1 files changed, 747 insertions, 0 deletions

diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c
new file mode 100644
index 000000000000..9ed59a452d1f
--- /dev/null
+++ b/tools/perf/util/thread-stack.c
@@ -0,0 +1,747 @@
+/*
+ * thread-stack.c: Synthesize a thread's stack using call / return events
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/rbtree.h>
+#include <linux/list.h>
+#include "thread.h"
+#include "event.h"
+#include "machine.h"
+#include "util.h"
+#include "debug.h"
+#include "symbol.h"
+#include "comm.h"
+#include "thread-stack.h"
+
+#define CALL_PATH_BLOCK_SHIFT 8
+#define CALL_PATH_BLOCK_SIZE (1 << CALL_PATH_BLOCK_SHIFT)
+#define CALL_PATH_BLOCK_MASK (CALL_PATH_BLOCK_SIZE - 1)
+
+struct call_path_block {
+        struct call_path cp[CALL_PATH_BLOCK_SIZE];
+        struct list_head node;
+};
+
+/**
+ * struct call_path_root - root of all call paths.
+ * @call_path: root call path
+ * @blocks: list of blocks to store call paths
+ * @next: next free space
+ * @sz: number of spaces
+ */
+struct call_path_root {
+        struct call_path call_path;
+        struct list_head blocks;
+        size_t next;
+        size_t sz;
+};
+
+/**
+ * struct call_return_processor - provides a call-back to consume call-return
+ *                                information.
+ * @cpr: call path root
+ * @process: call-back that accepts call/return information
+ * @data: anonymous data for call-back
+ */
+struct call_return_processor {
+        struct call_path_root *cpr;
+        int (*process)(struct call_return *cr, void *data);
+        void *data;
+};
+
+#define STACK_GROWTH 2048
+
+/**
+ * struct thread_stack_entry - thread stack entry.
+ * @ret_addr: return address
+ * @timestamp: timestamp (if known)
+ * @ref: external reference (e.g. db_id of sample)
+ * @branch_count: the branch count when the entry was created
+ * @cp: call path
+ * @no_call: a 'call' was not seen
+ */
+struct thread_stack_entry {
+        u64 ret_addr;
+        u64 timestamp;
+        u64 ref;
+        u64 branch_count;
+        struct call_path *cp;
+        bool no_call;
+};
+
+/**
+ * struct thread_stack - thread stack constructed from 'call' and 'return'
+ *                       branch samples.
+ * @stack: array that holds the stack
+ * @cnt: number of entries in the stack
+ * @sz: current maximum stack size
+ * @trace_nr: current trace number
+ * @branch_count: running branch count
+ * @kernel_start: kernel start address
+ * @last_time: last timestamp
+ * @crp: call/return processor
+ * @comm: current comm
+ */
+struct thread_stack {
+        struct thread_stack_entry *stack;
+        size_t cnt;
+        size_t sz;
+        u64 trace_nr;
+        u64 branch_count;
+        u64 kernel_start;
+        u64 last_time;
+        struct call_return_processor *crp;
+        struct comm *comm;
+};
+
+static int thread_stack__grow(struct thread_stack *ts)
+{
+        struct thread_stack_entry *new_stack;
+        size_t sz, new_sz;
+
+        new_sz = ts->sz + STACK_GROWTH;
+        sz = new_sz * sizeof(struct thread_stack_entry);
+
+        new_stack = realloc(ts->stack, sz);
+        if (!new_stack)
+                return -ENOMEM;
+
+        ts->stack = new_stack;
+        ts->sz = new_sz;
+
+        return 0;
+}
+
+static struct thread_stack *thread_stack__new(struct thread *thread,
+                                              struct call_return_processor *crp)
+{
+        struct thread_stack *ts;
+
+        ts = zalloc(sizeof(struct thread_stack));
+        if (!ts)
+                return NULL;
+
+        if (thread_stack__grow(ts)) {
+                free(ts);
+                return NULL;
+        }
+
+        if (thread->mg && thread->mg->machine)
+                ts->kernel_start = machine__kernel_start(thread->mg->machine);
+        else
+                ts->kernel_start = 1ULL << 63;
+        ts->crp = crp;
+
+        return ts;
+}
+
+static int thread_stack__push(struct thread_stack *ts, u64 ret_addr)
+{
+        int err = 0;
+
+        if (ts->cnt == ts->sz) {
+                err = thread_stack__grow(ts);
+                if (err) {
+                        pr_warning("Out of memory: discarding thread stack\n");
+                        ts->cnt = 0;
+                }
+        }
+
+        ts->stack[ts->cnt++].ret_addr = ret_addr;
+
+        return err;
+}
+
+static void thread_stack__pop(struct thread_stack *ts, u64 ret_addr)
+{
+        size_t i;
+
+        /*
+         * In some cases there may be functions which are not seen to return.
