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-rw-r--r--arch/arm/kernel/kgdb.c291
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
+};