From 9ce815ed50bbc518526106071f395deacaf94ad7 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Wed, 23 Dec 2015 15:02:47 -0500 Subject: [PATCH] tile: fix bug in setting PT_FLAGS_DISABLE_IRQ on kernel entry This flag value is saved in ptregs and used to decide whether to disable irqs when returning from the kernel. Commit 1168df528fe4 ("tile: don't assume user privilege is zero") performed a bad merge from some KVM-enabled code that had not yet been upstreamed. The only issue with the old code is that we will read the interrupt mask in more conditions than we need to (e.g., coming from user space when user space has the Interrupt Critical Section bit set, or coming from a guest kernel), which is a slow multi-cycle operation. This change saves those few cycles in the common case. Signed-off-by: Chris Metcalf --- arch/tile/kernel/intvec_64.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S index a41c994ce237..080b77269ccd 100644 --- a/arch/tile/kernel/intvec_64.S +++ b/arch/tile/kernel/intvec_64.S @@ -658,7 +658,7 @@ intvec_\vecname: */ mfspr r32, SPR_EX_CONTEXT_K_1 { - IS_KERNEL_EX1(r22, r22) + IS_KERNEL_EX1(r32, r32) PTREGS_PTR(r21, PTREGS_OFFSET_FLAGS) } beqzt r32, 1f /* zero if from user space */