/* kgdb support for MN10300
*
* Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/slab.h>
#include <linux/ptrace.h>
#include <linux/kgdb.h>
#include <linux/uaccess.h>
#include <unit/leds.h>
#include <unit/serial.h>
#include <asm/debugger.h>
#include <asm/serial-regs.h>
#include "internal.h"
/*
* Software single-stepping breakpoint save (used by __switch_to())
*/
static struct thread_info *kgdb_sstep_thread;
u8 *kgdb_sstep_bp_addr[2];
u8 kgdb_sstep_bp[2];
/*
* Copy kernel exception frame registers to the GDB register file
*/
void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
unsigned long ssp = (unsigned long) (regs + 1);
gdb_regs[GDB_FR_D0] = regs->d0;
gdb_regs[GDB_FR_D1] = regs->d1;
gdb_regs[GDB_FR_D2] = regs->d2;
gdb_regs[GDB_FR_D3] = regs->d3;
gdb_regs[GDB_FR_A0] = regs->a0;
gdb_regs[GDB_FR_A1] = regs->a1;
gdb_regs[GDB_FR_A2] = regs->a2;
gdb_regs[GDB_FR_A3] = regs->a3;
gdb_regs[GDB_FR_SP] = (regs->epsw & EPSW_nSL) ? regs->sp : ssp;
gdb_regs[GDB_FR_PC] = regs->pc;
gdb_regs[GDB_FR_MDR] = regs->mdr;
gdb_regs[GDB_FR_EPSW] = regs->epsw;
gdb_regs[GDB_FR_LIR] = regs->lir;
gdb_regs[GDB_FR_LAR] = regs->lar;
gdb_regs[GDB_FR_MDRQ] = regs->mdrq;
gdb_regs[GDB_FR_E0] = regs->e0;
gdb_regs[GDB_FR_E1] = regs->e1;
gdb_regs[GDB_FR_E2] = regs->e2;
gdb_regs[GDB_FR_E3] = regs->e3;
gdb_regs[GDB_FR_E4] = regs->e4;
gdb_regs[GDB_FR_E5] = regs->e5;
gdb_regs[GDB_FR_E6] = regs->e6;
gdb_regs[GDB_FR_E7] = regs->e7;
gdb_regs[GDB_FR_SSP] = ssp;
gdb_regs[GDB_FR_MSP] = 0;
gdb_regs[GDB_FR_USP] = regs->sp;
gdb_regs[GDB_FR_MCRH] = regs->mcrh;
gdb_regs[GDB_FR_MCRL] = regs->mcrl;
gdb_regs[GDB_FR_MCVF] = regs->mcvf;
gdb_regs[GDB_FR_DUMMY0] = 0;
gdb_regs[GDB_FR_DUMMY1] = 0;
gdb_regs[GDB_FR_FS0] = 0;
}
/*
* Extracts kernel SP/PC values understandable by gdb from the values
* saved by switch_to().
