aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--arch/Kconfig14
-rw-r--r--arch/sparc/include/asm/jump_label.h1
-rw-r--r--arch/x86/Makefile_32.cpu13
-rw-r--r--arch/x86/kernel/alternative.c69
-rw-r--r--arch/x86/kernel/apic/io_apic.c2
-rw-r--r--drivers/oprofile/buffer_sync.c2
-rw-r--r--drivers/oprofile/cpu_buffer.c10
-rw-r--r--drivers/oprofile/cpu_buffer.h1
-rw-r--r--drivers/oprofile/timer_int.c13
-rw-r--r--include/linux/jump_label.h7
-rw-r--r--kernel/jump_label.c77
-rw-r--r--kernel/kprobes.c26
12 files changed, 153 insertions, 82 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index 53d7f61..8bf0fa65 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -42,6 +42,20 @@ config KPROBES
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".
+config JUMP_LABEL
+ bool "Optimize trace point call sites"
+ depends on HAVE_ARCH_JUMP_LABEL
+ help
+ If it is detected that the compiler has support for "asm goto",
+ the kernel will compile trace point locations with just a
+ nop instruction. When trace points are enabled, the nop will
+ be converted to a jump to the trace function. This technique
+ lowers overhead and stress on the branch prediction of the
+ processor.
+
+ On i386, options added to the compiler flags may increase
+ the size of the kernel slightly.
+
config OPTPROBES
def_bool y
depends on KPROBES && HAVE_OPTPROBES
diff --git a/arch/sparc/include/asm/jump_label.h b/arch/sparc/include/asm/jump_label.h
index 65c0d30..427d468 100644
--- a/arch/sparc/include/asm/jump_label.h
+++ b/arch/sparc/include/asm/jump_label.h
@@ -13,6 +13,7 @@
"nop\n\t" \
"nop\n\t" \
".pushsection __jump_table, \"a\"\n\t"\
+ ".align 4\n\t" \
".word 1b, %l[" #label "], %c0\n\t" \
".popsection \n\t" \
: : "i" (key) : : label);\
diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu
index 1255d95..f2ee1ab 100644
--- a/arch/x86/Makefile_32.cpu
+++ b/arch/x86/Makefile_32.cpu
@@ -51,7 +51,18 @@ cflags-$(CONFIG_X86_GENERIC) += $(call tune,generic,$(call tune,i686))
# prologue (push %ebp, mov %esp, %ebp) which breaks the function graph
# tracer assumptions. For i686, generic, core2 this is set by the
# compiler anyway
-cflags-$(CONFIG_FUNCTION_GRAPH_TRACER) += $(call cc-option,-maccumulate-outgoing-args)
+ifeq ($(CONFIG_FUNCTION_GRAPH_TRACER), y)
+ADD_ACCUMULATE_OUTGOING_ARGS := y
+endif
+
+# Work around to a bug with asm goto with first implementations of it
+# in gcc causing gcc to mess up the push and pop of the stack in some
+# uses of asm goto.
+ifeq ($(CONFIG_JUMP_LABEL), y)
+ADD_ACCUMULATE_OUTGOING_ARGS := y
+endif
+
+cflags-$(ADD_ACCUMULATE_OUTGOING_ARGS) += $(call cc-option,-maccumulate-outgoing-args)
# Bug fix for binutils: this option is required in order to keep
# binutils from generating NOPL instructions against our will.
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 5ceeca3..5079f24 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -644,65 +644,26 @@ void *__kprobes text_poke_smp(void *addr, const void *opcode, size_t len)
#if defined(CONFIG_DYNAMIC_FTRACE) || defined(HAVE_JUMP_LABEL)
-unsigned char ideal_nop5[IDEAL_NOP_SIZE_5];
+#ifdef CONFIG_X86_64
+unsigned char ideal_nop5[5] = { 0x66, 0x66, 0x66, 0x66, 0x90 };
+#else
+unsigned char ideal_nop5[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
+#endif
void __init arch_init_ideal_nop5(void)
{
- extern const unsigned char ftrace_test_p6nop[];
- extern const unsigned char ftrace_test_nop5[];
- extern const unsigned char ftrace_test_jmp[];
- int faulted = 0;
-
/*
- * There is no good nop for all x86 archs.
- * We will default to using the P6_NOP5, but first we
- * will test to make sure that the nop will actually
- * work on this CPU. If it faults, we will then
- * go to a lesser efficient 5 byte nop. If that fails
- * we then just use a jmp as our nop. This isn't the most
- * efficient nop, but we can not use a multi part nop
- * since we would then risk being preempted in the middle
- * of that nop, and if we enabled tracing then, it might
- * cause a system crash.
+ * There is no good nop for all x86 archs. This selection
+ * algorithm should be unified with the one in find_nop_table(),
+ * but this should be good enough for now.
*
- * TODO: check the cpuid to determine the best nop.
+ * For cases other than the ones below, use the safe (as in
+ * always functional) defaults above.
*/
- asm volatile (
- "ftrace_test_jmp:"
- "jmp ftrace_test_p6nop\n"
- "nop\n"
- "nop\n"
- "nop\n" /* 2 byte jmp + 3 bytes */
- "ftrace_test_p6nop:"
- P6_NOP5
- "jmp 1f\n"
- "ftrace_test_nop5:"
- ".byte 0x66,0x66,0x66,0x66,0x90\n"
- "1:"
- ".section .fixup, \"ax\"\n"
- "2: movl $1, %0\n"
- " jmp ftrace_test_nop5\n"
- "3: movl $2, %0\n"
- " jmp 1b\n"
- ".previous\n"
- _ASM_EXTABLE(ftrace_test_p6nop, 2b)
- _ASM_EXTABLE(ftrace_test_nop5, 3b)
- : "=r"(faulted) : "0" (faulted));
-
- switch (faulted) {
- case 0:
- pr_info("converting mcount calls to 0f 1f 44 00 00\n");
- memcpy(ideal_nop5, ftrace_test_p6nop, IDEAL_NOP_SIZE_5);
- break;
- case 1:
- pr_info("converting mcount calls to 66 66 66 66 90\n");
- memcpy(ideal_nop5, ftrace_test_nop5, IDEAL_NOP_SIZE_5);
- break;
- case 2:
- pr_info("converting mcount calls to jmp . + 5\n");
- memcpy(ideal_nop5, ftrace_test_jmp, IDEAL_NOP_SIZE_5);
- break;
- }
-
+#ifdef CONFIG_X86_64
+ /* Don't use these on 32 bits due to broken virtualizers */
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
+ memcpy(ideal_nop5, p6_nops[5], 5);
+#endif
}
#endif
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 0929191..7cc0a72 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3109,7 +3109,7 @@ void destroy_irq(unsigned int irq)
irq_set_status_flags(irq, IRQ_NOREQUEST|IRQ_NOPROBE);
- if (intr_remapping_enabled)
+ if (irq_remapped(cfg))
free_irte(irq);
raw_spin_lock_irqsave(&vector_lock, flags);
__clear_irq_vector(irq, cfg);
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index b7e755f..a3984f4 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -190,7 +190,7 @@ void sync_stop(void)
profile_event_unregister(PROFILE_TASK_EXIT, &task_exit_nb);
task_handoff_unregister(&task_free_nb);
mutex_unlock(&buffer_mutex);
- flush_scheduled_work();
+ flush_cpu_work();
/* make sure we don't leak task structs */
process_task_mortuary();
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index f179ac2..59f5544 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -111,14 +111,18 @@ void start_cpu_work(void)
void end_cpu_work(void)
{
- int i;
-
work_enabled = 0;
+}
+
+void flush_cpu_work(void)
+{
+ int i;
for_each_online_cpu(i) {
struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);
- cancel_delayed_work(&b->work);
+ /* these works are per-cpu, no need for flush_sync */
+ flush_delayed_work(&b->work);
}
}
diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h
index 68ea16a..e1d097e 100644
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -25,6 +25,7 @@ void free_cpu_buffers(void);
void start_cpu_work(void);
void end_cpu_work(void);
+void flush_cpu_work(void);
/* CPU buffer is composed of such entries (which are
* also used for context switch notes)
diff --git a/drivers/oprofile/timer_int.c b/drivers/oprofile/timer_int.c
index dc0ae4d..0107251 100644
--- a/drivers/oprofile/timer_int.c
+++ b/drivers/oprofile/timer_int.c
@@ -21,6 +21,7 @@
#include "oprof.h"
static DEFINE_PER_CPU(struct hrtimer, oprofile_hrtimer);
+static int ctr_running;
static enum hrtimer_restart oprofile_hrtimer_notify(struct hrtimer *hrtimer)
{
@@ -33,6 +34,9 @@ static void __oprofile_hrtimer_start(void *unused)
{
struct hrtimer *hrtimer = &__get_cpu_var(oprofile_hrtimer);
+ if (!ctr_running)
+ return;
+
hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hrtimer->function = oprofile_hrtimer_notify;
@@ -42,7 +46,10 @@ static void __oprofile_hrtimer_start(void *unused)
static int oprofile_hrtimer_start(void)
{
+ get_online_cpus();
+ ctr_running = 1;
on_each_cpu(__oprofile_hrtimer_start, NULL, 1);
+ put_online_cpus();
return 0;
}
@@ -50,6 +57,9 @@ static void __oprofile_hrtimer_stop(int cpu)
{
struct hrtimer *hrtimer = &per_cpu(oprofile_hrtimer, cpu);
+ if (!ctr_running)
+ return;
+
hrtimer_cancel(hrtimer);
}
@@ -57,8 +67,11 @@ static void oprofile_hrtimer_stop(void)
{
int cpu;
+ get_online_cpus();
for_each_online_cpu(cpu)
__oprofile_hrtimer_stop(cpu);
+ ctr_running = 0;
+ put_online_cpus();
}
static int __cpuinit oprofile_cpu_notify(struct notifier_block *self,
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index b67cb18..7880f18 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -1,7 +1,7 @@
#ifndef _LINUX_JUMP_LABEL_H
#define _LINUX_JUMP_LABEL_H
-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_HAVE_ARCH_JUMP_LABEL)
+#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
# include <asm/jump_label.h>
# define HAVE_JUMP_LABEL
#endif
@@ -18,6 +18,8 @@ struct module;
extern struct jump_entry __start___jump_table[];
extern struct jump_entry __stop___jump_table[];
+extern void jump_label_lock(void);
+extern void jump_label_unlock(void);
extern void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type);
extern void arch_jump_label_text_poke_early(jump_label_t addr);
@@ -59,6 +61,9 @@ static inline int jump_label_text_reserved(void *start, void *end)
return 0;
}
+static inline void jump_label_lock(void) {}
+static inline void jump_label_unlock(void) {}
+
#endif
#define COND_STMT(key, stmt) \
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 7be868b..3b79bd9 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -39,6 +39,16 @@ struct jump_label_module_entry {
struct module *mod;
};
+void jump_label_lock(void)
+{
+ mutex_lock(&jump_label_mutex);
+}
+
+void jump_label_unlock(void)
+{
+ mutex_unlock(&jump_label_mutex);
+}
+
static int jump_label_cmp(const void *a, const void *b)
{
const struct jump_entry *jea = a;
@@ -152,7 +162,7 @@ void jump_label_update(unsigned long key, enum jump_label_type type)
struct jump_label_module_entry *e_module;
int count;
- mutex_lock(&jump_label_mutex);
+ jump_label_lock();
entry = get_jump_label_entry((jump_label_t)key);
if (entry) {
count = entry->nr_entries;
@@ -168,13 +178,14 @@ void jump_label_update(unsigned long key, enum jump_label_type type)
count = e_module->nr_entries;
iter = e_module->table;
while (count--) {
- if (kernel_text_address(iter->code))
+ if (iter->key &&
+ kernel_text_address(iter->code))
arch_jump_label_transform(iter, type);
iter++;
}
}
}
- mutex_unlock(&jump_label_mutex);
+ jump_label_unlock();
}
static int addr_conflict(struct jump_entry *entry, void *start, void *end)
@@ -231,6 +242,7 @@ out:
* overlaps with any of the jump label patch addresses. Code
* that wants to modify kernel text should first verify that
* it does not overlap with any of the jump label addresses.
+ * Caller must hold jump_label_mutex.
*
* returns 1 if there is an overlap, 0 otherwise
*/
@@ -241,7 +253,6 @@ int jump_label_text_reserved(void *start, void *end)
struct jump_entry *iter_stop = __start___jump_table;
int conflict = 0;
- mutex_lock(&jump_label_mutex);
iter = iter_start;
while (iter < iter_stop) {
if (addr_conflict(iter, start, end)) {
@@ -256,10 +267,16 @@ int jump_label_text_reserved(void *start, void *end)
conflict = module_conflict(start, end);
#endif
out:
- mutex_unlock(&jump_label_mutex);
return conflict;
}
+/*
+ * Not all archs need this.