+         * For example when setjmp / longjmp has been used.  Or the perf context
+         * switch in the kernel which doesn't stop and start tracing in exactly
+         * the same code path.  When that happens the return address will be
+         * further down the stack.  If the return address is not found at all,
+         * we assume the opposite (i.e. this is a return for a call that wasn't
+         * seen for some reason) and leave the stack alone.
+         */
+        for (i = ts->cnt; i; ) {
+                if (ts->stack[--i].ret_addr == ret_addr) {
+                        ts->cnt = i;
+                        return;
+                }
+        }
+}
+
+static bool thread_stack__in_kernel(struct thread_stack *ts)
+{
+        if (!ts->cnt)
+                return false;
+
+        return ts->stack[ts->cnt - 1].cp->in_kernel;
+}
+
+static int thread_stack__call_return(struct thread *thread,
+                                     struct thread_stack *ts, size_t idx,
+                                     u64 timestamp, u64 ref, bool no_return)
+{
+        struct call_return_processor *crp = ts->crp;
+        struct thread_stack_entry *tse;
+        struct call_return cr = {
+                .thread = thread,
+                .comm = ts->comm,
+                .db_id = 0,
+        };
+
+        tse = &ts->stack[idx];
+        cr.cp = tse->cp;
+        cr.call_time = tse->timestamp;
+        cr.return_time = timestamp;
+        cr.branch_count = ts->branch_count - tse->branch_count;
+        cr.call_ref = tse->ref;
+        cr.return_ref = ref;
+        if (tse->no_call)
+                cr.flags |= CALL_RETURN_NO_CALL;
+        if (no_return)
+                cr.flags |= CALL_RETURN_NO_RETURN;
+
+        return crp->process(&cr, crp->data);
+}
+
+static int thread_stack__flush(struct thread *thread, struct thread_stack *ts)
+{
+        struct call_return_processor *crp = ts->crp;
+        int err;
+
+        if (!crp) {
+                ts->cnt = 0;
+                return 0;
+        }
+
+        while (ts->cnt) {
+                err = thread_stack__call_return(thread, ts, --ts->cnt,
+                                                ts->last_time, 0, true);
+                if (err) {
+                        pr_err("Error flushing thread stack!\n");
+                        ts->cnt = 0;
+                        return err;
+                }
+        }
+
+        return 0;
+}
+
+int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip,
+                        u64 to_ip, u16 insn_len, u64 trace_nr)
+{
+        if (!thread)
+                return -EINVAL;
+
+        if (!thread->ts) {
+                thread->ts = thread_stack__new(thread, NULL);
+                if (!thread->ts) {
+                        pr_warning("Out of memory: no thread stack\n");
+                        return -ENOMEM;
+                }
+                thread->ts->trace_nr = trace_nr;
+        }
+
+        /*
+         * When the trace is discontinuous, the trace_nr changes.  In that case
+         * the stack might be completely invalid.  Better to report nothing than
+         * to report something misleading, so flush the stack.
