/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
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 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Page retirement can be an extended process due to the fact that a retirement
 * may not be possible when the original request is made.  The kernel will
 * repeatedly attempt to retire a given page, but will not let us know when the
 * page has been retired.  We therefore have to poll to see if the retirement
 * has been completed.  This poll is implemented with a bounded exponential
 * backoff to reduce the burden which we impose upon the system.
 *
 * To reduce the burden on fmd in the face of retirement storms, we schedule
 * all retries as a group.  In the simplest case, we attempt to retire a single
 * page.  When forced to retry, we initially schedule a retry at a configurable
 * interval t.  If the retry fails, we schedule another at 2 * t, and so on,
 * until t reaches the maximum interval (also configurable).  Future retries
 * for that page will occur with t equal to the maximum interval value.  We
 * will never give up on a retirement.
 *
 * With multiple retirements, the situation gets slightly more complicated.  As
 * indicated above, we schedule retries as a group.  We don't want to deny new
 * pages their short retry intervals, so we'll (re)set the retry interval to the
 * value appropriate for the newest page.
 */

#include <cma.h>

#include <time.h>
#include <errno.h>
#include <unistd.h>
#include <strings.h>
#include <fm/fmd_api.h>
#include <fm/libtopo.h>
#include <fm/fmd_fmri.h>
#include <fm/fmd_agent.h>
#include <sys/fm/protocol.h>

static void
cma_page_free(fmd_hdl_t *hdl, cma_page_t *page)
{
	nvlist_free(page->pg_asru);
	nvlist_free(page->pg_rsrc);
	fmd_hdl_free(hdl, page, sizeof (cma_page_t));
}

/*
 * Retire the specified ASRU, referring to a memory page by PA or by DIMM
 * offset (i.e. the encoded coordinates internal bank, row, and column).
 * In the initial FMA implementation, fault.memory.page exported an ASRU
 * with an explicit physical address, which is valid at the initial time of
 * diagnosis but may not be later following DR, DIMM removal, or interleave
 * changes.  On SPARC, this issue was solved by exporting the DIMM offset
 * and pushing the entire FMRI to the platform memory controller through
 * /dev/fm so it can derive the current PA from the DIMM and offset.
 * On x86, we also encode DIMM and offset in hc-specific, which is then used
 * by the x64 memory controller driver.
 * At some point these three approaches need to be rationalized: all platforms
 * should use the same scheme, either with decoding in the kernel or decoding
 * in userland (i.e. with a libtopo method to compute and update the PA).
 */
/*ARGSUSED*/
int
cma_page_retire(fmd_hdl_t *hdl, nvlist_t *nvl, nvlist_t *asru,
    const char *uuid, boolean_t repair)
{
	cma_page_t *page;
	uint64_t pageaddr;
	const char *action = repair ? "unretire" : "retire";
	int rc;
	nvlist_t *rsrc = NULL, *asrucp = NULL, *hcsp;

	(void) nvlist_lookup_nvlist(nvl, FM_FAULT_RESOURCE, &rsrc);

	if (nvlist_dup(asru, &asrucp, 0) != 0) {
		fmd_hdl_debug(hdl, "page retire nvlist dup failed\n");
		return (CMA_RA_FAILURE);
	}

	/* It should already be expanded, but we'll do it again anyway */
	if (fmd_nvl_fmri_expand(hdl, asrucp) < 0) {
		fmd_hdl_debug(hdl, "failed to expand page asru\n");
		cma_stats.bad_flts.fmds_value.ui64++;
		nvlist_free(asrucp);
		return (CMA_RA_FAILURE);
	}

	if (!repair && !fmd_nvl_fmri_present(hdl, asrucp)) {
		fmd_hdl_debug(hdl, "page retire overtaken by events\n");
		cma_stats.page_nonent.fmds_value.ui64++;
		nvlist_free(asrucp);
		return (CMA_RA_SUCCESS);
	}

	/* Figure out physaddr from resource or asru */
	if (rsrc == NULL ||
	    nvlist_lookup_nvlist(rsrc, FM_FMRI_HC_SPECIFIC, &hcsp) != 0 ||
	    (nvlist_lookup_uint64(hcsp, "asru-" FM_FMRI_HC_SPECIFIC_PHYSADDR,
	    &pageaddr) != 0 && nvlist_lookup_uint64(hcsp,
	    FM_FMRI_HC_SPECIFIC_PHYSADDR, &pageaddr) != 0)) {
		if (nvlist_lookup_uint64(asrucp, FM_FMRI_MEM_PHYSADDR,
		    &pageaddr) != 0) {
			fmd_hdl_debug(hdl, "mem fault missing 'physaddr'\n");
			cma_stats.bad_flts.fmds_value.ui64++;
			nvlist_free(asrucp);
			return (CMA_RA_FAILURE);
		}
	}

	if (repair) {
		if (!cma.cma_page_dounretire) {
			fmd_hdl_debug(hdl, "suppressed unretire of page %llx\n",
			    (u_longlong_t)pageaddr);
			cma_stats.page_supp.fmds_value.ui64++;
			nvlist_free(asrucp);
			return (CMA_RA_SUCCESS);
		}
		/* If unretire via topo fails, we fall back to legacy way */
		if (rsrc == NULL || (rc = fmd_nvl_fmri_unretire(hdl, rsrc)) < 0)
			rc = cma_fmri_page_unretire(hdl, asrucp);
	} else {
		if (!cma.cma_page_doretire) {
			fmd_hdl_debug(hdl, "suppressed retire of page %llx\n",
			    (u_longlong_t)pageaddr);
			cma_stats.page_supp.fmds_value.ui64++;
			nvlist_free(asrucp);
			return (CMA_RA_FAILURE);
		}
		/* If retire via topo fails, we fall back to legacy way */
		if (rsrc == NULL || (rc = fmd_nvl_fmri_retire(hdl, rsrc)) < 0)
			rc = cma_fmri_page_retire(hdl, asrucp);
	}

