Userspace tracing : facility registration and event logging through system
call.
patch15-2.6.18-lttng-core-0.6.36-userspace-tracing.diff
Signed-off-by : Mathieu Desnoyers <[email protected]>
--BEGIN--
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -82,6 +82,7 @@ #include <linux/timer.h>
#include <linux/hrtimer.h>
#include <asm/processor.h>
+#include <linux/ltt-facilities.h>
struct exec_domain;
struct futex_pi_state;
@@ -996,6 +997,9 @@ #endif
#ifdef CONFIG_TASK_DELAY_ACCT
struct task_delay_info *delays;
#endif
+#ifdef CONFIG_LTT_USERSPACE_GENERIC
+ ltt_facility_t ltt_facilities[LTT_FAC_PER_PROCESS];
+#endif //CONFIG_LTT_USERSPACE_GENERIC
};
static inline pid_t process_group(struct task_struct *tsk)
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -111,6 +111,8 @@ cond_syscall(sys_vm86old);
cond_syscall(sys_vm86);
cond_syscall(compat_sys_ipc);
cond_syscall(compat_sys_sysctl);
+cond_syscall(sys_ltt_trace_generic);
+cond_syscall(sys_ltt_register_generic);
/* arch-specific weak syscall entries */
cond_syscall(sys_pciconfig_read);
--- /dev/null
+++ b/ltt/ltt-syscall.c
@@ -0,0 +1,184 @@
+/******************************************************************************
+ * ltt-syscall.c
+ *
+ * Mathieu Desnoyers ([email protected])
+ * March 2006
+ *
+ * LTT userspace tracing syscalls
+ */
+
+#include <linux/errno.h>
+#include <linux/syscalls.h>
+#include <linux/sched.h>
+#include <linux/ltt-facilities.h>
+#include <ltt/ltt-tracer.h>
+
+#include <asm/uaccess.h>
+
+/* User event logging function */
+static inline int trace_user_event(unsigned int facility_id,
+ unsigned int event_id,
+ void __user *data, size_t data_size, int blocking,
+ int high_priority)
+{
+ int ret = 0;
+ unsigned int index;
+ struct ltt_channel_struct *channel;
+ struct ltt_trace_struct *trace;
+ void *transport_data;
+ void *buffer = NULL;
+ size_t real_to_base = 0; /* buffer allocated on arch_size alignment */
+ size_t *to_base = &real_to_base;
+ size_t real_to = 0;
+ size_t *to = &real_to;
+ size_t real_len = 0;
+ size_t *len = &real_len;
+ size_t reserve_size;
+ size_t slot_size;
+ u64 tsc;
+ size_t before_hdr_pad, after_hdr_pad, header_size;
+ struct user_dbg_data dbg;
+
+ dbg.avail_size = 0;
+ dbg.write = 0;
+ dbg.read = 0;
+
+ if (ltt_traces.num_active_traces == 0)
+ return 0;
+
+ /* Assume that the padding for alignment starts at a
+ * sizeof(void *) address. */
+
+ reserve_size = data_size;
+
+ if (high_priority)
+ index = GET_CHANNEL_INDEX(processes);
+ else
+ index = GET_CHANNEL_INDEX(cpu);
+
+ preempt_disable();
+
+ if (blocking) {
+ /* User space requested blocking mode :
+ * If one of the active traces has free space below a specific
+ * threshold value, we reenable preemption and block. */
+block_test_begin:
+ list_for_each_entry_rcu(trace, <t_traces.head, list) {
+ if (!trace->active)
+ continue;
+
+ if (trace->ops->user_blocking(trace, index, data_size,
+ &dbg))
+ goto block_test_begin;
+ }
+ }
+ ltt_nesting[smp_processor_id()]++;
+ list_for_each_entry_rcu(trace, <t_traces.head, list) {
+ if (!trace->active)
+ continue;
+ channel = ltt_get_channel_from_index(trace, index);
+ slot_size = 0;
+ buffer = ltt_reserve_slot(trace, channel, &transport_data,
+ reserve_size, &slot_size, &tsc,
+ &before_hdr_pad, &after_hdr_pad, &header_size);
+ if (!buffer) {
+ if (blocking)
+ trace->ops->user_errors(trace,
+ index, data_size, &dbg);
+ continue; /* buffer full */
+ }
+ *to_base = *to = *len = 0;
+ ltt_write_event_header(trace, channel, buffer,
+ facility_id, event_id,
+ reserve_size, before_hdr_pad, tsc);
+ *to_base += before_hdr_pad + after_hdr_pad + header_size;
+ /* Hope the user pages are not swapped out. In the rare case
+ * where it is, the slot will be zeroed and EFAULT returned. */
+ if (__copy_from_user_inatomic(buffer+*to_base+*to, data,
+ data_size))
+ ret = -EFAULT; /* Data is garbage in the slot */
+ ltt_commit_slot(channel, &transport_data, buffer, slot_size);
+ if (ret != 0)
+ break;
+ }
+ ltt_nesting[smp_processor_id()]--;
+ preempt_enable_no_resched();
+ return ret;
+}
+
+asmlinkage long sys_ltt_trace_generic(unsigned int facility_id,
+ unsigned int event_id,
+ void __user *data,
+ size_t data_size,
+ int blocking,
+ int high_priority)
+{
+ if (!ltt_facility_user_access_ok(facility_id))
+ return -EPERM;
+ if (!access_ok(VERIFY_READ, data, data_size))
+ return -EFAULT;
+
+ return trace_user_event(facility_id, event_id, data, data_size,
+ blocking, high_priority);
+}
+
+asmlinkage long sys_ltt_register_generic(unsigned int __user *facility_id,
+ const struct user_facility_info __user *info)
+{
+ struct user_facility_info kinfo;
+ int fac_id;
+ unsigned int i;
+
+ /* Check if the process has already registered the maximum number of
+ * allowed facilities */
+ if (current->ltt_facilities[LTT_FAC_PER_PROCESS-1] != 0)
+ return -EPERM;
+
+ if (copy_from_user(&kinfo, info, sizeof(*info)))
+ return -EFAULT;
+
+ /* Verify if facility is already registered */
+ printk(KERN_DEBUG "LTT register generic for %s\n", kinfo.name);
+ fac_id = ltt_facility_verify(LTT_FACILITY_TYPE_USER,
+ kinfo.name,
+ kinfo.num_events,
+ kinfo.checksum,
+ kinfo.int_size,
+ kinfo.long_size,
+ kinfo.pointer_size,
+ kinfo.size_t_size,
+ kinfo.alignment);
+
+ printk(KERN_DEBUG "LTT verify return %d\n", fac_id);
+ if (fac_id > 0)
+ goto found;
+
+ fac_id = ltt_facility_register(LTT_FACILITY_TYPE_USER,
+ kinfo.name,
+ kinfo.num_events,
+ kinfo.checksum,
+ kinfo.int_size,
+ kinfo.long_size,
+ kinfo.pointer_size,
+ kinfo.size_t_size,
+ kinfo.alignment);
+
+ printk(KERN_DEBUG "LTT register return %d\n", fac_id);
+ if (fac_id == 0)
+ return -EPERM;
+ if (fac_id < 0)
+ return fac_id; /* Error */
+found:
+ get_task_struct(current->group_leader);
+ for (i = 0; i < LTT_FAC_PER_PROCESS; i++) {
+ if (current->group_leader->ltt_facilities[i] == 0) {
+ current->group_leader->ltt_facilities[i] =
+ (ltt_facility_t)fac_id;
+ break;
+ }
+ }
+ put_task_struct(current->group_leader);
+ /* Write facility_id */
+ put_user((unsigned int)fac_id, facility_id);
+ return 0;
+}
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -38,6 +38,7 @@ #include <linux/compat.h>
#include <linux/pipe_fs_i.h>
#include <linux/audit.h> /* for audit_free() */
#include <linux/resource.h>
+#include <linux/ltt-facilities.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -59,6 +60,17 @@ static void __unhash_process(struct task
list_del_rcu(&p->tasks);
__get_cpu_var(process_counts)--;
+#ifdef CONFIG_LTT_USERSPACE_GENERIC
+ {
+ int i;
+ for (i = 0; i < LTT_FAC_PER_PROCESS; i++) {
+ if (p->ltt_facilities[i] == 0)
+ break;
+ WARN_ON(ltt_facility_unregister(
+ p->ltt_facilities[i]));
+ }
+ }
+#endif //CONFIG_LTT_USERSPACE_GENERIC
}
list_del_rcu(&p->thread_group);
remove_parent(p);
@@ -170,6 +182,7 @@ repeat:
write_unlock_irq(&tasklist_lock);
proc_flush_task(p);
release_thread(p);
+ MARK(kernel_process_free, "%d", p->pid);
call_rcu(&p->rcu, delayed_put_task_struct);
p = leader;
@@ -913,6 +926,8 @@ #endif
if (group_dead)
acct_process();
+ MARK(kernel_process_exit, "%d", tsk->pid);
+
exit_sem(tsk);
__exit_files(tsk);
__exit_fs(tsk);
@@ -1440,6 +1455,8 @@ static long do_wait(pid_t pid, int optio
struct task_struct *tsk;
int flag, retval;
+ MARK(kernel_process_wait, "%d", pid);
+
add_wait_queue(¤t->signal->wait_chldexit,&wait);
repeat:
/*
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -45,6 +45,7 @@ #include <linux/acct.h>
#include <linux/cn_proc.h>
#include <linux/delayacct.h>
#include <linux/taskstats_kern.h>
+#include <linux/ltt-facilities.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -64,6 +65,7 @@ int max_threads; /* tunable limit on nr
DEFINE_PER_CPU(unsigned long, process_counts) = 0;
__cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */
+EXPORT_SYMBOL(tasklist_lock);
int nr_processes(void)
{
@@ -1133,6 +1135,13 @@ #endif
* of CLONE_PTRACE.
