[S390] zfcpdump support.

s390 machines provide hardware support for creating Linux dumps on SCSI
disks. For creating a dump a special purpose dump Linux is used. The first
32 MB of memory are saved by the hardware before the dump Linux is
booted. Via an SCLP interface, the saved memory can be accessed from
Linux. This patch exports memory and registers of the crashed Linux to
userspace via a debugfs file. For more information refer to
Documentation/s390/zfcpdump.txt, which is included in this patch.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 255 insertions, 0 deletions

diff --git a/drivers/s390/char/sclp_sdias.c b/drivers/s390/char/sclp_sdias.c
new file mode 100644
index 000000000000..06a4d0897232
--- /dev/null
+++ b/drivers/s390/char/sclp_sdias.c
@@ -0,0 +1,255 @@
+/*
+ * Sclp "store data in absolut storage"
+ *
+ * Copyright IBM Corp. 2003,2007
+ * Author(s): Michael Holzheu
+ */
+
+#include <linux/sched.h>
+#include <asm/sclp.h>
+#include <asm/debug.h>
+#include <asm/ipl.h>
+#include "sclp.h"
+#include "sclp_rw.h"
+
+#define TRACE(x...) debug_sprintf_event(sdias_dbf, 1, x)
+#define ERROR_MSG(x...) printk ( KERN_ALERT "SDIAS: " x )
+
+#define SDIAS_RETRIES 300
+#define SDIAS_SLEEP_TICKS 50
+
+#define EQ_STORE_DATA	0x0
+#define EQ_SIZE		0x1
+#define DI_FCP_DUMP	0x0
+#define ASA_SIZE_32	0x0
+#define ASA_SIZE_64	0x1
+#define EVSTATE_ALL_STORED	0x0
+#define EVSTATE_NO_DATA		0x3
+#define EVSTATE_PART_STORED	0x10
+
+static struct debug_info *sdias_dbf;
+
+static struct sclp_register sclp_sdias_register = {
+	.send_mask = EvTyp_SDIAS_Mask,
+};
+
+struct sdias_evbuf {
+	struct	evbuf_header hdr;
+	u8	event_qual;
+	u8	data_id;
+	u64	reserved2;
+	u32	event_id;
+	u16	reserved3;
+	u8	asa_size;
+	u8	event_status;
+	u32	reserved4;
+	u32	blk_cnt;
+	u64	asa;
+	u32	reserved5;
+	u32	fbn;
+	u32	reserved6;
+	u32	lbn;
+	u16	reserved7;
+	u16	dbs;
+} __attribute__((packed));
+
+struct sdias_sccb {
+	struct sccb_header  hdr;
+	struct sdias_evbuf  evbuf;
+} __attribute__((packed));
+
+static struct sdias_sccb sccb __attribute__((aligned(4096)));
+
+static int sclp_req_done;
+static wait_queue_head_t sdias_wq;
+static DEFINE_MUTEX(sdias_mutex);
+
+static void sdias_callback(struct sclp_req *request, void *data)
+{
+	struct sdias_sccb *sccb;
+
+	sccb = (struct sdias_sccb *) request->sccb;
+	sclp_req_done = 1;
+	wake_up(&sdias_wq); /* Inform caller, that request is complete */
+	TRACE("callback done\n");
+}
+
+static int sdias_sclp_send(struct sclp_req *req)
+{
+	int retries;
+	int rc;
+
+	for (retries = SDIAS_RETRIES; retries; retries--) {
+		sclp_req_done = 0;
+		TRACE("add request\n");
+		rc = sclp_add_request(req);
+		if (rc) {
+			/* not initiated, wait some time and retry */
+			set_current_state(TASK_INTERRUPTIBLE);
+			TRACE("add request failed: rc = %i\n",rc);
+			schedule_timeout(SDIAS_SLEEP_TICKS);
+			continue;
+		}
+		/* initiated, wait for completion of service call */
+		wait_event(sdias_wq, (sclp_req_done == 1));
+		if (req->status == SCLP_REQ_FAILED) {
+			TRACE("sclp request failed\n");
+			rc = -EIO;
+			continue;
+		}
+		TRACE("request done\n");
+		break;
+	}
+	return rc;
+}
+
+/*
+ * Get number of blocks (4K) available in the HSA
+ */
+int sclp_sdias_blk_count(void)
+{
+	struct sclp_req request;
+	int rc;
+
+	mutex_lock(&sdias_mutex);
+
+	memset(&sccb, 0, sizeof(sccb));
+	memset(&request, 0, sizeof(request));
