ish: preserve panic data across reset

This commit stores panic data across reset by storing panic data in
the last 256 bytes of AON memory (before AON ROM).

> crash divzero
========== PANIC ==========
Reason: Divide By Zero

Error Code = 0xFF00B60C
EIP        = 0xFF010008
CS         = 0x00010202
EFLAGS     = 0x00103085
EAX        = 0x00000001
EBX        = 0xFF01B118
ECX        = 0x00000000
EDX        = 0x00000000
ESI        = 0x00000000
EDI        = 0xFF017E0E

Resetting system...
===========================
... ISH reset ...
> panicinfo
Saved panic data: (NEW)
Reason: Divide By Zero

Error Code = 0xFF00B60C
EIP        = 0xFF010008
CS         = 0x00010202
EFLAGS     = 0x00103085
EAX        = 0x00000001
EBX        = 0xFF01B118
ECX        = 0x00000000
EDX        = 0x00000000
ESI        = 0x00000000
EDI        = 0xFF017E0E

BUG=b:129425206
BRANCH=none
TEST=see console output above (on arcada_ish)

Change-Id: I5c9e458b53076eafe7fa50ba851f2c6e863f2247
Signed-off-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1593418
Reviewed-by: Jett Rink <jettrink@chromium.org>

5 files changed, 43 insertions, 19 deletions

diff --git a/chip/ish/config_chip.h b/chip/ish/config_chip.h
index 24cd558f6c..e82aad8ed3 100644
--- a/chip/ish/config_chip.h
+++ b/chip/ish/config_chip.h
@@ -54,6 +54,11 @@
 					 + CONFIG_AON_RAM_SIZE	\
 					 - CONFIG_AON_ROM_SIZE)
 
+/* Store persistent panic data in AON memory */
+#define CONFIG_PANIC_DATA_SIZE		0xFF
+#define CONFIG_PANIC_DATA_BASE		(CONFIG_AON_ROM_BASE	\
+					 - CONFIG_PANIC_DATA_SIZE)
+
 /* System stack size */
 #define CONFIG_STACK_SIZE		1024
 
diff --git a/common/panic_output.c b/common/panic_output.c
index e6b48a375d..8d34adaa38 100644
--- a/common/panic_output.c
+++ b/common/panic_output.c
@@ -114,6 +114,7 @@ void panic(const char *msg)
 
 struct panic_data *panic_get_data(void)
 {
+	BUILD_ASSERT(sizeof(struct panic_data) <= CONFIG_PANIC_DATA_SIZE);
 	return pdata_ptr->magic == PANIC_DATA_MAGIC ? pdata_ptr : NULL;
 }
 
diff --git a/core/minute-ia/panic.c b/core/minute-ia/panic.c
index 06c903be0c..40e8ee1cf0 100644
--- a/core/minute-ia/panic.c
+++ b/core/minute-ia/panic.c
@@ -13,14 +13,13 @@
 #include "task.h"
 #include "timer.h"
 #include "util.h"
-#include "watchdog.h"
 
 /*
  * This array maps an interrupt vector number to the corresponding
  * exception name. See see "Intel 64 and IA-32 Architectures Software
  * Developer's Manual", Volume 3A, Section 6.15.
  */
-const static char *PANIC_REASON[] = {
+const static char *panic_reason[] = {
 	"Divide By Zero",
 	"Debug Exception",
 	"NMI Interrupt",
@@ -45,13 +44,14 @@ const static char *PANIC_REASON[] = {
 };
 
