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>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4469247
Commit-Queue: Rob Barnes <robbarnes@google.com>
Reviewed-by: Boris Mittelberg <bmbm@google.com>
Tested-by: Rob Barnes <robbarnes@google.com>

5 files changed, 134 insertions, 13 deletions

diff --git a/chip/ish/config_chip.h b/chip/ish/config_chip.h
index 273bcd0788..63f3affa1f 100644
--- a/chip/ish/config_chip.h
+++ b/chip/ish/config_chip.h
@@ -40,6 +40,11 @@
 #define CONFIG_RAM_SIZE			CONFIG_ISH_SRAM_SIZE
 #define CONFIG_RAM_BASE			CONFIG_ISH_SRAM_BASE_START
 
+/* 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 06b2b7e51e..e9f8f696b3 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 c8cbe9d14c..7e1be1b76b 100644
--- a/core/minute-ia/panic.c
+++ b/core/minute-ia/panic.c
@@ -13,20 +13,62 @@
 #include "task.h"
 #include "timer.h"
 #include "util.h"
-#include "watchdog.h"
 
 /* Whether bus fault is ignored */
 static int bus_fault_ignored;
 
 /*
- * Print panic data
+ * 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.
  */
-void panic_data_print(const struct panic_data *pdata)
-{
-}
+const static char *panic_reason[] = {
+	"Divide By Zero",
+	"Debug Exception",
+	"NMI Interrupt",
+	"Breakpoint Exception",
+	"Overflow Exception",
+	"BOUND Range Exceeded Exception",
+	"Invalid Opcode Exception",
+	"Device Not Available Exception",
+	"Double Fault Exception",
+	"Coprocessor Segment Overrun",
+	"Invalid TSS Exception",
+	"Segment Not Present",
+	"Stack Fault Exception",
+	"General Protection Fault",
+	"Page Fault",
+	"Reserved",
+	"Math Fault",
+	"Alignment Check Exception",
+	"Machine Check Exception",
+	"SIMD Floating Point Exception",
+	"Virtualization Exception",
+};
 
-void __keep report_panic(void)
+/*
+ * 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)
 {
+	if (pdata->x86.vector <= 20)
+		panic_printf("Reason: %s\n", panic_reason[pdata->x86.vector]);
+	else
+		panic_printf("Interrupt vector number: 0x%08X (unknown)\n",
+			     pdata->x86.vector);
+	panic_printf("\n");
+	panic_printf("Error Code = 0x%08X\n", pdata->x86.error_code);
+	panic_printf("EIP        = 0x%08X\n", pdata->x86.eip);
+	panic_printf("CS         = 0x%08X\n", pdata->x86.cs);
+	panic_printf("EFLAGS     = 0x%08X\n", pdata->x86.eflags);
+	panic_printf("EAX        = 0x%08X\n", pdata->x86.eax);
+	panic_printf("EBX        = 0x%08X\n", pdata->x86.ebx);
+	panic_printf("ECX        = 0x%08X\n", pdata->x86.ecx);
+	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);
 }
 
 /**
@@ -37,6 +79,60 @@ void __keep report_panic(void)
 void __keep exception_panic(void);
 void exception_panic(void)
 {
+	/*
+	 * If a panic were to occur during the reset procedure, we want
+	 * to make sure that this panic will certainly cause a hard
+	 * reset, rather than aontaskfw reset. Track if paniced once
+	 * already.
+	 */
+	static int panic_once;
+
+	register uint32_t eax asm("eax");
+	register uint32_t ebx asm("ebx");
+	register uint32_t ecx asm("ecx");
+	register uint32_t edx asm("edx");
+	register uint32_t esi asm("esi");
+	register uint32_t edi asm("edi");
+
+	/* Save registers to global panic structure */
+	PANIC_DATA_PTR->x86.eax = eax;
+	PANIC_DATA_PTR->x86.ebx = ebx;
+	PANIC_DATA_PTR->x86.ecx = ecx;
+	PANIC_DATA_PTR->x86.edx = edx;
+	PANIC_DATA_PTR->x86.esi = esi;
+	PANIC_DATA_PTR->x86.edi = edi;
+
+	/* Save stack data to global panic structure */
+	PANIC_DATA_PTR->x86.vector = vector;
+	PANIC_DATA_PTR->x86.error_code = error_code;
+	PANIC_DATA_PTR->x86.eip = eip;
+	PANIC_DATA_PTR->x86.cs = cs;
+	PANIC_DATA_PTR->x86.eflags = eflags;
+
+	/* Initialize panic data */
+	PANIC_DATA_PTR->arch = PANIC_ARCH_X86;
+	PANIC_DATA_PTR->struct_version = 2;
+	PANIC_DATA_PTR->magic = PANIC_DATA_MAGIC;
+
+	/* Display the panic and reset */
+	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 {
+		panic_once = 1;
+		system_reset(0);
+	}
+
+	__builtin_unreachable();
 }
 
 #ifdef CONFIG_SOFTWARE_PANIC
diff --git a/include/config.h b/include/config.h
index 7467a0fe9e..f153145e30 100644
--- a/include/config.h
+++ b/include/config.h
@@ -2520,6 +2520,13 @@
 /* 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
 
@@ -3903,6 +3910,23 @@
 
 /******************************************************************************/
 /*
+ * 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 ffee055183..00a64b854d 100644
--- a/include/panic.h
+++ b/include/panic.h
@@ -68,13 +68,8 @@ enum panic_arch {
 	PANIC_ARCH_NDS32_N8 = 2,     /* NDS32 N8 architecture */
 };
 
-/*
- * 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 */