1 files changed, 93 insertions, 0 deletions
diff --git a/payloads/libpayload/arch/x86/gdb.c b/payloads/libpayload/arch/x86/gdb.c
new file mode 100644
index 0000000000..99db78f29b
--- /dev/null
+++ b/payloads/libpayload/arch/x86/gdb.c
@@ -0,0 +1,93 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but without any warranty; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <exception.h>
+#include <gdb.h>
+#include <libpayload.h>
+
+static const u8 type_to_signal[] = {
+	[EXC_DE]  = GDB_SIGFPE,
+	[EXC_DB]  = GDB_SIGTRAP,
+	[EXC_NMI] = GDB_SIGKILL,
+	[EXC_BP]  = GDB_SIGTRAP,
+	[EXC_OF]  = GDB_SIGFPE,
+	[EXC_BR]  = GDB_SIGSEGV,
+	[EXC_UD]  = GDB_SIGILL,
+	[EXC_NM]  = GDB_SIGEMT,
+	[EXC_DF]  = GDB_SIGKILL,
+	[EXC_TS]  = GDB_SIGSEGV,
+	[EXC_NP]  = GDB_SIGSEGV,
+	[EXC_SS]  = GDB_SIGBUS,
+	[EXC_GP]  = GDB_SIGSEGV,
+	[EXC_PF]  = GDB_SIGSEGV,
+	[EXC_MF]  = GDB_SIGEMT,
+	[EXC_AC]  = GDB_SIGBUS,
+	[EXC_MC]  = GDB_SIGKILL,
+	[EXC_XF]  = GDB_SIGFPE,
+	[EXC_SX]  = GDB_SIGFPE,
+};
+
+static int gdb_exception_hook(u32 type)
+{
+	if (type >= ARRAY_SIZE(type_to_signal) || !type_to_signal[type])
+		return 0;
+	gdb_command_loop(type_to_signal[type]);
+	return 1;
+}
+
+void gdb_arch_init(void)
+{
+	exception_install_hook(&gdb_exception_hook);
+}
+
+void gdb_arch_enter(void)
+{
+	u32 *esp;
+
+	asm volatile ("mov %%esp, %0" : "=r"(esp) );
+
+	/* Avoid reentrant exceptions, just call the hook if in one already. */
+	if (esp >= exception_stack && esp <= exception_stack_end)
+		gdb_exception_hook(EXC_BP);
+	else
+		asm volatile ("int3");
+}
+
+int gdb_arch_set_single_step(int on)
+{
+	const u32 tf_bit = 1 << 8;
+
+	if (on)
+		exception_state->regs.eflags |= tf_bit;
+	else
+		exception_state->regs.eflags &= ~tf_bit;
+
+	return 0;
+}
+
+void gdb_arch_encode_regs(struct gdb_message *message)
+{
+	gdb_message_encode_bytes(message, &exception_state->regs,
+				 sizeof(exception_state->regs));
+}
+
+void gdb_arch_decode_regs(int offset, struct gdb_message *message)
+{
+	gdb_message_decode_bytes(message, offset, &exception_state->regs,
+				 sizeof(exception_state->regs));
+}