From: Russell King Date: Fri, 24 Mar 2017 16:23:25 +0000 (+0000) Subject: ARM: avoid saving and restoring registers unnecessarily X-Git-Tag: v4.14-rc1~56^2^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dca778c5bbf3f1cfcf7f6ef6cadf5a7e5c5d972f;p=platform%2Fkernel%2Flinux-exynos.git ARM: avoid saving and restoring registers unnecessarily Avoid repeatedly saving and restoring registers around the calls to trace_hardirqs_on() and context_tracking_user_exit(). With the previous changes, we no longer need to preserve "lr" across these calls, and if we re-load r0-r3 later, we can avoid preserving these regsiters too. Signed-off-by: Russell King --- diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 1b3fc79..0b60adf 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -157,8 +157,9 @@ ENTRY(vector_swi) #endif zero_fp alignment_trap r10, ip, __cr_alignment - enable_irq - ct_user_exit + asm_trace_hardirqs_on save=0 + enable_irq_notrace + ct_user_exit save=0 /* * Get the system call number. @@ -216,6 +217,11 @@ ENTRY(vector_swi) eor scno, scno, #__NR_SYSCALL_BASE @ check OS number #endif get_thread_info tsk + /* + * Reload the registers that may have been corrupted on entry to + * the syscall assembly (by tracing or context tracking.) + */ + TRACE( ldmia sp, {r0 - r3} ) local_restart: ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing