kernelscripts: Allow devices to use GCC

- This patch is heavily inspired by [1].
- It was made to facilitate support for devices that build the kernel with GCC.

[1]: https://gerrit.aospa.co/c/AOSPA/android_vendor_pa/+/8673

Also squashes:

Author: Mashopy <eliasgheeraert@gmail.com>
Date:   Mon Apr 24 18:40:07 2023 +0200

    kernelscript: Enforce KERNEL_CROSS_COMPILE to aarch64-linux-gnu- and properly support vdso32

    KERNEL_CROSS_COMPILE should not been set to arm-eabi- since arm64 kernels expect an aarch64 GNU binary for CROSS_COMPILER.
    CROSS_COMPILE_ARM32 is currently used by Linux kernels who have an outdated vdso backport like 4.9, but is unused on
    Linux kernel 4.19 and newer since it got renamed to CROSS_COMPILE_COMPAT during vdso32 bringup.
    Add CROSS_COMPILE_COMPAT variable for properly support vdso32 on these newer Linux kernels.

    This also fix an issue where some CC related features like SCS, STACKPROTECTOR, INIT_STACK_ZERO and KASAN weren't available
    on some kernels despite that some of them depends over clang binary and not GNU binary.

    Also make sure llvm-objcopy is used as some kernels try to look for aarch64-linux-gnu-objcopy and fail to build.

    Change-Id: I093a6c7f798c0d111bd04d1cf089c4d5bc9a3028

Change-Id: Icaa9251a8e151d92f84fa10fa14b6b7becfd8927

3 files changed, 16 insertions, 9 deletions

diff --git a/build.sh b/build.sh
index 4da6dfc..2037f68 100755
--- a/build.sh
+++ b/build.sh
@@ -171,7 +171,7 @@ export INITRAMFS_STAGING_DIR=${MODULES_STAGING_DIR}/initramfs_staging
 
 cd ${ROOT_DIR}
 
-export CLANG_TRIPLE CROSS_COMPILE CROSS_COMPILE_ARM32 ARCH SUBARCH
+export CLANG_TRIPLE CROSS_COMPILE CROSS_COMPILE_ARM32 CROSS_COMPILE_COMPAT ARCH SUBARCH
 
 # Restore the previously saved CC argument that might have been overridden by
 # the BUILD_CONFIG.
diff --git a/buildkernel.sh b/buildkernel.sh
index e71e454..d1243c1 100755
--- a/buildkernel.sh
+++ b/buildkernel.sh
@@ -33,7 +33,7 @@ export KERNEL_PREBUILT_DIR=$(readlink -m ${KERNEL_DIR}/../ship_prebuilt)
 export MODULES_PRIVATE_DIR=$(readlink -m ${COMMON_OUT_DIR}/private)
 export DIST_DIR=$(readlink -m ${DIST_DIR:-${COMMON_OUT_DIR}/dist})
 export UNSTRIPPED_DIR=${KERNEL_MODULES_OUT}/unstripped
-export CLANG_TRIPLE CROSS_COMPILE CROSS_COMPILE_ARM32 ARCH SUBARCH
+export CLANG_TRIPLE CROSS_COMPILE CROSS_COMPILE_ARM32 CROSS_COMPILE_COMPAT ARCH SUBARCH
 
 #Setting up for build
 PREBUILT_KERNEL_IMAGE=$(basename ${TARGET_PREBUILT_INT_KERNEL})
diff --git a/kernel_definitions.mk b/kernel_definitions.mk
index 91e16e6..38991ef 100644
--- a/kernel_definitions.mk
+++ b/kernel_definitions.mk
@@ -89,11 +89,12 @@ KERNEL_CONFIG_OVERRIDE := CONFIG_ANDROID_BINDER_IPC_32BIT=y
 endif
 endif
 
