x86, bts, ftrace: adapt the hw-branch-tracer to the ds.c interface

Impact: restructure code, cleanup

Remove BTS bits from the hw-branch-tracer (renamed from bts-tracer) and
use the ds interface.

Signed-off-by: Markus Metzger <markut.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

5 files changed, 56 insertions, 129 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index bde6f03512d5..d8bae6f4219e 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -251,9 +251,9 @@ config STACK_TRACER
 
           Say N if unsure.
 
-config BTS_TRACER
+config HW_BRANCH_TRACER
         depends on HAVE_HW_BRANCH_TRACER
-        bool "Trace branches"
+        bool "Trace hw branches"
         select TRACING
         help
           This tracer records all branches on the system in a circular
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 62dc561b6676..349d5a93653f 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -31,7 +31,7 @@ obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o
 obj-$(CONFIG_BOOT_TRACER) += trace_boot.o
 obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += trace_functions_graph.o
 obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o
-obj-$(CONFIG_BTS_TRACER) += trace_bts.o
+obj-$(CONFIG_HW_BRANCH_TRACER) += trace_hw_branches.o
 obj-$(CONFIG_POWER_TRACER) += trace_power.o
 
 libftrace-y := ftrace.o
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8ebe0070c47a..639344a4d3a2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2425,7 +2425,7 @@ __tracing_open(struct inode *inode, struct file *file, int *ret)
 
         /* Notify the tracer early; before we stop tracing. */
         if (iter->trace && iter->trace->open)
-                        iter->trace->open(iter);
+                iter->trace->open(iter);
 
         /* Annotate start of buffers if we had overruns */
         if (ring_buffer_overruns(iter->tr->buffer))
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 5ac697065a48..f07c246dd73d 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -28,7 +28,7 @@ enum trace_type {
         TRACE_GRAPH_RET,
         TRACE_GRAPH_ENT,
         TRACE_USER_STACK,
-        TRACE_BTS,
+        TRACE_HW_BRANCHES,
         TRACE_POWER,
 
         __TRACE_LAST_TYPE
@@ -159,10 +159,10 @@ struct trace_branch {
         char                    correct;
 };
 
-struct bts_entry {
+struct hw_branch_entry {
         struct trace_entry      ent;
-        unsigned long           from;
-        unsigned long           to;
+        u64                     from;
+        u64                     to;
 };
 
 struct trace_power {
@@ -278,7 +278,7 @@ extern void __ftrace_bad_type(void);
                           TRACE_GRAPH_ENT);             \
                 IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,      \
                           TRACE_GRAPH_RET);             \
-                IF_ASSIGN(var, ent, struct bts_entry, TRACE_BTS);\
+                IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
                 IF_ASSIGN(var, ent, struct trace_power, TRACE_POWER); \
                 __ftrace_bad_type();                                    \
         } while (0)
@@ -414,9 +414,7 @@ void trace_function(struct trace_array *tr,
 
 void trace_graph_return(struct ftrace_graph_ret *trace);
 int trace_graph_entry(struct ftrace_graph_ent *trace);
-void trace_bts(struct trace_array *tr,
-               unsigned long from,
-               unsigned long to);
+void trace_hw_branch(struct trace_array *tr, u64 from, u64 to);
 
 void tracing_start_cmdline_record(void);
 void tracing_stop_cmdline_record(void);
diff --git a/kernel/trace/trace_bts.c b/kernel/trace/trace_hw_branches.c
index 23b76e4690ef..ee29e012aa97 100644
--- a/kernel/trace/trace_bts.c
+++ b/kernel/trace/trace_hw_branches.c
@@ -1,5 +1,5 @@
 /*
- * BTS tracer
+ * h/w branch tracer for x86 based on bts
  *
  * Copyright (C) 2008 Markus Metzger <markus.t.metzger@gmail.com>
  *
@@ -25,68 +25,6 @@ static DEFINE_PER_CPU(unsigned char[SIZEOF_BTS], buffer);
 #define this_buffer per_cpu(buffer, smp_processor_id())
 
