Save panic data across reboots, and add panicinfo command

Jump data now precedes the panic data, if any, in memory.

BUG=chrome-os-partner:7466
BRANCH=all
TEST=manual

1. boot system
2. sysjump rw --> display should stay on and keyboard should still work
   (this verifies jump data is properly read across sysjump still)
3. crash unaligned --> system should reboot
4. panicinfo --> should print the same crash dump as before, with (NEW)
5. panicinfo --> ditto, without (NEW)
6. sysjump rw
7. panicinfo --> ditto, without (NEW)

Original-Change-Id: I88285724e82a15553ab25877e3d8ec4c74a4dd5a
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/32051
Reviewed-on: https://gerrit.chromium.org/gerrit/32355
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit 5f92fdc0b6ec36beeb5c1d447f052e5f77d29e39)

Change-Id: Ibc3991c04797b88e453ef5bd25fa72751a056fac
Signed-off-by: Charlie Mooney <charliemooney@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/33452
Reviewed-by: Randall Spangler <rspangler@chromium.org>

3 files changed, 94 insertions, 42 deletions

diff --git a/common/system_common.c b/common/system_common.c
index b4c68ecc10..5014d8579f 100644
--- a/common/system_common.c
+++ b/common/system_common.c
@@ -15,6 +15,7 @@
 #include "hooks.h"
 #include "host_command.h"
 #include "lpc.h"
+#include "panic.h"
 #include "system.h"
 #include "task.h"
 #include "uart.h"
@@ -60,10 +61,8 @@ struct jump_data {
 			       * data from the previous image. */
 };
 
-/* Jump data goes at the end of RAM */
-static struct jump_data * const jdata =
-	(struct jump_data *)(CONFIG_RAM_BASE + CONFIG_RAM_SIZE
-			     - sizeof(struct jump_data));
+/* Jump data (at end of RAM, or preceding panic data) */
+static struct jump_data *jdata;
 
 /*
  * Reset flag descriptions.  Must be in same order as bits of RESET_FLAG_
@@ -165,7 +164,7 @@ int system_add_jump_tag(uint16_t tag, int version, int size, const void *data)
 	struct jump_tag *t;
 
 	/* Only allowed during a sysjump */
-	if (jdata->magic != JUMP_DATA_MAGIC)
+	if (!jdata || jdata->magic != JUMP_DATA_MAGIC)
 		return EC_ERROR_UNKNOWN;
 
 	/* Make room for the new tag */
@@ -188,6 +187,9 @@ const uint8_t *system_get_jump_tag(uint16_t tag, int *version, int *size)
 	const struct jump_tag *t;
 	int used = 0;
 
+	if (!jdata)
+		return NULL;
+
 	/* Search through tag data for a match */
 	while (used < jdata->jump_tag_total) {
 		/* Check the next tag */
@@ -456,6 +458,18 @@ const char *system_get_build_info(void)
 
 int system_common_pre_init(void)
 {
+	uint32_t addr;
+
+	/*
+	 * Put the jump data before the panic data, or at the end of RAM if
+	 * panic data is not present.
+	 */
+	addr = (uint32_t)panic_get_data();
+	if (!addr)
+		addr = CONFIG_RAM_BASE + CONFIG_RAM_SIZE;
+
+	jdata = (struct jump_data *)(addr - sizeof(struct jump_data));
+
 	/*
 	 * Check jump data if this is a jump between images.  Jumps all show up
 	 * as an unknown reset reason, because we jumped directly from one
diff --git a/core/cortex-m/panic.c b/core/cortex-m/panic.c
index fabd452052..b86295d49d 100644
--- a/core/cortex-m/panic.c
+++ b/core/cortex-m/panic.c
@@ -19,38 +19,6 @@
 /* Whether bus fault is ignored */
 static int bus_fault_ignored;
 
-/* Data saved across reboots */
-struct panic_data {
-	uint8_t arch;             /* Architecture (PANIC_ARCH_*) */
-	uint8_t struct_version;   /* Structure version (currently 1) */
-	uint8_t flags;            /* Flags (PANIC_DATA_FLAG_*) */
-	uint8_t reserved;         /* Reserved; set 0 */
-
-	uint32_t regs[11];        /* psp, ipsr, lr, r4-r11 */
-	uint32_t frame[8];        /* r0-r3, r12, lr, pc, xPSR */
-
-	uint32_t mmfs;
-	uint32_t bfar;
-	uint32_t mfar;
-	uint32_t shcsr;
-	uint32_t hfsr;
-	uint32_t dfsr;
-
-	/*
-	 * These fields go at the END of the struct so we can find it at the
-	 * end of memory.
-	 */
-	uint32_t struct_size;     /* Size of this struct */
-	uint32_t magic;           /* PANIC_SAVE_MAGIC if valid */
-};
-
-#define PANIC_DATA_MAGIC 0x21636e50  /* "Pnc!" */
-
-#define PANIC_ARCH_CORTEX_M 1
-
-/* Flags for panic_data.flags */
-#define PANIC_DATA_FLAG_FRAME_VALID (1 << 0)  /* panic_data.frame is valid */
-
 /*
  * 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
@@ -59,6 +27,7 @@ struct panic_data {
 static struct panic_data * const pdata_ptr =
 	(struct panic_data *)(CONFIG_RAM_BASE + CONFIG_RAM_SIZE
 			     - sizeof(struct panic_data));
+
 /* Preceded by stack, rounded down to nearest 64-bit-aligned boundary */
 static const uint32_t pstack_addr = (CONFIG_RAM_BASE + CONFIG_RAM_SIZE
 				     - sizeof(struct panic_data)) & ~7;
@@ -303,7 +272,7 @@ static void panic_show_extra(const struct panic_data *pdata)
 	panic_printf("mmfs = %x, ", pdata->mmfs);
 	panic_printf("shcsr = %x, ", pdata->shcsr);
 	panic_printf("hfsr = %x, ", pdata->hfsr);
-	panic_printf("dfsr = %x", pdata->dfsr);
+	panic_printf("dfsr = %x\n", pdata->dfsr);
 }
 #endif /* CONFIG_PANIC_HELP */
 
@@ -457,7 +426,10 @@ void panic(const char *msg)
 	panic_reboot();
 }
 
-
+struct panic_data *panic_get_data(void)
+{
+	return pdata_ptr->magic == PANIC_DATA_MAGIC ? pdata_ptr : NULL;
+}
 
 /*****************************************************************************/
 /* Console commands */
@@ -486,3 +458,24 @@ DECLARE_CONSOLE_COMMAND(crash, command_crash,
 			"[divzero | unaligned]",
 			"Crash the system (for testing)",
 			NULL);
+
+static int command_panicinfo(int argc, char **argv)
+{
+	if (pdata_ptr->magic == PANIC_DATA_MAGIC) {
+		ccprintf("Saved panic data:%s\n",
+			 (pdata_ptr->flags & PANIC_DATA_FLAG_OLD_CONSOLE ?
+			  "" : " (NEW)"));
+
+		panic_print(pdata_ptr);
+
+		/* Data has now been printed */
+		pdata_ptr->flags |= PANIC_DATA_FLAG_OLD_CONSOLE;
+	} else {
+		ccprintf("No saved panic data available.\n");
+	}
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(panicinfo, command_panicinfo,
+			NULL,
+			"Print info from a previous panic",
+			NULL);
diff --git a/include/panic.h b/include/panic.h
index ecf6eb0232..bb3e853bd2 100644
--- a/include/panic.h
+++ b/include/panic.h
@@ -6,9 +6,47 @@
  * device, which is currently the UART.
  */
 
-#ifndef __PANIC_H
+#ifndef __CROS_EC_PANIC_H
+#define __CROS_EC_PANIC_H
+
 #include <stdarg.h>
 
+/* Data saved across reboots */
+struct panic_data {
+	uint8_t arch;             /* Architecture (PANIC_ARCH_*) */
+	uint8_t struct_version;   /* Structure version (currently 1) */
+	uint8_t flags;            /* Flags (PANIC_DATA_FLAG_*) */
+	uint8_t reserved;         /* Reserved; set 0 */
+
+	uint32_t regs[11];        /* psp, ipsr, lr, r4-r11 */
+	uint32_t frame[8];        /* r0-r3, r12, lr, pc, xPSR */
+
+	uint32_t mmfs;
+	uint32_t bfar;
+	uint32_t mfar;
+	uint32_t shcsr;
+	uint32_t hfsr;
+	uint32_t dfsr;
+
+	/*
+	 * These fields go at the END of the struct so we can find it at the
+	 * end of memory.
+	 */
+	uint32_t struct_size;     /* Size of this struct */
+	uint32_t magic;           /* PANIC_SAVE_MAGIC if valid */
+};
+
+#define PANIC_DATA_MAGIC 0x21636e50  /* "Pnc!" */
+#define PANIC_ARCH_CORTEX_M 1        /* Cortex-M architecture */
+
+/* Flags for panic_data.flags */
+/* panic_data.frame is valid */
+#define PANIC_DATA_FLAG_FRAME_VALID (1 << 0)
+/* Already printed at console */
+#define PANIC_DATA_FLAG_OLD_CONSOLE (1 << 1)
+/* Already returned via host command */
+#define PANIC_DATA_FLAG_OLD_HOSTCMD (1 << 2)
+
 /**
  * Write a character to the panic reporting device
  *
@@ -56,7 +94,6 @@ void panic_vprintf(const char *format, va_list args);
  */
 void panic_printf(const char *format, ...);
 
-
 /**
  * Report an assertion failure and reset
  *
@@ -82,4 +119,12 @@ void panic(const char *msg);
  */
 void ignore_bus_fault(int ignored);
 
-#endif
+/**
+ * Return a pointer to the saved data from a previous panic.
+ *
+ * @param pointer to the panic data, or NULL if none available (for example,
+ * the last reboot was not caused by a panic).
+ */
+struct panic_data *panic_get_data(void);
+
+#endif  /* __CROS_EC_PANIC_H */