Commit 74c11e30 authored Jun 01, 2018 by Alexey Brodkin Committed by Vineet Gupta Jun 13, 2018

ARC: Explicitly add -mmedium-calls to CFLAGS



GCC built for arc*-*-linux has "-mmedium-calls" implicitly enabled by default
thus we don't see any problems during Linux kernel compilation.
----------------------------->8------------------------
arc-linux-gcc -mcpu=arc700 -Q --help=target | grep calls
  -mlong-calls                          [disabled]
  -mmedium-calls                        [enabled]
----------------------------->8------------------------

But if we try to use so-called Elf32 toolchain with GCC configured for
arc*-*-elf* then we'd see the following failure:
----------------------------->8------------------------
init/do_mounts.o: In function 'init_rootfs':
do_mounts.c:(.init.text+0x108): relocation truncated to fit: R_ARC_S21W_PCREL
against symbol 'unregister_filesystem' defined in .text section in fs/filesystems.o

arc-elf32-ld: final link failed: Symbol needs debug section which does not exist
make: *** [vmlinux] Error 1
----------------------------->8------------------------

That happens because neither "-mmedium-calls" nor "-mlong-calls" are enabled in
Elf32 GCC:
----------------------------->8------------------------
arc-elf32-gcc -mcpu=arc700 -Q --help=target | grep calls
  -mlong-calls                          [disabled]
  -mmedium-calls                        [disabled]
----------------------------->8------------------------

Now to make it possible to use Elf32 toolchain for building Linux kernel
we're explicitly add "-mmedium-calls" to CFLAGS.

And since we add "-mmedium-calls" to the global CFLAGS there's no point in
having per-file copies thus removing them.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

parent 29dcea88

arch/arc/Makefile

+1 −14

Original line number	Diff line number	Diff line
		@@ -16,7 +16,7 @@ endif

		KBUILD_DEFCONFIG := nsim_700_defconfig

		cflags-y += -fno-common -pipe -fno-builtin -D__linux__
		cflags-y += -fno-common -pipe -fno-builtin -mmedium-calls -D__linux__
		cflags-$(CONFIG_ISA_ARCOMPACT) += -mA7
		cflags-$(CONFIG_ISA_ARCV2) += -mcpu=archs

		@@ -140,16 +140,3 @@ dtbs: scripts

		archclean:
		$(Q)$(MAKE) $(clean)=$(boot)

		# Hacks to enable final link due to absence of link-time branch relexation
		# and gcc choosing optimal(shorter) branches at -O3
		#
		# vineetg Feb 2010: -mlong-calls switched off for overall kernel build
		# However lib/decompress_inflate.o (.init.text) calls
		# zlib_inflate_workspacesize (.text) causing relocation errors.
		# Thus forcing all exten calls in this file to be long calls
		export CFLAGS_decompress_inflate.o = -mmedium-calls
		export CFLAGS_initramfs.o = -mmedium-calls
		ifdef CONFIG_SMP
		export CFLAGS_core.o = -mmedium-calls
		endif