 
-/*
- * Information to interpret a BTS record.
- * This will go into an in-kernel BTS interface.
- */
-static unsigned char sizeof_field;
-static unsigned long debugctl_mask;
-
-#define sizeof_bts (3 * sizeof_field)
-
-static void bts_trace_cpuinit(struct cpuinfo_x86 *c)
-{
-        switch (c->x86) {
-        case 0x6:
-                switch (c->x86_model) {
-                case 0x0 ... 0xC:
-                        break;
-                case 0xD:
-                case 0xE: /* Pentium M */
-                        sizeof_field = sizeof(long);
-                        debugctl_mask = (1<<6)|(1<<7);
-                        break;
-                default:
-                        sizeof_field = 8;
-                        debugctl_mask = (1<<6)|(1<<7);
-                        break;
-                }
-                break;
-        case 0xF:
-                switch (c->x86_model) {
-                case 0x0:
-                case 0x1:
-                case 0x2: /* Netburst */
-                        sizeof_field = sizeof(long);
-                        debugctl_mask = (1<<2)|(1<<3);
-                        break;
-                default:
-                        /* sorry, don't know about them */
-                        break;
-                }
-                break;
-        default:
-                /* sorry, don't know about them */
-                break;
-        }
-}
-
-static inline void bts_enable(void)
-{
-        unsigned long debugctl;
-
-        rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
-        wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl | debugctl_mask);
-}
-
-static inline void bts_disable(void)
-{
-        unsigned long debugctl;
-
-        rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
-        wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl & ~debugctl_mask);
-}
-
 static void bts_trace_reset(struct trace_array *tr)
 {
         int cpu;
@@ -99,15 +37,17 @@ static void bts_trace_reset(struct trace_array *tr)
 
 static void bts_trace_start_cpu(void *arg)
 {
+        if (this_tracer)
+                ds_release_bts(this_tracer);
+
         this_tracer =
                 ds_request_bts(/* task = */ NULL, this_buffer, SIZEOF_BTS,
-                               /* ovfl = */ NULL, /* th = */ (size_t)-1);
+                               /* ovfl = */ NULL, /* th = */ (size_t)-1,
+                               BTS_KERNEL);
         if (IS_ERR(this_tracer)) {
                 this_tracer = NULL;
                 return;
         }
-
-        bts_enable();
 }
 
 static void bts_trace_start(struct trace_array *tr)
@@ -123,8 +63,6 @@ static void bts_trace_start(struct trace_array *tr)
 static void bts_trace_stop_cpu(void *arg)
 {
         if (this_tracer) {
-                bts_disable();
-
                 ds_release_bts(this_tracer);
                 this_tracer = NULL;
         }
@@ -140,7 +78,6 @@ static void bts_trace_stop(struct trace_array *tr)
 
 static int bts_trace_init(struct trace_array *tr)
 {
-        bts_trace_cpuinit(&boot_cpu_data);
         bts_trace_reset(tr);
         bts_trace_start(tr);
 
@@ -149,47 +86,37 @@ static int bts_trace_init(struct trace_array *tr)
 
 static void bts_trace_print_header(struct seq_file *m)
 {
-#ifdef __i386__
-        seq_puts(m, "# CPU#    FROM           TO     FUNCTION\n");
-        seq_puts(m, "#  |       |             |         |\n");
-#else
         seq_puts(m,
                  "# CPU#        FROM                   TO         FUNCTION\n");
         seq_puts(m,
                  "#  |           |                     |             |\n");
-#endif
 }
 
 static enum print_line_t bts_trace_print_line(struct trace_iterator *iter)
 {
         struct trace_entry *entry = iter->ent;
         struct trace_seq *seq = &iter->seq;
-        struct bts_entry *it;
+        struct hw_branch_entry *it;
 
         trace_assign_type(it, entry);
 
