minute-ia: load eip value from top of stack

For interrupt vectors (as opposed to exception handlers), the eip
value is on top of the stack (referentially the return address by C
calling convention). Use separate code for WDT vector.

BUG=b:129983997
BRANCH=none
TEST='crash watchdog' showing correct EIP, CS values

Change-Id: I7efb2c71aba63eefd89fc71af089bc14034b7d08
Signed-off-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1663188
Reviewed-by: Denis Brockus <dbrockus@chromium.org>
Reviewed-by: Yuval Peress <peress@chromium.org>

3 files changed, 44 insertions, 11 deletions

diff --git a/core/minute-ia/interrupts.c b/core/minute-ia/interrupts.c
index 275dba1e9d..1d87dba77a 100644
--- a/core/minute-ia/interrupts.c
+++ b/core/minute-ia/interrupts.c
@@ -12,6 +12,7 @@
 #include "interrupts.h"
 #include "irq_handler.h"
 #include "link_defs.h"
+#include "mia_panic_internal.h"
 #include "registers.h"
 #include "task.h"
 #include "task_defs.h"
@@ -176,11 +177,9 @@ static const irq_desc_t system_irqs[] = {
  */
 #define DEFINE_EXN_HANDLER(vector)				\
 	_DEFINE_EXN_HANDLER(vector, exception_panic_##vector)
-#define _DEFINE_EXN_HANDLER(vector, name)	\
-	__DEFINE_EXN_HANDLER(vector, name)
-#define __DEFINE_EXN_HANDLER(vector, name)		\
+#define _DEFINE_EXN_HANDLER(vector, name)		\
 	void __keep name(void);			\
-	__attribute__ ((noreturn)) void name(void)	\
+	__attribute__((noreturn)) void name(void)	\
 	{						\
 		__asm__ (				\
 			"push $" #vector "\n"		\
@@ -209,7 +208,22 @@ DEFINE_EXN_HANDLER(17);
 DEFINE_EXN_HANDLER(18);
 DEFINE_EXN_HANDLER(19);
 DEFINE_EXN_HANDLER(20);
-_DEFINE_EXN_HANDLER(ISH_WDT_VEC, exception_panic_wdt);
+
+/**
+ * Use a similar approach for defining an optional handler for
+ * watchdog timer expiration. However, this time, hardware does not
+ * push errorcode, and we must account for that by pushing zero.
+ */
+__attribute__((noreturn)) __keep
+void exception_panic_wdt(uint32_t cs)
+{
+	exception_panic(
+		CONFIG_MIA_WDT_VEC,
+		0,
+		(uint32_t)__builtin_return_address(0),
+		cs,
+		0);
+}
 
 void set_interrupt_gate(uint8_t num, isr_handler_t func, uint8_t flags)
 {
@@ -475,8 +489,8 @@ void init_interrupts(void)
 	 * retrieve EIP.
 	 */
 	if (IS_ENABLED(CONFIG_WATCHDOG))
-		set_interrupt_gate(ISH_WDT_VEC,
-				   exception_panic_wdt,
+		set_interrupt_gate(CONFIG_MIA_WDT_VEC,
+				   (isr_handler_t)exception_panic_wdt,
 				   IDT_DESC_FLAGS);
 
 	/* Note: At reset, ID field is already set to 0 in APIC ID register */
diff --git a/core/minute-ia/mia_panic_internal.h b/core/minute-ia/mia_panic_internal.h
new file mode 100644
index 0000000000..e4d3aa0cdd
--- /dev/null
+++ b/core/minute-ia/mia_panic_internal.h
@@ -0,0 +1,17 @@
+/* Copyright 2019 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**
+ * Handle an exception and reboot. The parameters after 'vector' are
+ * convenientely in the same order as pushed by hardwared during a
+ * processor exception.
+ */
+__attribute__((noreturn))
+void exception_panic(
+	uint32_t vector,
+	uint32_t errorcode,
+	uint32_t eip,
+	uint32_t cs,
+	uint32_t eflags);
diff --git a/core/minute-ia/panic.c b/core/minute-ia/panic.c
index 464d25ec52..cbdabc3eec 100644
--- a/core/minute-ia/panic.c
+++ b/core/minute-ia/panic.c
@@ -7,6 +7,7 @@
 #include "console.h"
 #include "cpu.h"
 #include "host_command.h"
+#include "mia_panic_internal.h"
 #include "panic.h"
 #include "printf.h"
 #include "software_panic.h"
@@ -90,7 +91,7 @@ void panic_data_print(const struct panic_data *pdata)
  * order pushed to the stack by hardware: see "Intel 64 and IA-32
  * Architectures Software Developer's Manual", Volume 3A, Figure 6-4.
  */
-__attribute__((noreturn)) void __keep exception_panic(
+void exception_panic(
 	uint32_t vector,
 	uint32_t error_code,
 	uint32_t eip,
@@ -121,10 +122,11 @@ __attribute__((noreturn)) void __keep exception_panic(
 	PANIC_DATA_PTR->x86.edi = edi;
 
 	/*
-	 * Convert ISH_WDT_VEC to be a SW Watchdog. This is for
-	 * code that is in system_common_pre_init
+	 * Convert watchdog timer vector number to be a SW
+	 * Watchdog. This is for code that is in
+	 * system_common_pre_init
 	 */
-	if (vector == ISH_WDT_VEC)
+	if (IS_ENABLED(CONFIG_WATCHDOG) && vector == CONFIG_MIA_WDT_VEC)
 		vector = PANIC_SW_WATCHDOG;
 
 	/* Save stack data to global panic structure */