 /*
- * Print panic data
+ * Print panic data. This may be called either from the report_panic
+ * procedure (below) while handling a panic, or from the panicinfo
+ * console command.
  */
 void panic_data_print(const struct panic_data *pdata)
 {
-	panic_printf("\n========== PANIC ==========\n");
 	if (pdata->x86.vector <= 20)
-		panic_printf("%s\n", PANIC_REASON[pdata->x86.vector]);
+		panic_printf("Reason: %s\n", panic_reason[pdata->x86.vector]);
 	else
 		panic_printf("Interrupt vector number: 0x%08X (unknown)\n",
 			     pdata->x86.vector);
@@ -66,13 +66,6 @@ void panic_data_print(const struct panic_data *pdata)
 	panic_printf("EDX        = 0x%08X\n", pdata->x86.edx);
 	panic_printf("ESI        = 0x%08X\n", pdata->x86.esi);
 	panic_printf("EDI        = 0x%08X\n", pdata->x86.edi);
-	panic_printf("\n");
-	panic_printf("Resetting system...\n");
-	panic_printf("===========================\n");
-}
-
-void __keep report_panic(void)
-{
 }
 
 /**
@@ -132,7 +125,13 @@ __attribute__ ((noreturn)) void __keep exception_panic(
 	if (panic_once)
 		panic_printf("\nWhile resetting from a panic, another panic"
 			     " occurred!");
+
+	panic_printf("\n========== PANIC ==========\n");
 	panic_data_print(PANIC_DATA_PTR);
+	panic_printf("\n");
+	panic_printf("Resetting system...\n");
+	panic_printf("===========================\n");
+
 	if (panic_once) {
 		system_reset(SYSTEM_RESET_HARD);
 	} else {
diff --git a/include/config.h b/include/config.h
index 2a62f4f665..86f6447157 100644
--- a/include/config.h
+++ b/include/config.h
@@ -2609,6 +2609,13 @@
 /* Support One Time Protection structure */
 #undef CONFIG_OTP
 
+/*
+ * Address to store persistent panic data at. By default, this will be
+ * at the end of RAM, and have a size of sizeof(struct panic_data)
+ */
+#undef CONFIG_PANIC_DATA_BASE
+#undef CONFIG_PANIC_DATA_SIZE
+
 /* Support PECI interface to x86 processor */
 #undef CONFIG_PECI
 
@@ -4073,6 +4080,23 @@
 
 /******************************************************************************/
 /*
+ * Store panic data at end of memory by default, unless otherwise
+ * configured.  This is safe because we don't context switch away from
+ * the panic handler before rebooting, and stacks and data start at
+ * the beginning of RAM.
+ */
+#ifndef CONFIG_PANIC_DATA_SIZE
+#define CONFIG_PANIC_DATA_SIZE	sizeof(struct panic_data)
+#endif
+
+#ifndef CONFIG_PANIC_DATA_BASE
+#define CONFIG_PANIC_DATA_BASE (CONFIG_RAM_BASE			\
+				+ CONFIG_RAM_SIZE			\
+				- CONFIG_PANIC_DATA_SIZE)
+#endif
+
+/******************************************************************************/
+/*
  * Set minimum shared memory size, unless it is defined in board file.
  */
 #ifndef CONFIG_SHAREDMEM_MINIMUM_SIZE
diff --git a/include/panic.h b/include/panic.h
index 45fc31583d..f3bccd18a0 100644
--- a/include/panic.h
+++ b/include/panic.h
@@ -89,13 +89,8 @@ enum panic_arch {
 	PANIC_ARCH_X86 = 3,          /* Intel x86 */
 };
 
-/*
- * Panic data goes at the end of RAM.  This is safe because we don't context
- * switch away from the panic handler before rebooting, and stacks and data
- * start at the beginning of RAM.
- */
-#define PANIC_DATA_PTR ((struct panic_data *)\
-	(CONFIG_RAM_BASE + CONFIG_RAM_SIZE - sizeof(struct panic_data)))
+/* Use PANIC_DATA_PTR to refer to the persistent storage location */
+#define PANIC_DATA_PTR ((struct panic_data *)CONFIG_PANIC_DATA_BASE)
 
 /* Flags for panic_data.flags */
 /* panic_data.frame is valid */