diff --git a/arch/arm64/include/asm/kgdb.h b/arch/arm64/include/asm/kgdb.h
index f69f69c8120c..da84645525b9 100644
--- a/arch/arm64/include/asm/kgdb.h
+++ b/arch/arm64/include/asm/kgdb.h
@@ -38,25 +38,54 @@ extern int kgdb_fault_expected;
 #endif /* !__ASSEMBLY__ */

 /*
- * gdb is expecting the following registers layout.
+ * gdb remote procotol (well most versions of it) expects the following
+ * register layout.
  *
  * General purpose regs:
  *     r0-r30: 64 bit
  *     sp,pc : 64 bit
- *     pstate  : 64 bit
- *     Total: 34
+ *     pstate  : 32 bit
+ *     Total: 33 + 1
  * FPU regs:
  *     f0-f31: 128 bit
- *     Total: 32
- * Extra regs
  *     fpsr & fpcr: 32 bit
- *     Total: 2
+ *     Total: 32 + 2
  *
+ * To expand a little on the "most versions of it"... when the gdb remote
+ * protocol for AArch64 was developed it depended on a statement in the
+ * Architecture Reference Manual that claimed "SPSR_ELx is a 32-bit register".
+ * and, as a result, allocated only 32-bits for the PSTATE in the remote
+ * protocol. In fact this statement is still present in ARM DDI 0487A.i.
+ *
+ * Unfortunately "is a 32-bit register" has a very special meaning for
+ * system registers. It means that "the upper bits, bits[63:32], are
+ * RES0.". RES0 is heavily used in the ARM architecture documents as a
+ * way to leave space for future architecture changes. So to translate a
+ * little for people who don't spend their spare time reading ARM architecture
+ * manuals, what "is a 32-bit register" actually means in this context is
+ * "is a 64-bit register but one with no meaning allocated to any of the
+ * upper 32-bits... *yet*".
+ *
+ * Perhaps then we should not be surprised that this has led to some
+ * confusion. Specifically a patch, influenced by the above translation,
+ * that extended PSTATE to 64-bit was accepted into gdb-7.7 but the patch
+ * was reverted in gdb-7.8.1 and all later releases, when this was
+ * discovered to be an undocumented protocol change.
+ *
+ * So... it is *not* wrong for us to only allocate 32-bits to PSTATE
+ * here even though the kernel itself allocates 64-bits for the same
+ * state. That is because this bit of code tells the kernel how the gdb
+ * remote protocol (well most versions of it) describes the register state.
+ *
+ * Note that if you are using one of the versions of gdb that supports
+ * the gdb-7.7 version of the protocol you cannot use kgdb directly
+ * without providing a custom register description (gdb can load new
+ * protocol descriptions at runtime).
  */

-#define _GP_REGS		34
+#define _GP_REGS		33
 #define _FP_REGS		32
-#define _EXTRA_REGS		2
+#define _EXTRA_REGS		3
 /*
  * general purpose registers size in bytes.
  * pstate is only 4 bytes. subtract 4 bytes
diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c
index b67531a13136..b5f063e5eff7 100644
--- a/arch/arm64/kernel/kgdb.c
+++ b/arch/arm64/kernel/kgdb.c
@@ -58,7 +58,17 @@ struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
 	{ "x30", 8, offsetof(struct pt_regs, regs[30])},
 	{ "sp", 8, offsetof(struct pt_regs, sp)},
 	{ "pc", 8, offsetof(struct pt_regs, pc)},
-	{ "pstate", 8, offsetof(struct pt_regs, pstate)},
+	/*
+	 * struct pt_regs thinks PSTATE is 64-bits wide but gdb remote
+	 * protocol disagrees. Therefore we must extract only the lower
+	 * 32-bits. Look for the big comment in asm/kgdb.h for more
+	 * detail.
+	 */
+	{ "pstate", 4, offsetof(struct pt_regs, pstate)
+#ifdef CONFIG_CPU_BIG_ENDIAN
+							+ 4
+#endif
+	},
 	{ "v0", 16, -1 },
 	{ "v1", 16, -1 },
 	{ "v2", 16, -1 },
@@ -128,6 +138,8 @@ sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
 	memset((char *)gdb_regs, 0, NUMREGBYTES);
 	thread_regs = task_pt_regs(task);
 	memcpy((void *)gdb_regs, (void *)thread_regs->regs, GP_REG_BYTES);
+	/* Special case for PSTATE (check comments in asm/kgdb.h for details) */
+	dbg_get_reg(33, gdb_regs + GP_REG_BYTES, thread_regs);
 }

 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
