Restartable sequences: x86 32/64 architecture support

Call the rseq_handle_notify_resume() function on return to userspace if
TIF_NOTIFY_RESUME thread flag is set.

Increment the event counter and perform fixup on the pre-signal frame
when a signal is delivered on top of a restartable sequence critical
section.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-api@vger.kernel.org

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c580d8c33562ec5eba4dbfc273ae3ed7b6b67072..ae688f345fd4dbc1889c52b0542532d1b8aeff3a 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -143,6 +143,7 @@ config X86
        select HAVE_PERF_REGS
        select HAVE_PERF_USER_STACK_DUMP
        select HAVE_REGS_AND_STACK_ACCESS_API
+       select HAVE_RSEQ
        select HAVE_SYSCALL_TRACEPOINTS
        select HAVE_UID16                       if X86_32 || IA32_EMULATION
        select HAVE_UNSTABLE_SCHED_CLOCK

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 1433f6b4607d6f6f38a1415afa02f43ca890d8d7..86e0c5fc39bc5012be6ba600a1a13fc013db7aff 100644 (file)
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -165,6 +165,7 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
                if (cached_flags & _TIF_NOTIFY_RESUME) {
                        clear_thread_flag(TIF_NOTIFY_RESUME);
                        tracehook_notify_resume(regs);
+                       rseq_handle_notify_resume(regs);
                }
 
                if (cached_flags & _TIF_USER_RETURN_NOTIFY)

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 04cb3212db2d1d6e0e3263cef736121e6b0ad0d6..d7252b5dad5ccc8d9011ad76ac1c2d9e9b85986c 100644 (file)
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -683,6 +683,12 @@ setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
        sigset_t *set = sigmask_to_save();
        compat_sigset_t *cset = (compat_sigset_t *) set;
 
+       /*
+        * Increment event counter and perform fixup for the pre-signal
+        * frame.
+        */
+       rseq_signal_deliver(regs);
+
        /* Set up the stack frame */
        if (is_ia32_frame()) {
                if (ksig->ka.sa.sa_flags & SA_SIGINFO)