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Commit bf5a3c13 authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

x86: Syscall hooks for userspace RCU extended QS 



Add syscall slow path hooks to notify syscall entry
and exit on CPUs that want to support userspace RCU
extended quiescent state.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent 04e7e951

arch/x86/include/asm/thread_info.h

+7 −3
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ struct thread_info { 
#define TIF_NOTSC		16	/* TSC is not accessible in userland */

#define TIF_IA32		17	/* IA32 compatibility process */

#define TIF_FORK		18	/* ret_from_fork */

#define TIF_NOHZ		19	/* in adaptive nohz mode */

#define TIF_MEMDIE		20	/* is terminating due to OOM killer */

#define TIF_DEBUG		21	/* uses debug registers */

#define TIF_IO_BITMAP		22	/* uses I/O bitmap */
@@ -114,6 +115,7 @@ struct thread_info { 
#define _TIF_NOTSC		(1 << TIF_NOTSC)

#define _TIF_IA32		(1 << TIF_IA32)

#define _TIF_FORK		(1 << TIF_FORK)

#define _TIF_NOHZ		(1 << TIF_NOHZ)

#define _TIF_DEBUG		(1 << TIF_DEBUG)

#define _TIF_IO_BITMAP		(1 << TIF_IO_BITMAP)

#define _TIF_FORCED_TF		(1 << TIF_FORCED_TF)
@@ -126,12 +128,13 @@ struct thread_info { 
/* work to do in syscall_trace_enter() */

#define _TIF_WORK_SYSCALL_ENTRY	\

	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT |	\

	 _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT)

	 _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT |	\

	 _TIF_NOHZ)



/* work to do in syscall_trace_leave() */

#define _TIF_WORK_SYSCALL_EXIT	\

	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP |	\

	 _TIF_SYSCALL_TRACEPOINT)

	 _TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ)



/* work to do on interrupt/exception return */

#define _TIF_WORK_MASK							\
@@ -141,7 +144,8 @@ struct thread_info { 


/* work to do on any return to user space */

#define _TIF_ALLWORK_MASK						\

	((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT)

	((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT |	\

	_TIF_NOHZ)



/* Only used for 64 bit */

#define _TIF_DO_NOTIFY_MASK						\

arch/x86/kernel/ptrace.c

+5 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/signal.h>

#include <linux/perf_event.h>

#include <linux/hw_breakpoint.h>

#include <linux/rcupdate.h>



#include <asm/uaccess.h>

#include <asm/pgtable.h>
@@ -1463,6 +1464,8 @@ long syscall_trace_enter(struct pt_regs *regs) 
{

	long ret = 0;



	rcu_user_exit();



	/*

	 * If we stepped into a sysenter/syscall insn, it trapped in

	 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
@@ -1526,4 +1529,6 @@ void syscall_trace_leave(struct pt_regs *regs) 
			!test_thread_flag(TIF_SYSCALL_EMU);

	if (step || test_thread_flag(TIF_SYSCALL_TRACE))

		tracehook_report_syscall_exit(regs, step);



	rcu_user_enter();

}