From: cheloha <cheloha@openbsd.org>
Date: Tue, 4 Jul 2023 17:29:32 +0000 (+0000)
Subject: amd64: cpu_info: rearrange members, keep ci_mds_tmp 32-byte aligned
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=a8972bbdccfe12ff7cd06e6c7b306bd7d7b7c727;p=openbsd

amd64: cpu_info: rearrange members, keep ci_mds_tmp 32-byte aligned

ci_mds_tmp needs to be 32-byte aligned, otherwise we trip a CTASSERT
in amd64/cpu.c and break kernel compilation.  However, ci_mds_tmp's
32-byte alignment is at risk: the size of schedstate_percpu is about
to change.

Move ci_curproc and ci_schedstate up just after ci_mds_buf.  This puts
ci_mds_tmp at page offset 64 with no structs ahead of it in cpu_info.
With this arrangement it should remain 32-byte aligned without much
effort.

With input from guenther@.

ok guenther@
---

diff --git a/sys/arch/amd64/include/cpu.h b/sys/arch/amd64/include/cpu.h
index eea800a78ff..d9980176657 100644
--- a/sys/arch/amd64/include/cpu.h
+++ b/sys/arch/amd64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.154 2022/11/29 21:41:39 guenther Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.155 2023/07/04 17:29:32 cheloha Exp $	*/
 /*	$NetBSD: cpu.h,v 1.1 2003/04/26 18:39:39 fvdl Exp $	*/
 
 /*-
@@ -112,10 +112,8 @@ struct cpu_info {
 #define ci_PAGEALIGN	ci_dev
 	struct device *ci_dev;		/* [I] */
 	struct cpu_info *ci_self;	/* [I] */
-	struct schedstate_percpu ci_schedstate; /* scheduler state */
 	struct cpu_info *ci_next;	/* [I] */
 
-	struct proc *ci_curproc;	/* [o] */
 	u_int ci_cpuid;			/* [I] */
 	u_int ci_apicid;		/* [I] */
 	u_int ci_acpi_proc_id;		/* [I] */
@@ -129,6 +127,9 @@ struct cpu_info {
 	char		ci_mds_tmp[32];	/* [o] 32byte aligned */
 	void		*ci_mds_buf;	/* [I] */
 
+	struct proc *ci_curproc;	/* [o] */
+	struct schedstate_percpu ci_schedstate; /* scheduler state */
+
 	struct pmap *ci_proc_pmap;	/* last userspace pmap */
 	struct pcb *ci_curpcb;		/* [o] */
 	struct pcb *ci_idle_pcb;	/* [o] */