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-rw-r--r--include/linux/ftrace.h8
-rw-r--r--kernel/trace/ftrace.c243
-rw-r--r--kernel/trace/trace.c3
3 files changed, 38 insertions, 216 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 1c4835f..703eb53 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -44,8 +44,6 @@ static inline void ftrace_kill(void) { }
#endif /* CONFIG_FUNCTION_TRACER */
#ifdef CONFIG_DYNAMIC_FTRACE
-# define FTRACE_HASHBITS 10
-# define FTRACE_HASHSIZE (1<<FTRACE_HASHBITS)
enum {
FTRACE_FL_FREE = (1 << 0),
@@ -58,9 +56,9 @@ enum {
};
struct dyn_ftrace {
- struct hlist_node node;
- unsigned long ip; /* address of mcount call-site */
- unsigned long flags;
+ struct list_head list;
+ unsigned long ip; /* address of mcount call-site */
+ unsigned long flags;
};
int ftrace_force_update(void);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 226fd91..07762c0 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -25,7 +25,6 @@
#include <linux/ftrace.h>
#include <linux/sysctl.h>
#include <linux/ctype.h>
-#include <linux/hash.h>
#include <linux/list.h>
#include <asm/ftrace.h>
@@ -189,9 +188,7 @@ static int ftrace_filtered;
static int tracing_on;
static int frozen_record_count;
-static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
-
-static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
+static LIST_HEAD(ftrace_new_addrs);
static DEFINE_MUTEX(ftrace_regex_lock);
@@ -210,8 +207,6 @@ struct ftrace_page {
static struct ftrace_page *ftrace_pages_start;
static struct ftrace_page *ftrace_pages;
-static int ftrace_record_suspend;
-
static struct dyn_ftrace *ftrace_free_records;
@@ -242,72 +237,6 @@ static inline int record_frozen(struct dyn_ftrace *rec)
# define record_frozen(rec) ({ 0; })
#endif /* CONFIG_KPROBES */
-int skip_trace(unsigned long ip)
-{
- unsigned long fl;
- struct dyn_ftrace *rec;
- struct hlist_node *t;
- struct hlist_head *head;
-
- if (frozen_record_count == 0)
- return 0;
-
- head = &ftrace_hash[hash_long(ip, FTRACE_HASHBITS)];
- hlist_for_each_entry_rcu(rec, t, head, node) {
- if (rec->ip == ip) {
- if (record_frozen(rec)) {
- if (rec->flags & FTRACE_FL_FAILED)
- return 1;
-
- if (!(rec->flags & FTRACE_FL_CONVERTED))
- return 1;
-
- if (!tracing_on || !ftrace_enabled)
- return 1;
-
- if (ftrace_filtered) {
- fl = rec->flags & (FTRACE_FL_FILTER |
- FTRACE_FL_NOTRACE);
- if (!fl || (fl & FTRACE_FL_NOTRACE))
- return 1;
- }
- }
- break;
- }
- }
-
- return 0;
-}
-
-static inline int
-ftrace_ip_in_hash(unsigned long ip, unsigned long key)
-{
- struct dyn_ftrace *p;
- struct hlist_node *t;
- int found = 0;
-
- hlist_for_each_entry_rcu(p, t, &ftrace_hash[key], node) {
- if (p->ip == ip) {
- found = 1;
- break;
- }
- }
-
- return found;
-}
-
-static inline void
-ftrace_add_hash(struct dyn_ftrace *node, unsigned long key)
-{
- hlist_add_head_rcu(&node->node, &ftrace_hash[key]);
-}
-
-/* called from kstop_machine */
-static inline void ftrace_del_hash(struct dyn_ftrace *node)
-{
- hlist_del(&node->node);
-}
-
static void ftrace_free_rec(struct dyn_ftrace *rec)
{
rec->ip = (unsigned long)ftrace_free_records;
@@ -362,69 +291,36 @@ static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
}
if (ftrace_pages->index == ENTRIES_PER_PAGE) {
- if (!ftrace_pages->next)
- return NULL;
+ if (!ftrace_pages->next) {
+ /* allocate another page */
+ ftrace_pages->next =
+ (void *)get_zeroed_page(GFP_KERNEL);
+ if (!ftrace_pages->next)
+ return NULL;
+ }
ftrace_pages = ftrace_pages->next;
}
return &ftrace_pages->records[ftrace_pages->index++];
}
-static void
+static struct dyn_ftrace *
ftrace_record_ip(unsigned long ip)
{
- struct dyn_ftrace *node;
- unsigned long key;
- int resched;
- int cpu;
+ struct dyn_ftrace *rec;
if (!ftrace_enabled || ftrace_disabled)
- return;
-
- resched = need_resched();
- preempt_disable_notrace();
-
- /*
- * We simply need to protect against recursion.
