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/* SPDX-License-Identifier: BSD-3-Clause */
#include <types.h>
#include <arch/barrier.h>
#include <arch/exception.h>
#include <arch/transition.h>
#include <console/console.h>
#include <console/uart.h>
#include <arch/lib_helpers.h>
uint8_t exception_stack[2*KiB] __attribute__((aligned(16)));
static const char *exception_names[NUM_EXC_VIDS] = {
[EXC_VID_CUR_SP_EL0_SYNC] = "_sync_sp_el0",
[EXC_VID_CUR_SP_EL0_IRQ] = "_irq_sp_el0",
[EXC_VID_CUR_SP_EL0_FIRQ] = "_fiq_sp_el0",
[EXC_VID_CUR_SP_EL0_SERR] = "_serror_sp_el0",
[EXC_VID_CUR_SP_ELX_SYNC] = "_sync_sp_el3",
[EXC_VID_CUR_SP_ELX_IRQ] = "_irq_sp_el3",
[EXC_VID_CUR_SP_ELX_FIQ] = "_fiq_sp_el3",
[EXC_VID_CUR_SP_ELX_SERR] = "_serror_sp_el3",
[EXC_VID_LOW64_SYNC] = "_sync_elx_64",
[EXC_VID_LOW64_IRQ] = "_irq_elx_64",
[EXC_VID_LOW64_FIQ] = "_fiq_elx_64",
[EXC_VID_LOW64_SERR] = "_serror_elx_64",
[EXC_VID_LOW32_SYNC] = "_sync_elx_32",
[EXC_VID_LOW32_IRQ] = "_irq_elx_32",
[EXC_VID_LOW32_FIQ] = "_fiq_elx_32",
[EXC_VID_LOW32_SERR] = "_serror_elx_32"
};
static void dump_stack(uintptr_t addr, size_t bytes)
{
int i, j;
const int words_per_line = 8;
uint64_t *ptr = (void *)ALIGN_DOWN(addr, words_per_line * sizeof(*ptr));
printk(BIOS_DEBUG, "Dumping stack:\n");
for (i = bytes / sizeof(*ptr); i >= 0; i -= words_per_line) {
printk(BIOS_DEBUG, "%p: ", ptr + i);
for (j = i; j < i + words_per_line; j++)
printk(BIOS_DEBUG, "%016llx ", *(ptr + j));
printk(BIOS_DEBUG, "\n");
}
}
static void print_regs(struct exc_state *exc_state)
{
int i;
struct elx_state *elx = &exc_state->elx;
struct regs *regs = &exc_state->regs;
printk(BIOS_DEBUG, "ELR = 0x%016llx ESR = 0x%08llx\n",
elx->elr, raw_read_esr());
printk(BIOS_DEBUG, "FAR = 0x%016llx SPSR = 0x%08llx\n",
raw_read_far(), raw_read_spsr());
for (i = 0; i < 30; i += 2) {
printk(BIOS_DEBUG,
"X%02d = 0x%016llx X%02d = 0x%016llx\n",
i, regs->x[i], i + 1, regs->x[i + 1]);
}
printk(BIOS_DEBUG, "X30 = 0x%016llx SP = 0x%016llx\n",
regs->x[30], regs->sp);
}
static struct exception_handler *handlers[NUM_EXC_VIDS];
enum cb_err exception_handler_register(uint64_t vid, struct exception_handler *h)
{
if (vid >= NUM_EXC_VIDS)
return CB_ERR;
/* Just place at head of queue. */
h->next = handlers[vid];
store_release(&handlers[vid], h);
return CB_SUCCESS;
}
enum cb_err exception_handler_unregister(uint64_t vid, struct exception_handler *h)
{
struct exception_handler *cur;
struct exception_handler **prev;
if (vid >= NUM_EXC_VIDS)
return CB_ERR;
prev = &handlers[vid];
for (cur = handlers[vid]; cur != NULL; cur = cur->next) {
if (cur != h)
continue;
/* Update previous pointer. */
store_release(prev, cur->next);
return CB_SUCCESS;
}
/* Not found */
return CB_ERR;
}
static void print_exception_info(struct exc_state *state, uint64_t idx)
{
/*
* Sign of life in case printk() is shot. Prints !EXCEPT! to UART
* Not using a loop but instead calling __uart_tx_byte separately is intentionally here
* because in rare cases it will not print if it needs to access memory addresses
*/
__uart_tx_byte('\r');
__uart_tx_byte('\n');
__uart_tx_byte('!');
__uart_tx_byte('E');
__uart_tx_byte('X');
__uart_tx_byte('C');
__uart_tx_byte('E');
__uart_tx_byte('P');
__uart_tx_byte('T');
__uart_tx_byte('!');
printk(BIOS_DEBUG, "\nexception %s\n",
idx < NUM_EXC_VIDS ? exception_names[idx] : "_unknown");
print_regs(state);
/* Few words below SP in case we need state from a returned function. */
dump_stack(state->regs.sp - 32, 512);
}
static void print_exception_and_die(struct exc_state *state, uint64_t idx)
{
print_exception_info(state, idx);
die("exception death");
}
static int handle_exception(struct exc_state *state, uint64_t idx)
{
int ret = EXC_RET_ABORT;
struct exception_handler *h;
for (h = handlers[idx]; h != NULL; h = h->next) {
int hret;
hret = h->handler(state, idx);
if (hret > ret)
ret = hret;
}
return ret;
}
void exc_dispatch(struct exc_state *state, uint64_t idx)
{
int ret;
if (idx >= NUM_EXC_VIDS) {
printk(BIOS_DEBUG, "Bad exception index %x.\n", (int)idx);
print_exception_and_die(state, idx);
}
ret = handle_exception(state, idx);
if (ret == EXC_RET_ABORT)
print_exception_and_die(state, idx);
if (ret == EXC_RET_IGNORED || ret == EXC_RET_HANDLED_DUMP_STATE)
print_exception_info(state, idx);
exc_exit(&state->regs);
}
static int test_exception_handler(struct exc_state *state, uint64_t vector_id)
{
/* Update instruction pointer to next instruction. */
state->elx.elr += sizeof(uint32_t);
raw_write_elr(state->elx.elr);
return EXC_RET_HANDLED;
}
static uint64_t test_exception(void)
{
struct exception_handler sync_elx;
struct exception_handler sync_el0;
unsigned long long *a = (void *)0xffffffff00000000ULL;
sync_elx.handler = &test_exception_handler;
sync_el0.handler = &test_exception_handler;
exception_handler_register(EXC_VID_CUR_SP_ELX_SYNC, &sync_elx);
exception_handler_register(EXC_VID_CUR_SP_EL0_SYNC, &sync_el0);
force_read(*a);
exception_handler_unregister(EXC_VID_CUR_SP_ELX_SYNC, &sync_elx);
exception_handler_unregister(EXC_VID_CUR_SP_EL0_SYNC, &sync_el0);
return 0;
}
void exception_init(void)
{
/* Load the exception table and initialize SP_EL3. */
exception_init_asm(exception_stack + ARRAY_SIZE(exception_stack));
printk(BIOS_DEBUG, "ARM64: Exception handlers installed.\n");
/* Only spend time testing on debug builds that are trying to detect more errors. */
if (CONFIG(FATAL_ASSERTS)) {
printk(BIOS_DEBUG, "ARM64: Testing exception\n");
test_exception();
printk(BIOS_DEBUG, "ARM64: Done test exception\n");
}
}
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