+
+	sccb.hdr.length = sizeof(sccb);
+	sccb.evbuf.hdr.length = sizeof(struct sdias_evbuf);
+	sccb.evbuf.hdr.type = EvTyp_SDIAS;
+	sccb.evbuf.event_qual = EQ_SIZE;
+	sccb.evbuf.data_id = DI_FCP_DUMP;
+	sccb.evbuf.event_id = 4712;
+	sccb.evbuf.dbs = 1;
+
+	request.sccb = &sccb;
+	request.command = SCLP_CMDW_WRITE_EVENT_DATA;
+	request.status = SCLP_REQ_FILLED;
+	request.callback = sdias_callback;
+
+	rc = sdias_sclp_send(&request);
+	if (rc) {
+		ERROR_MSG("sclp_send failed for get_nr_blocks\n");
+		goto out;
+	}
+	if (sccb.hdr.response_code != 0x0020) {
+		TRACE("send failed: %x\n", sccb.hdr.response_code);
+		rc = -EIO;
+		goto out;
+	}
+
+	switch (sccb.evbuf.event_status) {
+		case 0:
+			rc = sccb.evbuf.blk_cnt;
+			break;
+		default:
+			ERROR_MSG("SCLP error: %x\n", sccb.evbuf.event_status);
+			rc = -EIO;
+			goto out;
+	}
+	TRACE("%i blocks\n", rc);
+out:
+	mutex_unlock(&sdias_mutex);
+	return rc;
+}
+
+/*
+ * Copy from HSA to absolute storage (not reentrant):
+ *
+ * @dest     : Address of buffer where data should be copied
+ * @start_blk: Start Block (beginning with 1)
+ * @nr_blks  : Number of 4K blocks to copy
+ *
+ * Return Value: 0 : Requested 'number' of blocks of data copied
+ *		 <0: ERROR - negative event status
+ */
+int sclp_sdias_copy(void *dest, int start_blk, int nr_blks)
+{
+	struct sclp_req request;
+	int rc;
+
+	mutex_lock(&sdias_mutex);
+
+	memset(&sccb, 0, sizeof(sccb));
+	memset(&request, 0, sizeof(request));
+
+	sccb.hdr.length = sizeof(sccb);
+	sccb.evbuf.hdr.length = sizeof(struct sdias_evbuf);
+	sccb.evbuf.hdr.type = EvTyp_SDIAS;
+	sccb.evbuf.hdr.flags = 0;
+	sccb.evbuf.event_qual = EQ_STORE_DATA;
+	sccb.evbuf.data_id = DI_FCP_DUMP;
+	sccb.evbuf.event_id = 4712;
+#ifdef __s390x__
+	sccb.evbuf.asa_size = ASA_SIZE_64;
+#else
+	sccb.evbuf.asa_size = ASA_SIZE_32;
+#endif
+	sccb.evbuf.event_status = 0;
+	sccb.evbuf.blk_cnt = nr_blks;
+	sccb.evbuf.asa = (unsigned long)dest;
+	sccb.evbuf.fbn = start_blk;
+	sccb.evbuf.lbn = 0;
+	sccb.evbuf.dbs = 1;
+
+	request.sccb	 = &sccb;
+	request.command  = SCLP_CMDW_WRITE_EVENT_DATA;
+	request.status	 = SCLP_REQ_FILLED;
+	request.callback = sdias_callback;
+
+	rc = sdias_sclp_send(&request);
+	if (rc) {
+		ERROR_MSG("sclp_send failed: %x\n", rc);
+		goto out;
+	}
+	if (sccb.hdr.response_code != 0x0020) {
+		TRACE("copy failed: %x\n", sccb.hdr.response_code);
+		rc = -EIO;
+		goto out;
+	}
+
+	switch (sccb.evbuf.event_status) {
+		case EVSTATE_ALL_STORED:
+			TRACE("all stored\n");
+		case EVSTATE_PART_STORED:
+			TRACE("part stored: %i\n", sccb.evbuf.blk_cnt);
+			break;
+		case EVSTATE_NO_DATA:
+			TRACE("no data\n");
+		default:
+			ERROR_MSG("Error from SCLP while copying hsa. "
+				  "Event status = %x\n",
+				sccb.evbuf.event_status);
+			rc = -EIO;
+	}
+out:
+	mutex_unlock(&sdias_mutex);
+	return rc;
+}
+
+int __init sdias_init(void)
+{
+	int rc;
+
+	if (ipl_info.type != IPL_TYPE_FCP_DUMP)
+		return 0;
+	sdias_dbf = debug_register("dump_sdias", 4, 1, 4 * sizeof(long));
+	debug_register_view(sdias_dbf, &debug_sprintf_view);
+	debug_set_level(sdias_dbf, 6);
+	rc = sclp_register(&sclp_sdias_register);
+	if (rc) {
+		ERROR_MSG("sclp register failed\n");
+		return rc;
+	}
+	init_waitqueue_head(&sdias_wq);
+	TRACE("init done\n");
+	return 0;
+}
+
+void __exit sdias_exit(void)
+{
+	debug_unregister(sdias_dbf);
+	sclp_unregister(&sclp_sdias_register);
+}