Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-27 14:41:39 +00:00
Code Issues Packages Projects Releases Wiki Activity

ARM: make configuration of userspace Thumb support an expert option

Browse Source 
David Mosberger reports random segfaults and other problems when running
his buildroot userspace.  It turns out that his kernel did not have
support for Thumb userspace, nor did his application, but glibc made use
of Thumb instructions in glibc.

The kernel Thumb support option already recommends being enabled, and
is also so biased, but clearly this is not enough of a recommendation.

So, hide this behind CONFIG_EXPERT as well, and include a note to
indicate the potential issues if it's turned off and userspace Thumb
mode is made use of.

Reported-by: David Mosberger <davidm@egauge.net>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Russell King 2017-05-19 16:35:56 +01:00
parent 801f19b951
commit 1515b186c2
1 changed files with 5 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/arm/mm/Kconfig
View File

@ -679,7 +679,7 @@ config ARCH_DMA_ADDR_T_64BIT
bool
config ARM_THUMB
bool "Support Thumb user binaries" if !CPU_THUMBONLY
bool "Support Thumb user binaries" if !CPU_THUMBONLY && EXPERT
depends on CPU_THUMB_CAPABLE
default y
help
@ -690,6 +690,10 @@ config ARM_THUMB
instruction set resulting in smaller binaries at the expense of
slightly less efficient code.
If this option is disabled, and you run userspace that switches to
Thumb mode, signal handling will not work correctly, resulting in
segmentation faults or illegal instruction aborts.
If you don't know what this all is, saying Y is a safe choice.
config ARM_THUMBEE