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@xxxxxxxxxxxx>
CC: Russell King <linux@xxxxxxxxxxxxxxxx>
CC: Catalin Marinas <catalin.marinas@xxxxxxx>
CC: Will Deacon <will.deacon@xxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: Paul Turner <pjt@xxxxxxxxxx>
CC: Andrew Hunter <ahh@xxxxxxxxxx>
CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CC: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
CC: Andi Kleen <andi@xxxxxxxxxxxxxx>
CC: Dave Watson <davejwatson@xxxxxx>
CC: Chris Lameter <cl@xxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Ben Maurer <bmaurer@xxxxxx>
CC: Steven Rostedt <rostedt@xxxxxxxxxxx>
CC: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
CC: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: linux-api@xxxxxxxxxxxxxxx
---
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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