hdata: Reserve Trace Areas

When hostboot is configured to setup in memory tracing it will reserve
some memory for use by the hardware tracing facility. We need to mark
these areas as off limits to the operating system and firmware.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

Author: oohal

hdata/memory.c

@@ -474,6 +474,51 @@ static void get_hb_reserved_mem(struct HDIF_common_hdr *ms_vpd)
 	}
 }
 
+static void parse_trace_reservations(struct HDIF_common_hdr *ms_vpd)
+{
+	unsigned int size;
+	int count, i;
+
+	/*
+	 * The trace arrays are only setup when hostboot is explicitly
+	 * configured to enable them. We need to check and gracefully handle
+	 * when they're not present.
+	 */
+
+	if (!HDIF_get_idata(ms_vpd, MSVPD_IDATA_TRACE_AREAS, &size) || !size) {
+		prlog(PR_DEBUG, "MS VPD: No trace areas found.");
+		return;
+	}
+
+	count = HDIF_get_iarray_size(ms_vpd, MSVPD_IDATA_TRACE_AREAS);
+	if (count <= 0) {
+		prlog(PR_DEBUG, "MS VPD: No trace areas found.");
+		return;
+	}
+
+	prlog(PR_INFO, "MS VPD: Found %d trace areas\n", count);
+
+	for (i = 0; i < count; i++) {
+		const struct msvpd_trace *trace_area;
+		u64 start, end;
+
+		trace_area = HDIF_get_iarray_item(ms_vpd,
+				MSVPD_IDATA_TRACE_AREAS, i, &size);
+
+		if (!trace_area)
+			return; /* shouldn't happen */
+
+		start = be64_to_cpu(trace_area->start) & ~HRMOR_BIT;
+		end = be64_to_cpu(trace_area->end) & ~HRMOR_BIT;
+
+		prlog(PR_INFO,
+			"MSVPD: Trace area: 0x%.16"PRIx64"-0x%.16"PRIx64"\n",
+			start, end);
+
+		mem_reserve_hwbuf("trace-area", start, end - start);
+	}
+}
+
 static bool __memory_parse(struct dt_node *root)
 {
 	struct HDIF_common_hdr *ms_vpd;
@@ -524,6 +569,8 @@ static bool __memory_parse(struct dt_node *root)
 
 	get_hb_reserved_mem(ms_vpd);
 
+	parse_trace_reservations(ms_vpd);
+
 	prlog(PR_INFO, "MS VPD: Total MB of RAM: 0x%llx\n",
 	       (long long)be64_to_cpu(tcms->total_in_mb));
 

hdata/spira.h

@@ -513,6 +513,11 @@ struct msvpd_pmover_bsr_synchro {
 } __packed;
 
 /* Idata index 3: Memory Trace Array */
+#define MSVPD_IDATA_TRACE_AREAS		3
+struct msvpd_trace {
+	__be64 start, end;
+	char reserved[16];
+};
 
 /* Idata index 4: UE Address Array */
 

hdata/test/stubs.c

@@ -99,6 +99,7 @@ STUB(op_display);
 STUB(fsp_preload_lid);
 STUB(fsp_wait_lid_loaded);
 STUB(fsp_adjust_lid_side);
+STUB(backtrace);
 
 /* Add HW specific stubs here */
 static void noop_function(void) {}