payloads/libpayload/arch/arm64/exception.c

   1 /*
   2  *
   3  * Copyright 2014 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 <exception.h>
  30 #include <libpayload.h>
  31 #include <stdint.h>
  32
  33 u64 exception_stack[2*KiB] __attribute__((aligned(16)));
  34 u64 *exception_stack_end = exception_stack + ARRAY_SIZE(exception_stack);
  35
  36 struct exception_handler_info
  37 {
  38         const char *name;
  39 };
  40
  41 static exception_hook hook;
  42 struct exception_state exception_state;
  43
  44 static struct exception_handler_info exceptions[EXC_COUNT] = {
  45         [EXC_SYNC_SP0] = { "_sync_sp_el0" },
  46         [EXC_IRQ_SP0]  = { "_irq_sp_el0" },
  47         [EXC_FIQ_SP0]  = { "_fiq_sp_el0" },
  48         [EXC_SERROR_SP0] = {"_serror_sp_el0"},
  49         [EXC_SYNC_SPX] = { "_sync_spx" },
  50         [EXC_IRQ_SPX]  = { "_irq_spx" },
  51         [EXC_FIQ_SPX]  = { "_fiq_spx" },
  52         [EXC_SERROR_SPX] = {"_serror_spx"},
  53         [EXC_SYNC_ELX_64] = { "_sync_elx_64" },
  54         [EXC_IRQ_ELX_64]  = { "_irq_elx_64" },
  55         [EXC_FIQ_ELX_64]  = { "_fiq_elx_64" },
  56         [EXC_SERROR_ELX_64] = {"_serror_elx_64"},
  57         [EXC_SYNC_ELX_32] = { "_sync_elx_32" },
  58         [EXC_IRQ_ELX_32]  = { "_irq_elx_32" },
  59         [EXC_FIQ_ELX_32]  = { "_fiq_elx_32" },
  60         [EXC_SERROR_ELX_32] = {"_serror_elx_32"},
  61 };
  62
  63 static void dump_stack(uintptr_t addr, size_t bytes)
  64 {
  65         int i, j;
  66         const int words_per_line = 8;
  67         uint64_t *ptr = (void *)ALIGN_DOWN(addr, words_per_line * sizeof(*ptr));
  68
  69         printf("Dumping stack:\n");
  70         for (i = bytes / sizeof(*ptr); i >= 0; i -= words_per_line) {
  71                 printf("%p: ", ptr + i);
  72                 for (j = i; j < i + words_per_line; j++)
  73                         printf("%016llx ", *(ptr + j));
  74                 printf("\n");
  75         }
  76 }
  77
  78 static void print_regs(struct exception_state *state)
  79 {
  80         int i;
  81
  82         printf("ELR = 0x%016llx         ESR = 0x%08llx\n",
  83                state->elr, state->esr);
  84         printf("FAR = 0x%016llx        SPSR = 0x%08llx\n",
  85                raw_read_far_el2(), raw_read_spsr_el2());
  86         for (i = 0; i < 30; i += 2) {
  87                 printf("X%02d = 0x%016llx         X%02d = 0x%016llx\n",
  88                        i, state->regs[i], i + 1, state->regs[i + 1]);
  89         }
  90         printf("X30 = 0x%016llx          SP = 0x%016llx\n",
  91                state->regs[30], state->sp);
  92 }
  93
  94 void exception_dispatch(struct exception_state *state, int idx);
  95 void exception_dispatch(struct exception_state *state, int idx)
  96 {
  97         if (idx >= EXC_COUNT) {
  98                 printf("Bad exception index %d.\n", idx);
  99         } else {
 100                 struct exception_handler_info *info = &exceptions[idx];
 101                 if (hook && hook(idx))
 102                         return;
 103
 104                 if (info->name)
 105                         printf("exception %s\n", info->name);
 106                 else
 107                         printf("exception _not_used.\n");
 108         }
 109         print_regs(state);
 110         /* Few words below SP in case we need state from a returned function. */
 111         dump_stack(state->sp - 32, 512);
 112
 113         halt();
 114 }
 115
 116 void exception_init(void)
 117 {
 118         extern uint64_t exception_table[];
 119         raw_write_vbar_el2((uintptr_t)exception_table);
 120         exception_set_state_ptr(&exception_state);
 121 }
 122
 123 void exception_install_hook(exception_hook h)
 124 {
 125         die_if(hook, "Implement support for a list of hooks if you need it.");
 126         hook = h;
 127 }