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arch/arm: add support for Thumb2

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Until now, we were using the default ARM instruction set, as used by
the toolchain: the 32 bits ARM instruction set for the internal
backend, and for external toolchain, whatever default was chosen when
the toolchain was generated.

This commit adds support for the Thumb2 instruction set. To do so, it:

 * provides a menuconfig choice between ARM and Thumb2. The choice is
   only shown when Thumb2 is supported, i.e on ARMv7-A CPUs.

 * passes the --with-mode={arm,thumb} option when building gcc in the
   internal backend. This tells the compiler which type of
   instructions it should generate.

 * passes the m{arm,thumb} option in the external toolchain
   wrapper. ARM and Thumb2 code can freely be mixed together, so the
   fact that the C library has been built either ARM or Thumb2 and
   that the rest of the code is built Thumb2 or ARM is not a problem.

[Peter: fix empty BR2_GCC_TARGET_MODE check]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
This commit is contained in:
Thomas Petazzoni 2013-07-16 10:03:22 +02:00 committed by Peter Korsgaard
parent d2e3cc389d
commit 85d0769ac5
5 changed files with 55 additions and 0 deletions
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6
arch/Config.in
View File

@ -207,6 +207,12 @@ config BR2_GCC_TARGET_FPU
config BR2_GCC_TARGET_FLOAT_ABI
string
# The value of this option will be passed as --with-mode=<value> when
# building gcc (internal backend) or -m<value> in the toolchain
# wrapper (external toolchain)
config BR2_GCC_TARGET_MODE
string
# Set up target binary format
choice
prompt "Target Binary Format"

36
arch/Config.in.arm
View File

@ -31,6 +31,9 @@ config BR2_ARM_CPU_HAS_VFPV4
bool
select BR2_ARM_CPU_HAS_VFPV3
config BR2_ARM_CPU_HAS_THUMB2
bool
choice
prompt "Target Architecture Variant"
depends on BR2_arm || BR2_armeb
@ -65,22 +68,27 @@ config BR2_cortex_a5
bool "cortex-A5"
select BR2_ARM_CPU_MAYBE_HAS_NEON
select BR2_ARM_CPU_MAYBE_HAS_VFPV4
select BR2_ARM_CPU_HAS_THUMB2
config BR2_cortex_a7
bool "cortex-A7"
select BR2_ARM_CPU_HAS_NEON
select BR2_ARM_CPU_HAS_VFPV4
select BR2_ARM_CPU_HAS_THUMB2
config BR2_cortex_a8
bool "cortex-A8"
select BR2_ARM_CPU_HAS_NEON
select BR2_ARM_CPU_HAS_VFPV3
select BR2_ARM_CPU_HAS_THUMB2
config BR2_cortex_a9
bool "cortex-A9"
select BR2_ARM_CPU_MAYBE_HAS_NEON
select BR2_ARM_CPU_MAYBE_HAS_VFPV3
select BR2_ARM_CPU_HAS_THUMB2
config BR2_cortex_a15
bool "cortex-A15"
select BR2_ARM_CPU_HAS_NEON
select BR2_ARM_CPU_HAS_VFPV4
select BR2_ARM_CPU_HAS_THUMB2
config BR2_fa526
bool "fa526/626"
config BR2_pj4
@ -275,6 +283,30 @@ config BR2_ARM_FPU_NEON_VFPV4
endchoice
choice
prompt "ARM instruction set"
depends on BR2_ARM_CPU_HAS_THUMB2
config BR2_ARM_INSTRUCTIONS_ARM_CHOICE
bool "ARM"
help
This option instructs the compiler to generate regular ARM
instructions, that are all 32 bits wide.
config BR2_ARM_INSTRUCTIONS_THUMB2
bool "Thumb2"
help
This option instructions the compiler to generate Thumb2
instructions, which allows to mix 16 bits instructions and
32 bits instructions. This generally provides a much smaller
compiled binary size.
endchoice
config BR2_ARM_INSTRUCTIONS_ARM
def_bool y
depends on !BR2_ARM_INSTRUCTIONS_THUMB2
config BR2_ARCH
default "arm" if BR2_arm
default "armeb" if BR2_armeb
@ -344,3 +376,7 @@ config BR2_GCC_TARGET_FLOAT_ABI
default "soft" if BR2_ARM_SOFT_FLOAT
default "softfp" if !BR2_ARM_SOFT_FLOAT && BR2_ARM_EABI
default "hard" if !BR2_ARM_SOFT_FLOAT && BR2_ARM_EABIHF
config BR2_GCC_TARGET_MODE
default "arm" if BR2_ARM_INSTRUCTIONS_ARM
default "thumb" if BR2_ARM_INSTRUCTIONS_THUMB2

5
package/gcc/gcc.mk
View File

@ -177,6 +177,11 @@ ifneq ($(GCC_TARGET_FLOAT_ABI),)
HOST_GCC_COMMON_CONF_OPT += --with-float=$(GCC_TARGET_FLOAT_ABI)
endif
GCC_TARGET_MODE = $(call qstrip,$(BR2_GCC_TARGET_MODE))
ifneq ($(GCC_TARGET_MODE),)
HOST_GCC_COMMON_CONF_OPT += --with-mode=$(GCC_TARGET_MODE)
endif
# Branding works on >= 4.3
ifneq ($(findstring x4.2.,x$(GCC_VERSION)),x4.2.)
HOST_GCC_COMMON_CONF_OPT += \

5
toolchain/toolchain-external/ext-tool.mk
View File

@ -147,6 +147,7 @@ CC_TARGET_ARCH_:=$(call qstrip,$(BR2_GCC_TARGET_ARCH))
CC_TARGET_ABI_:=$(call qstrip,$(BR2_GCC_TARGET_ABI))
CC_TARGET_FPU_:=$(call qstrip,$(BR2_GCC_TARGET_FPU))
CC_TARGET_FLOAT_ABI_:=$(call qstrip,$(BR2_GCC_TARGET_FLOAT_ABI))
CC_TARGET_MODE_:=$(call qstrip,$(BR2_GCC_TARGET_MODE))
# march/mtune/floating point mode needs to be passed to the external toolchain
# to select the right multilib variant
@ -178,6 +179,10 @@ ifneq ($(CC_TARGET_FLOAT_ABI_),)
TOOLCHAIN_EXTERNAL_CFLAGS += -mfloat-abi=$(CC_TARGET_FLOAT_ABI_)
TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_FLOAT_ABI='"$(CC_TARGET_FLOAT_ABI_)"'
endif
ifneq ($(CC_TARGET_MODE_),)
TOOLCHAIN_EXTERNAL_CFLAGS += -m$(CC_TARGET_MODE_)
TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_MODE='"$(CC_TARGET_MODE_)"'
endif
ifeq ($(BR2_BINFMT_FLAT),y)
TOOLCHAIN_EXTERNAL_CFLAGS += -Wl,-elf2flt
TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_BINFMT_FLAT

3
toolchain/toolchain-external/ext-toolchain-wrapper.c
View File

@ -47,6 +47,9 @@ static char *predef_args[] = {
#ifdef BR_SOFTFLOAT
"-msoft-float",
#endif /* BR_SOFTFLOAT */
#ifdef BR_MODE
"-m" BR_MODE,
#endif
#ifdef BR_64
"-m64",
#endif