text: /* Copyright (c) 2014 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.
   */
  
  #include "common.h"
  #include "console.h"
  #include "cpu.h"
  #include "host_command.h"
  #include "panic.h"
  #include "printf.h"
  #include "system.h"
  #include "task.h"
  #include "timer.h"
  #include "util.h"
  #include "watchdog.h"
  
  /* Whether bus fault is ignored */
  static int bus_fault_ignored;
  
  
  /* Panic data goes at the end of RAM. */
  static struct panic_data * const pdata_ptr = PANIC_DATA_PTR;
  
  /* 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;
  
  /**
   * Print the name and value of a register
   *
   * This is a convenient helper function for displaying a register value.
   * It shows the register name in a 3 character field, followed by a colon.
   * The register value is regs[index], and this is shown in hex. If regs is
   * NULL, then we display spaces instead.
   *
   * After displaying the value, either a space or \n is displayed depending
   * on the register number, so that (assuming the caller passes all 16
   * registers in sequence) we put 4 values per line like this
   *
   * r0 :0000000b r1 :00000047 r2 :60000000 r3 :200012b5
   * r4 :00000000 r5 :08004e64 r6 :08004e1c r7 :200012a8
   * r8 :08004e64 r9 :00000002 r10:00000000 r11:00000000
   * r12:0000003f sp :200009a0 lr :0800270d pc :0800351a
   *
   * @param regnum	Register number to display (0-15)
   * @param regs		Pointer to array holding the registers, or NULL
   * @param index		Index into array where the register value is present
   */
  static void print_reg(int regnum, const uint32_t *regs, int index)
  {
  	static const char regname[] = "r10r11r12sp lr pc ";
  	static char rname[3] = "r  ";
  	const char *name;
  
  	rname[1] = '0' + regnum;
  	name = regnum < 10 ? rname : &regname[(regnum - 10) * 3];
  	panic_printf("%c%c%c:", name[0], name[1], name[2]);
  	if (regs)
  		panic_printf("%08x", regs[index]);
  	else
  		panic_puts("        ");
  	panic_puts((regnum & 3) == 3 ? "\n" : " ");
  }
  
  /*
   * Returns non-zero if the exception frame was created on the main stack, or
   * zero if it's on the process stack.
   *
   * See B1.5.8 "Exception return behavior" of ARM DDI 0403D for details.
   */
  static int32_t is_frame_in_handler_stack(const uint32_t exc_return)
  {
  	return (exc_return & 0xf) == 1 || (exc_return & 0xf) == 9;
  }
  
  /*
   * Print panic data
   */
  void panic_data_print(const struct panic_data *pdata)
  {
  	const uint32_t *lregs = pdata->cm.regs;
  	const uint32_t *sregs = NULL;
  	const int32_t in_handler =
  		is_frame_in_handler_stack(pdata->cm.regs[11]);
  	int i;
  
  	if (pdata->flags & PANIC_DATA_FLAG_FRAME_VALID)
  		sregs = pdata->cm.frame;
  
  	panic_printf("\n=== %s EXCEPTION: %02x ====== xPSR: %08x ===\n",
  		     in_handler ? "HANDLER" : "PROCESS",
  		     lregs[1] & 0xff, sregs ? sregs[7] : -1);
  	for (i = 0; i < 4; i++)
  		print_reg(i, sregs, i);
  	for (i = 4; i < 10; i++)
  		print_reg(i, lregs, i - 1);
  	print_reg(10, lregs, 9);
  	print_reg(11, lregs, 10);
  	print_reg(12, sregs, 4);
  	print_reg(13, lregs, in_handler ? 2 : 0);
  	print_reg(14, sregs, 5);
  	print_reg(15, sregs, 6);
  }
  
  void __keep report_panic(void)
  {
  	struct panic_data *pdata = pdata_ptr;
  	uint32_t sp;
  
  	pdata->magic = PANIC_DATA_MAGIC;
  	pdata->struct_size = sizeof(*pdata);
  	pdata->struct_version = 2;
  	pdata->arch = PANIC_ARCH_CORTEX_M;
  	pdata->flags = 0;
  	pdata->reserved = 0;
  
