s390/pci: Add pci_msg debug view to PCI report

Using the newly introduced debug_dump() mechanism add formatted content
of pci_debug_msg_id to the PCI report. The formatting is based on the
existing sprintf format but removes caller pointer and area index and
adds an column header. This will allow the platform to collect this log
data together with hardware errors. This sets the reverse flag such that
the newest log entries get added to the PCI report even if not all debug
log entries fit.

Reviewed-by: Halil Pasic <[e-mail]>
Co-developed-by: Halil Pasic <[e-mail]>
Signed-off-by: Halil Pasic <[e-mail]>
Signed-off-by: Niklas Schnelle <[e-mail]>
Signed-off-by: Alexander Gordeev <[e-mail]>

arch/s390/include/asm/debug.h

···
 			 int area, debug_entry_t *entry,
 			 char *out_buf, size_t out_buf_size);
 
+#define DEBUG_SPRINTF_MAX_ARGS 10
+int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
+			    char *out_buf, size_t out_buf_size,
+			    const char *inbuf);
 struct debug_view {
 	char name[DEBUG_MAX_NAME_LEN];
 	debug_prolog_proc_t *prolog_proc;

arch/s390/kernel/debug.c

···
 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
 				     char *out_buf, size_t out_buf_size,
 				     const char *in_buf);
-static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
-				   char *out_buf, size_t out_buf_size,
-				   const char *inbuf);
 static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
 static void debug_events_append(debug_info_t *dest, debug_info_t *src);
 
···
 
 #define DEBUG_SPRINTF_MAX_ARGS 10
 
-static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
-				   char *out_buf, size_t out_buf_size, const char *inbuf)
+int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
+			    char *out_buf, size_t out_buf_size, const char *inbuf)
 {
 	debug_sprintf_entry_t *curr_event = (debug_sprintf_entry_t *)inbuf;
 	int num_longs, num_used_args = 0, i, rc = 0;
···
 out:
 	return rc;
 }
+EXPORT_SYMBOL(debug_sprintf_format_fn);
 
 /*
  * debug_init:

arch/s390/pci/pci_report.c

···
 #include <linux/pci.h>
 
 #include <asm/sclp.h>
+#include <asm/debug.h>
+#include <asm/pci_debug.h>
 
 #include "pci_report.h"
 
···
 	};
 }
 
+static int debug_log_header_fn(debug_info_t *id, struct debug_view *view,
+			       int area, debug_entry_t *entry, char *out_buf,
+			       size_t out_buf_size)
+{
+	unsigned long sec, usec;
+	unsigned int level;
+	char *except_str;
+	int rc = 0;
+
+	level = entry->level;
+	sec = entry->clock;
+	usec = do_div(sec, USEC_PER_SEC);
+
+	if (entry->exception)
+		except_str = "*";
+	else
+		except_str = "-";
+	rc += scnprintf(out_buf, out_buf_size, "%011ld:%06lu %1u %1s %04u  ",
+			sec, usec, level, except_str,
+			entry->cpu);
+	return rc;
+}
+
+static int debug_prolog_header(debug_info_t *id, struct debug_view *view,
+			       char *out_buf, size_t out_buf_size)
+{
+	return scnprintf(out_buf, out_buf_size, "sec:usec level except cpu  msg\n");
+}
+
+static struct debug_view debug_log_view = {
+	"pci_msg_log",
+	&debug_prolog_header,
+	&debug_log_header_fn,
+	&debug_sprintf_format_fn,
+	NULL,
+	NULL
+};
+
 /**
  * zpci_report_status - Report the status of operations on a PCI device
  * @zdev:	The PCI device for which to report status
···
  * Event Data mechanism. Besides the operation and status strings the report
  * also contains additional information about the device deemed useful for
  * debug such as the currently bound device driver, if any, and error state.
+ * Additionally a string representation of pci_debug_msg_id, or as much as fits,
+ * is also included.
  *
  * Return: 0 on success an error code < 0 otherwise.
  */
···
 	buf += scnprintf(buf, end - buf, "state: %s\n",
 			 (pdev) ? zpci_state_str(pdev->error_state) : "n/a");
 	buf += scnprintf(buf, end - buf, "driver: %s\n", (driver) ? driver->name : "n/a");
+	ret = debug_dump(pci_debug_msg_id, &debug_log_view, buf, end - buf, true);
+	if (ret < 0)
+		pr_err("Reading PCI debug messages failed with code %d\n", ret);
+	else
+		buf += ret;
 
 	report->header.version = 1;
 	report->header.action = SCLP_ERRNOTIFY_AQ_INFO_LOG;