1 files changed, 265 insertions, 0 deletions
diff --git a/roms/skiboot/core/trace.c b/roms/skiboot/core/trace.c
new file mode 100644
index 000000000..561bd79e0
--- /dev/null
+++ b/roms/skiboot/core/trace.c
@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+/*
+ * Trace various things into in-memory buffers
+ *
+ * Copyright 2013-2019 IBM Corp.
+ */
+
+#include <trace.h>
+#include <timebase.h>
+#include <lock.h>
+#include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <cpu.h>
+#include <device.h>
+#include <libfdt.h>
+#include <processor.h>
+#include <skiboot.h>
+#include <opal-api.h>
+#include <debug_descriptor.h>
+#include <nvram.h>
+
+#define DEBUG_TRACES
+
+#define MAX_SIZE sizeof(union trace)
+
+/* Smaller trace buffer for early booting */
+#define BOOT_TBUF_SZ 65536
+static struct {
+	struct trace_info trace_info;
+	char buf[BOOT_TBUF_SZ + MAX_SIZE];
+} boot_tracebuf __section(".data.boot_trace");
+
+void init_boot_tracebuf(struct cpu_thread *boot_cpu)
+{
+	init_lock(&boot_tracebuf.trace_info.lock);
+	boot_tracebuf.trace_info.tb.buf_size = cpu_to_be64(BOOT_TBUF_SZ);
+	boot_tracebuf.trace_info.tb.max_size = cpu_to_be32(MAX_SIZE);
+
+	boot_cpu->trace = &boot_tracebuf.trace_info;
+}
+
+static size_t tracebuf_extra(void)
+{
+	/* We make room for the largest possible record */
+	return TBUF_SZ + MAX_SIZE;
+}
+
+/* To avoid bloating each entry, repeats are actually specific entries.
+ * tb->last points to the last (non-repeat) entry. */
+static bool handle_repeat(struct tracebuf *tb, const union trace *trace)
+{
+	struct trace_hdr *prev;
+	struct trace_repeat *rpt;
+	u32 len;
+
+	prev = (void *)tb->buf + be64_to_cpu(tb->last) % be64_to_cpu(tb->buf_size);
+
+	if (prev->type != trace->hdr.type
+	    || prev->len_div_8 != trace->hdr.len_div_8
+	    || prev->cpu != trace->hdr.cpu)
+		return false;
+
+	len = prev->len_div_8 << 3;
+	if (memcmp(prev + 1, &trace->hdr + 1, len - sizeof(*prev)) != 0)
+		return false;
+
+	/* If they've consumed prev entry, don't repeat. */
+	if (be64_to_cpu(tb->last) < be64_to_cpu(tb->start))
+		return false;
+
+	/* OK, it's a duplicate.  Do we already have repeat? */
+	if (be64_to_cpu(tb->last) + len != be64_to_cpu(tb->end)) {
+		u64 pos = be64_to_cpu(tb->last) + len;
+		/* FIXME: Reader is not protected from seeing this! */
+		rpt = (void *)tb->buf + pos % be64_to_cpu(tb->buf_size);
+		assert(pos + rpt->len_div_8*8 == be64_to_cpu(tb->end));
+		assert(rpt->type == TRACE_REPEAT);
+
+		/* If this repeat entry is full, don't repeat. */
+		if (be16_to_cpu(rpt->num) == 0xFFFF)
+			return false;
+
+		rpt->num = cpu_to_be16(be16_to_cpu(rpt->num) + 1);
+		rpt->timestamp = trace->hdr.timestamp;
+		return true;
+	}
+
+	/*
+	 * Generate repeat entry: it's the smallest possible entry, so we
+	 * must have eliminated old entries.
+	 */
+	assert(trace->hdr.len_div_8 * 8 >= sizeof(*rpt));
+
+	rpt = (void *)tb->buf + be64_to_cpu(tb->end) % be64_to_cpu(tb->buf_size);
+	rpt->timestamp = trace->hdr.timestamp;
+	rpt->type = TRACE_REPEAT;
+	rpt->len_div_8 = sizeof(*rpt) >> 3;
+	rpt->cpu = trace->hdr.cpu;
+	rpt->prev_len = cpu_to_be16(trace->hdr.len_div_8 << 3);
+	rpt->num = cpu_to_be16(1);
+	lwsync(); /* write barrier: complete repeat record before exposing */
+	tb->end = cpu_to_be64(be64_to_cpu(tb->end) + sizeof(*rpt));
+	return true;
+}
+
+void trace_add(union trace *trace, u8 type, u16 len)
+{
+	struct trace_info *ti = this_cpu()->trace;
+	unsigned int tsz;
+
+	trace->hdr.type = type;
+	trace->hdr.len_div_8 = (len + 7) >> 3;
+
+	tsz = trace->hdr.len_div_8 << 3;
+
+#ifdef DEBUG_TRACES
+	assert(tsz >= sizeof(trace->hdr));
+	assert(tsz <= sizeof(*trace));
+	assert(trace->hdr.type != TRACE_REPEAT);
+	assert(trace->hdr.type != TRACE_OVERFLOW);
+#endif
+	/* Skip traces not enabled in the debug descriptor */
+	if (trace->hdr.type < (8 * sizeof(debug_descriptor.trace_mask)) &&
+	    !((1ul << trace->hdr.type) & be64_to_cpu(debug_descriptor.trace_mask)))
+		return;
+
+	trace->hdr.timestamp = cpu_to_be64(mftb());
+	trace->hdr.cpu = cpu_to_be16(this_cpu()->server_no);
+
+	lock(&ti->lock);
+
