Return zero in aarch64_linux_can_use_hw_breakpoint if target doesn't support HW watchpoint/breakpoint

Nowadays aarch64_linux_can_use_hw_breakpoint always return one, but it
can be smarter, say, if GDB knows target doesn't support HW watchpoint
or breakpoint because HW watchpoint/breakpoint is disabled in linux
kernel, for example, it can safely return zero.

gdb:

2015-07-23  Yao Qi  <yao.qi@linaro.org>

	* aarch64-linux-nat.c (aarch64_linux_can_use_hw_breakpoint): If
	TYPE is watchpoint, return zero if aarch64_num_wp_regs is zero.
	If TYPE is breakpoint, return zero if arch64_num_bp_regs is zero.
This commit is contained in:
Yao Qi 2015-07-23 11:22:34 +01:00
parent 070fe95d07
commit c2fbdc5901
2 changed files with 27 additions and 8 deletions

View File

@ -1,3 +1,9 @@
2015-07-23 Yao Qi <yao.qi@linaro.org>
* aarch64-linux-nat.c (aarch64_linux_can_use_hw_breakpoint): If
TYPE is watchpoint, return zero if aarch64_num_wp_regs is zero.
If TYPE is breakpoint, return zero if arch64_num_bp_regs is zero.
2015-07-21 Yao Qi <yao.qi@linaro.org>
* aarch64-linux-nat.c (aarch64_linux_get_debug_reg_capacity):

View File

@ -707,19 +707,32 @@ aarch64_linux_read_description (struct target_ops *ops)
bp_read_watchpoint, bp_write_watchpoint, or bp_hardware_breakpoint.
CNT is the number of such watchpoints used so far (including this
one). OTHERTYPE is non-zero if other types of watchpoints are
currently enabled.
We always return 1 here because we don't have enough information
about possible overlap of addresses that they want to watch. As an
extreme example, consider the case where all the watchpoints watch
the same address and the same region length: then we can handle a
virtually unlimited number of watchpoints, due to debug register
sharing implemented via reference counts. */
currently enabled. */
static int
aarch64_linux_can_use_hw_breakpoint (struct target_ops *self,
int type, int cnt, int othertype)
{
if (type == bp_hardware_watchpoint || type == bp_read_watchpoint
|| type == bp_access_watchpoint || type == bp_watchpoint)
{
if (aarch64_num_wp_regs == 0)
return 0;
}
else if (type == bp_hardware_breakpoint)
{
if (aarch64_num_bp_regs == 0)
return 0;
}
else
gdb_assert_not_reached ("unexpected breakpoint type");
/* We always return 1 here because we don't have enough information
about possible overlap of addresses that they want to watch. As an
extreme example, consider the case where all the watchpoints watch
the same address and the same region length: then we can handle a
virtually unlimited number of watchpoints, due to debug register
sharing implemented via reference counts. */
return 1;
}