/*
* Singlestep is implemented by disabling the current kprobe and setting one
* on the next instruction, following branches. Two probes are set if the
* branch is conditional.
*/
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t *addr = NULL;
saved_current_opcode.addr = (kprobe_opcode_t *) (regs->pc);
addr = saved_current_opcode.addr;
if (p != NULL) {
arch_disarm_kprobe(p);
if (OPCODE_JSR(p->opcode) || OPCODE_JMP(p->opcode)) {
unsigned int reg_nr = ((p->opcode >> 8) & 0x000F);
saved_next_opcode.addr =
(kprobe_opcode_t *) regs->regs[reg_nr];
} else if (OPCODE_BRA(p->opcode) || OPCODE_BSR(p->opcode)) {
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
{
__get_cpu_var(saved_current_opcode).addr = (kprobe_opcode_t *)regs->pc;
if (p != NULL) {
struct kprobe *op1, *op2;
arch_disarm_kprobe(p);
op1 = &__get_cpu_var(saved_next_opcode);
op2 = &__get_cpu_var(saved_next_opcode2);
if (OPCODE_JSR(p->opcode) || OPCODE_JMP(p->opcode)) {
unsigned int reg_nr = ((p->opcode >> 8) & 0x000F);
op1->addr = (kprobe_opcode_t *) regs->regs[reg_nr];
} else if (OPCODE_BRA(p->opcode) || OPCODE_BSR(p->opcode)) {
/*
Analyzes the next instruction, to see where the program
will go to when it runs. Returns the destination address.
*/
static long get_stepi_dest (void)
{
short op = *(short*)register_file.pc;
long addr = register_file.pc + 2;
/* BT, BT/S (untested!), BF and BF/S (untested!)
TODO: test delay-slot branches */
if (((OPCODE_BT(op) || OPCODE_BTS(op))
&& (register_file.sr & SR_T_BIT_MASK))
|| ((OPCODE_BF(op) || OPCODE_BFS(op))
&& !(register_file.sr & SR_T_BIT_MASK)))
{
/* we're taking the branch */
/* per 6.12 of the SH1/SH2 programming manual,
PC+disp is address of the second instruction
after the branch instruction, so we have to add 4 */
/* TODO: spend more time understanding this magic */
addr = register_file.pc + 4 + OPCODE_BTF_DISP(op);
}
/* BRA */
else if (OPCODE_BRA(op))
addr = register_file.pc + 4 + OPCODE_BRA_DISP(op);
/* BRAF */
else if (OPCODE_BRAF(op))
addr = register_file.pc + 4
+ register_file.r[OPCODE_BRAF_REG(op)];
/* BSR */
else if (OPCODE_BSR(op))
addr = register_file.pc + 4 + OPCODE_BSR_DISP(op);
/* BSRF */
else if (OPCODE_BSRF(op))
addr = register_file.pc + 4
+ register_file.r[OPCODE_BSRF_REG(op)];
/* JMP */
else if (OPCODE_JMP(op))
addr = register_file.r[OPCODE_JMP_REG(op)];
/* JSR */
else if (OPCODE_JSR(op))
addr = register_file.r[OPCODE_JSR_REG(op)];
/* RTS */
else if (OPCODE_RTS(op))
addr = register_file.pr;
/* RTE */
else if (OPCODE_RTE(op))
addr = *(unsigned long*)(register_file.r[15]);
/* TRAPA */
else if (OPCODE_TRAPA(op))
addr = register_file.vbr[OPCODE_TRAPA_DISP(op)];
return addr;
}
