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x86: implement kdb watchpoint functions

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Add wrappers around the dbreg interface that can be consumed by MI
kernel debugger code. The dbreg functions themselves are updated to
return error codes, not just -1. dbreg_set_watchpoint() is extended to
accept access bits as an argument.

Reviewed by:	jhb, kib, markj
MFC after:	3 weeks
Sponsored by:	NetApp, Inc.
Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D29155
This commit is contained in:
Mitchell Horne 2021-02-19 18:36:08 -04:00
parent 763107f26c
commit 15dc1d4452
5 changed files with 47 additions and 5 deletions
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3
sys/amd64/amd64/db_trace.c
View File

@ -389,7 +389,8 @@ int
db_md_set_watchpoint(db_expr_t addr, db_expr_t size)
{
return (dbreg_set_watchpoint((vm_offset_t)addr, (vm_size_t)size));
return (dbreg_set_watchpoint((vm_offset_t)addr, (vm_size_t)size,
DBREG_DR7_WRONLY));
}
int

3
sys/amd64/include/kdb.h
View File

@ -36,6 +36,9 @@
#define KDB_STOPPEDPCB(pc) &stoppcbs[pc->pc_cpuid]
int kdb_cpu_set_watchpoint(vm_offset_t addr, vm_size_t size, int access);
int kdb_cpu_clr_watchpoint(vm_offset_t addr, vm_size_t size);
static __inline void
kdb_cpu_clear_singlestep(void)
{

3
sys/i386/include/kdb.h
View File

@ -36,6 +36,9 @@
#define KDB_STOPPEDPCB(pc) &stoppcbs[pc->pc_cpuid]
int kdb_cpu_set_watchpoint(vm_offset_t addr, vm_size_t size, int access);
int kdb_cpu_clr_watchpoint(vm_offset_t addr, vm_size_t size);
static __inline void
kdb_cpu_clear_singlestep(void)
{

2
sys/x86/include/x86_var.h
View File

@ -120,7 +120,7 @@ vm_paddr_t cpu_getmaxphyaddr(void);
bool cpu_mwait_usable(void);
void cpu_probe_amdc1e(void);
void cpu_setregs(void);
int dbreg_set_watchpoint(vm_offset_t addr, vm_size_t size);
int dbreg_set_watchpoint(vm_offset_t addr, vm_size_t size, int access);
int dbreg_clr_watchpoint(vm_offset_t addr, vm_size_t size);
void dbreg_list_watchpoints(void);
bool disable_wp(void);

41
sys/x86/x86/dbreg.c
View File

@ -27,11 +27,13 @@
#include "opt_ddb.h"
#include <sys/types.h>
#include <sys/kdb.h>
#include <sys/pcpu.h>
#include <sys/smp.h>
#include <sys/systm.h>
#include <machine/frame.h>
#include <machine/kdb.h>
#include <machine/md_var.h>
#include <ddb/ddb.h>
@ -127,7 +129,7 @@ dbreg_sync(struct dbreg *dp)
}
int
dbreg_set_watchpoint(vm_offset_t addr, vm_size_t size)
dbreg_set_watchpoint(vm_offset_t addr, vm_size_t size, int access)
{
struct dbreg *d;
int avail, i, wsize;
@ -140,6 +142,11 @@ dbreg_set_watchpoint(vm_offset_t addr, vm_size_t size)
d = &d_temp;
#endif
/* Validate the access type */
if (access != DBREG_DR7_EXEC && access != DBREG_DR7_WRONLY &&
access != DBREG_DR7_RDWR)
return (EINVAL);
fill_dbregs(NULL, d);
/*
@ -153,7 +160,7 @@ dbreg_set_watchpoint(vm_offset_t addr, vm_size_t size)
}
if (avail * MAXWATCHSIZE < size)
return (-1);
return (EBUSY);
for (i = 0; i < NDBREGS && size > 0; i++) {
if (!DBREG_DR7_ENABLED(d->dr[7], i)) {
@ -164,7 +171,7 @@ dbreg_set_watchpoint(vm_offset_t addr, vm_size_t size)
wsize = 4;
else
wsize = size;
dbreg_set_watchreg(i, addr, wsize, DBREG_DR7_WRONLY, d);
dbreg_set_watchreg(i, addr, wsize, access, d);
addr += wsize;
size -= wsize;
avail--;
@ -265,3 +272,31 @@ amd64_db_resume_dbreg(void)
}
}
#endif
int
kdb_cpu_set_watchpoint(vm_offset_t addr, vm_size_t size, int access)
{
/* Convert the KDB access type */
switch (access) {
case KDB_DBG_ACCESS_W:
access = DBREG_DR7_WRONLY;
break;
case KDB_DBG_ACCESS_RW:
access = DBREG_DR7_RDWR;
break;
case KDB_DBG_ACCESS_R:
/* FALLTHROUGH: read-only not supported */
default:
return (EINVAL);
}
return (dbreg_set_watchpoint(addr, size, access));
}
int
kdb_cpu_clr_watchpoint(vm_offset_t addr, vm_size_t size)
{
return (dbreg_clr_watchpoint(addr, size));
}