payloads/libpayload/arch/arm/exception.c

   1 /*
   2  *
   3  * Copyright 2013 Google Inc.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <arch/cache.h>
  30 #include <arch/exception.h>
  31 #include <exception.h>
  32 #include <libpayload.h>
  33 #include <stdint.h>
  34
  35 u32 exception_stack[0x400] __attribute__((aligned(8)));
  36 struct exception_state exception_state;
  37
  38 static exception_hook hook;
  39 static const char *names[EXC_COUNT] = {
  40         [EXC_UNDEF]  = "Undefined Instruction",
  41         [EXC_SWI]    = "Software Interrupt",
  42         [EXC_PABORT] = "Prefetch Abort",
  43         [EXC_DABORT] = "Data Abort",
  44         [EXC_IRQ]    = "Interrupt",
  45         [EXC_FIQ]    = "Fast Interrupt",
  46 };
  47
  48 static void dump_stack(uintptr_t addr, size_t bytes)
  49 {
  50         int i, j;
  51         const int line = 8;
  52         uint32_t *ptr = (uint32_t *)(addr & ~(line * sizeof(*ptr) - 1));
  53
  54         printf("Dumping stack:\n");
  55         for (i = bytes / sizeof(*ptr); i >= 0; i -= line) {
  56                 printf("%p: ", ptr + i);
  57                 for (j = i; j < i + line; j++)
  58                         printf("%08x ", *(ptr + j));
  59                 printf("\n");
  60         }
  61 }
  62
  63 static void print_regs(void)
  64 {
  65         int i;
  66
  67         for (i = 0; i < 16; i++) {
  68                 if (i == 15)
  69                         printf("PC");
  70                 else if (i == 14)
  71                         printf("LR");
  72                 else if (i == 13)
  73                         printf("SP");
  74                 else if (i == 12)
  75                         printf("IP");
  76                 else
  77                         printf("R%d", i);
  78                 printf(" = 0x%08x\n", exception_state.regs[i]);
  79         }
  80         printf("CPSR = 0x%08x\n", exception_state.cpsr);
  81 }
  82
  83 void exception_dispatch(u32 idx)
  84 {
  85         die_if(idx >= EXC_COUNT || !names[idx], "Bad exception index %u!", idx);
  86
  87         if (hook && hook(idx))
  88                 return;
  89
  90         printf("%s Exception\n", names[idx]);
  91         print_regs();
  92         switch (idx) {
  93         case EXC_PABORT:
  94                 printf("IFAR = %#.8x\n", read_ifar());
  95                 printf("IFSR = %#.8x\n", read_ifsr());
  96                 printf("AIFSR = %#.8x\n", read_aifsr());
  97                 break;
  98         case EXC_DABORT:
  99                 printf("DFAR = %#.8x\n", read_dfar());
 100                 printf("DFSR = %#.8x\n", read_dfsr());
 101                 printf("ADFSR = %#.8x\n", read_adfsr());
 102                 break;
 103         };
 104         dump_stack(exception_state.regs[13], 512);
 105         halt();
 106 }
 107
 108 void exception_init(void)
 109 {
 110         uint32_t sctlr = read_sctlr();
 111         /* Handle exceptions in ARM mode. */
 112         sctlr &= ~SCTLR_TE;
 113         /* Set V=0 in SCTLR so VBAR points to the exception vector table. */
 114         sctlr &= ~SCTLR_V;
 115         write_sctlr(sctlr);
 116
 117         extern uint32_t exception_table[];
 118         set_vbar((uintptr_t)exception_table);
 119
 120         exception_stack_end = exception_stack + ARRAY_SIZE(exception_stack);
 121         exception_state_ptr = &exception_state;
 122 }
 123
 124 void exception_install_hook(exception_hook h)
 125 {
 126         die_if(hook, "Implement support for a list of hooks if you need it.");
 127         hook = h;
 128 }