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RE: Patch for gdb5.0; enable hardware watchpoints on UnixWare
- To: "Peter.Schauer" <Peter dot Schauer at Regent dot E-Technik dot TU-Muenchen dot DE>
- Subject: RE: Patch for gdb5.0; enable hardware watchpoints on UnixWare
- From: "John Hughes" <john at Calva dot COM>
- Date: Mon, 30 Oct 2000 17:11:58 +0100
- Cc: <gdb-patches at sources dot redhat dot com>
> But all the i386v4-nat.c code has to be conditionalized on
> UNIXWARE (or better yet, moved to a new i386sco-nat.c file), as
> i386v4-nat.c is used by x86 Solaris as well, and Solaris uses page
> faulting instead of debug registers for watchpoints, and would not
> compile with your patches installed.
Aha. Here's a fixed version of the patch; the i386v4-nat.c changes
are conditional on UNIXWARE.
I didn't go as far as making a i386v42mp-nat.c file (I don't think
it should be called i386sco-nat.c, in a few months i386caldera-nat.c
would make about as much sense!). I'm too lazy. Sorry.
2000-10-30 John Hughes <john@CalvaEDI.COM>
* i386v4-nat.c (i386_insert_watchpoint, i386_remove_watchpoint,
i386_check_watch_resources, i386_stopped_by_watchpoint,
i386_insert_aligned_watchpoint, i386_insert_unaliged_watchpoint):
use i386 debug registers to implement hardware watchpoints on
UnixWare systems.
* procfs.c (proc_family) allow access to family specific
information (contains debug registers on UnixWare systems).
* procfs.c (proc_command) allow other modules to issue commands
to the procfs ctl file.
* config/i386/tm-i386v42mp.c (TARGET_HAS_HARDWARE_WATCHPOINTS,
TARGET_CAN_USE_HARDWARE_WATCHPOINT, HAVE_CONTINUABLE_WATCHPOINT,
HAVE_STEPPABLE_WATCHPOINT, STOPPED_BY_WATCHPOINT,
target_insert_watchpoint, target_remove_watchpoint): define.
--
John Hughes <john@Calva.COM>,
CalvaEDI SA. Tel: +33-1-4313-3131
66 rue du Moulin de la Pointe, Fax: +33-1-4313-3139
75013 PARIS.
--- config/i386/tm-i386v42mp.h.orig Tue Jan 11 04:07:28 2000
+++ config/i386/tm-i386v42mp.h Sat Oct 28 08:15:21 2000
@@ -61,4 +61,23 @@
/* Return whether PID contains a user-space thread id. */
#define ISTID(PID) ((PID) & 0x40000000)
+/* We can also do hardware watchpoints */
+#define TARGET_HAS_HARDWARE_WATCHPOINTS
+#define TARGET_CAN_USE_HARDWARE_WATCHPOINT(type, cnt, ot) \
+ i386_check_watch_resources (type, cnt, ot)
+/* After a watchpoint trap, the PC points to the instruction which
+ caused the trap. But we can continue over it without disabling the
+ trap. */
+#define HAVE_CONTINUABLE_WATCHPOINT
+#define HAVE_STEPPABLE_WATCHPOINT
+
+#define STOPPED_BY_WATCHPOINT(W) \
+ i386_stopped_by_watchpoint (inferior_pid)
+
+#define target_insert_watchpoint(addr, len, type) \
+ i386_insert_watchpoint (inferior_pid, addr, len, type)
+
+#define target_remove_watchpoint(addr, len, type) \
+ i386_remove_watchpoint (inferior_pid, addr, len)
+
#endif /* ifndef TM_I386V42MP_H */
--- i386v4-nat.c.orig Thu Apr 13 20:15:49 2000
+++ i386v4-nat.c Mon Oct 30 16:53:51 2000
@@ -250,4 +250,226 @@
#endif /* defined (HAVE_FPREGSET_T) */
+#ifdef UNIXWARE
+
+#include <sys/debugreg.h>
+
+/* Record which address associates with which register. */
+static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
+
+static int
+i386_insert_aligned_watchpoint PARAMS ((int, CORE_ADDR, CORE_ADDR, int,
+ int));
+
+static int
+i386_insert_nonaligned_watchpoint PARAMS ((int, CORE_ADDR, CORE_ADDR, int,
+ int));
+
+/* Insert a watchpoint. */
+
+int
+i386_insert_watchpoint (pid, addr, len, rw)
+ int pid;
+ CORE_ADDR addr;
+ int len;
+ int rw;
+{
+ return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
+}
+
+pfamily_t *proc_family (int pid);
+
+static int
+i386_insert_aligned_watchpoint (pid, waddr, addr, len, rw)
+ int pid;
+ CORE_ADDR waddr;
+ CORE_ADDR addr;
+ int len;
+ int rw;
+{
+ int i;
+ int read_write_bits, len_bits;
+ int free_debug_register;
+ int register_number;
+ pfamily_t *family;
+ int control;
+
+ if (!(family = proc_family (pid))) return -1;
+
+ /* Look for a free debug register. */
+ for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
+ {
+ if (address_lookup[i - DR_FIRSTADDR] == 0)
+ break;
+ }
+
+ /* No more debug registers! */
+ if (i > DR_LASTADDR)
+ return -1;
+
