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Commit d82991a8 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull restartable sequence support from Thomas Gleixner:
 "The restartable sequences syscall (finally):

  After a lot of back and forth discussion and massive delays caused by
  the speculative distraction of maintainers, the core set of
  restartable sequences has finally reached a consensus.

  It comes with the basic non disputed core implementation along with
  support for arm, powerpc and x86 and a full set of selftests

  It was exposed to linux-next earlier this week, so it does not fully
  comply with the merge window requirements, but there is really no
  point to drag it out for yet another cycle"

* 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rseq/selftests: Provide Makefile, scripts, gitignore
  rseq/selftests: Provide parametrized tests
  rseq/selftests: Provide basic percpu ops test
  rseq/selftests: Provide basic test
  rseq/selftests: Provide rseq library
  selftests/lib.mk: Introduce OVERRIDE_TARGETS
  powerpc: Wire up restartable sequences system call
  powerpc: Add syscall detection for restartable sequences
  powerpc: Add support for restartable sequences
  x86: Wire up restartable sequence system call
  x86: Add support for restartable sequences
  arm: Wire up restartable sequences system call
  arm: Add syscall detection for restartable sequences
  arm: Add restartable sequences support
  rseq: Introduce restartable sequences system call
  uapi/headers: Provide types_32_64.h
parents f4e5b30d ccba8b64

MAINTAINERS

+12 −0
Original line number Diff line number Diff line
@@ -12134,6 +12134,18 @@ F: include/dt-bindings/reset/ 
F:	include/linux/reset.h

F:	include/linux/reset-controller.h



RESTARTABLE SEQUENCES SUPPORT

M:	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

M:	Peter Zijlstra <peterz@infradead.org>

M:	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

M:	Boqun Feng <boqun.feng@gmail.com>

L:	linux-kernel@vger.kernel.org

S:	Supported

F:	kernel/rseq.c

F:	include/uapi/linux/rseq.h

F:	include/trace/events/rseq.h

F:	tools/testing/selftests/rseq/



RFKILL

M:	Johannes Berg <johannes@sipsolutions.net>

L:	linux-wireless@vger.kernel.org

arch/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -272,6 +272,13 @@ config HAVE_REGS_AND_STACK_ACCESS_API 
	  declared in asm/ptrace.h

	  For example the kprobes-based event tracer needs this API.



config HAVE_RSEQ

	bool

	depends on HAVE_REGS_AND_STACK_ACCESS_API

	help

	  This symbol should be selected by an architecture if it

	  supports an implementation of restartable sequences.



config HAVE_CLK

	bool

	help

arch/arm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -91,6 +91,7 @@ config ARM 
	select HAVE_PERF_USER_STACK_DUMP

	select HAVE_RCU_TABLE_FREE if (SMP && ARM_LPAE)

	select HAVE_REGS_AND_STACK_ACCESS_API

	select HAVE_RSEQ

	select HAVE_SYSCALL_TRACEPOINTS

	select HAVE_UID16

	select HAVE_VIRT_CPU_ACCOUNTING_GEN

arch/arm/kernel/entry-common.S

+19 −6
Original line number Diff line number Diff line
@@ -39,12 +39,13 @@ saved_pc .req lr 


	.section .entry.text,"ax",%progbits

	.align	5

#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING))

#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING) || \

	IS_ENABLED(CONFIG_DEBUG_RSEQ))

/*

 * This is the fast syscall return path.  We do as little as possible here,

 * such as avoiding writing r0 to the stack.  We only use this path if we

 * have tracing and context tracking disabled - the overheads from those

 * features make this path too inefficient.

 * have tracing, context tracking and rseq debug disabled - the overheads

 * from those features make this path too inefficient.

 */

ret_fast_syscall:

 UNWIND(.fnstart	)
@@ -71,14 +72,20 @@ fast_work_pending: 
	/* fall through to work_pending */

#else

/*

 * The "replacement" ret_fast_syscall for when tracing or context tracking

 * is enabled.  As we will need to call out to some C functions, we save

 * r0 first to avoid needing to save registers around each C function call.

 * The "replacement" ret_fast_syscall for when tracing, context tracking,

 * or rseq debug is enabled.  As we will need to call out to some C functions,

 * we save r0 first to avoid needing to save registers around each C function

 * call.

 */

ret_fast_syscall:

 UNWIND(.fnstart	)

 UNWIND(.cantunwind	)

	str	r0, [sp, #S_R0 + S_OFF]!	@ save returned r0

#if IS_ENABLED(CONFIG_DEBUG_RSEQ)

	/* do_rseq_syscall needs interrupts enabled. */

	mov	r0, sp				@ 'regs'

	bl	do_rseq_syscall

#endif

	disable_irq_notrace			@ disable interrupts

	ldr	r2, [tsk, #TI_ADDR_LIMIT]

	cmp	r2, #TASK_SIZE
@@ -113,6 +120,12 @@ ENDPROC(ret_fast_syscall) 
 */

ENTRY(ret_to_user)

ret_slow_syscall:

#if IS_ENABLED(CONFIG_DEBUG_RSEQ)

	/* do_rseq_syscall needs interrupts enabled. */

	enable_irq_notrace			@ enable interrupts

	mov	r0, sp				@ 'regs'

	bl	do_rseq_syscall

#endif

	disable_irq_notrace			@ disable interrupts

ENTRY(ret_to_user_from_irq)

	ldr	r2, [tsk, #TI_ADDR_LIMIT]

arch/arm/kernel/signal.c

+14 −0
Original line number Diff line number Diff line
@@ -540,6 +540,12 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) 
	sigset_t *oldset = sigmask_to_save();

	int ret;



	/*

	 * Increment event counter and perform fixup for the pre-signal

	 * frame.

	 */

	rseq_signal_deliver(regs);



	/*

	 * Set up the stack frame

	 */
@@ -660,6 +666,7 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) 
			} else {

				clear_thread_flag(TIF_NOTIFY_RESUME);

				tracehook_notify_resume(regs);

				rseq_handle_notify_resume(regs);

			}

		}

		local_irq_disable();
@@ -703,3 +710,10 @@ asmlinkage void addr_limit_check_failed(void) 
{

	addr_limit_user_check();

}



#ifdef CONFIG_DEBUG_RSEQ

asmlinkage void do_rseq_syscall(struct pt_regs *regs)

{

	rseq_syscall(regs);

}

#endif