	if (rc == FMD_AGENT_RETIRE_DONE) {
		fmd_hdl_debug(hdl, "%sd page 0x%llx\n",
		    action, (u_longlong_t)pageaddr);
		if (repair)
			cma_stats.page_repairs.fmds_value.ui64++;
		else
			cma_stats.page_flts.fmds_value.ui64++;
		nvlist_free(asrucp);
		return (CMA_RA_SUCCESS);
	} else if (repair || rc != FMD_AGENT_RETIRE_ASYNC) {
		fmd_hdl_debug(hdl, "%s of page 0x%llx failed, will not "
		    "retry: %s\n", action, (u_longlong_t)pageaddr,
		    strerror(errno));

		cma_stats.page_fails.fmds_value.ui64++;
		nvlist_free(asrucp);
		return (CMA_RA_FAILURE);
	}

	/*
	 * The page didn't immediately retire.  We'll need to periodically
	 * check to see if it has been retired.
	 */
	fmd_hdl_debug(hdl, "page didn't retire - sleeping\n");

	page = fmd_hdl_zalloc(hdl, sizeof (cma_page_t), FMD_SLEEP);
	page->pg_addr = pageaddr;
	if (rsrc != NULL)
		(void) nvlist_dup(rsrc, &page->pg_rsrc, 0);
	page->pg_asru = asrucp;
	if (uuid != NULL)
		page->pg_uuid = fmd_hdl_strdup(hdl, uuid, FMD_SLEEP);

	page->pg_next = cma.cma_pages;
	cma.cma_pages = page;

	if (cma.cma_page_timerid != 0)
		fmd_timer_remove(hdl, cma.cma_page_timerid);

	cma.cma_page_curdelay = cma.cma_page_mindelay;

	cma.cma_page_timerid =
	    fmd_timer_install(hdl, NULL, NULL, cma.cma_page_curdelay);

	/* Don't free asrucp here.  This FMRI will be needed for retry. */
	return (CMA_RA_FAILURE);
}

static int
page_retry(fmd_hdl_t *hdl, cma_page_t *page)
{
	int rc;

	if (page->pg_asru != NULL &&
	    !fmd_nvl_fmri_present(hdl, page->pg_asru)) {
		fmd_hdl_debug(hdl, "page retire overtaken by events");
		cma_stats.page_nonent.fmds_value.ui64++;

		if (page->pg_uuid != NULL)
			fmd_case_uuclose(hdl, page->pg_uuid);
		return (1); /* no longer a page to retire */
	}

	if (page->pg_rsrc == NULL ||
	    (rc = fmd_nvl_fmri_service_state(hdl, page->pg_rsrc)) < 0)
		rc = cma_fmri_page_service_state(hdl, page->pg_asru);

	if (rc == FMD_SERVICE_STATE_UNUSABLE) {
		fmd_hdl_debug(hdl, "retired page 0x%llx on retry %u\n",
		    page->pg_addr, page->pg_nretries);
		cma_stats.page_flts.fmds_value.ui64++;

		if (page->pg_uuid != NULL)
			fmd_case_uuclose(hdl, page->pg_uuid);
		return (1); /* page retired */
	}

	if (rc == FMD_SERVICE_STATE_ISOLATE_PENDING) {
		fmd_hdl_debug(hdl, "scheduling another retry for 0x%llx\n",
		    page->pg_addr);
		return (0); /* schedule another retry */
	} else {
		fmd_hdl_debug(hdl, "failed to retry page 0x%llx "
		    "retirement: %s\n", page->pg_addr,
		    strerror(errno));

		cma_stats.page_fails.fmds_value.ui64++;
		return (1); /* give up */
	}
}

void
cma_page_retry(fmd_hdl_t *hdl)
{
	cma_page_t **pagep;

	cma.cma_page_timerid = 0;

	fmd_hdl_debug(hdl, "page_retry: timer fired\n");

	pagep = &cma.cma_pages;
	while (*pagep != NULL) {
		cma_page_t *page = *pagep;

		if (page_retry(hdl, page)) {
			/*
			 * Successful retry or we're giving up - remove from
			 * the list
			 */
			*pagep = page->pg_next;

			if (page->pg_uuid != NULL)
				fmd_hdl_strfree(hdl, page->pg_uuid);

			cma_page_free(hdl, page);
		} else {
			page->pg_nretries++;
			pagep = &page->pg_next;
		}
	}

	if (cma.cma_pages == NULL)
		return; /* no more retirements */

	/*
	 * We still have retirements that haven't completed.  Back the delay
	 * off, and schedule a retry.
	 */
	cma.cma_page_curdelay = MIN(cma.cma_page_curdelay * 2,
	    cma.cma_page_maxdelay);

	fmd_hdl_debug(hdl, "scheduled page retirement retry for %llu secs\n",
	    (u_longlong_t)(cma.cma_page_curdelay / NANOSEC));

	cma.cma_page_timerid =
	    fmd_timer_install(hdl, NULL, NULL, cma.cma_page_curdelay);
}

void
cma_page_fini(fmd_hdl_t *hdl)
{
	cma_page_t *page;

	while ((page = cma.cma_pages) != NULL) {
		cma.cma_pages = page->pg_next;
		if (page->pg_uuid != NULL)
			fmd_hdl_strfree(hdl, page->pg_uuid);
		cma_page_free(hdl, page);
	}
}