*/
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
gdb_regs[GDB_FR_SSP] = p->thread.sp;
gdb_regs[GDB_FR_PC] = p->thread.pc;
gdb_regs[GDB_FR_A3] = p->thread.a3;
gdb_regs[GDB_FR_USP] = p->thread.usp;
gdb_regs[GDB_FR_FPCR] = p->thread.fpu_state.fpcr;
}
/*
* Fill kernel exception frame registers from the GDB register file
*/
void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
regs->d0 = gdb_regs[GDB_FR_D0];
regs->d1 = gdb_regs[GDB_FR_D1];
regs->d2 = gdb_regs[GDB_FR_D2];
regs->d3 = gdb_regs[GDB_FR_D3];
regs->a0 = gdb_regs[GDB_FR_A0];
regs->a1 = gdb_regs[GDB_FR_A1];
regs->a2 = gdb_regs[GDB_FR_A2];
regs->a3 = gdb_regs[GDB_FR_A3];
regs->sp = gdb_regs[GDB_FR_SP];
regs->pc = gdb_regs[GDB_FR_PC];
regs->mdr = gdb_regs[GDB_FR_MDR];
regs->epsw = gdb_regs[GDB_FR_EPSW];
regs->lir = gdb_regs[GDB_FR_LIR];
regs->lar = gdb_regs[GDB_FR_LAR];
regs->mdrq = gdb_regs[GDB_FR_MDRQ];
regs->e0 = gdb_regs[GDB_FR_E0];
regs->e1 = gdb_regs[GDB_FR_E1];
regs->e2 = gdb_regs[GDB_FR_E2];
regs->e3 = gdb_regs[GDB_FR_E3];
regs->e4 = gdb_regs[GDB_FR_E4];
regs->e5 = gdb_regs[GDB_FR_E5];
regs->e6 = gdb_regs[GDB_FR_E6];
regs->e7 = gdb_regs[GDB_FR_E7];
regs->sp = gdb_regs[GDB_FR_SSP];
/* gdb_regs[GDB_FR_MSP]; */
// regs->usp = gdb_regs[GDB_FR_USP];
regs->mcrh = gdb_regs[GDB_FR_MCRH];
regs->mcrl = gdb_regs[GDB_FR_MCRL];
regs->mcvf = gdb_regs[GDB_FR_MCVF];
/* gdb_regs[GDB_FR_DUMMY0]; */
/* gdb_regs[GDB_FR_DUMMY1]; */
// regs->fpcr = gdb_regs[GDB_FR_FPCR];
// regs->fs0 = gdb_regs[GDB_FR_FS0];
}
struct kgdb_arch arch_kgdb_ops = {
.gdb_bpt_instr = { 0xff },
.flags = KGDB_HW_BREAKPOINT,
};
static const unsigned char mn10300_kgdb_insn_sizes[256] =
{
/* 1 2 3 4 5 6 7 8 9 a b c d e f */
1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, /* 0 */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 1 */
2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, /* 2 */
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, /* 3 */
1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, /* 4 */
1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, /* 5 */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 6 */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 7 */
2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 8 */
2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 9 */
2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* a */
2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* b */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 2, /* c */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* d */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* e */
0, 2, 2, 2, 2, 2, 2, 4, 0, 3, 0, 4, 0, 6, 7, 1 /* f */
};
/*
* Attempt to emulate single stepping by means of breakpoint instructions.
* Although there is a single-step trace flag in EPSW, its use is not
* sufficiently documented and is only intended for use with the JTAG debugger.
*/
static int kgdb_arch_do_singlestep(struct pt_regs *regs)
{
unsigned long arg;
unsigned size;
u8 *pc = (u8 *)regs->pc, *sp = (u8 *)(regs + 1), cur;
u8 *x = NULL, *y = NULL;
int ret;
ret = probe_kernel_read(&cur, pc, 1);
if (ret < 0)
return ret;
size = mn10300_kgdb_insn_sizes[cur];
if (size > 0) {
x = pc + size;
goto set_x;
}
switch (cur) {
/* Bxx (d8,PC) */
case 0xc0 ... 0xca:
ret = probe_kernel_read(&arg, pc + 1, 1);
if (ret < 0)