- * Use the the raw version of smp_processor_id and not
- * __get_cpu_var which can call debug hooks that can
- * cause a recursive crash here.
- */
- cpu = raw_smp_processor_id();
- per_cpu(ftrace_shutdown_disable_cpu, cpu)++;
- if (per_cpu(ftrace_shutdown_disable_cpu, cpu) != 1)
- goto out;
-
- if (unlikely(ftrace_record_suspend))
- goto out;
-
- key = hash_long(ip, FTRACE_HASHBITS);
-
- FTRACE_WARN_ON_ONCE(key >= FTRACE_HASHSIZE);
-
- if (ftrace_ip_in_hash(ip, key))
- goto out;
-
- /* This ip may have hit the hash before the lock */
- if (ftrace_ip_in_hash(ip, key))
- goto out;
-
- node = ftrace_alloc_dyn_node(ip);
- if (!node)
- goto out;
+ return NULL;
- node->ip = ip;
+ rec = ftrace_alloc_dyn_node(ip);
+ if (!rec)
+ return NULL;
- ftrace_add_hash(node, key);
+ rec->ip = ip;
- out:
- per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
+ list_add(&rec->list, &ftrace_new_addrs);
- /* prevent recursion with scheduler */
- if (resched)
- preempt_enable_no_resched_notrace();
- else
- preempt_enable_notrace();
+ return rec;
}
#define FTRACE_ADDR ((long)(ftrace_caller))
@@ -543,7 +439,6 @@ static void ftrace_replace_code(int enable)
rec->flags |= FTRACE_FL_FAILED;
if ((system_state == SYSTEM_BOOTING) ||
!core_kernel_text(rec->ip)) {
- ftrace_del_hash(rec);
ftrace_free_rec(rec);
}
}
@@ -551,15 +446,6 @@ static void ftrace_replace_code(int enable)
}
}
-static void ftrace_shutdown_replenish(void)
-{
- if (ftrace_pages->next)
- return;
-
- /* allocate another page */
- ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
-}
-
static void print_ip_ins(const char *fmt, unsigned char *p)
{
int i;
@@ -616,18 +502,11 @@ ftrace_code_disable(struct dyn_ftrace *rec)
return 1;
}
-static int ftrace_update_code(void *ignore);
-
static int __ftrace_modify_code(void *data)
{
int *command = data;
if (*command & FTRACE_ENABLE_CALLS) {
- /*
- * Update any recorded ips now that we have the
- * machine stopped
- */
- ftrace_update_code(NULL);
ftrace_replace_code(1);
tracing_on = 1;
} else if (*command & FTRACE_DISABLE_CALLS) {
@@ -738,84 +617,34 @@ static cycle_t ftrace_update_time;
static unsigned long ftrace_update_cnt;
unsigned long ftrace_update_tot_cnt;
-static int ftrace_update_code(void *ignore)
+static int ftrace_update_code(void)
{
- int i, save_ftrace_enabled;
+ struct dyn_ftrace *p, *t;
cycle_t start, stop;
- struct dyn_ftrace *p;
- struct hlist_node *t, *n;
- struct hlist_head *head, temp_list;
-
- /* Don't be recording funcs now */
- ftrace_record_suspend++;
- save_ftrace_enabled = ftrace_enabled;
- ftrace_enabled = 0;
start = ftrace_now(raw_smp_processor_id());
ftrace_update_cnt = 0;
- /* No locks needed, the machine is stopped! */
- for (i = 0; i < FTRACE_HASHSIZE; i++) {
- INIT_HLIST_HEAD(&temp_list);
- head = &ftrace_hash[i];
+ list_for_each_entry_safe(p, t, &ftrace_new_addrs, list) {
- /* all CPUS are stopped, we are safe to modify code */
- hlist_for_each_entry_safe(p, t, n, head, node) {
- /* Skip over failed records which have not been
- * freed. */
- if (p->flags & FTRACE_FL_FAILED)
- continue;
+ /* If something went wrong, bail without enabling anything */
+ if (unlikely(ftrace_disabled))
+ return -1;
- /* Unconverted records are always at the head of the
- * hash bucket. Once we encounter a converted record,
- * simply skip over to the next bucket. Saves ftraced
- * some processor cycles (ftrace does its bid for
- * global warming :-p ). */
- if (p->flags & (FTRACE_FL_CONVERTED))
- break;
+ list_del_init(&p->list);
- /* Ignore updates to this record's mcount site.
