[src/trunk]: src/sys/arch/amd64/amd64 compat32: Implement PT_GETDBREGS and PT...

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

details:   https://anonhg.NetBSD.org/src/rev/b8052ad0ab3d
branches:  trunk
changeset: 451793:b8052ad0ab3d
user:      mgorny <mgorny%NetBSD.org@localhost>
date:      Tue Jun 04 16:30:19 2019 +0000

description:
compat32: Implement PT_GETDBREGS and PT_SETDBREGS

Uncomment and improve the implementation of compat32 support for
PT_GETDBREGS and PT_SETDBREGS requests.

The new implementation uses x86_dbregs_read() and x86_dbregs_write()
function instead of accessing pcb directly.  While this might be
a little slower, it guarantees that the needed pcb field is allocated
correctly.

Furthermore, the code introduces necessary sanity checks
for PT_SETDBREGS arguments.

diffstat:

 sys/arch/amd64/amd64/netbsd32_machdep.c |  56 +++++++++++++++++---------------
 1 files changed, 29 insertions(+), 27 deletions(-)

diffs (93 lines):

diff -r 0524ca42793d -r b8052ad0ab3d sys/arch/amd64/amd64/netbsd32_machdep.c
--- a/sys/arch/amd64/amd64/netbsd32_machdep.c   Tue Jun 04 16:29:53 2019 +0000
+++ b/sys/arch/amd64/amd64/netbsd32_machdep.c   Tue Jun 04 16:30:19 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: netbsd32_machdep.c,v 1.122 2019/06/04 16:29:53 mgorny Exp $    */
+/*     $NetBSD: netbsd32_machdep.c,v 1.123 2019/06/04 16:30:19 mgorny Exp $    */
 
 /*
  * Copyright (c) 2001 Wasabi Systems, Inc.
@@ -36,7 +36,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: netbsd32_machdep.c,v 1.122 2019/06/04 16:29:53 mgorny Exp $");
+__KERNEL_RCSID(0, "$NetBSD: netbsd32_machdep.c,v 1.123 2019/06/04 16:30:19 mgorny Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_compat_netbsd.h"
@@ -395,23 +395,19 @@
 int
 netbsd32_process_read_dbregs(struct lwp *l, struct dbreg32 *regs, size_t *sz)
 {
-#if notyet
-       struct pcb *pcb;
-
-       pcb = lwp_getpcb(l);
+       struct dbreg regs64;
 
-       regs->dr[0] = pcb->pcb_dbregs->dr[0] & 0xffffffff;
-       regs->dr[1] = pcb->pcb_dbregs->dr[1] & 0xffffffff;
-       regs->dr[2] = pcb->pcb_dbregs->dr[2] & 0xffffffff;
-       regs->dr[3] = pcb->pcb_dbregs->dr[3] & 0xffffffff;
+       x86_dbregs_read(l, &regs64);
+       memset(regs, 0, sizeof(*regs));
+       regs->dr[0] = regs64.dr[0] & 0xffffffff;
+       regs->dr[1] = regs64.dr[1] & 0xffffffff;
+       regs->dr[2] = regs64.dr[2] & 0xffffffff;
+       regs->dr[3] = regs64.dr[3] & 0xffffffff;
 
-       regs->dr[6] = pcb->pcb_dbregs->dr[6] & 0xffffffff;
-       regs->dr[7] = pcb->pcb_dbregs->dr[7] & 0xffffffff;
+       regs->dr[6] = regs64.dr[6] & 0xffffffff;
+       regs->dr[7] = regs64.dr[7] & 0xffffffff;
 
        return 0;
-#else
-       return ENOTSUP;
-#endif
 }
 
 int
@@ -478,23 +474,29 @@
 netbsd32_process_write_dbregs(struct lwp *l, const struct dbreg32 *regs,
     size_t sz)
 {
-#if notyet
-       struct pcb *pcb;
+       size_t i;
+       struct dbreg regs64;
 
-       pcb = lwp_getpcb(l);
+       /* Check that DR0-DR3 contain user-space address */
+       for (i = 0; i < X86_DBREGS; i++) {
+               if (regs->dr[i] >= VM_MAXUSER_ADDRESS32)
+                       return EINVAL;
+       }
 
-       pcb->pcb_dbregs->dr[0] = regs->dr[0];
-       pcb->pcb_dbregs->dr[1] = regs->dr[1];
-       pcb->pcb_dbregs->dr[2] = regs->dr[2];
-       pcb->pcb_dbregs->dr[3] = regs->dr[3];
+       if (regs->dr[7] & X86_DR7_GENERAL_DETECT_ENABLE) {
+               return EINVAL;
+       }
 
-       pcb->pcb_dbregs->dr[6] = regs->dr[6];
-       pcb->pcb_dbregs->dr[7] = regs->dr[7];
+       regs64.dr[0] = regs->dr[0];
+       regs64.dr[1] = regs->dr[1];
+       regs64.dr[2] = regs->dr[2];
+       regs64.dr[3] = regs->dr[3];
 
+       regs64.dr[6] = regs->dr[6];
+       regs64.dr[7] = regs->dr[7];
+
+       x86_dbregs_write(l, &regs64);
        return 0;
-#else
-       return ENOTSUP;
-#endif
 }
 
 int