[src/trunk]: src/sys/arch Don't embed our own values in the reserved fields o...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0059c5543c1e
branches:  trunk
changeset: 827510:0059c5543c1e
user:      maxv <maxv%NetBSD.org@localhost>
date:      Tue Oct 31 12:02:20 2017 +0000

description:
Don't embed our own values in the reserved fields of the XSAVE area, it
really is a bad idea. Move them into the PCB.

diffstat:

 sys/arch/amd64/include/pcb.h              |   9 +++++----
 sys/arch/i386/include/pcb.h               |   9 +++++----
 sys/arch/x86/include/cpu_extended_state.h |  12 +-----------
 sys/arch/x86/x86/fpu.c                    |  16 ++++++++++------
 4 files changed, 21 insertions(+), 25 deletions(-)

diffs (171 lines):

diff -r 12ddb1442862 -r 0059c5543c1e sys/arch/amd64/include/pcb.h
--- a/sys/arch/amd64/include/pcb.h      Tue Oct 31 11:46:45 2017 +0000
+++ b/sys/arch/amd64/include/pcb.h      Tue Oct 31 12:02:20 2017 +0000
@@ -1,6 +1,6 @@
-/*     $NetBSD: pcb.h,v 1.26 2017/02/23 03:34:22 kamil Exp $   */
+/*     $NetBSD: pcb.h,v 1.27 2017/10/31 12:02:20 maxv Exp $    */
 
-/*-
+/*
  * Copyright (c) 1998 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
@@ -29,7 +29,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-/*-
+/*
  * Copyright (c) 1990 The Regents of the University of California.
  * All rights reserved.
  *
@@ -91,9 +91,10 @@
        uint64_t  pcb_fs;
        uint64_t  pcb_gs;
        struct dbreg *pcb_dbregs;
+       uint16_t pcb_fpu_dflt_cw;
        int pcb_iopl;
 
-       uint32_t pcb_unused[9];         /* unused */
+       uint32_t pcb_unused[8];         /* unused */
 
        struct cpu_info *pcb_fpcpu;     /* cpu holding our fp state. */
        union savefpu   pcb_savefpu __aligned(64); /* floating point state */
diff -r 12ddb1442862 -r 0059c5543c1e sys/arch/i386/include/pcb.h
--- a/sys/arch/i386/include/pcb.h       Tue Oct 31 11:46:45 2017 +0000
+++ b/sys/arch/i386/include/pcb.h       Tue Oct 31 12:02:20 2017 +0000
@@ -1,6 +1,6 @@
-/*     $NetBSD: pcb.h,v 1.56 2017/08/12 12:48:47 maxv Exp $    */
+/*     $NetBSD: pcb.h,v 1.57 2017/10/31 12:02:20 maxv Exp $    */
 
-/*-
+/*
  * Copyright (c) 1998, 2009 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
@@ -29,7 +29,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-/*-
+/*
  * Copyright (c) 1990 The Regents of the University of California.
  * All rights reserved.
  *
@@ -91,8 +91,9 @@
        void    *pcb_onfault;           /* copyin/out fault recovery */
        char    *pcb_iomap;             /* I/O permission bitmap */
        struct dbreg    *pcb_dbregs;    /* CPU Debug Registers */
+       uint16_t pcb_fpu_dflt_cw;
 
-       int     not_used[17];
+       int     not_used[16];
 
        /* floating point state */
        struct cpu_info *pcb_fpcpu;     /* cpu holding our fp state. */
diff -r 12ddb1442862 -r 0059c5543c1e sys/arch/x86/include/cpu_extended_state.h
--- a/sys/arch/x86/include/cpu_extended_state.h Tue Oct 31 11:46:45 2017 +0000
+++ b/sys/arch/x86/include/cpu_extended_state.h Tue Oct 31 12:02:20 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu_extended_state.h,v 1.12 2017/10/31 10:39:13 maxv Exp $     */
+/*     $NetBSD: cpu_extended_state.h,v 1.13 2017/10/31 12:02:20 maxv Exp $     */
 