- * Reintroduce this record at the head of this
- * bucket to attempt to "convert" it again if
- * the kprobe on it is unregistered before the
- * next run. */
- if (get_kprobe((void *)p->ip)) {
- ftrace_del_hash(p);
- INIT_HLIST_NODE(&p->node);
- hlist_add_head(&p->node, &temp_list);
- freeze_record(p);
- continue;
- } else {
- unfreeze_record(p);
- }
-
- /* convert record (i.e, patch mcount-call with NOP) */
- if (ftrace_code_disable(p)) {
- p->flags |= FTRACE_FL_CONVERTED;
- ftrace_update_cnt++;
- } else {
- if ((system_state == SYSTEM_BOOTING) ||
- !core_kernel_text(p->ip)) {
- ftrace_del_hash(p);
- ftrace_free_rec(p);
- }
- }
- }
-
- hlist_for_each_entry_safe(p, t, n, &temp_list, node) {
- hlist_del(&p->node);
- INIT_HLIST_NODE(&p->node);
- hlist_add_head(&p->node, head);
- }
+ /* convert record (i.e, patch mcount-call with NOP) */
+ if (ftrace_code_disable(p)) {
+ p->flags |= FTRACE_FL_CONVERTED;
+ ftrace_update_cnt++;
+ } else
+ ftrace_free_rec(p);
}
stop = ftrace_now(raw_smp_processor_id());
ftrace_update_time = stop - start;
ftrace_update_tot_cnt += ftrace_update_cnt;
- ftrace_enabled = save_ftrace_enabled;
- ftrace_record_suspend--;
-
return 0;
}
@@ -847,7 +676,7 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
pg = ftrace_pages = ftrace_pages_start;
cnt = num_to_init / ENTRIES_PER_PAGE;
- pr_info("ftrace: allocating %ld hash entries in %d pages\n",
+ pr_info("ftrace: allocating %ld entries in %d pages\n",
num_to_init, cnt);
for (i = 0; i < cnt; i++) {
@@ -1451,20 +1280,18 @@ static int ftrace_convert_nops(unsigned long *start,
unsigned long addr;
unsigned long flags;
+ mutex_lock(&ftrace_start_lock);
p = start;
while (p < end) {
addr = ftrace_call_adjust(*p++);
- /* should not be called from interrupt context */
- spin_lock(&ftrace_lock);
ftrace_record_ip(addr);
- spin_unlock(&ftrace_lock);
- ftrace_shutdown_replenish();
}
- /* p is ignored */
+ /* disable interrupts to prevent kstop machine */
local_irq_save(flags);
- ftrace_update_code(p);
+ ftrace_update_code();
local_irq_restore(flags);
+ mutex_unlock(&ftrace_start_lock);
return 0;
}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 333a516..06951e2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -865,9 +865,6 @@ function_trace_call(unsigned long ip, unsigned long parent_ip)
if (unlikely(!ftrace_function_enabled))
return;
- if (skip_trace(ip))
- return;
-
pc = preempt_count();
resched = need_resched();
preempt_disable_notrace();
generated by cgit v1.1 at 2024-12-26 18:58:00 +0000