Module Name: src
Committed By: maxv
Date: Tue Oct 31 10:35:58 UTC 2017
Modified Files:
src/sys/arch/x86/x86: fpu.c
Log Message:
Remove comments that are more misleading than anything else. While here
make sure we zero out the FPU area entirely, and not just its legacy
region.
To generate a diff of this commit:
cvs rdiff -u -r1.14 -r1.15 src/sys/arch/x86/x86/fpu.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/x86/x86/fpu.c
diff -u src/sys/arch/x86/x86/fpu.c:1.14 src/sys/arch/x86/x86/fpu.c:1.15
--- src/sys/arch/x86/x86/fpu.c:1.14 Mon Oct 9 17:49:28 2017
+++ src/sys/arch/x86/x86/fpu.c Tue Oct 31 10:35:58 2017
@@ -1,6 +1,6 @@
-/* $NetBSD: fpu.c,v 1.14 2017/10/09 17:49:28 maya Exp $ */
+/* $NetBSD: fpu.c,v 1.15 2017/10/31 10:35:58 maxv Exp $ */
-/*-
+/*
* Copyright (c) 2008 The NetBSD Foundation, Inc. All
* rights reserved.
*
@@ -29,7 +29,7 @@
* POSSIBILITY OF SUCH DAMAGE.
*/
-/*-
+/*
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
*
@@ -60,7 +60,7 @@
* @(#)npx.c 7.2 (Berkeley) 5/12/91
*/
-/*-
+/*
* Copyright (c) 1994, 1995, 1998 Charles M. Hannum. All rights reserved.
* Copyright (c) 1990 William Jolitz.
*
@@ -96,7 +96,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.14 2017/10/09 17:49:28 maya Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.15 2017/10/31 10:35:58 maxv Exp $");
#include "opt_multiprocessor.h"
@@ -465,7 +465,7 @@ fpusave_lwp(struct lwp *l, bool save)
panic("xen_send_ipi(%s, XEN_IPI_SYNCH_FPU) failed.",
cpu_name(oci));
}
-#else /* XEN */
+#else
x86_send_ipi(oci, X86_IPI_SYNCH_FPU);
#endif
while (pcb->pcb_fpcpu == oci && ticks == hardclock_ticks) {
@@ -490,10 +490,6 @@ fpu_set_default_cw(struct lwp *l, unsign
fpu_save->sv_os.fxo_dflt_cw = x87_cw;
}
-/*
- * Exec needs to clear the fpu save area to avoid leaking info from the
- * old process to userspace.
- */
void
fpu_save_area_clear(struct lwp *l, unsigned int x87_cw)
{
@@ -503,7 +499,7 @@ fpu_save_area_clear(struct lwp *l, unsig
fpu_save = process_fpframe(l);
if (i386_use_fxsave) {
- memset(&fpu_save->sv_xmm, 0, sizeof(fpu_save->sv_xmm));
+ memset(&fpu_save->sv_xmm, 0, x86_fpu_save_size);
fpu_save->sv_xmm.fx_mxcsr = __INITIAL_MXCSR__;
fpu_save->sv_xmm.fx_mxcsr_mask = __INITIAL_MXCSR_MASK__;
fpu_save->sv_xmm.fx_cw = x87_cw;
@@ -515,12 +511,15 @@ fpu_save_area_clear(struct lwp *l, unsig
fpu_save->sv_os.fxo_dflt_cw = x87_cw;
}
-/* For signal handlers the register values don't matter */
void
fpu_save_area_reset(struct lwp *l)
{
union savefpu *fpu_save = process_fpframe(l);
+ /*
+ * For signal handlers the register values don't matter. Just reset
+ * a few fields.
+ */
if (i386_use_fxsave) {
fpu_save->sv_xmm.fx_mxcsr = __INITIAL_MXCSR__;
fpu_save->sv_xmm.fx_mxcsr_mask = __INITIAL_MXCSR_MASK__;
@@ -532,15 +531,15 @@ fpu_save_area_reset(struct lwp *l)
}
}
-/* During fork the xsave data needs to be copied */
void
fpu_save_area_fork(struct pcb *pcb2, const struct pcb *pcb1)
{
ssize_t extra;
- /* The pcb itself has been copied, but the xsave area
- * extends further. */
-
+ /*
+ * The pcb itself has been copied, but the xsave area
+ * extends further.
+ */
extra = offsetof(struct pcb, pcb_savefpu) + x86_fpu_save_size -
sizeof (struct pcb);
@@ -548,11 +547,6 @@ fpu_save_area_fork(struct pcb *pcb2, con
memcpy(pcb2 + 1, pcb1 + 1, extra);
}
-
-/*
- * Write the FP registers.
- * Buffer has usually come from userspace so should not be trusted.
- */
void
process_write_fpregs_xmm(struct lwp *l, const struct fxsave *fpregs)
{
@@ -570,7 +564,6 @@ process_write_fpregs_xmm(struct lwp *l,
}
}
-/* We need to use x87 format for 32bit ptrace */
void
process_write_fpregs_s87(struct lwp *l, const struct save87 *fpregs)
{
@@ -588,10 +581,6 @@ process_write_fpregs_s87(struct lwp *l,
}
}
-/*
- * Read fpu registers, the buffer is usually copied out to userspace.
- * Ensure we write to the entire structure.
- */
void
process_read_fpregs_xmm(struct lwp *l, struct fxsave *fpregs)
{
@@ -603,7 +592,6 @@ process_read_fpregs_xmm(struct lwp *l, s
if (i386_use_fxsave) {
memcpy(fpregs, &fpu_save->sv_xmm, sizeof(fpu_save->sv_xmm));
} else {
- /* This usually gets copied to userspace */
memset(fpregs, 0, sizeof(*fpregs));
process_s87_to_xmm(&fpu_save->sv_87, fpregs);
}