+ */
+void __weak arch_jump_label_text_poke_early(jump_label_t addr)
+{
+}
+
static __init int init_jump_label(void)
{
int ret;
@@ -267,7 +284,7 @@ static __init int init_jump_label(void)
struct jump_entry *iter_stop = __stop___jump_table;
struct jump_entry *iter;
- mutex_lock(&jump_label_mutex);
+ jump_label_lock();
ret = build_jump_label_hashtable(__start___jump_table,
__stop___jump_table);
iter = iter_start;
@@ -275,7 +292,7 @@ static __init int init_jump_label(void)
arch_jump_label_text_poke_early(iter->code);
iter++;
}
- mutex_unlock(&jump_label_mutex);
+ jump_label_unlock();
return ret;
}
early_initcall(init_jump_label);
@@ -366,6 +383,39 @@ static void remove_jump_label_module(struct module *mod)
}
}
+static void remove_jump_label_module_init(struct module *mod)
+{
+ struct hlist_head *head;
+ struct hlist_node *node, *node_next, *module_node, *module_node_next;
+ struct jump_label_entry *e;
+ struct jump_label_module_entry *e_module;
+ struct jump_entry *iter;
+ int i, count;
+
+ /* if the module doesn't have jump label entries, just return */
+ if (!mod->num_jump_entries)
+ return;
+
+ for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
+ head = &jump_label_table[i];
+ hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
+ hlist_for_each_entry_safe(e_module, module_node,
+ module_node_next,
+ &(e->modules), hlist) {
+ if (e_module->mod != mod)
+ continue;
+ count = e_module->nr_entries;
+ iter = e_module->table;
+ while (count--) {
+ if (within_module_init(iter->code, mod))
+ iter->key = 0;
+ iter++;
+ }
+ }
+ }
+ }
+}
+
static int
jump_label_module_notify(struct notifier_block *self, unsigned long val,
void *data)
@@ -375,16 +425,21 @@ jump_label_module_notify(struct notifier_block *self, unsigned long val,
switch (val) {
case MODULE_STATE_COMING:
- mutex_lock(&jump_label_mutex);
+ jump_label_lock();
ret = add_jump_label_module(mod);
if (ret)
remove_jump_label_module(mod);
- mutex_unlock(&jump_label_mutex);
+ jump_label_unlock();
break;
case MODULE_STATE_GOING:
- mutex_lock(&jump_label_mutex);
+ jump_label_lock();
remove_jump_label_module(mod);
- mutex_unlock(&jump_label_mutex);
+ jump_label_unlock();
+ break;
+ case MODULE_STATE_LIVE:
+ jump_label_lock();
+ remove_jump_label_module_init(mod);
+ jump_label_unlock();
break;
}
return ret;
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 99865c3..9737a76 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1145,14 +1145,13 @@ int __kprobes register_kprobe(struct kprobe *p)
if (ret)
return ret;
+ jump_label_lock();
preempt_disable();
if (!kernel_text_address((unsigned long) p->addr) ||
in_kprobes_functions((unsigned long) p->addr) ||
ftrace_text_reserved(p->addr, p->addr) ||
- jump_label_text_reserved(p->addr, p->addr)) {
- preempt_enable();
- return -EINVAL;
- }
+ jump_label_text_reserved(p->addr, p->addr))
+ goto fail_with_jump_label;
/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
p->flags &= KPROBE_FLAG_DISABLED;
@@ -1166,10 +1165,9 @@ int __kprobes register_kprobe(struct kprobe *p)
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
*/
- if (unlikely(!try_module_get(probed_mod))) {
- preempt_enable();
- return -EINVAL;
- }
+ if (unlikely(!try_module_get(probed_mod)))
+ goto fail_with_jump_label;
+
/*
* If the module freed .init.text, we couldn't insert
* kprobes in there.
@@ -1177,16 +1175,18 @@ int __kprobes register_kprobe(struct kprobe *p)
if (within_module_init((unsigned long)p->addr, probed_mod) &&
probed_mod->state != MODULE_STATE_COMING) {
module_put(probed_mod);
- preempt_enable();
- return -EINVAL;
+ goto fail_with_jump_label;
}
}
preempt_enable();
+ jump_label_unlock();
p->nmissed = 0;
INIT_LIST_HEAD(&p->list);
mutex_lock(&kprobe_mutex);
+ jump_label_lock(); /* needed to call jump_label_text_reserved() */
+
get_online_cpus(); /* For avoiding text_mutex deadlock. */
mutex_lock(&text_mutex);
@@ -1214,12 +1214,18 @@ int __kprobes register_kprobe(struct kprobe *p)
out:
mutex_unlock(&text_mutex);
put_online_cpus();
+ jump_label_unlock();
mutex_unlock(&kprobe_mutex);
if (probed_mod)
module_put(probed_mod);
return ret;
+
+fail_with_jump_label:
+ preempt_enable();
+ jump_label_unlock();
+ return -EINVAL;
}
EXPORT_SYMBOL_GPL(register_kprobe);
generated by cgit v1.1 at 2024-12-28 04:31:42 +0000