v4.19.13 snapshot.
diff --git a/arch/arc/kernel/kgdb.c b/arch/arc/kernel/kgdb.c
new file mode 100644
index 0000000..9a3c34a
--- /dev/null
+++ b/arch/arc/kernel/kgdb.c
@@ -0,0 +1,214 @@
+/*
+ * kgdb support for ARC
+ *
+ * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kgdb.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <asm/disasm.h>
+#include <asm/cacheflush.h>
+
+static void to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs,
+ struct callee_regs *cregs)
+{
+ int regno;
+
+ for (regno = 0; regno <= 26; regno++)
+ gdb_regs[_R0 + regno] = get_reg(regno, kernel_regs, cregs);
+
+ for (regno = 27; regno < GDB_MAX_REGS; regno++)
+ gdb_regs[regno] = 0;
+
+ gdb_regs[_FP] = kernel_regs->fp;
+ gdb_regs[__SP] = kernel_regs->sp;
+ gdb_regs[_BLINK] = kernel_regs->blink;
+ gdb_regs[_RET] = kernel_regs->ret;
+ gdb_regs[_STATUS32] = kernel_regs->status32;
+ gdb_regs[_LP_COUNT] = kernel_regs->lp_count;
+ gdb_regs[_LP_END] = kernel_regs->lp_end;
+ gdb_regs[_LP_START] = kernel_regs->lp_start;
+ gdb_regs[_BTA] = kernel_regs->bta;
+ gdb_regs[_STOP_PC] = kernel_regs->ret;
+}
+
+static void from_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs,
+ struct callee_regs *cregs)
+{
+ int regno;
+
+ for (regno = 0; regno <= 26; regno++)
+ set_reg(regno, gdb_regs[regno + _R0], kernel_regs, cregs);
+
+ kernel_regs->fp = gdb_regs[_FP];
+ kernel_regs->sp = gdb_regs[__SP];
+ kernel_regs->blink = gdb_regs[_BLINK];
+ kernel_regs->ret = gdb_regs[_RET];
+ kernel_regs->status32 = gdb_regs[_STATUS32];
+ kernel_regs->lp_count = gdb_regs[_LP_COUNT];
+ kernel_regs->lp_end = gdb_regs[_LP_END];
+ kernel_regs->lp_start = gdb_regs[_LP_START];
+ kernel_regs->bta = gdb_regs[_BTA];
+}
+
+
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
+{
+ to_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *)
+ current->thread.callee_reg);
+}
+
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
+{
+ from_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *)
+ current->thread.callee_reg);
+}
+
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
+ struct task_struct *task)
+{
+ if (task)
+ to_gdb_regs(gdb_regs, task_pt_regs(task),
+ (struct callee_regs *) task->thread.callee_reg);
+}
+
+struct single_step_data_t {
+ uint16_t opcode[2];
+ unsigned long address[2];
+ int is_branch;
+ int armed;
+} single_step_data;
+
+static void undo_single_step(struct pt_regs *regs)
+{
+ if (single_step_data.armed) {
+ int i;
+
+ for (i = 0; i < (single_step_data.is_branch ? 2 : 1); i++) {
+ memcpy((void *) single_step_data.address[i],
+ &single_step_data.opcode[i],
+ BREAK_INSTR_SIZE);
+
+ flush_icache_range(single_step_data.address[i],
+ single_step_data.address[i] +
+ BREAK_INSTR_SIZE);
+ }
+ single_step_data.armed = 0;
+ }
+}
+
+static void place_trap(unsigned long address, void *save)
+{
+ memcpy(save, (void *) address, BREAK_INSTR_SIZE);
+ memcpy((void *) address, &arch_kgdb_ops.gdb_bpt_instr,
+ BREAK_INSTR_SIZE);
+ flush_icache_range(address, address + BREAK_INSTR_SIZE);
+}
+
+static void do_single_step(struct pt_regs *regs)
+{
+ single_step_data.is_branch = disasm_next_pc((unsigned long)
+ regs->ret, regs, (struct callee_regs *)
+ current->thread.callee_reg,
+ &single_step_data.address[0],
+ &single_step_data.address[1]);
+
+ place_trap(single_step_data.address[0], &single_step_data.opcode[0]);
+
+ if (single_step_data.is_branch) {
+ place_trap(single_step_data.address[1],
+ &single_step_data.opcode[1]);
+ }
+
+ single_step_data.armed++;
+}
+
+int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
+ char *remcomInBuffer, char *remcomOutBuffer,
+ struct pt_regs *regs)
+{
+ unsigned long addr;
+ char *ptr;
+
+ undo_single_step(regs);
+
+ switch (remcomInBuffer[0]) {
+ case 's':
+ case 'c':
+ ptr = &remcomInBuffer[1];
+ if (kgdb_hex2long(&ptr, &addr))
+ regs->ret = addr;
+
+ case 'D':
+ case 'k':
+ atomic_set(&kgdb_cpu_doing_single_step, -1);
+
+ if (remcomInBuffer[0] == 's') {
+ do_single_step(regs);
+ atomic_set(&kgdb_cpu_doing_single_step,
+ smp_processor_id());
+ }
+
+ return 0;
+ }
+ return -1;
+}
+
+int kgdb_arch_init(void)
+{
+ single_step_data.armed = 0;
+ return 0;
+}
+
+void kgdb_trap(struct pt_regs *regs)
+{
+ /* trap_s 3 is used for breakpoints that overwrite existing
+ * instructions, while trap_s 4 is used for compiled breakpoints.
+ *
+ * with trap_s 3 breakpoints the original instruction needs to be
+ * restored and continuation needs to start at the location of the
+ * breakpoint.
+ *
+ * with trap_s 4 (compiled) breakpoints, continuation needs to
+ * start after the breakpoint.
+ */
+ if (regs->ecr_param == 3)
+ instruction_pointer(regs) -= BREAK_INSTR_SIZE;
+
+ kgdb_handle_exception(1, SIGTRAP, 0, regs);
+}
+
+void kgdb_arch_exit(void)
+{
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+ instruction_pointer(regs) = ip;
+}
+
+static void kgdb_call_nmi_hook(void *ignored)
+{
+ kgdb_nmicallback(raw_smp_processor_id(), NULL);
+}
+
+void kgdb_roundup_cpus(unsigned long flags)
+{
+ local_irq_enable();
+ smp_call_function(kgdb_call_nmi_hook, NULL, 0);
+ local_irq_disable();
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+ /* breakpoint instruction: TRAP_S 0x3 */
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ .gdb_bpt_instr = {0x78, 0x7e},
+#else
+ .gdb_bpt_instr = {0x7e, 0x78},
+#endif
+};