+++ /dev/null
-From feb9f08cfe8ddd1fd4fb62265e17ee35147ab268 Mon Sep 17 00:00:00 2001
-From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
-Date: Sun, 20 Mar 2016 17:58:35 +0100
-Subject: [PATCH] arm: simplify handling of Thumb related options
-
-Currently, the Thumb support on ARM has three related Config.in
-options, which are not trivial for users to understand, and are in
-fact not needed:
-
- - The USE_BX option is not needed: knowing whether BX is available or
- not is easy. If you have an ARM > v4 or ARMv4T, then BX is
- available, otherwise it's not. This is the logic used in glibc.
-
- - The USE_LDREXSTREX option is not needed: whenever Thumb2 is
- available, ldrex/strex are available, so we can simply rely on
- __thumb2__ to determine whether ldrex/strex should be used, without
- requiring a Config.in option.
-
- - Once USE_BX and USE_LDREXSTREX are removed, the only thing left
- that COMPILE_IN_THUMB does is to set -mthumb. This makes the option
- unnecessary, as on ARM at least, the user is already supposed to
- pass -march=<foo> or other compiler options tuning the library for
- a specific ARM variant. There is no reason to do otherwise for
- Thumb, which allows to get rid of the COMPILE_IN_THUMB option.
-
-Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
-[Backport from upstream feb9f08cfe8ddd1fd4fb62265e17ee35147ab268.]
----
- Rules.mak | 1 -
- extra/Configs/Config.arm | 22 ----------------------
- libc/sysdeps/linux/arm/bits/arm_bx.h | 10 ++++------
- libc/sysdeps/linux/arm/clone.S | 2 +-
- .../linuxthreads.old/sysdeps/arm/pt-machine.h | 7 +++----
- 5 files changed, 8 insertions(+), 34 deletions(-)
-
-diff --git a/Rules.mak b/Rules.mak
-index fc53ad1..dc1a02e 100644
---- a/Rules.mak
-+++ b/Rules.mak
-@@ -392,7 +392,6 @@ endif
- ifeq ($(TARGET_ARCH),arm)
- CPU_CFLAGS-$(ARCH_LITTLE_ENDIAN)+=-mlittle-endian
- CPU_CFLAGS-$(ARCH_BIG_ENDIAN)+=-mbig-endian
-- CPU_CFLAGS-$(COMPILE_IN_THUMB_MODE)+=-mthumb
- endif
-
- ifeq ($(TARGET_ARCH),metag)
-diff --git a/extra/Configs/Config.arm b/extra/Configs/Config.arm
-index 00cf982..0d02e3f 100644
---- a/extra/Configs/Config.arm
-+++ b/extra/Configs/Config.arm
-@@ -24,25 +24,3 @@ config CONFIG_ARM_EABI
-
- If you say 'n' here, then the library will be built for the
- old Linux ABI.
--
--config COMPILE_IN_THUMB_MODE
-- bool "Build using Thumb mode"
-- select USE_BX
-- select USE_LDREXSTREX
-- help
-- Say 'y' here to force building uClibc in thumb mode.
-- Say 'n' to use your compiler's default mode.
--
--config USE_BX
-- bool "Use BX in function return"
-- help
-- Say 'y' to use BX to return from functions on your thumb-aware
-- processor. Say 'y' if you need to use interworking. Say 'n' if not.
-- It is safe to say 'y' even if you're not doing interworking.
--
--config USE_LDREXSTREX
-- bool "Use load-store exclusive ASM ops (not supported in SmartFusion)"
-- depends on COMPILE_IN_THUMB_MODE
-- default n
-- help
-- Say 'y' to use LDREX/STREX ASM ops.
-diff --git a/libc/sysdeps/linux/arm/bits/arm_bx.h b/libc/sysdeps/linux/arm/bits/arm_bx.h
-index 2c29089..1c775b6 100644
---- a/libc/sysdeps/linux/arm/bits/arm_bx.h
-+++ b/libc/sysdeps/linux/arm/bits/arm_bx.h
-@@ -23,13 +23,11 @@
- #error Please include features.h first
- #endif /* features.h not yet included */
-
--#if defined(__USE_BX__)
--# if (__ARM_ARCH <= 4 && !defined __ARM_ARCH_4T__)
--# error Use of BX was requested, but is not available on the target processor.
--# endif /* ARCH level */
--#endif /* __USE_BX__ */
-+#if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
-+# define ARCH_HAS_BX
-+#endif
-
--#if defined(__USE_BX__) && (__ARM_ARCH > 4 || (__ARM_ARCH == 4 && defined __ARM_ARCH_4T__))
-+#if defined(ARCH_HAS_BX)
- # define BX(reg) bx reg
- # define BXC(cond, reg) bx##cond reg
- #else
-diff --git a/libc/sysdeps/linux/arm/clone.S b/libc/sysdeps/linux/arm/clone.S
-index b4c7d8a..fd7590d 100644
---- a/libc/sysdeps/linux/arm/clone.S
-+++ b/libc/sysdeps/linux/arm/clone.S
-@@ -69,7 +69,7 @@ __clone:
-
- @ pick the function arg and call address off the stack and execute
- ldr r0, [sp, #4]
--#if defined(__USE_BX__)
-+#if defined(ARCH_HAS_BX)
- ldr r1, [sp]
- bl 2f @ blx r1
- #else
-diff --git a/libpthread/linuxthreads.old/sysdeps/arm/pt-machine.h b/libpthread/linuxthreads.old/sysdeps/arm/pt-machine.h
-index 2b877f9..fc17e9b 100644
---- a/libpthread/linuxthreads.old/sysdeps/arm/pt-machine.h
-+++ b/libpthread/linuxthreads.old/sysdeps/arm/pt-machine.h
-@@ -28,8 +28,7 @@
- # define PT_EI __extern_always_inline
- #endif
-
--#if defined(__thumb__)
--#if defined(__USE_LDREXSTREX__)
-+#if defined(__thumb2__)
- PT_EI long int ldrex(int *spinlock)
- {
- long int ret;
-@@ -63,7 +62,7 @@ testandset (int *spinlock)
- return ret;
- }
-
--#else /* __USE_LDREXSTREX__ */
-+#elif defined(__thumb__)
-
- /* This will not work on ARM1 or ARM2 because SWP is lacking on those
- machines. Unfortunately we have no way to detect this at compile
-@@ -88,7 +87,7 @@ PT_EI long int testandset (int *spinlock)
- : "0"(1), "r"(spinlock));
- return ret;
- }
--#endif
-+
- #else /* __thumb__ */
-
- PT_EI long int testandset (int *spinlock);
---
-2.6.4
-
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