  	/* Choose the right sp (psp or msp) based on EXC_RETURN value */
  	sp = is_frame_in_handler_stack(pdata->cm.regs[11])
  		? pdata->cm.regs[2] : pdata->cm.regs[0];
  	/* If stack is valid, copy exception frame to pdata */
  	if ((sp & 3) == 0 &&
  	    sp >= CONFIG_RAM_BASE &&
  	    sp <= CONFIG_RAM_BASE + CONFIG_RAM_SIZE - 8 * sizeof(uint32_t)) {
  		const uint32_t *sregs = (const uint32_t *)sp;
  		int i;
  		for (i = 0; i < 8; i++)
  			pdata->cm.frame[i] = sregs[i];
  		pdata->flags |= PANIC_DATA_FLAG_FRAME_VALID;
  	}
  
  	panic_data_print(pdata);
  	panic_reboot();
  }
  
  /**
   * Default exception handler, which reports a panic.
   *
   * Declare this as a naked call so we can extract raw LR and IPSR values.
   */
  __keep void exception_panic(void) __attribute__((naked));
  void exception_panic(void)
  {
  	/* Save registers and branch directly to panic handler */
  	asm volatile(
  		"mov r0, %[pregs]\n"
  		"mrs r1, psp\n"
  		"mrs r2, ipsr\n"
  		"mov r3, sp\n"
  		"stmia r0!, {r1-r7}\n"
  		"mov r1, r8\n"
  		"mov r2, r9\n"
  		"mov r3, r10\n"
  		"mov r4, r11\n"
  		"mov r5, lr\n"
  		"stmia r0!, {r1-r5}\n"
  		"mov sp, %[pstack]\n"
  		"b report_panic\n" : :
  			[pregs] "r" (pdata_ptr->cm.regs),
  			[pstack] "r" (pstack_addr) :
  			/* Constraints protecting these from being clobbered.
  			 * Gcc should be using r0 & r12 for pregs and pstack. */
  			"r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9",
  			"r10", "r11", "cc", "memory"
  		);
  }
  
  #ifdef CONFIG_SOFTWARE_PANIC
  void software_panic(uint32_t reason, uint32_t info)
  {
  	__asm__("mov " STRINGIFY(SOFTWARE_PANIC_INFO_REG) ", %0\n"
  		"mov " STRINGIFY(SOFTWARE_PANIC_REASON_REG) ", %1\n"
  		"bl exception_panic\n"
  		: : "r"(info), "r"(reason));
  }
  
  void panic_set_reason(uint32_t reason, uint32_t info, uint8_t exception)
  {
  	uint32_t *lregs = pdata_ptr->cm.regs;
  
  	/* Setup panic data structure */
  	memset(pdata_ptr, 0, sizeof(*pdata_ptr));
  	pdata_ptr->magic = PANIC_DATA_MAGIC;
  	pdata_ptr->struct_size = sizeof(*pdata_ptr);
  	pdata_ptr->struct_version = 2;
  	pdata_ptr->arch = PANIC_ARCH_CORTEX_M;
  
  	/* Log panic cause */
  	lregs[1] = exception;
  	lregs[3] = reason;
  	lregs[4] = info;
  }
  
  void panic_get_reason(uint32_t *reason, uint32_t *info, uint8_t *exception)
  {
  	uint32_t *lregs = pdata_ptr->cm.regs;
  
  	if (pdata_ptr->magic == PANIC_DATA_MAGIC &&
  	    pdata_ptr->struct_version == 2) {
  		*exception = lregs[1];
  		*reason = lregs[3];
  		*info = lregs[4];
  	} else {
  		*exception = *reason = *info = 0;
  	}
  }
  #endif
  
  void bus_fault_handler(void)
  {
  	if (!bus_fault_ignored)
  		exception_panic();
  }
  
  void ignore_bus_fault(int ignored)
  {
  	bus_fault_ignored = ignored;
  }
  