return ret;
x = pc + 2;
if (arg >= 0 && arg <= 2)
goto set_x;
y = pc + (s8)arg;
goto set_x_and_y;
/* LXX (d8,PC) */
case 0xd0 ... 0xda:
x = pc + 1;
if (regs->pc == regs->lar)
goto set_x;
y = (u8 *)regs->lar;
goto set_x_and_y;
/* SETLB - loads the next four bytes into the LIR register
* (which mustn't include a breakpoint instruction) */
case 0xdb:
x = pc + 5;
goto set_x;
/* JMP (d16,PC) or CALL (d16,PC) */
case 0xcc:
case 0xcd:
ret = probe_kernel_read(&arg, pc + 1, 2);
if (ret < 0)
return ret;
x = pc + (s16)arg;
goto set_x;
/* JMP (d32,PC) or CALL (d32,PC) */
case 0xdc:
case 0xdd:
ret = probe_kernel_read(&arg, pc + 1, 4);
if (ret < 0)
return ret;
x = pc + (s32)arg;
goto set_x;
/* RETF */
case 0xde:
x = (u8 *)regs->mdr;
goto set_x;
/* RET */
case 0xdf:
ret = probe_kernel_read(&arg, pc + 2, 1);
if (ret < 0)
return ret;
ret = probe_kernel_read(&x, sp + (s8)arg, 4);
if (ret < 0)
return ret;
goto set_x;
case 0xf0:
ret = probe_kernel_read(&cur, pc + 1, 1);
if (ret < 0)
return ret;
if (cur >= 0xf0 && cur <= 0xf7) {
/* JMP (An) / CALLS (An) */
switch (cur & 3) {
case 0: x = (u8 *)regs->a0; break;
case 1: x = (u8 *)regs->a1; break;
case 2: x = (u8 *)regs->a2; break;
case 3: x = (u8 *)regs->a3; break;
}
goto set_x;
} else if (cur == 0xfc) {
/* RETS */
ret = probe_kernel_read(&x, sp, 4);
if (ret < 0)
return ret;
goto set_x;
} else if (cur == 0xfd) {
/* RTI */
ret = probe_kernel_read(&x, sp + 4, 4);
if (ret < 0)
return ret;
goto set_x;
} else {
x = pc + 2;
goto set_x;
}
break;
/* potential 3-byte conditional branches */
case 0xf8:
ret = probe_kernel_read(&cur, pc + 1, 1);
if (ret < 0)
return ret;
x = pc + 3;
if (cur >= 0xe8 && cur <= 0xeb) {
ret = probe_kernel_read(&arg, pc + 2, 1);
if (ret < 0)
return ret;
if (arg >= 0 && arg <= 3)
goto set_x;
y = pc + (s8)arg;
goto set_x_and_y;
}
goto set_x;
case 0xfa:
ret = probe_kernel_read(&cur, pc + 1, 1);
if (ret < 0)
return ret;
if (cur == 0xff) {
/* CALLS (d16,PC) */
ret = probe_kernel_read(&arg, pc + 2, 2);
if (ret < 0)
return ret;
x = pc + (s16)arg;
goto set_x;
}
x = pc + 4;
goto set_x;
case 0xfc:
ret = probe_kernel_read(&cur, pc + 1, 1);
if (ret < 0)
return ret;
if (cur == 0xff) {
/* CALLS (d32,PC) */
ret = probe_kernel_read(&arg, pc + 2, 4);
if (ret < 0)
return ret;
x = pc + (s32)arg;
goto set_x;
}
x = pc + 6;
goto set_x;
}
return 0;
set_x:
kgdb_sstep_bp_addr[0] = x;
kgdb_sstep_bp_addr[1] = NULL;
ret = probe_kernel_read(&kgdb_sstep_bp[0], x, 1);
if (ret < 0)
return ret;
ret = probe_kernel_write(x, &arch_kgdb_ops.gdb_bpt_instr, 1);
if (ret < 0)
return ret;
kgdb_sstep_thread = current_thread_info();
debugger_local_cache_flushinv_one(x);
return ret;
set_x_and_y:
kgdb_sstep_bp_addr[0] = x;
kgdb_sstep_bp_addr[1] = y;
ret = probe_kernel_read(&kgdb_sstep_bp[0], x, 1);
if (ret < 0)
return ret;
ret = probe_kernel_read(&kgdb_sstep_bp[1], y, 1);
if (ret < 0)
return ret;
ret = probe_kernel_write(x, &arch_kgdb_ops.gdb_bpt_instr, 1);
if (ret < 0)
return ret;
ret = probe_kernel_write(y, &arch_kgdb_ops.gdb_bpt_instr, 1);
if (ret < 0) {
probe_kernel_write(kgdb_sstep_bp_addr[0],
&kgdb_sstep_bp[0], 1);
} else {
kgdb_sstep_thread = current_thread_info();
}
debugger_local_cache_flushinv_one(x);
debugger_local_cache_flushinv_one(y);
return ret;
}
/*
* Remove emplaced single-step breakpoints, returning true if we hit one of
* them.
