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ARM: always use ARM_UNWIND for thumb2 kernels

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Thumb2 kernels cannot be built with frame pointers, but can use the
ARM_UNWIND feature for unwinding instead. This makes sure that all
features that rely on unwinding includeing CONFIG_LATENCYTOP and
FAULT_INJECTION_STACKTRACE_FILTER do not enable frame pointers
when the unwinder is already selected, and we always build with
the unwinder when we want a thumb2 kernel, to make sure we do not
get the frame pointers instead.

A different option would be to redefine the CONFIG_FRAME_POINTERS
option on ARM to mean builing with either frame pointers or
the unwinder, and then select which one to use based on the
CPU architecture or another user option. That would still allow
building thumb2 kernels without the unwinder but would also be
more confusing.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann 2011-06-10 14:12:21 +00:00
parent 9934ebb8ff
commit 89bace652c
2 changed files with 3 additions and 2 deletions
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1
arch/arm/Kconfig
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@ -1457,6 +1457,7 @@ config THUMB2_KERNEL
depends on CPU_V7 && !CPU_V6 && !CPU_V6K && EXPERIMENTAL
select AEABI
select ARM_ASM_UNIFIED
select ARM_UNWIND
help
By enabling this option, the kernel will be compiled in
Thumb-2 mode. A compiler/assembler that understand the unified

4
lib/Kconfig.debug
View File

@ -1081,7 +1081,7 @@ config FAULT_INJECTION_STACKTRACE_FILTER
depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
depends on !X86_64
select STACKTRACE
select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE
select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
help
Provide stacktrace filter for fault-injection capabilities
@ -1091,7 +1091,7 @@ config LATENCYTOP
depends on DEBUG_KERNEL
depends on STACKTRACE_SUPPORT
depends on PROC_FS
select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE
select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
select KALLSYMS
select KALLSYMS_ALL
select STACKTRACE