Wire up the thread local ABI on ARM32. Call the thread_local_abi_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. [ Untested. ] 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: 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: Thomas Gleixner <[email protected]> CC: [email protected] --- arch/arm/include/uapi/asm/unistd.h | 1 + arch/arm/kernel/calls.S | 1 + arch/arm/kernel/signal.c | 2 ++ 3 files changed, 4 insertions(+) diff --git a/arch/arm/include/uapi/asm/unistd.h b/arch/arm/include/uapi/asm/unistd.h index 7a2a32a..859433a 100644 --- a/arch/arm/include/uapi/asm/unistd.h +++ b/arch/arm/include/uapi/asm/unistd.h @@ -416,6 +416,7 @@ #define __NR_execveat (__NR_SYSCALL_BASE+387) #define __NR_userfaultfd (__NR_SYSCALL_BASE+388) #define __NR_membarrier (__NR_SYSCALL_BASE+389) +#define __NR_thread_local_abi (__NR_SYSCALL_BASE+390) /* * The following SWIs are ARM private. diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S index fde6c88..82b59cc 100644 --- a/arch/arm/kernel/calls.S +++ b/arch/arm/kernel/calls.S @@ -399,6 +399,7 @@ CALL(sys_execveat) CALL(sys_userfaultfd) CALL(sys_membarrier) +/* 390 */ CALL(sys_thread_local_abi) #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..c64cd2f 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -594,6 +594,8 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) } else { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); + if (thread_local_abi_active(current)) + thread_local_abi_handle_notify_resume(current); } } local_irq_disable(); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