*/
clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
+#ifdef CONFIG_MARKERS
+ /*
+ * Syscall tracing must always be turned on when markers are enabled.
+ * Use the syscall audit thread flag for now, as it is never cleared.
+ */
+ set_tsk_thread_flag(p, TIF_SYSCALL_AUDIT);
+#endif
#ifdef TIF_SYSCALL_EMU
clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
#endif
@@ -1142,6 +1151,20 @@ #endif
p->parent_exec_id = p->self_exec_id;
+#ifdef CONFIG_LTT_USERSPACE_GENERIC
+ if (clone_flags & CLONE_THREAD)
+ memset(p->ltt_facilities, 0, sizeof(p->ltt_facilities));
+ else {
+ int i;
+ for (i = 0; i < LTT_FAC_PER_PROCESS; i++) {
+ p->ltt_facilities[i] = current->ltt_facilities[i];
+ if (p->ltt_facilities[i] != 0)
+ ltt_facility_ref(p->ltt_facilities[i]);
+ }
+ }
+
+#endif //CONFIG_LTT_USERSPACE_GENERIC
+
/* ok, now we should be set up.. */
p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
p->pdeath_signal = 0;
@@ -1198,7 +1221,7 @@ #endif
spin_unlock(¤t->sighand->siglock);
write_unlock_irq(&tasklist_lock);
retval = -ERESTARTNOINTR;
- goto bad_fork_cleanup_namespace;
+ goto bad_fork_cleanup_ltt_facilities;
}
if (clone_flags & CLONE_THREAD) {
@@ -1251,6 +1274,18 @@ #endif
proc_fork_connector(p);
return p;
+bad_fork_cleanup_ltt_facilities:
+#ifdef CONFIG_LTT_USERSPACE_GENERIC
+ {
+ int i;
+ for (i = 0; i < LTT_FAC_PER_PROCESS; i++) {
+ if (p->ltt_facilities[i] == 0)
+ break;
+ WARN_ON(ltt_facility_unregister(
+ p->ltt_facilities[i]));
+ }
+ }
+#endif //CONFIG_LTT_USERSPACE_GENERIC
bad_fork_cleanup_namespace:
exit_namespace(p);
bad_fork_cleanup_keys:
@@ -1364,6 +1399,9 @@ long do_fork(unsigned long clone_flags,
if (!IS_ERR(p)) {
struct completion vfork;
+ MARK(kernel_process_fork, "%d %d %d",
+ current->pid, p->pid, p->tgid);
+
if (clone_flags & CLONE_VFORK) {
p->vfork_done = &vfork;
init_completion(&vfork);
--- a/include/asm-arm/unistd.h
+++ b/include/asm-arm/unistd.h
@@ -347,6 +347,8 @@ #define __NR_inotify_rm_watch (__NR_SYS
#define __NR_mbind (__NR_SYSCALL_BASE+319)
#define __NR_get_mempolicy (__NR_SYSCALL_BASE+320)
#define __NR_set_mempolicy (__NR_SYSCALL_BASE+321)
+#define __NR_ltt_trace_generic (__NR_SYSCALL_BASE+322)
+#define __NR_ltt_register_generic (__NR_SYSCALL_BASE+323)
/*
* The following SWIs are ARM private.
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -323,10 +323,12 @@ #define __NR_sync_file_range 314
#define __NR_tee 315
#define __NR_vmsplice 316
#define __NR_move_pages 317
+#define __NR_ltt_trace_generic 318
+#define __NR_ltt_register_generic 319
#ifdef __KERNEL__
-#define NR_syscalls 318
+#define NR_syscalls 320
/*
* user-visible error numbers are in the range -1 - -128: see
--- a/include/asm-mips/unistd.h
+++ b/include/asm-mips/unistd.h
@@ -329,16 +329,18 @@ #define __NR_sync_file_range (__NR_Linu
#define __NR_tee (__NR_Linux + 306)
#define __NR_vmsplice (__NR_Linux + 307)
#define __NR_move_pages (__NR_Linux + 308)
+#define __NR_ltt_trace_generic (__NR_Linux + 309)
+#define __NR_ltt_register_generic (__NR_Linux + 310)
/*
* Offset of the last Linux o32 flavoured syscall
*/
-#define __NR_Linux_syscalls 308
+#define __NR_Linux_syscalls 310
#endif /* _MIPS_SIM == _MIPS_SIM_ABI32 */
#define __NR_O32_Linux 4000
-#define __NR_O32_Linux_syscalls 308
+#define __NR_O32_Linux_syscalls 310
#if _MIPS_SIM == _MIPS_SIM_ABI64
@@ -614,16 +616,18 @@ #define __NR_sync_file_range (__NR_Linu
#define __NR_tee (__NR_Linux + 265)
#define __NR_vmsplice (__NR_Linux + 266)
#define __NR_move_pages (__NR_Linux + 267)
+#define __NR_ltt_trace_generic (__NR_Linux + 268)
+#define __NR_ltt_register_generic (__NR_Linux + 269)
/*
* Offset of the last Linux 64-bit flavoured syscall
*/
-#define __NR_Linux_syscalls 267
+#define __NR_Linux_syscalls 269
#endif /* _MIPS_SIM == _MIPS_SIM_ABI64 */
#define __NR_64_Linux 5000
-#define __NR_64_Linux_syscalls 267
+#define __NR_64_Linux_syscalls 269
#if _MIPS_SIM == _MIPS_SIM_NABI32
@@ -903,16 +907,19 @@ #define __NR_sync_file_range (__NR_Linu
#define __NR_tee (__NR_Linux + 269)
#define __NR_vmsplice (__NR_Linux + 270)
#define __NR_move_pages (__NR_Linux + 271)
+#define __NR_ltt_trace_generic (__NR_Linux + 272)
+#define __NR_ltt_register_generic (__NR_Linux + 273)
+
/*
* Offset of the last N32 flavoured syscall
*/
-#define __NR_Linux_syscalls 271
+#define __NR_Linux_syscalls 273
#endif /* _MIPS_SIM == _MIPS_SIM_NABI32 */
#define __NR_N32_Linux 6000
-#define __NR_N32_Linux_syscalls 271
+#define __NR_N32_Linux_syscalls 273
#ifdef __KERNEL__
--- a/include/asm-powerpc/unistd.h
+++ b/include/asm-powerpc/unistd.h
@@ -323,10 +323,12 @@ #define __NR_fchmodat 297
#define __NR_faccessat 298
#define __NR_get_robust_list 299
#define __NR_set_robust_list 300
+#define __NR_ltt_trace_generic 301
+#define __NR_ltt_register_generic 302
#ifdef __KERNEL__
-#define __NR_syscalls 301
+#define __NR_syscalls 303
#define __NR__exit __NR_exit
#define NR_syscalls __NR_syscalls
--- a/include/asm-powerpc/systbl.h
+++ b/include/asm-powerpc/systbl.h
@@ -304,3 +304,5 @@ SYSCALL_SPU(fchmodat)
SYSCALL_SPU(faccessat)
COMPAT_SYS_SPU(get_robust_list)
COMPAT_SYS_SPU(set_robust_list)
+SYSCALL(ltt_trace_generic)
+SYSCALL(ltt_register_generic)
--- a/include/asm-x86_64/unistd.h
+++ b/include/asm-x86_64/unistd.h
@@ -619,10 +619,14 @@ #define __NR_vmsplice 278
__SYSCALL(__NR_vmsplice, sys_vmsplice)
#define __NR_move_pages 279
__SYSCALL(__NR_move_pages, sys_move_pages)
+#define __NR_ltt_trace_generic 280
+__SYSCALL(__NR_ltt_trace_generic, sys_ltt_trace_generic)
+#define __NR_ltt_register_generic 281
+__SYSCALL(__NR_ltt_register_generic, sys_ltt_register_generic)
#ifdef __KERNEL__
-#define __NR_syscall_max __NR_move_pages
+#define __NR_syscall_max __NR_ltt_register_generic
#ifndef __NO_STUBS
--END--
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On Fri, Nov 24, 2006 at 05:04:13PM -0500, Mathieu Desnoyers wrote:
> Userspace tracing : facility registration and event logging through system
> call.
The patch defines the syscall numbers for several architectures but
doesn't change arch/i386/kernel/syscall_table.S, arch/mips/kernel/scall*.S
etc.
Ralf
* Ralf Baechle ([email protected]) wrote:
> On Fri, Nov 24, 2006 at 05:04:13PM -0500, Mathieu Desnoyers wrote:
>
> > Userspace tracing : facility registration and event logging through system
> > call.
>
> The patch defines the syscall numbers for several architectures but
> doesn't change arch/i386/kernel/syscall_table.S, arch/mips/kernel/scall*.S
> etc.
>
> Ralf
>
Hi Ralf,
I stripped them from my complete version (it is in my instrumentation
patches). Only tracing from user space application is affected. As this is a
minor issue, I will only fix it in my next post.
Thanks,
Mathieu
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