On Mon, 16 Nov 2020 12:42:01 -0500 Gabriel Krisman Bertazi <[email protected]> wrote:
> For architectures that rely on the generic syscall entry code, use the > syscall_work field in struct thread_info and the specific SYSCALL_WORK > flag. This set of flags has the advantage of being architecture > independent. > > Users of the flag outside of the generic entry code should rely on the > accessor macros, such that the flag is still correctly resolved for > architectures that don't use the generic entry code and still rely on > TIF flags for system call work. > > Signed-off-by: Gabriel Krisman Bertazi <[email protected]> Reviewed-by: Steven Rostedt (VMware) <[email protected]> Also added Mathieu to Cc. -- Steve > > --- > Changes since v2: > - Drop explicit value assignment in enum (tglx) > - Avoid FLAG/_FLAG defines (tglx) > - Fix comment to refer to SYSCALL_WORK_SECCOMP (me) > --- > include/linux/entry-common.h | 13 +++++-------- > include/linux/thread_info.h | 2 ++ > include/trace/syscall.h | 6 +++--- > kernel/entry/common.c | 4 ++-- > kernel/trace/trace_events.c | 8 ++++---- > kernel/tracepoint.c | 4 ++-- > 6 files changed, 18 insertions(+), 19 deletions(-) > > diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h > index f3fc4457f63f..8aba367e5c79 100644 > --- a/include/linux/entry-common.h > +++ b/include/linux/entry-common.h > @@ -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() > diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h > index 1d6488130b5c..ff0ac2ebb4ff 100644 > --- a/include/linux/thread_info.h > +++ b/include/linux/thread_info.h > @@ -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> > > diff --git a/include/trace/syscall.h b/include/trace/syscall.h > index dc8ac27d27c1..8e193f3a33b3 100644 > --- a/include/trace/syscall.h > +++ b/include/trace/syscall.h > @@ -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) > diff --git a/kernel/entry/common.c b/kernel/entry/common.c > index c321056c73d7..4e2b3c08d939 100644 > --- a/kernel/entry/common.c > +++ b/kernel/entry/common.c > @@ -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); > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index 47a71f96e5bc..adf65b502453 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -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) > { > diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c > index 3f659f855074..7261fa0f5e3c 100644 > --- a/kernel/tracepoint.c > +++ b/kernel/tracepoint.c > @@ -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); > }
