linux-brain/arch
Ard Biesheuvel 81e0dac378 ARM: 8961/2: Fix Kbuild issue caused by per-task stack protector GCC plugin
commit 89604523a76eb3e13014b2bdab7f8870becee284 upstream.

When using plugins, GCC requires that the -fplugin= options precedes
any of its plugin arguments appearing on the command line as well.
This is usually not a concern, but as it turns out, this requirement
is causing some issues with ARM's per-task stack protector plugin
and Kbuild's implementation of $(cc-option).

When the per-task stack protector plugin is enabled, and we tweak
the implementation of cc-option not to pipe the stderr output of
GCC to /dev/null, the following output is generated when GCC is
executed in the context of cc-option:

  cc1: error: plugin arm_ssp_per_task_plugin should be specified before \
         -fplugin-arg-arm_ssp_per_task_plugin-tso=1 in the command line
  cc1: error: plugin arm_ssp_per_task_plugin should be specified before \
         -fplugin-arg-arm_ssp_per_task_plugin-offset=24 in the command line

These errors will cause any option passed to cc-option to be treated
as unsupported, which is obviously incorrect.

The cause of this issue is the fact that the -fplugin= argument is
added to GCC_PLUGINS_CFLAGS, whereas the arguments above are added
to KBUILD_CFLAGS, and the contents of the former get filtered out of
the latter before being passed to the GCC running the cc-option test,
and so the -fplugin= option does not appear at all on the GCC command
line.

Adding the arguments to GCC_PLUGINS_CFLAGS instead of KBUILD_CFLAGS
would be the correct approach here, if it weren't for the fact that we
are using $(eval) to defer the moment that they are added until after
asm-offsets.h is generated, which is after the point where the contents
of GCC_PLUGINS_CFLAGS are added to KBUILD_CFLAGS. So instead, we have
to add our plugin arguments to both.

For similar reasons, we cannot append DISABLE_ARM_SSP_PER_TASK_PLUGIN
to KBUILD_CFLAGS, as it will be passed to GCC when executing in the
context of cc-option, whereas the other plugin arguments will have
been filtered out, resulting in a similar error and false negative
result as above. So add it to ccflags-y instead.

Fixes: 189af46571 ("ARM: smp: add support for per-task stack canaries")
Reported-by: Merlijn Wajer <merlijn@wizzup.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-21 08:11:59 +01:00
..
alpha mm: introduce MADV_PAGEOUT 2019-09-25 17:51:41 -07:00
arc ARC: define __ALIGN_STR and __ALIGN symbols for ARC 2020-03-18 07:17:52 +01:00
arm ARM: 8961/2: Fix Kbuild issue caused by per-task stack protector GCC plugin 2020-03-21 08:11:59 +01:00
arm64 arm64: dts: meson: fix gxm-khadas-vim2 wifi 2020-03-12 13:00:31 +01:00
c6x mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
csky csky: Implement copy_thread_tls 2020-03-12 13:00:32 +01:00
h8300 mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
hexagon hexagon: work around compiler crash 2020-01-17 19:49:07 +01:00
ia64 mm/memory_hotplug: shrink zones when offlining memory 2020-01-09 10:19:56 +01:00
m68k mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
microblaze microblaze: Prevent the overflow of the start 2020-02-24 08:37:02 +01:00
mips MIPS: VPE: Fix a double free and a memory leak in 'release_vpe()' 2020-03-05 16:43:45 +01:00
nds32 asm-generic/nds32: don't redefine cacheflush primitives 2020-01-17 19:48:43 +01:00
nios2 nios2 update for v5.4-rc1 2019-09-27 13:02:19 -07:00
openrisc mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
parisc parisc: Use proper printk format for resource_size_t 2020-02-05 21:22:46 +00:00
powerpc powerpc: fix hardware PMU exception bug on PowerVM compatibility mode systems 2020-03-12 13:00:31 +01:00
riscv riscv, bpf: Fix broken BPF tail calls 2020-02-11 04:35:28 -08:00
s390 s390/mm: fix panic in gup_fast on large pud 2020-03-12 13:00:22 +01:00
sh pinctrl: sh-pfc: sh7269: Fix CAN function GPIOs 2020-02-24 08:36:41 +01:00
sparc sparc: Add .exit.data section. 2020-02-24 08:36:27 +01:00
um Revert "um: Enable CONFIG_CONSTRUCTORS" 2020-02-01 09:34:53 +00:00
unicore32 mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
x86 x86/mce: Fix logic and comments around MSR_PPIN_CTL 2020-03-18 07:17:54 +01:00
xtensa xtensa: Implement copy_thread_tls 2020-01-14 20:08:35 +01:00
.gitignore
Kconfig asm-generic/tlb: add missing CONFIG symbol 2020-02-24 08:37:02 +01:00