1 files changed, 291 insertions, 0 deletions
diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
new file mode 100644
index 0000000000..22f937e6f3
--- /dev/null
+++ b/arch/arm/kernel/kgdb.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * arch/arm/kernel/kgdb.c
+ *
+ * ARM KGDB support
+ *
+ * Copyright (c) 2002-2004 MontaVista Software, Inc
+ * Copyright (c) 2008 Wind River Systems, Inc.
+ *
+ * Authors:  George Davis <davis_g@mvista.com>
+ *           Deepak Saxena <dsaxena@plexity.net>
+ */
+#include <linux/irq.h>
+#include <linux/kdebug.h>
+#include <linux/kgdb.h>
+#include <linux/uaccess.h>
+
+#include <asm/patch.h>
+#include <asm/traps.h>
+
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
+{
+	{ "r0", 4, offsetof(struct pt_regs, ARM_r0)},
+	{ "r1", 4, offsetof(struct pt_regs, ARM_r1)},
+	{ "r2", 4, offsetof(struct pt_regs, ARM_r2)},
+	{ "r3", 4, offsetof(struct pt_regs, ARM_r3)},
+	{ "r4", 4, offsetof(struct pt_regs, ARM_r4)},
+	{ "r5", 4, offsetof(struct pt_regs, ARM_r5)},
+	{ "r6", 4, offsetof(struct pt_regs, ARM_r6)},
+	{ "r7", 4, offsetof(struct pt_regs, ARM_r7)},
+	{ "r8", 4, offsetof(struct pt_regs, ARM_r8)},
+	{ "r9", 4, offsetof(struct pt_regs, ARM_r9)},
+	{ "r10", 4, offsetof(struct pt_regs, ARM_r10)},
+	{ "fp", 4, offsetof(struct pt_regs, ARM_fp)},
+	{ "ip", 4, offsetof(struct pt_regs, ARM_ip)},
+	{ "sp", 4, offsetof(struct pt_regs, ARM_sp)},
+	{ "lr", 4, offsetof(struct pt_regs, ARM_lr)},
+	{ "pc", 4, offsetof(struct pt_regs, ARM_pc)},
+	{ "f0", 12, -1 },
+	{ "f1", 12, -1 },
+	{ "f2", 12, -1 },
+	{ "f3", 12, -1 },
+	{ "f4", 12, -1 },
+	{ "f5", 12, -1 },
+	{ "f6", 12, -1 },
+	{ "f7", 12, -1 },
+	{ "fps", 4, -1 },
+	{ "cpsr", 4, offsetof(struct pt_regs, ARM_cpsr)},
+};
+
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
+{
+	if (regno >= DBG_MAX_REG_NUM || regno < 0)
+		return NULL;
+
+	if (dbg_reg_def[regno].offset != -1)
+		memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
+		       dbg_reg_def[regno].size);
+	else
+		memset(mem, 0, dbg_reg_def[regno].size);
+	return dbg_reg_def[regno].name;
+}
+
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
+{
+	if (regno >= DBG_MAX_REG_NUM || regno < 0)
+		return -EINVAL;
+
+	if (dbg_reg_def[regno].offset != -1)
+		memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
+		       dbg_reg_def[regno].size);
+	return 0;
+}
+
+void
+sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
+{
+	struct thread_info *ti;
+	int regno;
+
+	/* Just making sure... */
+	if (task == NULL)
+		return;
+
+	/* Initialize to zero */
+	for (regno = 0; regno < GDB_MAX_REGS; regno++)
+		gdb_regs[regno] = 0;
+
+	/* Otherwise, we have only some registers from switch_to() */
+	ti			= task_thread_info(task);
+	gdb_regs[_R4]		= ti->cpu_context.r4;
+	gdb_regs[_R5]		= ti->cpu_context.r5;
+	gdb_regs[_R6]		= ti->cpu_context.r6;
+	gdb_regs[_R7]		= ti->cpu_context.r7;
+	gdb_regs[_R8]		= ti->cpu_context.r8;
+	gdb_regs[_R9]		= ti->cpu_context.r9;
+	gdb_regs[_R10]		= ti->cpu_context.sl;
+	gdb_regs[_FP]		= ti->cpu_context.fp;
+	gdb_regs[_SPT]		= ti->cpu_context.sp;
+	gdb_regs[_PC]		= ti->cpu_context.pc;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+	regs->ARM_pc = pc;
+}
+
+static int compiled_break;
+
+int kgdb_arch_handle_exception(int exception_vector, int signo,
+			       int err_code, char *remcom_in_buffer,
+			       char *remcom_out_buffer,
+			       struct pt_regs *linux_regs)
+{
+	unsigned long addr;
+	char *ptr;
+
+	switch (remcom_in_buffer[0]) {
+	case 'D':
+	case 'k':
+	case 'c':
+		/*
+		 * Try to read optional parameter, pc unchanged if no parm.
+		 * If this was a compiled breakpoint, we need to move
+		 * to the next instruction or we will just breakpoint
+		 * over and over again.
