x86: Wire up restartable sequence system call

Wire up the rseq system call on x86 32/64.

This provides an ABI improving the speed of a user-space getcpu
operation on x86 by removing the need to perform a function call, "lsl"
instruction, or system call on the fast path, as well as improving the
speed of user-space operations on per-cpu data.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Watson <davejwatson@fb.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Chris Lameter <cl@linux.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Andrew Hunter <ahh@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Maurer <bmaurer@fb.com>
Cc: linux-api@vger.kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/20180602124408.8430-8-mathieu.desnoyers@efficios.com

diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 14a2f996e543a12fdf65b00b2cce8b804c3b9ece..3cf7b533b3d1304b44b5eefe7ab55cc09398b2c2 100644 (file)
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -397,3 +397,4 @@
 383    i386    statx                   sys_statx                       __ia32_sys_statx
 384    i386    arch_prctl              sys_arch_prctl                  __ia32_compat_sys_arch_prctl
 385    i386    io_pgetevents           sys_io_pgetevents               __ia32_compat_sys_io_pgetevents
+386    i386    rseq                    sys_rseq                        __ia32_sys_rseq

diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index cd36232ab62f593ecb5f1cd4577de99bcd00402d..f0b1709a5ffb2b0901d7f2492252876d17bc25a0 100644 (file)
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -342,6 +342,7 @@
 331    common  pkey_free               __x64_sys_pkey_free
 332    common  statx                   __x64_sys_statx
 333    common  io_pgetevents           __x64_sys_io_pgetevents
+334    common  rseq                    __x64_sys_rseq
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact