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tracepoints: Migrate to use SYSCALL_WORK flag 

On architectures using the generic syscall entry code the architecture
independent syscall work is moved to flags in thread_info::syscall_work.
This removes architecture dependencies and frees up TIF bits.

Define SYSCALL_WORK_SYSCALL_TRACEPOINT, use it in the generic entry code
and convert the code which uses the TIF specific helper functions to use
the new *_syscall_work() helpers which either resolve to the new mode for
users of the generic entry code or to the TIF based functions for the other
architectures.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-6-krisman@collabora.com
This commit is contained in:
Gabriel Krisman Bertazi 2020-11-16 12:42:01 -05:00 committed by Thomas Gleixner
parent 23d67a5485
commit 524666cb5d
6 changed files with 18 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
include/linux/entry-common.h
View File

@ -17,10 +17,6 @@
# define _TIF_SYSCALL_EMU (0)
#endif
#ifndef _TIF_SYSCALL_TRACEPOINT
# define _TIF_SYSCALL_TRACEPOINT (0)
#endif
#ifndef _TIF_SYSCALL_AUDIT
# define _TIF_SYSCALL_AUDIT (0)
#endif
@ -46,7 +42,7 @@
#define SYSCALL_ENTER_WORK \
(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_EMU | \
_TIF_SYSCALL_EMU | \
ARCH_SYSCALL_ENTER_WORK)
/*
@ -58,10 +54,11 @@
#define SYSCALL_EXIT_WORK \
(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_TRACEPOINT | ARCH_SYSCALL_EXIT_WORK)
ARCH_SYSCALL_EXIT_WORK)
#define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP)
#define SYSCALL_WORK_EXIT (0)
#define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP | \
SYSCALL_WORK_SYSCALL_TRACEPOINT)
#define SYSCALL_WORK_EXIT (SYSCALL_WORK_SYSCALL_TRACEPOINT)
/*
* TIF flags handled in exit_to_user_mode_loop()

2
include/linux/thread_info.h
View File

@ -37,9 +37,11 @@ enum {
enum syscall_work_bit {
SYSCALL_WORK_BIT_SECCOMP,
SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT,
};
#define SYSCALL_WORK_SECCOMP BIT(SYSCALL_WORK_BIT_SECCOMP)
#define SYSCALL_WORK_SYSCALL_TRACEPOINT BIT(SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT)
#include <asm/thread_info.h>

6
include/trace/syscall.h
View File

@ -37,10 +37,10 @@ struct syscall_metadata {
#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_HAVE_SYSCALL_TRACEPOINTS)
static inline void syscall_tracepoint_update(struct task_struct *p)
{
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
set_tsk_thread_flag(p, TIF_SYSCALL_TRACEPOINT);
if (test_syscall_work(SYSCALL_TRACEPOINT))
set_task_syscall_work(p, SYSCALL_TRACEPOINT);
else
clear_tsk_thread_flag(p, TIF_SYSCALL_TRACEPOINT);
clear_task_syscall_work(p, SYSCALL_TRACEPOINT);
}
#else
static inline void syscall_tracepoint_update(struct task_struct *p)

4
kernel/entry/common.c
View File

@ -63,7 +63,7 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall,
/* Either of the above might have changed the syscall number */
syscall = syscall_get_nr(current, regs);
if (unlikely(ti_work & _TIF_SYSCALL_TRACEPOINT))
if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT))
trace_sys_enter(regs, syscall);
syscall_enter_audit(regs, syscall);
@ -233,7 +233,7 @@ static void syscall_exit_work(struct pt_regs *regs, unsigned long ti_work,
audit_syscall_exit(regs);
if (ti_work & _TIF_SYSCALL_TRACEPOINT)
if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT)
trace_sys_exit(regs, syscall_get_return_value(current, regs));
step = report_single_step(ti_work);

8
kernel/trace/trace_events.c
View File

@ -3428,10 +3428,10 @@ static __init int event_trace_enable(void)
* initialize events and perhaps start any events that are on the
* command line. Unfortunately, there are some events that will not
* start this early, like the system call tracepoints that need
* to set the TIF_SYSCALL_TRACEPOINT flag of pid 1. But event_trace_enable()
* is called before pid 1 starts, and this flag is never set, making
* the syscall tracepoint never get reached, but the event is enabled
* regardless (and not doing anything).
* to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
* event_trace_enable() is called before pid 1 starts, and this flag
* is never set, making the syscall tracepoint never get reached, but
* the event is enabled regardless (and not doing anything).
*/
static __init int event_trace_enable_again(void)
{

4
kernel/tracepoint.c
View File

@ -594,7 +594,7 @@ int syscall_regfunc(void)
if (!sys_tracepoint_refcount) {
read_lock(&tasklist_lock);
for_each_process_thread(p, t) {
set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
set_task_syscall_work(t, SYSCALL_TRACEPOINT);
}
read_unlock(&tasklist_lock);
}
@ -611,7 +611,7 @@ void syscall_unregfunc(void)
if (!sys_tracepoint_refcount) {
read_lock(&tasklist_lock);
for_each_process_thread(p, t) {
clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
clear_task_syscall_work(t, SYSCALL_TRACEPOINT);
}
read_unlock(&tasklist_lock);
}