arm64: prevent potential circular header dependencies in asm/bug.h

Currently, using BUG_ON() in header files is cumbersome, due to the fact
that asm/bug.h transitively includes a lot of other header files, resulting
in the actual BUG_ON() invocation appearing before its definition in the
preprocessor input. So let's reverse the #include dependency between
asm/bug.h and asm/debug-monitors.h, by moving the definition of BUG_BRK_IMM
from the latter to the former. Also fix up one user of asm/debug-monitors.h
which relied on a transitive include.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: Ard Biesheuvel

arch/arm64/include/asm/bug.h

@@ -18,7 +18,7 @@
 #ifndef _ARCH_ARM64_ASM_BUG_H
 #define _ARCH_ARM64_ASM_BUG_H
 
-#include <asm/debug-monitors.h>
+#define BUG_BRK_IMM			0x800
 
 #ifdef CONFIG_GENERIC_BUG
 #define HAVE_ARCH_BUG

arch/arm64/include/asm/debug-monitors.h

@@ -20,6 +20,7 @@
 
 #include <linux/errno.h>
 #include <linux/types.h>
+#include <asm/bug.h>
 #include <asm/esr.h>
 #include <asm/insn.h>
 #include <asm/ptrace.h>
@@ -57,7 +58,6 @@
 #define FAULT_BRK_IMM			0x100
 #define KGDB_DYN_DBG_BRK_IMM		0x400
 #define KGDB_COMPILED_DBG_BRK_IMM	0x401
-#define BUG_BRK_IMM			0x800
 
 /*
  * BRK instruction encoding

arch/arm64/kvm/hyp/debug-sr.c

@@ -18,6 +18,7 @@
 #include <linux/compiler.h>
 #include <linux/kvm_host.h>
 
+#include <asm/debug-monitors.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_mmu.h>