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 <[email protected]>
CC: Russell King <[email protected]>
CC: Catalin Marinas <[email protected]>
CC: Will Deacon <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: Paul Turner <[email protected]>
CC: Andrew Hunter <[email protected]>
CC: Peter Zijlstra <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Andi Kleen <[email protected]>
CC: Dave Watson <[email protected]>
CC: Chris Lameter <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: "H. Peter Anvin" <[email protected]>
CC: Ben Maurer <[email protected]>
CC: Steven Rostedt <[email protected]>
CC: "Paul E. McKenney" <[email protected]>
CC: Josh Triplett <[email protected]>
CC: Linus Torvalds <[email protected]>
CC: Andrew Morton <[email protected]>
CC: Boqun Feng <[email protected]>
CC: [email protected]
---
 arch/x86/Kconfig         | 1 +
 arch/x86/entry/common.c  | 1 +
 arch/x86/kernel/signal.c | 6 ++++++
 3 files changed, 8 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c580d8c..ae688f3 100644
--- 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 1433f6b..86e0c5f 100644
--- 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 04cb321..d7252b5 100644
--- 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)
-- 
2.1.4

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