*/
static bool kgdb_arch_undo_singlestep(struct pt_regs *regs)
{
bool hit = false;
u8 *x = kgdb_sstep_bp_addr[0], *y = kgdb_sstep_bp_addr[1];
u8 opcode;
if (kgdb_sstep_thread == current_thread_info()) {
if (x) {
if (x == (u8 *)regs->pc)
hit = true;
if (probe_kernel_read(&opcode, x,
1) < 0 ||
opcode != 0xff)
BUG();
probe_kernel_write(x, &kgdb_sstep_bp[0], 1);
debugger_local_cache_flushinv_one(x);
}
if (y) {
if (y == (u8 *)regs->pc)
hit = true;
if (probe_kernel_read(&opcode, y,
1) < 0 ||
opcode != 0xff)
BUG();
probe_kernel_write(y, &kgdb_sstep_bp[1], 1);
debugger_local_cache_flushinv_one(y);
}
}
kgdb_sstep_bp_addr[0] = NULL;
kgdb_sstep_bp_addr[1] = NULL;
kgdb_sstep_thread = NULL;
return hit;
}
/*
* Catch a single-step-pending thread being deleted and make sure the global
* single-step state is cleared. At this point the breakpoints should have
* been removed by __switch_to().
*/
void arch_release_thread_info(struct thread_info *ti)
{
if (kgdb_sstep_thread == ti) {
kgdb_sstep_thread = NULL;
/* However, we may now be running in degraded mode, with most
* of the CPUs disabled until such a time as KGDB is reentered,
* so force immediate reentry */
kgdb_breakpoint();
}
}
/*
* Handle unknown packets and [CcsDk] packets
* - at this point breakpoints have been installed
*/
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
char *remcom_in_buffer, char *remcom_out_buffer,
struct pt_regs *regs)
{
long addr;
char *ptr;
switch (remcom_in_buffer[0]) {
case 'c':
case 's':
/* try to read optional parameter, pc unchanged if no parm */
ptr = &remcom_in_buffer[1];
if (kgdb_hex2long(&ptr, &addr))
regs->pc = addr;
case 'D':
case 'k':
atomic_set(&kgdb_cpu_doing_single_step, -1);
if (remcom_in_buffer[0] == 's') {
kgdb_arch_do_singlestep(regs);
kgdb_single_step = 1;
atomic_set(&kgdb_cpu_doing_single_step,
raw_smp_processor_id());
}
return 0;
}
return -1; /* this means that we do not want to exit from the handler */
}
/*
* Handle event interception
* - returns 0 if the exception should be skipped, -ERROR otherwise.
*/
int debugger_intercept(enum exception_code excep, int signo, int si_code,
struct pt_regs *regs)
{
int ret;
if (kgdb_arch_undo_singlestep(regs)) {
excep = EXCEP_TRAP;
signo = SIGTRAP;
si_code = TRAP_TRACE;
}
ret = kgdb_handle_exception(excep, signo, si_code, regs);
debugger_local_cache_flushinv();
return ret;
}
/*
* Determine if we've hit a debugger special breakpoint
*/
int at_debugger_breakpoint(struct pt_regs *regs)
{
return regs->pc == (unsigned long)&__arch_kgdb_breakpoint;
}
/*
* Initialise kgdb
*/
int kgdb_arch_init(void)
{
return 0;
}
/*
* Do something, perhaps, but don't know what.
*/
void kgdb_arch_exit(void)
{
}
#ifdef CONFIG_SMP
void debugger_nmi_interrupt(struct pt_regs *regs, enum exception_code code)
{
kgdb_nmicallback(arch_smp_processor_id(), regs);
debugger_local_cache_flushinv();
}
void kgdb_roundup_cpus(unsigned long flags)
{
smp_jump_to_debugger();
}
#endif