+		 */
+		ptr = &remcom_in_buffer[1];
+		if (kgdb_hex2long(&ptr, &addr))
+			linux_regs->ARM_pc = addr;
+		else if (compiled_break == 1)
+			linux_regs->ARM_pc += 4;
+
+		compiled_break = 0;
+
+		return 0;
+	}
+
+	return -1;
+}
+
+static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
+{
+	kgdb_handle_exception(1, SIGTRAP, 0, regs);
+
+	return 0;
+}
+
+static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
+{
+	compiled_break = 1;
+	kgdb_handle_exception(1, SIGTRAP, 0, regs);
+
+	return 0;
+}
+
+static struct undef_hook kgdb_brkpt_arm_hook = {
+	.instr_mask		= 0xffffffff,
+	.instr_val		= KGDB_BREAKINST,
+	.cpsr_mask		= PSR_T_BIT | MODE_MASK,
+	.cpsr_val		= SVC_MODE,
+	.fn			= kgdb_brk_fn
+};
+
+static struct undef_hook kgdb_brkpt_thumb_hook = {
+	.instr_mask		= 0xffff,
+	.instr_val		= KGDB_BREAKINST & 0xffff,
+	.cpsr_mask		= PSR_T_BIT | MODE_MASK,
+	.cpsr_val		= PSR_T_BIT | SVC_MODE,
+	.fn			= kgdb_brk_fn
+};
+
+static struct undef_hook kgdb_compiled_brkpt_arm_hook = {
+	.instr_mask		= 0xffffffff,
+	.instr_val		= KGDB_COMPILED_BREAK,
+	.cpsr_mask		= PSR_T_BIT | MODE_MASK,
+	.cpsr_val		= SVC_MODE,
+	.fn			= kgdb_compiled_brk_fn
+};
+
+static struct undef_hook kgdb_compiled_brkpt_thumb_hook = {
+	.instr_mask		= 0xffff,
+	.instr_val		= KGDB_COMPILED_BREAK & 0xffff,
+	.cpsr_mask		= PSR_T_BIT | MODE_MASK,
+	.cpsr_val		= PSR_T_BIT | SVC_MODE,
+	.fn			= kgdb_compiled_brk_fn
+};
+
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+	struct pt_regs *regs = args->regs;
+
+	if (kgdb_handle_exception(1, args->signr, cmd, regs))
+		return NOTIFY_DONE;
+	return NOTIFY_STOP;
+}
+static int
+kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = __kgdb_notify(ptr, cmd);
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static struct notifier_block kgdb_notifier = {
+	.notifier_call	= kgdb_notify,
+	.priority	= -INT_MAX,
+};
+
+
+/**
+ *	kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ *	This function will handle the initalization of any architecture
+ *	specific callbacks.
+ */
+int kgdb_arch_init(void)
+{
+	int ret = register_die_notifier(&kgdb_notifier);
+
+	if (ret != 0)
+		return ret;
+
+	register_undef_hook(&kgdb_brkpt_arm_hook);
+	register_undef_hook(&kgdb_brkpt_thumb_hook);
+	register_undef_hook(&kgdb_compiled_brkpt_arm_hook);
+	register_undef_hook(&kgdb_compiled_brkpt_thumb_hook);
+
+	return 0;
+}
+
+/**
+ *	kgdb_arch_exit - Perform any architecture specific uninitalization.
+ *
+ *	This function will handle the uninitalization of any architecture
+ *	specific callbacks, for dynamic registration and unregistration.
+ */
+void kgdb_arch_exit(void)
+{
+	unregister_undef_hook(&kgdb_brkpt_arm_hook);
+	unregister_undef_hook(&kgdb_brkpt_thumb_hook);
+	unregister_undef_hook(&kgdb_compiled_brkpt_arm_hook);
+	unregister_undef_hook(&kgdb_compiled_brkpt_thumb_hook);
+	unregister_die_notifier(&kgdb_notifier);
+}
+
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+	int err;
+
+	/* patch_text() only supports int-sized breakpoints */
+	BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE);
+
+	err = copy_from_kernel_nofault(bpt->saved_instr, (char *)bpt->bpt_addr,
+				BREAK_INSTR_SIZE);
+	if (err)
+		return err;
+
+	/* Machine is already stopped, so we can use __patch_text() directly */
+	__patch_text((void *)bpt->bpt_addr,
+		     *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr);
+
+	return err;
+}
+
+int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+	/* Machine is already stopped, so we can use __patch_text() directly */
+	__patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr);
+
+	return 0;
+}
+
+/*
+ * Register our undef instruction hooks with ARM undef core.
+ * We register a hook specifically looking for the KGB break inst
+ * and we handle the normal undef case within the do_undefinstr
+ * handler.
+ */
+const struct kgdb_arch arch_kgdb_ops = {
+#ifndef __ARMEB__
+	.gdb_bpt_instr		= {0xfe, 0xde, 0xff, 0xe7}
+#else /* ! __ARMEB__ */
+	.gdb_bpt_instr		= {0xe7, 0xff, 0xde, 0xfe}
+#endif
+};