queue-4.4/arc-explicitly-add-mmedium-calls-to-cflags.patch

   1 From foo@baz Wed Aug 22 10:28:26 CEST 2018
   2 From: Alexey Brodkin <abrodkin@synopsys.com>
   3 Date: Fri, 1 Jun 2018 14:34:33 +0300
   4 Subject: ARC: Explicitly add -mmedium-calls to CFLAGS
   5
   6 From: Alexey Brodkin <abrodkin@synopsys.com>
   7
   8 [ Upstream commit 74c11e300c103af47db5b658fdcf28002421e250 ]
   9
  10 GCC built for arc*-*-linux has "-mmedium-calls" implicitly enabled by default
  11 thus we don't see any problems during Linux kernel compilation.
  12 ----------------------------->8------------------------
  13 arc-linux-gcc -mcpu=arc700 -Q --help=target | grep calls
  14   -mlong-calls                          [disabled]
  15   -mmedium-calls                        [enabled]
  16 ----------------------------->8------------------------
  17
  18 But if we try to use so-called Elf32 toolchain with GCC configured for
  19 arc*-*-elf* then we'd see the following failure:
  20 ----------------------------->8------------------------
  21 init/do_mounts.o: In function 'init_rootfs':
  22 do_mounts.c:(.init.text+0x108): relocation truncated to fit: R_ARC_S21W_PCREL
  23 against symbol 'unregister_filesystem' defined in .text section in fs/filesystems.o
  24
  25 arc-elf32-ld: final link failed: Symbol needs debug section which does not exist
  26 make: *** [vmlinux] Error 1
  27 ----------------------------->8------------------------
  28
  29 That happens because neither "-mmedium-calls" nor "-mlong-calls" are enabled in
  30 Elf32 GCC:
  31 ----------------------------->8------------------------
  32 arc-elf32-gcc -mcpu=arc700 -Q --help=target | grep calls
  33   -mlong-calls                          [disabled]
  34   -mmedium-calls                        [disabled]
  35 ----------------------------->8------------------------
  36
  37 Now to make it possible to use Elf32 toolchain for building Linux kernel
  38 we're explicitly add "-mmedium-calls" to CFLAGS.
  39
  40 And since we add "-mmedium-calls" to the global CFLAGS there's no point in
  41 having per-file copies thus removing them.
  42
  43 Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
  44 Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
  45
  46 Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
  47 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  48 ---
  49  arch/arc/Makefile |   15 +--------------
  50  1 file changed, 1 insertion(+), 14 deletions(-)
  51
  52 --- a/arch/arc/Makefile
  53 +++ b/arch/arc/Makefile
  54 @@ -14,7 +14,7 @@ endif
  55
  56  KBUILD_DEFCONFIG := nsim_700_defconfig
  57
  58 -cflags-y       += -fno-common -pipe -fno-builtin -D__linux__
  59 +cflags-y       += -fno-common -pipe -fno-builtin -mmedium-calls -D__linux__
  60  cflags-$(CONFIG_ISA_ARCOMPACT) += -mA7
  61  cflags-$(CONFIG_ISA_ARCV2)     += -mcpu=archs
  62
  63 @@ -137,16 +137,3 @@ dtbs: scripts
  64
  65  archclean:
  66         $(Q)$(MAKE) $(clean)=$(boot)
  67 -
  68 -# Hacks to enable final link due to absence of link-time branch relexation
  69 -# and gcc choosing optimal(shorter) branches at -O3
  70 -#
  71 -# vineetg Feb 2010: -mlong-calls switched off for overall kernel build
  72 -# However lib/decompress_inflate.o (.init.text) calls
  73 -# zlib_inflate_workspacesize (.text) causing relocation errors.
  74 -# Thus forcing all exten calls in this file to be long calls
  75 -export CFLAGS_decompress_inflate.o = -mmedium-calls
  76 -export CFLAGS_initramfs.o = -mmedium-calls
  77 -ifdef CONFIG_SMP
  78 -export CFLAGS_core.o = -mmedium-calls
  79 -endif