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swtch.s: During context save, use the correct bit mask for clearing

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the non-reserved bits of dr7.

         During context restore, load dr7 in such a way as to not
         disturb reserved bits.

machdep.c: Don't explicitly disallow the setting of the reserved bits
           in dr7 since we now keep from setting them when we load dr7
           from the PCB.

           This allows one to write back the dr7 value obtained from
           the system without triggering an EINVAL (one of the
           reserved bits always seems to be set after taking a trace
           trap).

MFC after:	7 days
This commit is contained in:
Brian S. Dean 2001-07-19 04:37:27 +00:00
parent 2d075e994c
commit 3ad234d4ef
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=79893
5 changed files with 24 additions and 12 deletions
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10
sys/amd64/amd64/cpu_switch.S
View file

@ -104,7 +104,7 @@ ENTRY(cpu_switch)
jz 1f /* no, skip over */
movl %dr7,%eax /* yes, do the save */
movl %eax,PCB_DR7(%edx)
andl $0x0000ff00, %eax /* disable all watchpoints */
andl $0x0000fc00, %eax /* disable all watchpoints */
movl %eax,%dr7
movl %dr6,%eax
movl %eax,PCB_DR6(%edx)
@ -271,7 +271,13 @@ cpu_switch_load_gs:
movl %eax,%dr1
movl PCB_DR0(%edx),%eax
movl %eax,%dr0
movl PCB_DR7(%edx),%eax
movl %dr7,%eax /* load dr7 so as not to disturb */
andl $0x0000fc00,%eax /* reserved bits */
pushl %ebx
movl PCB_DR7(%edx),%ebx
andl $~0x0000fc00,%ebx
orl %ebx,%eax
popl %ebx
movl %eax,%dr7
1:
ret

3
sys/amd64/amd64/machdep.c
View file

@ -2314,9 +2314,6 @@ set_dbregs(p, dbregs)
if ((dbregs->dr7 & mask1) == mask2)
return (EINVAL);
if (dbregs->dr7 & 0x0000fc00)
return (EINVAL);
pcb = &p->p_addr->u_pcb;
/*

10
sys/amd64/amd64/swtch.s
View file

@ -104,7 +104,7 @@ ENTRY(cpu_switch)
jz 1f /* no, skip over */
movl %dr7,%eax /* yes, do the save */
movl %eax,PCB_DR7(%edx)
andl $0x0000ff00, %eax /* disable all watchpoints */
andl $0x0000fc00, %eax /* disable all watchpoints */
movl %eax,%dr7
movl %dr6,%eax
movl %eax,PCB_DR6(%edx)
@ -271,7 +271,13 @@ cpu_switch_load_gs:
movl %eax,%dr1
movl PCB_DR0(%edx),%eax
movl %eax,%dr0
movl PCB_DR7(%edx),%eax
movl %dr7,%eax /* load dr7 so as not to disturb */
andl $0x0000fc00,%eax /* reserved bits */
pushl %ebx
movl PCB_DR7(%edx),%ebx
andl $~0x0000fc00,%ebx
orl %ebx,%eax
popl %ebx
movl %eax,%dr7
1:
ret

3
sys/i386/i386/machdep.c
View file

@ -2314,9 +2314,6 @@ set_dbregs(p, dbregs)
if ((dbregs->dr7 & mask1) == mask2)
return (EINVAL);
if (dbregs->dr7 & 0x0000fc00)
return (EINVAL);
pcb = &p->p_addr->u_pcb;
/*

10
sys/i386/i386/swtch.s
View file

@ -104,7 +104,7 @@ ENTRY(cpu_switch)
jz 1f /* no, skip over */
movl %dr7,%eax /* yes, do the save */
movl %eax,PCB_DR7(%edx)
andl $0x0000ff00, %eax /* disable all watchpoints */
andl $0x0000fc00, %eax /* disable all watchpoints */
movl %eax,%dr7
movl %dr6,%eax
movl %eax,PCB_DR6(%edx)
@ -271,7 +271,13 @@ cpu_switch_load_gs:
movl %eax,%dr1
movl PCB_DR0(%edx),%eax
movl %eax,%dr0
movl PCB_DR7(%edx),%eax
movl %dr7,%eax /* load dr7 so as not to disturb */
andl $0x0000fc00,%eax /* reserved bits */
pushl %ebx
movl PCB_DR7(%edx),%ebx
andl $~0x0000fc00,%ebx
orl %ebx,%eax
popl %ebx
movl %eax,%dr7
1:
ret