From f8d9514e79b653cd6c6b2041e16d7f7a8dc30140 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ciro=20Santilli=20=E5=85=AD=E5=9B=9B=E4=BA=8B=E4=BB=B6=20?=
 =?UTF-8?q?=E6=B3=95=E8=BD=AE=E5=8A=9F?= <ciro.santilli@gmail.com>
Date: Tue, 4 Dec 2018 00:00:01 +0000
Subject: [PATCH] add --custom-config-file-gem5 option to build gem5 kernels
 more easily

---
 README.adoc |  4 ++--
 build-linux | 17 ++++++++++++++---
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/README.adoc b/README.adoc
index bf4827b..ddd4694 100644
--- a/README.adoc
+++ b/README.adoc
@@ -3495,7 +3495,7 @@ git -C "$(./getvar linux_source_dir)" fetch https://gem5.googlesource.com/arm/li
 git -C "$(./getvar linux_source_dir)" checkout gem5/v4.15
 ./build-linux \
   --arch arm \
-  --custom-config-file "$(./getvar linux_source_dir)/arch/arm/configs/gem5_defconfig" \
+  --custom-config-file-gem5 \
   --linux-build-id gem5-v4.15 \
 ;
 git -C "$(./getvar linux_source_dir)" checkout -
@@ -3571,7 +3571,7 @@ git -C "$(./getvar linux_source_dir)" checkout gem5/v4.15
 ./build-linux \
   --arch aarch64 \
   --config-fragment linux_config/display \
-  --custom-config-file "$(./getvar linux_source_dir)/arch/arm64/configs/gem5_defconfig" \
+  --custom-config-file-gem5 \
   --linux-build-id gem5-v4.15 \
 ;
 git -C "$(./getvar linux_source_dir)" checkout -
diff --git a/build-linux b/build-linux
index eed3514..aecceed 100755
--- a/build-linux
+++ b/build-linux
@@ -28,6 +28,13 @@ Pass multiple times to use multiple fragment files.
 Ignore all default kernel configurations and use this file instead.
 Still uses options explicitly passed with `--config` and
 `--config-fragment` on top of it.
+'''
+        )
+        parser.add_argument(
+            '--custom-config-file-gem5', default=False, action='store_true',
+            help='''\
+Use the gem5 Linux kernel fork config as the custom config file.
+Ignore --custom-config-file.
 '''
         )
         parser.add_argument(
@@ -77,10 +84,14 @@ Configure the kernel, but don't build it.
             'CC={}'.format(cc), common.Newline,
             'O={}'.format(build_dir), common.Newline,
         ] + verbose
-        if args.custom_config_file is not None:
-            if not os.path.exists(args.custom_config_file):
+        if args.custom_config_file_gem5:
+            custom_config_file = os.path.join(common.linux_source_dir, 'arch', common.linux_arch, 'configs', 'gem5_defconfig')
+        else:
+            custom_config_file = args.custom_config_file
+        if custom_config_file is not None:
+            if not os.path.exists(custom_config_file):
                 raise Exception('config fragment file does not exist: {}'.format(args.custom_config_file))
-            base_config_file = args.custom_config_file
+            base_config_file = custom_config_file
             config_fragments = []
         else:
             base_config_file = os.path.join(common.linux_config_dir, 'buildroot-{}'.format(args.arch))