+         */
+        if (trace_nr != thread->ts->trace_nr) {
+                if (thread->ts->trace_nr)
+                        thread_stack__flush(thread, thread->ts);
+                thread->ts->trace_nr = trace_nr;
+        }
+
+        /* Stop here if thread_stack__process() is in use */
+        if (thread->ts->crp)
+                return 0;
+
+        if (flags & PERF_IP_FLAG_CALL) {
+                u64 ret_addr;
+
+                if (!to_ip)
+                        return 0;
+                ret_addr = from_ip + insn_len;
+                if (ret_addr == to_ip)
+                        return 0; /* Zero-length calls are excluded */
+                return thread_stack__push(thread->ts, ret_addr);
+        } else if (flags & PERF_IP_FLAG_RETURN) {
+                if (!from_ip)
+                        return 0;
+                thread_stack__pop(thread->ts, to_ip);
+        }
+
+        return 0;
+}
+
+void thread_stack__set_trace_nr(struct thread *thread, u64 trace_nr)
+{
+        if (!thread || !thread->ts)
+                return;
+
+        if (trace_nr != thread->ts->trace_nr) {
+                if (thread->ts->trace_nr)
+                        thread_stack__flush(thread, thread->ts);
+                thread->ts->trace_nr = trace_nr;
+        }
+}
+
+void thread_stack__free(struct thread *thread)
+{
+        if (thread->ts) {
+                thread_stack__flush(thread, thread->ts);
+                zfree(&thread->ts->stack);
+                zfree(&thread->ts);
+        }
+}
+
+void thread_stack__sample(struct thread *thread, struct ip_callchain *chain,
+                          size_t sz, u64 ip)
+{
+        size_t i;
+
+        if (!thread || !thread->ts)
+                chain->nr = 1;
+        else
+                chain->nr = min(sz, thread->ts->cnt + 1);
+
+        chain->ips[0] = ip;
+
+        for (i = 1; i < chain->nr; i++)
+                chain->ips[i] = thread->ts->stack[thread->ts->cnt - i].ret_addr;
+}
+
+static void call_path__init(struct call_path *cp, struct call_path *parent,
+                            struct symbol *sym, u64 ip, bool in_kernel)
+{
+        cp->parent = parent;
+        cp->sym = sym;
+        cp->ip = sym ? 0 : ip;
+        cp->db_id = 0;
+        cp->in_kernel = in_kernel;
+        RB_CLEAR_NODE(&cp->rb_node);
+        cp->children = RB_ROOT;
+}
+
+static struct call_path_root *call_path_root__new(void)
+{
+        struct call_path_root *cpr;
+
+        cpr = zalloc(sizeof(struct call_path_root));
+        if (!cpr)
+                return NULL;
+        call_path__init(&cpr->call_path, NULL, NULL, 0, false);
+        INIT_LIST_HEAD(&cpr->blocks);
+        return cpr;
+}
+
+static void call_path_root__free(struct call_path_root *cpr)
+{
+        struct call_path_block *pos, *n;
+
+        list_for_each_entry_safe(pos, n, &cpr->blocks, node) {
+                list_del(&pos->node);
+                free(pos);
+        }
+        free(cpr);
+}
+
+static struct call_path *call_path__new(struct call_path_root *cpr,
+                                        struct call_path *parent,
+                                        struct symbol *sym, u64 ip,
+                                        bool in_kernel)
+{
+        struct call_path_block *cpb;
+        struct call_path *cp;
+        size_t n;
+
+        if (cpr->next < cpr->sz) {
+                cpb = list_last_entry(&cpr->blocks, struct call_path_block,
+                                      node);
+        } else {
+                cpb = zalloc(sizeof(struct call_path_block));
+                if (!cpb)
+                        return NULL;
+                list_add_tail(&cpb->node, &cpr->blocks);
+                cpr->sz += CALL_PATH_BLOCK_SIZE;
+        }
+
+        n = cpr->next++ & CALL_PATH_BLOCK_MASK;
+        cp = &cpb->cp[n];
+
+        call_path__init(cp, parent, sym, ip, in_kernel);
+
+        return cp;
+}
+
+static struct call_path *call_path__findnew(struct call_path_root *cpr,
+                                            struct call_path *parent,
+                                            struct symbol *sym, u64 ip, u64 ks)
+{
+        struct rb_node **p;
+        struct rb_node *node_parent = NULL;
+        struct call_path *cp;