 #ifndef _X86_CPU_EXTENDED_STATE_H_
 #define _X86_CPU_EXTENDED_STATE_H_
@@ -120,15 +120,6 @@
 __CTASSERT_NOLINT(sizeof(struct fxsave) == 512);
 
 /*
- * The end of the fsave buffer can be used by the operating system
- */
-struct fxsave_os {
-       uint8_t fxo_fxsave[512 - 48];
-       /* 48 bytes available, NB copied to/from userspace */
-       uint16_t fxo_dflt_cw;   /* Control word for signal handlers */
-};
-
-/*
  * For XSAVE, a 64byte header follows the fxsave data.
  */
 struct xsave_header {
@@ -158,7 +149,6 @@
        struct save87           sv_87;
        struct fxsave           sv_xmm;
 #ifdef _KERNEL
-       struct fxsave_os        sv_os;
        struct xsave_header     sv_xsave_hdr;
 #endif
 };
diff -r 12ddb1442862 -r 0059c5543c1e sys/arch/x86/x86/fpu.c
--- a/sys/arch/x86/x86/fpu.c    Tue Oct 31 11:46:45 2017 +0000
+++ b/sys/arch/x86/x86/fpu.c    Tue Oct 31 12:02:20 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpu.c,v 1.16 2017/10/31 11:37:05 maxv Exp $    */
+/*     $NetBSD: fpu.c,v 1.17 2017/10/31 12:02:20 maxv Exp $    */
 
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.  All
@@ -96,7 +96,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.16 2017/10/31 11:37:05 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.17 2017/10/31 12:02:20 maxv Exp $");
 
 #include "opt_multiprocessor.h"
 
@@ -493,21 +493,24 @@
 fpu_set_default_cw(struct lwp *l, unsigned int x87_cw)
 {
        union savefpu *fpu_save = process_fpframe(l);
+       struct pcb *pcb = lwp_getpcb(l);
 
        if (i386_use_fxsave)
                fpu_save->sv_xmm.fx_cw = x87_cw;
        else
                fpu_save->sv_87.s87_cw = x87_cw;
-       fpu_save->sv_os.fxo_dflt_cw = x87_cw;
+       pcb->pcb_fpu_dflt_cw = x87_cw;
 }
 
 void
 fpu_save_area_clear(struct lwp *l, unsigned int x87_cw)
 {
        union savefpu *fpu_save;
+       struct pcb *pcb;
 
        fpusave_lwp(l, false);
        fpu_save = process_fpframe(l);
+       pcb = lwp_getpcb(l);
 
        if (i386_use_fxsave) {
                memset(&fpu_save->sv_xmm, 0, x86_fpu_save_size);
@@ -519,13 +522,14 @@
                fpu_save->sv_87.s87_tw = 0xffff;
                fpu_save->sv_87.s87_cw = x87_cw;
        }
-       fpu_save->sv_os.fxo_dflt_cw = x87_cw;
+       pcb->pcb_fpu_dflt_cw = x87_cw;
 }
 
 void
 fpu_save_area_reset(struct lwp *l)
 {
        union savefpu *fpu_save = process_fpframe(l);
+       struct pcb *pcb = lwp_getpcb(l);
 
        /*
         * For signal handlers the register values don't matter. Just reset
@@ -535,10 +539,10 @@
                fpu_save->sv_xmm.fx_mxcsr = __INITIAL_MXCSR__;
                fpu_save->sv_xmm.fx_mxcsr_mask = __INITIAL_MXCSR_MASK__;
                fpu_save->sv_xmm.fx_tw = 0;
-               fpu_save->sv_xmm.fx_cw = fpu_save->sv_os.fxo_dflt_cw;
+               fpu_save->sv_xmm.fx_cw = pcb->pcb_fpu_dflt_cw;
        } else {
                fpu_save->sv_87.s87_tw = 0xffff;
-               fpu_save->sv_87.s87_cw = fpu_save->sv_os.fxo_dflt_cw;
+               fpu_save->sv_87.s87_cw = pcb->pcb_fpu_dflt_cw;
        }
 }