+ read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;
+
+ if (len == 1)
+ len_bits = DR_LEN_1;
+ else if (len == 2)
+ {
+ if (addr % 2)
+ return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
+ len_bits = DR_LEN_2;
+ }
+
+ else if (len == 4)
+ {
+ if (addr % 4)
+ return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
+ len_bits = DR_LEN_4;
+ }
+ else
+ return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
+
+ free_debug_register = i;
+ register_number = free_debug_register - DR_FIRSTADDR;
+
+ control = family->pf_dbreg.debugreg[DR_CONTROL];
+
+ control |=
+ ((read_write_bits | len_bits)
+ << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
+ control |=
+ (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
+ control |= DR_LOCAL_SLOWDOWN;
+ control &= ~DR_CONTROL_RESERVED;
+
+ family->pf_dbreg.debugreg[DR_CONTROL] = control;
+ family->pf_dbreg.debugreg[free_debug_register] = addr;
+
+ proc_command (pid, PCSDBREG, &family->pf_dbreg, sizeof family->pf_dbreg);
+
+ /* Record where we came from. */
+ address_lookup[register_number] = waddr;
+ return 0;
+}
+
+static int
+i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw)
+ int pid;
+ CORE_ADDR waddr;
+ CORE_ADDR addr;
+ int len;
+ int rw;
+{
+ int align;
+ int size;
+ int rv;
+
+ static int size_try_array[16] =
+ {
+ 1, 1, 1, 1, /* trying size one */
+ 2, 1, 2, 1, /* trying size two */
+ 2, 1, 2, 1, /* trying size three */
+ 4, 1, 2, 1 /* trying size four */
+ };
+
+ rv = 0;
+ while (len > 0)
+ {
+ align = addr % 4;
+ /* Four is the maximum length for 386. */
+ size = (len > 4) ? 3 : len - 1;
+ size = size_try_array[size * 4 + align];
+
+ rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
+ if (rv)
+ {
+ i386_remove_watchpoint (pid, waddr, size);
+ return rv;
+ }
+ addr += size;
+ len -= size;
+ }
+ return rv;
+}
+
+/* Remove a watchpoint. */
+
+int
+i386_remove_watchpoint (pid, addr, len)
+ int pid;
+ CORE_ADDR addr;
+ int len;
+{
+ int i;
+ int register_number;
+ int control;
+ pfamily_t *family = proc_family (pid);
+
+ control = family->pf_dbreg.debugreg[DR_CONTROL];
+
+ for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
+ {
+ register_number = i - DR_FIRSTADDR;
+ if (address_lookup[register_number] == addr)
+ {
+ control &=
+ ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
+ address_lookup[register_number] = 0;
+ }
+ }
+
+ family->pf_dbreg.debugreg[DR_CONTROL] = control;
+ family->pf_dbreg.debugreg[DR_STATUS] = 0;
+
+ proc_command (pid, PCSDBREG, &family->pf_dbreg, sizeof family->pf_dbreg);
+
+ return 0;
+}
+
+/* Check if stopped by a watchpoint. */
+
+CORE_ADDR
+i386_stopped_by_watchpoint (pid)
+ int pid;
+{
+ int i;
+ int status;
+ pfamily_t *family;
+
+ if (!(family = proc_family (pid))) return 0;
+
+ if (!(status = family->pf_dbreg.debugreg [DR_STATUS])) return 0;
+
+ family->pf_dbreg.debugreg[DR_STATUS] = 0;
+
+ proc_command (pid, PCSDBREG, &family->pf_dbreg, sizeof family->pf_dbreg);
+
+ for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
+ {
+ if (status & (1 << (i - DR_FIRSTADDR)))
+ return address_lookup[i - DR_FIRSTADDR];
+ }
+
+ return 0;
+}
+
+
+/*
+ * This is not good enough 'cos non-aligned watchpoints can gobble
+ * up more debug registers.
+ */
+
+i386_check_watch_resources (type, cnt, ot)
+ int type;
+ int cnt;
+ int ot;
+{
+ if (type == bp_hardware_breakpoint) return 0;
+
+ if (cnt <= DR_LASTADDR - DR_FIRSTADDR + 1) return 1;
+
+ return -1;
+}
+
+
+#endif /* UNIXWARE */
+
#endif /* HAVE_SYS_PROCFS_H */
--- procfs.c.orig Fri Apr 7 06:33:21 2000
+++ procfs.c Mon Oct 30 12:01:21 2000
@@ -5256,3 +5256,43 @@
else
return -1;
}
+
+
+#ifdef UNIXWARE
+
+/* Messy debug register interface for UW7 */
+
+pfamily_t *
+proc_family (pid)
+ int pid;
+{
+ procinfo *pi;
+ pi = find_procinfo_or_die (PIDGET (pid), 0);
+ return &pi->prstatus.pr_lwp.pr_family;
+}
+
+#include <sys/uio.h>
+
+int
+proc_command (pid, cmd, buf, len)
+ int pid;
+ int cmd;
+ void *buf;
+ int len;
+{
+ procinfo *pi;
+ int res;
+ struct iovec iov [2];
+
+ pi = find_procinfo_or_die (PIDGET (pid), 0);
+
+ iov [0].iov_len = sizeof cmd;
+ iov [0].iov_base = &cmd;
+ iov [1].iov_len = len;
+ iov [1].iov_base = buf;
+
+ return writev (pi->ctl_fd, iov, 2);
+}
+
+#endif
+