+        bool in_kernel = ip >= ks;
+
+        if (sym)
+                ip = 0;
+
+        if (!parent)
+                return call_path__new(cpr, parent, sym, ip, in_kernel);
+
+        p = &parent->children.rb_node;
+        while (*p != NULL) {
+                node_parent = *p;
+                cp = rb_entry(node_parent, struct call_path, rb_node);
+
+                if (cp->sym == sym && cp->ip == ip)
+                        return cp;
+
+                if (sym < cp->sym || (sym == cp->sym && ip < cp->ip))
+                        p = &(*p)->rb_left;
+                else
+                        p = &(*p)->rb_right;
+        }
+
+        cp = call_path__new(cpr, parent, sym, ip, in_kernel);
+        if (!cp)
+                return NULL;
+
+        rb_link_node(&cp->rb_node, node_parent, p);
+        rb_insert_color(&cp->rb_node, &parent->children);
+
+        return cp;
+}
+
+struct call_return_processor *
+call_return_processor__new(int (*process)(struct call_return *cr, void *data),
+                           void *data)
+{
+        struct call_return_processor *crp;
+
+        crp = zalloc(sizeof(struct call_return_processor));
+        if (!crp)
+                return NULL;
+        crp->cpr = call_path_root__new();
+        if (!crp->cpr)
+                goto out_free;
+        crp->process = process;
+        crp->data = data;
+        return crp;
+
+out_free:
+        free(crp);
+        return NULL;
+}
+
+void call_return_processor__free(struct call_return_processor *crp)
+{
+        if (crp) {
+                call_path_root__free(crp->cpr);
+                free(crp);
+        }
+}
+
+static int thread_stack__push_cp(struct thread_stack *ts, u64 ret_addr,
+                                 u64 timestamp, u64 ref, struct call_path *cp,
+                                 bool no_call)
+{
+        struct thread_stack_entry *tse;
+        int err;
+
+        if (ts->cnt == ts->sz) {
+                err = thread_stack__grow(ts);
+                if (err)
+                        return err;
+        }
+
+        tse = &ts->stack[ts->cnt++];
+        tse->ret_addr = ret_addr;
+        tse->timestamp = timestamp;
+        tse->ref = ref;
+        tse->branch_count = ts->branch_count;
+        tse->cp = cp;
+        tse->no_call = no_call;
+
+        return 0;
+}
+
+static int thread_stack__pop_cp(struct thread *thread, struct thread_stack *ts,
+                                u64 ret_addr, u64 timestamp, u64 ref,
+                                struct symbol *sym)
+{
+        int err;
+
+        if (!ts->cnt)
+                return 1;
+
+        if (ts->cnt == 1) {
+                struct thread_stack_entry *tse = &ts->stack[0];
+
+                if (tse->cp->sym == sym)
+                        return thread_stack__call_return(thread, ts, --ts->cnt,
+                                                         timestamp, ref, false);
+        }
+
+        if (ts->stack[ts->cnt - 1].ret_addr == ret_addr) {
+                return thread_stack__call_return(thread, ts, --ts->cnt,
+                                                 timestamp, ref, false);
+        } else {
+                size_t i = ts->cnt - 1;
+
+                while (i--) {
+                        if (ts->stack[i].ret_addr != ret_addr)
+                                continue;
+                        i += 1;
+                        while (ts->cnt > i) {
+                                err = thread_stack__call_return(thread, ts,
+                                                                --ts->cnt,
+                                                                timestamp, ref,
+                                                                true);
+                                if (err)
+                                        return err;
+                        }
+                        return thread_stack__call_return(thread, ts, --ts->cnt,
+                                                         timestamp, ref, false);
+                }
+        }
+
+        return 1;
+}
+
+static int thread_stack__bottom(struct thread *thread, struct thread_stack *ts,
+                                struct perf_sample *sample,
+                                struct addr_location *from_al,
