7e8d74b02d0a143</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/math-emu/single.h?id=030305d69fc6963c16003f50d7e8d74b02d0a143'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=030305d69fc6963c16003f50d7e8d74b02d0a143'>363a4e34d199178769b7e7eeb26ea2620a55847b</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/math-emu/single.h?h=nds-private-remove&amp;id=030305d69fc6963c16003f50d7e8d74b02d0a143'>include/math-emu/single.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/math-emu/single.h?h=nds-private-remove&amp;id=4d191b1b63c209e37bf27938ef365244d3c41084'>4d191b1b63c209e37bf27938ef365244d3c41084</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/math-emu/single.h?h=nds-private-remove&amp;id=030305d69fc6963c16003f50d7e8d74b02d0a143&amp;id2=4d191b1b63c209e37bf27938ef365244d3c41084'>diff</a>)</td></tr></table>
<div class='commit-subject'>PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies</div><div class='commit-msg'>In a struct pcie_link_state, link-&gt;root points to the pcie_link_state of
the root of the PCIe hierarchy.  For the topmost link, this points to
itself (link-&gt;root = link).  For others, we copy the pointer from the
parent (link-&gt;root = link-&gt;parent-&gt;root).

Previously we recognized that Root Ports originated PCIe hierarchies, but
we treated PCI/PCI-X to PCIe Bridges as being in the middle of the
hierarchy, and when we tried to copy the pointer from link-&gt;parent-&gt;root,
there was no parent, and we dereferenced a NULL pointer:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
  IP: [&lt;ffffffff9e424350&gt;] pcie_aspm_init_link_state+0x170/0x820

Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just
like Root Ports do, so link-&gt;root for these devices should also point to
itself.

Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181
Tested-by: lists@ssl-mail.com
Tested-by: Jayachandran C. &lt;jnair@caviumnetworks.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
CC: stable@vger.kernel.org	# v4.2+</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=030305d69fc6963c16003f50d7e8d74b02d0a143'>Diffstat</a> (limited to 'include/math-emu/single.h')</div><table summary='diffstat' class='diffstat'>