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 0761cbcbdd6dfde83f46ddb5ec43e52d3ae5829d..1e75a8923a8d1e14ab0a78743ec6210b3020b2cc 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 b52ebff09ac81b7fad8ed184108cf1a09f21e6e4..a77df59d9ca53d1c1ba11717d10785ea6366f702 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 53a0df6e4d92c9ebf59f1b4471f9be615fd5e904..0220afda32005fad771c3ff7c6d53fecf90ff0ca 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;