Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-mn10300

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-mn10300:
  MN10300: gcc 4.6 vs am33 inline assembly
  MN10300: Deprecate gdbstub
  MN10300: Allow KGDB to use the MN10300 serial ports
  MN10300: Emulate single stepping in KGDB on MN10300
  MN10300: Generalise kernel debugger kernel halt, reboot or power off hook
  KGDB: Notify GDB of machine halt, reboot or power off
  MN10300: Use KGDB
  MN10300: Create generic kernel debugger hooks
  MN10300: Create general kernel debugger cache flushing
  MN10300: Introduce a general config option for kernel debugger hooks
  MN10300: The icache invalidate functions should disable the icache first
  MN10300: gdbstub: Restrict single-stepping to non-preemptable non-SMP configs

1 files changed, 502 insertions, 0 deletions

diff --git a/arch/mn10300/kernel/kgdb.c b/arch/mn10300/kernel/kgdb.c
new file mode 100644
index 000000000000..f6c981db2a36
--- /dev/null
+++ b/arch/mn10300/kernel/kgdb.c
@@ -0,0 +1,502 @@
+/* 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 free_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();
+	}
+	kfree(ti);
+}
+
+/*
+ * 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