kernel: debug: Centralize dbg_[de]activate_sw_breakpoints

During debug trap execution we expect dbg_deactivate_sw_breakpoints()
to be paired with an dbg_activate_sw_breakpoint(). Currently although
the calls are paired correctly they are needlessly smeared across three
different functions. Worse this also results in code to drive polled I/O
being called with breakpoints activated which, in turn, needlessly
increases the set of functions that will recursively trap if breakpointed.

Fix this by moving the activation of breakpoints into the debug core.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200927211531.1380577-4-daniel.thompson@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 0761cbc..1e75a89 100644 (file)
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -760,6 +760,8 @@ cpu_master_loop:
                }
        }
 
+       dbg_activate_sw_breakpoints();
+
        /* Call the I/O driver's post_exception routine */
        if (dbg_io_ops->post_exception)
                dbg_io_ops->post_exception();

diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c
index b52ebff..a77df59 100644 (file)
--- a/kernel/debug/gdbstub.c
+++ b/kernel/debug/gdbstub.c
@@ -1061,7 +1061,6 @@ int gdb_serial_stub(struct kgdb_state *ks)
                                error_packet(remcom_out_buffer, -EINVAL);
                                break;
                        }
-                       dbg_activate_sw_breakpoints();
                        fallthrough;    /* to default processing */
                default:
 default_handle:

diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c
index 53a0df6..0220afd 100644 (file)
--- a/kernel/debug/kdb/kdb_debugger.c
+++ b/kernel/debug/kdb/kdb_debugger.c
@@ -147,7 +147,6 @@ int kdb_stub(struct kgdb_state *ks)
                return DBG_PASS_EVENT;
        }
        kdb_bp_install(ks->linux_regs);
-       dbg_activate_sw_breakpoints();
        /* Set the exit state to a single step or a continue */
        if (KDB_STATE(DOING_SS))
                gdbstub_state(ks, "s");
@@ -167,7 +166,6 @@ int kdb_stub(struct kgdb_state *ks)
                 * differently vs the gdbstub
                 */
                kgdb_single_step = 0;
-               dbg_deactivate_sw_breakpoints();
                return DBG_SWITCH_CPU_EVENT;
        }
        return kgdb_info[ks->cpu].ret_state;