-        if (entry->type == TRACE_BTS) {
-                int ret;
-#ifdef CONFIG_KALLSYMS
-                char function[KSYM_SYMBOL_LEN];
-                sprint_symbol(function, it->from);
-#else
-                char *function = "<unknown>";
-#endif
-
-                ret = trace_seq_printf(seq, "%4d  0x%lx -> 0x%lx [%s]\n",
-                                       entry->cpu, it->from, it->to, function);
-                if (!ret)
-                        return TRACE_TYPE_PARTIAL_LINE;;
-                return TRACE_TYPE_HANDLED;
+        if (entry->type == TRACE_HW_BRANCHES) {
+                if (trace_seq_printf(seq, "%4d  ", entry->cpu) &&
+                    trace_seq_printf(seq, "0x%016llx -> 0x%016llx ",
+                                     it->from, it->to) &&
+                    (!it->from ||
+                     seq_print_ip_sym(seq, it->from, /* sym_flags = */ 0)) &&
+                    trace_seq_printf(seq, "\n"))
+                        return TRACE_TYPE_HANDLED;
+                return TRACE_TYPE_PARTIAL_LINE;;
         }
         return TRACE_TYPE_UNHANDLED;
 }
 
-void trace_bts(struct trace_array *tr, unsigned long from, unsigned long to)
+void trace_hw_branch(struct trace_array *tr, u64 from, u64 to)
 {
         struct ring_buffer_event *event;
-        struct bts_entry *entry;
+        struct hw_branch_entry *entry;
         unsigned long irq;
 
         event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq);
@@ -197,56 +124,58 @@ void trace_bts(struct trace_array *tr, unsigned long from, unsigned long to)
                 return;
         entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(&entry->ent, 0, from);
-        entry->ent.type = TRACE_BTS;
+        entry->ent.type = TRACE_HW_BRANCHES;
         entry->ent.cpu = smp_processor_id();
         entry->from = from;
         entry->to   = to;
         ring_buffer_unlock_commit(tr->buffer, event, irq);
 }
 
-static void trace_bts_at(struct trace_array *tr, size_t index)
+static void trace_bts_at(struct trace_array *tr,
+                         const struct bts_trace *trace, void *at)
 {
-        const void *raw = NULL;
-        unsigned long from, to;
-        int err;
+        struct bts_struct bts;
+        int err = 0;
 
-        err = ds_access_bts(this_tracer, index, &raw);
-        if (err < 0)
+        WARN_ON_ONCE(!trace->read);
+        if (!trace->read)
                 return;
 
-        from = *(const unsigned long *)raw;
-        to = *(const unsigned long *)((const char *)raw + sizeof_field);
+        err = trace->read(this_tracer, at, &bts);
+        if (err < 0)
+                return;
 
-        trace_bts(tr, from, to);
+        switch (bts.qualifier) {
+        case BTS_BRANCH:
+                trace_hw_branch(tr, bts.variant.lbr.from, bts.variant.lbr.to);
+                break;
+        }
 }
 
 static void trace_bts_cpu(void *arg)
 {
         struct trace_array *tr = (struct trace_array *) arg;
-        size_t index = 0, end = 0, i;
-        int err;
+        const struct bts_trace *trace;
+        unsigned char *at;
 
         if (!this_tracer)
                 return;
 
-        bts_disable();
-
-        err = ds_get_bts_index(this_tracer, &index);
-        if (err < 0)
-                goto out;
-
-        err = ds_get_bts_end(this_tracer, &end);
-        if (err < 0)
+        ds_suspend_bts(this_tracer);
+        trace = ds_read_bts(this_tracer);
+        if (!trace)
                 goto out;
 
-        for (i = index; i < end; i++)
-                trace_bts_at(tr, i);
+        for (at = trace->ds.top; (void *)at < trace->ds.end;
+             at += trace->ds.size)
+                trace_bts_at(tr, trace, at);
 
-        for (i = 0; i < index; i++)
-                trace_bts_at(tr, i);
+        for (at = trace->ds.begin; (void *)at < trace->ds.top;
+             at += trace->ds.size)
+                trace_bts_at(tr, trace, at);
 
 out:
-        bts_enable();
+        ds_resume_bts(this_tracer);
 }
 
 static void trace_bts_prepare(struct trace_iterator *iter)
@@ -259,7 +188,7 @@ static void trace_bts_prepare(struct trace_iterator *iter)
 
 struct tracer bts_tracer __read_mostly =
 {
-        .name           = "bts",
+        .name           = "hw-branch-tracer",
         .init           = bts_trace_init,
         .reset          = bts_trace_stop,
         .print_header   = bts_trace_print_header,