Author: nyan
Date: Sun Oct 31 08:02:47 2010
New Revision: 214589
URL: http://svn.freebsd.org/changeset/base/214589
Log:
MFC: revision 208632
Clarify a potential issue in get_fpcontext() use.
Modified:
stable/8/sys/pc98/pc98/machdep.c
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/amd64/include/xen/ (props changed)
stable/8/sys/cddl/contrib/opensolaris/ (props changed)
stable/8/sys/contrib/dev/acpica/ (props changed)
stable/8/sys/contrib/pf/ (props changed)
stable/8/sys/dev/xen/xenpci/ (props changed)
Modified: stable/8/sys/pc98/pc98/machdep.c
==============================================================================
--- stable/8/sys/pc98/pc98/machdep.c Sun Oct 31 07:57:05 2010
(r214588)
+++ stable/8/sys/pc98/pc98/machdep.c Sun Oct 31 08:02:47 2010
(r214589)
@@ -561,6 +561,13 @@ sendsig(sig_t catcher, ksiginfo_t *ksi,
sf.sf_uc.uc_mcontext.mc_gs = rgs();
bcopy(regs, &sf.sf_uc.uc_mcontext.mc_fs, sizeof(*regs));
sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */
+
+ /*
+ * The get_fpcontext() call must be placed before assignments
+ * to mc_fsbase and mc_gsbase due to the alignment-override
+ * code in get_fpcontext() that possibly clobbers 12 bytes of
+ * mcontext after mc_fpstate.
+ */
get_fpcontext(td, &sf.sf_uc.uc_mcontext);
fpstate_drop(td);
/*
@@ -2453,6 +2460,13 @@ get_mcontext(struct thread *td, mcontext
mcp->mc_esp = tp->tf_esp;
mcp->mc_ss = tp->tf_ss;
mcp->mc_len = sizeof(*mcp);
+
+ /*
+ * The get_fpcontext() call must be placed before assignments
+ * to mc_fsbase and mc_gsbase due to the alignment-override
+ * code in get_fpcontext() that possibly clobbers 12 bytes of
+ * mcontext after mc_fpstate.
+ */
get_fpcontext(td, mcp);
sdp = &td->td_pcb->pcb_fsd;
mcp->mc_fsbase = sdp->sd_hibase << 24 | sdp->sd_lobase;
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