Toolchain: Build aarch64-gdb for cross-debugging on x86

Meta/debug-kernel.sh

@@ -1,8 +1,18 @@
 #!/bin/sh
 
+SCRIPT_DIR="$(dirname "${0}")"
+
 # Set this environment variable to override the default debugger.
 #
-[ -z "$SERENITY_KERNEL_DEBUGGER" ] && SERENITY_KERNEL_DEBUGGER="gdb"
+if [ -z "$SERENITY_KERNEL_DEBUGGER" ]; then
+    if [ "$SERENITY_ARCH" = "aarch64" ]; then
+        # Prepend the toolchain aarch64 bin directory so we pick up GDB from there
+        PATH="$SCRIPT_DIR/../Toolchain/Local/aarch64/bin:$PATH"
+        SERENITY_KERNEL_DEBUGGER="aarch64-pc-serenity-gdb"
+    else
+        SERENITY_KERNEL_DEBUGGER="gdb"
+    fi
+fi
 
 # The QEMU -s option (enabled by default in ./run) sets up a debugger
 # remote on localhost:1234. So point our debugger there, and inform
@@ -12,10 +22,14 @@ if [ "$SERENITY_ARCH" = "x86_64" ]; then
     gdb_arch=i386:x86-64
     prekernel_image=Prekernel64
     kernel_base=0x2000200000
-else
+elif [ "$SERENITY_ARCH" = "i686" ]; then
     gdb_arch=i386:intel
-    prekernel_image=Prekernel
+    prekernel_image=Prekernel32
     kernel_base=0xc0200000
+elif [ "$SERENITY_ARCH" = "aarch64" ]; then
+    gdb_arch=aarch64:armv8-r
+    prekernel_image=Prekernel
+    kernel_base=0xc0000000 # FIXME
 fi
 
 # FIXME: This doesn't work when running QEMU inside the WSL2 VM
@@ -25,16 +39,17 @@ else
     gdb_host=localhost
 fi
 
+
 exec $SERENITY_KERNEL_DEBUGGER \
-    -ex "file $(dirname "$0")/../Build/${SERENITY_ARCH:-i686}/Kernel/Prekernel/$prekernel_image" \
+    -ex "file $SCRIPT_DIR/../Build/${SERENITY_ARCH:-i686}/Kernel/Prekernel/$prekernel_image" \
     -ex "set confirm off" \
-    -ex "directory $(dirname "$0")/../Build/${SERENITY_ARCH:-i686}/" \
-    -ex "add-symbol-file $(dirname "$0")/../Build/${SERENITY_ARCH:-i686}/Kernel/Kernel -o $kernel_base" \
+    -ex "directory $SCRIPT_DIR/../Build/${SERENITY_ARCH:-i686}/" \
+    -ex "add-symbol-file $SCRIPT_DIR/../Build/${SERENITY_ARCH:-i686}/Kernel/Kernel -o $kernel_base" \
     -ex "set confirm on" \
     -ex "set arch $gdb_arch" \
     -ex "set print frame-arguments none" \
     -ex "target remote ${gdb_host}:1234" \
-    -ex "source $(dirname "$0")/serenity_gdb.py" \
+    -ex "source $SCRIPT_DIR/serenity_gdb.py" \
     -ex "layout asm" \
     -ex "fs next" \
     "$@"

Toolchain/BuildIt.sh

@@ -78,6 +78,12 @@ BINUTILS_NAME="binutils-$BINUTILS_VERSION"
 BINUTILS_PKG="${BINUTILS_NAME}.tar.gz"
 BINUTILS_BASE_URL="http://ftp.gnu.org/gnu/binutils"
 
+GDB_VERSION="10.2"
+GDB_MD5SUM="7aeb896762924ae9a2ec59525088bada"
+GDB_NAME="gdb-$GDB_VERSION"
+GDB_PKG="${GDB_NAME}.tar.gz"
+GDB_BASE_URL="http://ftp.gnu.org/gnu/gdb"
+
 # Note: If you bump the gcc version, you also have to update the matching
 #       GCC_VERSION variable in the project's root CMakeLists.txt
 GCC_VERSION="11.2.0"
@@ -174,6 +180,21 @@ popd
 # === DOWNLOAD AND PATCH ===
 
 pushd "$DIR/Tarballs"
+    # Build aarch64-gdb for cross-debugging support on x86 systems
+    if [ "$ARCH" = "aarch64" ]; then
+        md5=""
+        if [ -e "$GDB_PKG" ]; then
+            md5="$($MD5SUM $GDB_PKG | cut -f1 -d' ')"
+            echo "bu md5='$md5'"
+        fi
+        if [ "$md5" != ${GDB_MD5SUM} ] ; then
+            rm -f $GDB_PKG
+            curl -LO "$GDB_BASE_URL/$GDB_PKG"
+        else
+            echo "Skipped downloading gdb"
+        fi
+    fi
+
     md5=""
     if [ -e "$BINUTILS_PKG" ]; then
         md5="$($MD5SUM $BINUTILS_PKG | cut -f1 -d' ')"
@@ -198,6 +219,27 @@ pushd "$DIR/Tarballs"
         echo "Skipped downloading gcc"
     fi
 
+    if [ "$ARCH" = "aarch64" ]; then
+        if [ -d ${GDB_NAME} ]; then
+            rm -rf "${GDB_NAME}"
+            rm -rf "$DIR/Build/$ARCH/$GDB_NAME"
+        fi
+        echo "Extracting GDB..."
+        tar -xzf ${GDB_PKG}
+
+        pushd ${GDB_NAME}
+            if [ "$git_patch" = "1" ]; then
+                git init > /dev/null
+                git add . > /dev/null
+                git commit -am "BASE" > /dev/null
+                git apply "$DIR"/Patches/gdb.patch > /dev/null
+            else
+                patch -p1 < "$DIR"/Patches/gdb.patch > /dev/null
+            fi
+            $MD5SUM "$DIR"/Patches/gdb.patch > .patch.applied
+        popd
+    fi
+
     if [ -d ${BINUTILS_NAME} ]; then
         rm -rf "${BINUTILS_NAME}"
         rm -rf "$DIR/Build/$ARCH/$BINUTILS_NAME"
@@ -259,6 +301,24 @@ mkdir -p "$DIR/Build/$ARCH"
 pushd "$DIR/Build/$ARCH"
     unset PKG_CONFIG_LIBDIR # Just in case
 
+    if [ "$ARCH" = "aarch64" ]; then
+        rm -rf gdb
+        mkdir -p gdb
+
+        pushd gdb
+            echo "XXX configure gdb"
+            buildstep "gdb/configure" "$DIR"/Tarballs/$GDB_NAME/configure --prefix="$PREFIX" \
+                                                     --target="$TARGET" \
+                                                     --with-sysroot="$SYSROOT" \
+                                                     --enable-shared \
+                                                     --disable-nls \
+                                                     ${TRY_USE_LOCAL_TOOLCHAIN:+"--quiet"} || exit 1
+            echo "XXX build gdb"
+            buildstep "gdb/build" "$MAKE" -j "$MAKEJOBS" || exit 1
+            buildstep "gdb/install" "$MAKE" install || exit 1
+        popd
+    fi
+
     rm -rf binutils
     mkdir -p binutils
 

Toolchain/Patches/gdb.patch

@@ -0,0 +1,40 @@
+diff -ur gdb-10.2-orig/bfd/config.bfd gdb-10.2/bfd/config.bfd
+--- gdb-10.2-orig/bfd/config.bfd	2021-04-25 07:06:26.000000000 +0300
++++ gdb-10.2/bfd/config.bfd	2021-09-07 01:14:58.781960654 +0300
+@@ -224,7 +224,25 @@
+ 
+ case "${targ}" in
+ # START OF targmatch.h
++  i[3-7]86-*-serenity*)
++    targ_defvec=i386_elf32_vec
++    targ_selvecs=
++    ;;
++  arm-*-serenity*)
++    targ_defvec=arm_elf32_le_vec
++    targ_selvecs=
++    ;;
+ #ifdef BFD64
++  x86_64-*-serenity*)
++    targ_defvec=x86_64_elf64_vec
++    targ_selvecs=i386_elf32_vec
++    want64=true
++    ;;
++  aarch64-*-serenity*)
++    targ_defvec=aarch64_elf64_le_vec
++    targ_selvecs=
++    want64=true
++    ;;
+   aarch64-*-darwin*)
+     targ_defvec=aarch64_mach_o_vec
+     targ_selvecs="arm_mach_o_vec mach_o_le_vec mach_o_be_vec mach_o_fat_vec"
+diff -ur gdb-10.2-orig/config.sub gdb-10.2/config.sub
+--- gdb-10.2-orig/config.sub	2021-04-25 07:06:26.000000000 +0300
++++ gdb-10.2/config.sub	2021-09-07 01:20:15.360899801 +0300
+@@ -1339,6 +1339,7 @@
+ 	# Each alternative MUST end in a * to match a version number.
+ 	# sysv* is not here because it comes later, after sysvr4.
+ 	gnu* | bsd* | mach* | minix* | genix* | ultrix* | irix* \
++	     | serenity* \
+ 	     | *vms* | esix* | aix* | cnk* | sunos | sunos[34]*\
+ 	     | hpux* | unos* | osf* | luna* | dgux* | auroraux* | solaris* \
+ 	     | sym* | kopensolaris* | plan9* \