From c2fbdc5901a9220d0953f14c27760c3d3ae13074 Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Thu, 23 Jul 2015 11:22:34 +0100 Subject: 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 * 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. --- gdb/ChangeLog | 6 ++++++ gdb/aarch64-linux-nat.c | 29 +++++++++++++++++++++-------- 2 files changed, 27 insertions(+), 8 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 69a086b..8f390a4 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2015-07-23 Yao Qi + + * 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 * aarch64-linux-nat.c (aarch64_linux_get_debug_reg_capacity): diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c index 1c962b6..dae0c15 100644 --- a/gdb/aarch64-linux-nat.c +++ b/gdb/aarch64-linux-nat.c @@ -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; } -- cgit v1.1