+	/* Throw away old entries before we overwrite them. */
+	while ((be64_to_cpu(ti->tb.start) + be64_to_cpu(ti->tb.buf_size))
+	       < (be64_to_cpu(ti->tb.end) + tsz)) {
+		struct trace_hdr *hdr;
+
+		hdr = (void *)ti->tb.buf +
+			be64_to_cpu(ti->tb.start) % be64_to_cpu(ti->tb.buf_size);
+		ti->tb.start = cpu_to_be64(be64_to_cpu(ti->tb.start) +
+					   (hdr->len_div_8 << 3));
+	}
+
+	/* Must update ->start before we rewrite new entries. */
+	lwsync(); /* write barrier */
+
+	/* Check for duplicates... */
+	if (!handle_repeat(&ti->tb, trace)) {
+		/* This may go off end, and that's why ti->tb.buf is oversize */
+		memcpy(ti->tb.buf + be64_to_cpu(ti->tb.end) % be64_to_cpu(ti->tb.buf_size),
+		       trace, tsz);
+		ti->tb.last = ti->tb.end;
+		lwsync(); /* write barrier: write entry before exposing */
+		ti->tb.end = cpu_to_be64(be64_to_cpu(ti->tb.end) + tsz);
+	}
+	unlock(&ti->lock);
+}
+
+void trace_add_dt_props(void)
+{
+	uint64_t boot_buf_phys = (uint64_t) &boot_tracebuf.trace_info;
+	struct dt_node *exports, *traces;
+	unsigned int i;
+	fdt64_t *prop;
+	u64 tmask;
+	char tname[256];
+
+	exports = dt_find_by_path(opal_node, "firmware/exports");
+	if (!exports)
+		return;
+
+	/*
+	 * nvram hack to put all the trace buffer exports in the exports
+	 * node. This is useful if the kernel doesn't also export subnodes.
+	 */
+	if (nvram_query_safe("flat-trace-buf"))
+		traces = exports;
+	else
+		traces = dt_new(exports, "traces");
+
+	prop = malloc(sizeof(u64) * 2 * be32_to_cpu(debug_descriptor.num_traces));
+
+	for (i = 0; i < be32_to_cpu(debug_descriptor.num_traces); i++) {
+		uint64_t addr = be64_to_cpu(debug_descriptor.trace_phys[i]);
+		uint64_t size = be32_to_cpu(debug_descriptor.trace_size[i]);
+		uint32_t pir = be16_to_cpu(debug_descriptor.trace_pir[i]);
+
+		prop[i * 2]     = cpu_to_fdt64(addr);
+		prop[i * 2 + 1] = cpu_to_fdt64(size);
+
+		if (addr == boot_buf_phys)
+			snprintf(tname, sizeof(tname), "boot-%x", pir);
+		else
+			snprintf(tname, sizeof(tname), "trace-%x", pir);
+
+		dt_add_property_u64s(traces, tname, addr, size);
+	}
+
+	dt_add_property(opal_node, "ibm,opal-traces",
+			prop, sizeof(u64) * 2 * i);
+	free(prop);
+
+	tmask = (uint64_t)&debug_descriptor.trace_mask;
+	dt_add_property_u64(opal_node, "ibm,opal-trace-mask", tmask);
+}
+
+static void trace_add_desc(struct trace_info *t, uint64_t size, uint16_t pir)
+{
+	unsigned int i = be32_to_cpu(debug_descriptor.num_traces);
+
+	if (i >= DEBUG_DESC_MAX_TRACES) {
+		prerror("TRACE: Debug descriptor trace list full !\n");
+		return;
+	}
+
+	debug_descriptor.num_traces = cpu_to_be32(i + 1);
+	debug_descriptor.trace_phys[i] = cpu_to_be64((uint64_t)t);
+	debug_descriptor.trace_tce[i] = 0; /* populated later */
+	debug_descriptor.trace_size[i] = cpu_to_be32(size);
+	debug_descriptor.trace_pir[i] = cpu_to_be16(pir);
+}
+
+/* Allocate trace buffers once we know memory topology */
+void init_trace_buffers(void)
+{
+	struct cpu_thread *t;
+	struct trace_info *any = &boot_tracebuf.trace_info;
+	uint64_t size;
+
+	/* Boot the boot trace in the debug descriptor */
+	trace_add_desc(any, sizeof(boot_tracebuf), this_cpu()->pir);
+
+	/* Allocate a trace buffer for each primary cpu. */
+	for_each_cpu(t) {
+		if (t->is_secondary)
+			continue;
+
+		/* Use a 64K alignment for TCE mapping */
+		size = ALIGN_UP(sizeof(*t->trace) + tracebuf_extra(), 0x10000);
+		t->trace = local_alloc(t->chip_id, size, 0x10000);
+		if (t->trace) {
+			any = t->trace;
+			memset(t->trace, 0, size);
+			init_lock(&t->trace->lock);
+			t->trace->tb.max_size = cpu_to_be32(MAX_SIZE);
+			t->trace->tb.buf_size = cpu_to_be64(TBUF_SZ);
+			trace_add_desc(any, sizeof(t->trace->tb) +
+				       tracebuf_extra(), t->pir);
+		} else
+			prerror("TRACE: cpu 0x%x allocation failed\n", t->pir);
+	}
+
+	/* In case any allocations failed, share trace buffers. */
+	for_each_cpu(t) {
+		if (!t->is_secondary && !t->trace)
+			t->trace = any;
+	}
+
+	/* And copy those to the secondaries. */
+	for_each_cpu(t) {
+		if (!t->is_secondary)
+			continue;
+		t->trace = t->primary->trace;
+	}
+}