+                                struct addr_location *to_al, u64 ref)
+{
+        struct call_path_root *cpr = ts->crp->cpr;
+        struct call_path *cp;
+        struct symbol *sym;
+        u64 ip;
+
+        if (sample->ip) {
+                ip = sample->ip;
+                sym = from_al->sym;
+        } else if (sample->addr) {
+                ip = sample->addr;
+                sym = to_al->sym;
+        } else {
+                return 0;
+        }
+
+        cp = call_path__findnew(cpr, &cpr->call_path, sym, ip,
+                                ts->kernel_start);
+        if (!cp)
+                return -ENOMEM;
+
+        return thread_stack__push_cp(thread->ts, ip, sample->time, ref, cp,
+                                     true);
+}
+
+static int thread_stack__no_call_return(struct thread *thread,
+                                        struct thread_stack *ts,
+                                        struct perf_sample *sample,
+                                        struct addr_location *from_al,
+                                        struct addr_location *to_al, u64 ref)
+{
+        struct call_path_root *cpr = ts->crp->cpr;
+        struct call_path *cp, *parent;
+        u64 ks = ts->kernel_start;
+        int err;
+
+        if (sample->ip >= ks && sample->addr < ks) {
+                /* Return to userspace, so pop all kernel addresses */
+                while (thread_stack__in_kernel(ts)) {
+                        err = thread_stack__call_return(thread, ts, --ts->cnt,
+                                                        sample->time, ref,
+                                                        true);
+                        if (err)
+                                return err;
+                }
+
+                /* If the stack is empty, push the userspace address */
+                if (!ts->cnt) {
+                        cp = call_path__findnew(cpr, &cpr->call_path,
+                                                to_al->sym, sample->addr,
+                                                ts->kernel_start);
+                        if (!cp)
+                                return -ENOMEM;
+                        return thread_stack__push_cp(ts, 0, sample->time, ref,
+                                                     cp, true);
+                }
+        } else if (thread_stack__in_kernel(ts) && sample->ip < ks) {
+                /* Return to userspace, so pop all kernel addresses */
+                while (thread_stack__in_kernel(ts)) {
+                        err = thread_stack__call_return(thread, ts, --ts->cnt,
+                                                        sample->time, ref,
+                                                        true);
+                        if (err)
+                                return err;
+                }
+        }
+
+        if (ts->cnt)
+                parent = ts->stack[ts->cnt - 1].cp;
+        else
+                parent = &cpr->call_path;
+
+        /* This 'return' had no 'call', so push and pop top of stack */
+        cp = call_path__findnew(cpr, parent, from_al->sym, sample->ip,
+                                ts->kernel_start);
+        if (!cp)
+                return -ENOMEM;
+
+        err = thread_stack__push_cp(ts, sample->addr, sample->time, ref, cp,
+                                    true);
+        if (err)
+                return err;
+
+        return thread_stack__pop_cp(thread, ts, sample->addr, sample->time, ref,
+                                    to_al->sym);
+}
+
+static int thread_stack__trace_begin(struct thread *thread,
+                                     struct thread_stack *ts, u64 timestamp,
+                                     u64 ref)
+{
+        struct thread_stack_entry *tse;
+        int err;
+
+        if (!ts->cnt)
+                return 0;
+
+        /* Pop trace end */
+        tse = &ts->stack[ts->cnt - 1];
+        if (tse->cp->sym == NULL && tse->cp->ip == 0) {
+                err = thread_stack__call_return(thread, ts, --ts->cnt,
+                                                timestamp, ref, false);
+                if (err)
+                        return err;
+        }
+
