linux/arch/x86/kernel/cpu
Linus Torvalds 050e9baa9d Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables
The changes to automatically test for working stack protector compiler
support in the Kconfig files removed the special STACKPROTECTOR_AUTO
option that picked the strongest stack protector that the compiler
supported.

That was all a nice cleanup - it makes no sense to have the AUTO case
now that the Kconfig phase can just determine the compiler support
directly.

HOWEVER.

It also meant that doing "make oldconfig" would now _disable_ the strong
stackprotector if you had AUTO enabled, because in a legacy config file,
the sane stack protector configuration would look like

  CONFIG_HAVE_CC_STACKPROTECTOR=y
  # CONFIG_CC_STACKPROTECTOR_NONE is not set
  # CONFIG_CC_STACKPROTECTOR_REGULAR is not set
  # CONFIG_CC_STACKPROTECTOR_STRONG is not set
  CONFIG_CC_STACKPROTECTOR_AUTO=y

and when you ran this through "make oldconfig" with the Kbuild changes,
it would ask you about the regular CONFIG_CC_STACKPROTECTOR (that had
been renamed from CONFIG_CC_STACKPROTECTOR_REGULAR to just
CONFIG_CC_STACKPROTECTOR), but it would think that the STRONG version
used to be disabled (because it was really enabled by AUTO), and would
disable it in the new config, resulting in:

  CONFIG_HAVE_CC_STACKPROTECTOR=y
  CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
  CONFIG_CC_STACKPROTECTOR=y
  # CONFIG_CC_STACKPROTECTOR_STRONG is not set
  CONFIG_CC_HAS_SANE_STACKPROTECTOR=y

That's dangerously subtle - people could suddenly find themselves with
the weaker stack protector setup without even realizing.

The solution here is to just rename not just the old RECULAR stack
protector option, but also the strong one.  This does that by just
removing the CC_ prefix entirely for the user choices, because it really
is not about the compiler support (the compiler support now instead
automatially impacts _visibility_ of the options to users).

This results in "make oldconfig" actually asking the user for their
choice, so that we don't have any silent subtle security model changes.
The end result would generally look like this:

  CONFIG_HAVE_CC_STACKPROTECTOR=y
  CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
  CONFIG_STACKPROTECTOR=y
  CONFIG_STACKPROTECTOR_STRONG=y
  CONFIG_CC_HAS_SANE_STACKPROTECTOR=y

where the "CC_" versions really are about internal compiler
infrastructure, not the user selections.

Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-14 12:21:18 +09:00
..
mcheck treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
microcode x86/microcode: Make the late update update_lock a raw lock for RT 2018-05-27 21:50:09 +02:00
mtrr treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
.gitignore
amd.c Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 18:19:18 -07:00
aperfmperf.c x86 / CPU: Always show current CPU frequency in /proc/cpuinfo 2017-11-15 19:46:50 +01:00
bugs.c x86/bugs: Switch the selection of mitigation from CPU vendor to CPU features 2018-06-06 14:13:17 +02:00
cacheinfo.c x86/CPU: Move cpu_detect_cache_sizes() into init_intel_cacheinfo() 2018-05-13 16:14:24 +02:00
centaur.c x86/CPU: Move x86_cpuinfo::x86_max_cores assignment to detect_num_cpu_cores() 2018-05-13 16:14:24 +02:00
common.c Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables 2018-06-14 12:21:18 +09:00
cpu.h Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 18:19:18 -07:00
cpuid-deps.c x86/cpuid: Switch to 'static const' specifier 2018-03-08 12:23:42 +01:00
cyrix.c x86/cpu: Rename cpu_data.x86_mask to cpu_data.x86_stepping 2018-02-15 01:15:52 +01:00
hypervisor.c x86/jailhouse: Add infrastructure for running in non-root cell 2018-01-14 21:11:54 +01:00
intel_pconfig.c x86/pconfig: Detect PCONFIG targets 2018-03-12 12:10:54 +01:00
intel_rdt_ctrlmondata.c x86/intel_rdt/mba_sc: Add schemata support 2018-05-19 13:16:44 +02:00
intel_rdt_monitor.c x86/intel_rdt/mba_sc: Feedback loop to dynamically update mem bandwidth 2018-05-19 13:16:44 +02:00
intel_rdt_rdtgroup.c x86/intel_rdt/mba_sc: Add initialization support 2018-05-19 13:16:43 +02:00
intel_rdt.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-10 09:44:53 -07:00
intel_rdt.h x86/intel_rdt/mba_sc: Feedback loop to dynamically update mem bandwidth 2018-05-19 13:16:44 +02:00
intel.c Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 18:19:18 -07:00
Makefile x86/CPU: Rename intel_cacheinfo.c to cacheinfo.c 2018-05-06 12:49:15 +02:00
match.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mkcapflags.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mshyperv.c ARM: 2018-04-09 11:42:31 -07:00
perfctr-watchdog.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
powerflags.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
proc.c x86/cpu: Change type of x86_cache_size variable to unsigned int 2018-02-15 01:15:53 +01:00
rdrand.c x86, asm: Use CC_SET()/CC_OUT() and static_cpu_has() in archrandom.h 2016-06-08 12:41:20 -07:00
scattered.c Merge branch 'x86/hyperv' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-02-01 15:04:17 +01:00
topology.c x86/CPU: Modify detect_extended_topology() to return result 2018-05-06 12:49:16 +02:00
transmeta.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
umc.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vmware.c x86/virt: Add enum for hypervisors to replace x86_hyper 2017-11-10 10:03:12 +01:00