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-rw-r--r--arch/x86/Kconfig1
-rw-r--r--kernel/debug/debug_core.c25
-rw-r--r--lib/Kconfig.kgdb18
3 files changed, 34 insertions, 10 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1197b5596d5a..5f44955ee21c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -60,6 +60,7 @@ config X86
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEVMEM_IS_ALLOWED
+ select ARCH_HAS_EARLY_DEBUG if KGDB
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FAST_MULTIPLIER
select ARCH_HAS_FILTER_PGPROT
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index b542f36499c6..1cd8e8b41115 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -948,6 +948,14 @@ void kgdb_panic(const char *msg)
kgdb_breakpoint();
}
+static void kgdb_initial_breakpoint(void)
+{
+ kgdb_break_asap = 0;
+
+ pr_crit("Waiting for connection from remote gdb...\n");
+ kgdb_breakpoint();
+}
+
void __weak kgdb_arch_late(void)
{
}
@@ -958,6 +966,9 @@ void __init dbg_late_init(void)
if (kgdb_io_module_registered)
kgdb_arch_late();
kdb_init(KDB_INIT_FULL);
+
+ if (kgdb_io_module_registered && kgdb_break_asap)
+ kgdb_initial_breakpoint();
}
static int
@@ -1053,14 +1064,6 @@ void kgdb_schedule_breakpoint(void)
}
EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint);
-static void kgdb_initial_breakpoint(void)
-{
- kgdb_break_asap = 0;
-
- pr_crit("Waiting for connection from remote gdb...\n");
- kgdb_breakpoint();
-}
-
/**
* kgdb_register_io_module - register KGDB IO module
* @new_dbg_io_ops: the io ops vector
@@ -1097,7 +1100,8 @@ int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops)
/* Arm KGDB now. */
kgdb_register_callbacks();
- if (kgdb_break_asap)
+ if (kgdb_break_asap &&
+ (!dbg_is_early || IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG)))
kgdb_initial_breakpoint();
return 0;
@@ -1167,7 +1171,8 @@ static int __init opt_kgdb_wait(char *str)
kgdb_break_asap = 1;
kdb_init(KDB_INIT_EARLY);
- if (kgdb_io_module_registered)
+ if (kgdb_io_module_registered &&
+ IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG))
kgdb_initial_breakpoint();
return 0;
diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb
index 933680b59e2d..ffa7a76de086 100644
--- a/lib/Kconfig.kgdb
+++ b/lib/Kconfig.kgdb
@@ -124,4 +124,22 @@ config KDB_CONTINUE_CATASTROPHIC
CONFIG_KDB_CONTINUE_CATASTROPHIC == 2. KDB forces a reboot.
If you are not sure, say 0.
+config ARCH_HAS_EARLY_DEBUG
+ bool
+ default n
+ help
+ If an architecture can definitely handle entering the debugger
+ when early_param's are parsed then it select this config.
+ Otherwise, if "kgdbwait" is passed on the kernel command line it
+ won't actually be processed until dbg_late_init() just after the
+ call to kgdb_arch_late() is made.
+
+ NOTE: Even if this isn't selected by an architecture we will
+ still try to register kgdb to handle breakpoints and crashes
+ when early_param's are parsed, we just won't act on the
+ "kgdbwait" parameter until dbg_late_init(). If you get a
+ crash and try to drop into kgdb somewhere between these two
+ places you might or might not end up being able to use kgdb
+ depending on exactly how far along the architecture has initted.
+
endif # KGDB