|
|
@@ -0,0 +1,147 @@
|
|
|
+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
|
|
|
+
|
Thomas Petazzoni