-TARGET_KERNEL_CROSS_COMPILE_PREFIX := $(strip $(TARGET_KERNEL_CROSS_COMPILE_PREFIX))
-ifeq ($(TARGET_KERNEL_CROSS_COMPILE_PREFIX),)
-KERNEL_CROSS_COMPILE := arm-eabi-
+ifeq ($(KERNEL_NEW_GCC_SUPPORT),true)
+KERNEL_CROSS_COMPILE := aarch64-none-linux-gnu-
+KERNEL_CROSS_COMPILE_ARM32 := arm-none-eabi-
 else
-KERNEL_CROSS_COMPILE := $(shell pwd)/$(TARGET_TOOLS_PREFIX)
+KERNEL_CROSS_COMPILE := aarch64-linux-gnu-
+KERNEL_CROSS_COMPILE_ARM32 := arm-linux-gnueabi-
 endif
 
 ifeq ($(TARGET_PREBUILT_KERNEL),)
@@ -107,7 +108,12 @@ CLANG_ARCH := arm-linux-gnueabi-
 endif
 
 cc_args :=
-ifeq ($(KERNEL_LLVM_SUPPORT),true)
+ifeq ($(KERNEL_NEW_GCC_SUPPORT), true)  #Using gcc compiler
+  KERNEL_ARM64_GCC_BIN := $(SOURCE_ROOT)/prebuilts/gcc/$(BUILD_OS)-x86/aarch64/aarch64-none-linux-gnu/bin
+  KERNEL_ARM32_GCC_BIN := $(SOURCE_ROOT)/prebuilts/gcc/$(BUILD_OS)-x86/arm/arm-none-eabi/bin
+  $(warning "Using latest gcc" $(KERNEL_ARM64_GCC_BIN)/gcc)
+  cc_args := PATH=$(KERNEL_ARM64_GCC_BIN):$(KERNEL_ARM32_GCC_BIN):$$PATH
+else ifeq ($(KERNEL_LLVM_SUPPORT),true)
   ifeq ($(KERNEL_SD_LLVM_SUPPORT), true)  #Using sd-llvm compiler
     ifeq ($(shell echo $(SDCLANG_PATH) | head -c 1),/)
        KERNEL_LLVM_BIN := $(SDCLANG_PATH)
@@ -124,7 +130,7 @@ ifeq ($(KERNEL_LLVM_SUPPORT),true)
        $(warning "Not using latest aosp-llvm" $(KERNEL_LLVM_BIN)/clang)
     endif
   endif
-  cc_args := PATH=$(KERNEL_LLVM_BIN):$$PATH CC=clang REAL_CC=clang CLANG_TRIPLE=$(CLANG_ARCH) AR=llvm-ar LD=ld.lld NM=llvm-nm LLVM=1 LLVM_IAS=1
+  cc_args := PATH=$(KERNEL_LLVM_BIN):$$PATH CC=clang REAL_CC=clang CLANG_TRIPLE=$(CLANG_ARCH) AR=llvm-ar LD=ld.lld NM=llvm-nm OBJCOPY=llvm-objcopy LLVM=1 LLVM_IAS=1
 else
 ifeq ($(strip $(KERNEL_GCC_NOANDROID_CHK)),0)
 KERNEL_CFLAGS := KCFLAGS=-mno-android
@@ -278,7 +284,8 @@ define build-kernel
 	MAKE_PATH=$(MAKE_PATH)\
 	ARCH=$(KERNEL_ARCH) \
 	CROSS_COMPILE=$(KERNEL_CROSS_COMPILE) \
-	CROSS_COMPILE_ARM32=$(TARGET_KERNEL_CROSS_COMPILE_ARM32_PREFIX) \
+	CROSS_COMPILE_ARM32=$(KERNEL_CROSS_COMPILE_ARM32) \
+	CROSS_COMPILE_COMPAT=$(KERNEL_CROSS_COMPILE_ARM32) \
 	KERNEL_MODULES_OUT=$(3) \
 	KERNEL_HEADERS_INSTALL=$(4) \
 	HEADERS_INSTALL=$(5) \