+        return 0;
+}
+
+static int thread_stack__trace_end(struct thread_stack *ts,
+                                   struct perf_sample *sample, u64 ref)
+{
+        struct call_path_root *cpr = ts->crp->cpr;
+        struct call_path *cp;
+        u64 ret_addr;
+
+        /* No point having 'trace end' on the bottom of the stack */
+        if (!ts->cnt || (ts->cnt == 1 && ts->stack[0].ref == ref))
+                return 0;
+
+        cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp, NULL, 0,
+                                ts->kernel_start);
+        if (!cp)
+                return -ENOMEM;
+
+        ret_addr = sample->ip + sample->insn_len;
+
+        return thread_stack__push_cp(ts, ret_addr, sample->time, ref, cp,
+                                     false);
+}
+
+int thread_stack__process(struct thread *thread, struct comm *comm,
+                          struct perf_sample *sample,
+                          struct addr_location *from_al,
+                          struct addr_location *to_al, u64 ref,
+                          struct call_return_processor *crp)
+{
+        struct thread_stack *ts = thread->ts;
+        int err = 0;
+
+        if (ts) {
+                if (!ts->crp) {
+                        /* Supersede thread_stack__event() */
+                        thread_stack__free(thread);
+                        thread->ts = thread_stack__new(thread, crp);
+                        if (!thread->ts)
+                                return -ENOMEM;
+                        ts = thread->ts;
+                        ts->comm = comm;
+                }
+        } else {
+                thread->ts = thread_stack__new(thread, crp);
+                if (!thread->ts)
+                        return -ENOMEM;
+                ts = thread->ts;
+                ts->comm = comm;
+        }
+
+        /* Flush stack on exec */
+        if (ts->comm != comm && thread->pid_ == thread->tid) {
+                err = thread_stack__flush(thread, ts);
+                if (err)
+                        return err;
+                ts->comm = comm;
+        }
+
+        /* If the stack is empty, put the current symbol on the stack */
+        if (!ts->cnt) {
+                err = thread_stack__bottom(thread, ts, sample, from_al, to_al,
+                                           ref);
+                if (err)
+                        return err;
+        }
+
+        ts->branch_count += 1;
+        ts->last_time = sample->time;
+
+        if (sample->flags & PERF_IP_FLAG_CALL) {
+                struct call_path_root *cpr = ts->crp->cpr;
+                struct call_path *cp;
+                u64 ret_addr;
+
+                if (!sample->ip || !sample->addr)
+                        return 0;
+
+                ret_addr = sample->ip + sample->insn_len;
+                if (ret_addr == sample->addr)
+                        return 0; /* Zero-length calls are excluded */
+
+                cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,
+                                        to_al->sym, sample->addr,
+                                        ts->kernel_start);
+                if (!cp)
+                        return -ENOMEM;
+                err = thread_stack__push_cp(ts, ret_addr, sample->time, ref,
+                                            cp, false);
+        } else if (sample->flags & PERF_IP_FLAG_RETURN) {
+                if (!sample->ip || !sample->addr)
+                        return 0;
+
+                err = thread_stack__pop_cp(thread, ts, sample->addr,
+                                           sample->time, ref, from_al->sym);
+                if (err) {
+                        if (err < 0)
+                                return err;
+                        err = thread_stack__no_call_return(thread, ts, sample,
+                                                           from_al, to_al, ref);
+                }
+        } else if (sample->flags & PERF_IP_FLAG_TRACE_BEGIN) {
+                err = thread_stack__trace_begin(thread, ts, sample->time, ref);
+        } else if (sample->flags & PERF_IP_FLAG_TRACE_END) {
+                err = thread_stack__trace_end(ts, sample, ref);
+        }
+
+        return err;
+}