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