Messages in this thread Patch in this message | | | From | Mathieu Desnoyers <> | Subject | [RFC PATCH v2 2/3] getcpu_cache: wire up ARM system call | Date | Wed, 27 Jan 2016 11:54:42 -0500 |
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Wire up the getcpu cache system call on 32-bit ARM. Call the getcpu_cache_handle_notify_resume() function on return to userspace if TIF_NOTIFY_RESUME thread flag is set.
This provides an ABI improving the speed of a getcpu operation on ARM by skipping the getcpu system call on the fast path.
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: 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: Thomas Gleixner <tglx@linutronix.de> CC: linux-api@vger.kernel.org --- arch/arm/include/uapi/asm/unistd.h | 1 + arch/arm/kernel/calls.S | 1 + arch/arm/kernel/signal.c | 1 + 3 files changed, 3 insertions(+)
diff --git a/arch/arm/include/uapi/asm/unistd.h b/arch/arm/include/uapi/asm/unistd.h index ede692f..ea0ea94 100644 --- a/arch/arm/include/uapi/asm/unistd.h +++ b/arch/arm/include/uapi/asm/unistd.h @@ -417,6 +417,7 @@ #define __NR_userfaultfd (__NR_SYSCALL_BASE+388) #define __NR_membarrier (__NR_SYSCALL_BASE+389) #define __NR_mlock2 (__NR_SYSCALL_BASE+390) +#define __NR_getcpu_cache (__NR_SYSCALL_BASE+391) /* * The following SWIs are ARM private. diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S index ac368bb..aa43e29 100644 --- a/arch/arm/kernel/calls.S +++ b/arch/arm/kernel/calls.S @@ -400,6 +400,7 @@ CALL(sys_userfaultfd) CALL(sys_membarrier) CALL(sys_mlock2) +/* 391 */ CALL(sys_getcpu_cache) #ifndef syscalls_counted .equ syscalls_padding, ((NR_syscalls + 3) & ~3) - NR_syscalls #define syscalls_counted diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 7b8f214..ff5052c 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -594,6 +594,7 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) } else { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); + getcpu_cache_handle_notify_resume(current); } } local_irq_disable(); -- 2.1.4
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