diff options
Diffstat (limited to 'kernel/trace/trace_syscalls.c')
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 99 |
1 files changed, 79 insertions, 20 deletions
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 8712ce3c6a0..9fbce6c9d2e 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -2,7 +2,7 @@ #include <trace/events/syscalls.h> #include <linux/kernel.h> #include <linux/ftrace.h> -#include <linux/perf_counter.h> +#include <linux/perf_event.h> #include <asm/syscall.h> #include "trace_output.h" @@ -384,10 +384,13 @@ static int sys_prof_refcount_exit; static void prof_syscall_enter(struct pt_regs *regs, long id) { - struct syscall_trace_enter *rec; struct syscall_metadata *sys_data; + struct syscall_trace_enter *rec; + unsigned long flags; + char *raw_data; int syscall_nr; int size; + int cpu; syscall_nr = syscall_get_nr(current, regs); if (!test_bit(syscall_nr, enabled_prof_enter_syscalls)) @@ -402,20 +405,38 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) size = ALIGN(size + sizeof(u32), sizeof(u64)); size -= sizeof(u32); - do { - char raw_data[size]; + if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE, + "profile buffer not large enough")) + return; + + /* Protect the per cpu buffer, begin the rcu read side */ + local_irq_save(flags); - /* zero the dead bytes from align to not leak stack to user */ - *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; + cpu = smp_processor_id(); + + if (in_nmi()) + raw_data = rcu_dereference(trace_profile_buf_nmi); + else + raw_data = rcu_dereference(trace_profile_buf); + + if (!raw_data) + goto end; - rec = (struct syscall_trace_enter *) raw_data; - tracing_generic_entry_update(&rec->ent, 0, 0); - rec->ent.type = sys_data->enter_id; - rec->nr = syscall_nr; - syscall_get_arguments(current, regs, 0, sys_data->nb_args, - (unsigned long *)&rec->args); - perf_tpcounter_event(sys_data->enter_id, 0, 1, rec, size); - } while(0); + raw_data = per_cpu_ptr(raw_data, cpu); + + /* zero the dead bytes from align to not leak stack to user */ + *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; + + rec = (struct syscall_trace_enter *) raw_data; + tracing_generic_entry_update(&rec->ent, 0, 0); + rec->ent.type = sys_data->enter_id; + rec->nr = syscall_nr; + syscall_get_arguments(current, regs, 0, sys_data->nb_args, + (unsigned long *)&rec->args); + perf_tp_event(sys_data->enter_id, 0, 1, rec, size); + +end: + local_irq_restore(flags); } int reg_prof_syscall_enter(char *name) @@ -460,8 +481,12 @@ void unreg_prof_syscall_enter(char *name) static void prof_syscall_exit(struct pt_regs *regs, long ret) { struct syscall_metadata *sys_data; - struct syscall_trace_exit rec; + struct syscall_trace_exit *rec; + unsigned long flags; int syscall_nr; + char *raw_data; + int size; + int cpu; syscall_nr = syscall_get_nr(current, regs); if (!test_bit(syscall_nr, enabled_prof_exit_syscalls)) @@ -471,12 +496,46 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) if (!sys_data) return; - tracing_generic_entry_update(&rec.ent, 0, 0); - rec.ent.type = sys_data->exit_id; - rec.nr = syscall_nr; - rec.ret = syscall_get_return_value(current, regs); + /* We can probably do that at build time */ + size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64)); + size -= sizeof(u32); - perf_tpcounter_event(sys_data->exit_id, 0, 1, &rec, sizeof(rec)); + /* + * Impossible, but be paranoid with the future + * How to put this check outside runtime? + */ + if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE, + "exit event has grown above profile buffer size")) + return; + + /* Protect the per cpu buffer, begin the rcu read side */ + local_irq_save(flags); + cpu = smp_processor_id(); + + if (in_nmi()) + raw_data = rcu_dereference(trace_profile_buf_nmi); + else + raw_data = rcu_dereference(trace_profile_buf); + + if (!raw_data) + goto end; + + raw_data = per_cpu_ptr(raw_data, cpu); + + /* zero the dead bytes from align to not leak stack to user */ + *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; + + rec = (struct syscall_trace_exit *)raw_data; + + tracing_generic_entry_update(&rec->ent, 0, 0); + rec->ent.type = sys_data->exit_id; + rec->nr = syscall_nr; + rec->ret = syscall_get_return_value(current, regs); + + perf_tp_event(sys_data->exit_id, 0, 1, rec, size); + +end: + local_irq_restore(flags); } int reg_prof_syscall_exit(char *name) |