From: Luming Yu <luyu@redhat.com> Date: Mon, 24 Mar 2008 11:38:56 +0800 Subject: [ia64] remove assembler warnings on head.S Message-id: 47E72250.5090908@redhat.com O-Subject: [RHEL 5.2 PATCH] bz438230 : ia64: suspecious compile warning in brew Bugzilla: 438230 RH-Acked-by: Prarit Bhargava <prarit@redhat.com> bz438230 Description of problem: In the build log diffs between -85.el5 and -86.el5, the following warning popped up and looked interesting: arch/ia64/kernel/head.S:###: Warning: Use of 'ldf.fill.nta' violates RAW dependency 'CR[PTA]' (data)mm/mmap. c: In function 'split_vma': This is fixed by the attached patch, which has already been in the mainline kernel. According to IPF SDM,Serialization is needed to ensure new values in PTA are visible to the hardware Virtual Hash Page Table (VHPT) walker before a dependent instruction fetch or data access. Upstream status: 091062284c05d13b3393f4fcfcedc0f52cb948b4 I have tested the patch. It fixes the problem. Please review,and ACK. Thanks, Luming arch/ia64/kernel/head.S | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S index dded6f2..bd9d2da 100644 --- a/arch/ia64/kernel/head.S +++ b/arch/ia64/kernel/head.S @@ -1180,6 +1180,7 @@ tlb_purge_done: RESTORE_REG(cr.dcr, r25, r17);; RESTORE_REG(cr.iva, r25, r17);; RESTORE_REG(cr.pta, r25, r17);; + srlz.d;; // required not to violate RAW dependency RESTORE_REG(cr.itv, r25, r17);; RESTORE_REG(cr.pmv, r25, r17);; RESTORE_REG(cr.cmcv, r25, r17);;