cfb4c03204
The uClibc patches to simplify the ARM Thumb configuration options have been merged, but instead of being 5 separate patches, they have been merged as a single patch. This commit updates the Buildroot uClibc package to use the patch that was actually upstreamed. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
148 lines
5.0 KiB
Diff
148 lines
5.0 KiB
Diff
From feb9f08cfe8ddd1fd4fb62265e17ee35147ab268 Mon Sep 17 00:00:00 2001
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From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
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Date: Sun, 20 Mar 2016 17:58:35 +0100
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Subject: [PATCH] arm: simplify handling of Thumb related options
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Currently, the Thumb support on ARM has three related Config.in
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options, which are not trivial for users to understand, and are in
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fact not needed:
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- The USE_BX option is not needed: knowing whether BX is available or
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not is easy. If you have an ARM > v4 or ARMv4T, then BX is
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available, otherwise it's not. This is the logic used in glibc.
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- The USE_LDREXSTREX option is not needed: whenever Thumb2 is
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available, ldrex/strex are available, so we can simply rely on
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__thumb2__ to determine whether ldrex/strex should be used, without
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requiring a Config.in option.
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- Once USE_BX and USE_LDREXSTREX are removed, the only thing left
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that COMPILE_IN_THUMB does is to set -mthumb. This makes the option
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unnecessary, as on ARM at least, the user is already supposed to
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pass -march=<foo> or other compiler options tuning the library for
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a specific ARM variant. There is no reason to do otherwise for
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Thumb, which allows to get rid of the COMPILE_IN_THUMB option.
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Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
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[Backport from upstream feb9f08cfe8ddd1fd4fb62265e17ee35147ab268.]
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---
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Rules.mak | 1 -
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extra/Configs/Config.arm | 22 ----------------------
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libc/sysdeps/linux/arm/bits/arm_bx.h | 10 ++++------
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libc/sysdeps/linux/arm/clone.S | 2 +-
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.../linuxthreads.old/sysdeps/arm/pt-machine.h | 7 +++----
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5 files changed, 8 insertions(+), 34 deletions(-)
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diff --git a/Rules.mak b/Rules.mak
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index fc53ad1..dc1a02e 100644
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--- a/Rules.mak
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+++ b/Rules.mak
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@@ -392,7 +392,6 @@ endif
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ifeq ($(TARGET_ARCH),arm)
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CPU_CFLAGS-$(ARCH_LITTLE_ENDIAN)+=-mlittle-endian
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CPU_CFLAGS-$(ARCH_BIG_ENDIAN)+=-mbig-endian
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- CPU_CFLAGS-$(COMPILE_IN_THUMB_MODE)+=-mthumb
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endif
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ifeq ($(TARGET_ARCH),metag)
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diff --git a/extra/Configs/Config.arm b/extra/Configs/Config.arm
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index 00cf982..0d02e3f 100644
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--- a/extra/Configs/Config.arm
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+++ b/extra/Configs/Config.arm
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@@ -24,25 +24,3 @@ config CONFIG_ARM_EABI
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If you say 'n' here, then the library will be built for the
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old Linux ABI.
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-
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-config COMPILE_IN_THUMB_MODE
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- bool "Build using Thumb mode"
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- select USE_BX
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- select USE_LDREXSTREX
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- help
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- Say 'y' here to force building uClibc in thumb mode.
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- Say 'n' to use your compiler's default mode.
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-
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-config USE_BX
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- bool "Use BX in function return"
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- help
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- Say 'y' to use BX to return from functions on your thumb-aware
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- processor. Say 'y' if you need to use interworking. Say 'n' if not.
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- It is safe to say 'y' even if you're not doing interworking.
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-
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-config USE_LDREXSTREX
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- bool "Use load-store exclusive ASM ops (not supported in SmartFusion)"
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- depends on COMPILE_IN_THUMB_MODE
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- default n
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- help
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- Say 'y' to use LDREX/STREX ASM ops.
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diff --git a/libc/sysdeps/linux/arm/bits/arm_bx.h b/libc/sysdeps/linux/arm/bits/arm_bx.h
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index 2c29089..1c775b6 100644
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--- a/libc/sysdeps/linux/arm/bits/arm_bx.h
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+++ b/libc/sysdeps/linux/arm/bits/arm_bx.h
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@@ -23,13 +23,11 @@
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#error Please include features.h first
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#endif /* features.h not yet included */
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-#if defined(__USE_BX__)
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-# if (__ARM_ARCH <= 4 && !defined __ARM_ARCH_4T__)
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-# error Use of BX was requested, but is not available on the target processor.
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-# endif /* ARCH level */
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-#endif /* __USE_BX__ */
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+#if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
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+# define ARCH_HAS_BX
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+#endif
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-#if defined(__USE_BX__) && (__ARM_ARCH > 4 || (__ARM_ARCH == 4 && defined __ARM_ARCH_4T__))
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+#if defined(ARCH_HAS_BX)
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# define BX(reg) bx reg
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# define BXC(cond, reg) bx##cond reg
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#else
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diff --git a/libc/sysdeps/linux/arm/clone.S b/libc/sysdeps/linux/arm/clone.S
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index b4c7d8a..fd7590d 100644
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--- a/libc/sysdeps/linux/arm/clone.S
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+++ b/libc/sysdeps/linux/arm/clone.S
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@@ -69,7 +69,7 @@ __clone:
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@ pick the function arg and call address off the stack and execute
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ldr r0, [sp, #4]
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-#if defined(__USE_BX__)
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+#if defined(ARCH_HAS_BX)
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ldr r1, [sp]
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bl 2f @ blx r1
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#else
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diff --git a/libpthread/linuxthreads.old/sysdeps/arm/pt-machine.h b/libpthread/linuxthreads.old/sysdeps/arm/pt-machine.h
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index 2b877f9..fc17e9b 100644
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--- a/libpthread/linuxthreads.old/sysdeps/arm/pt-machine.h
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+++ b/libpthread/linuxthreads.old/sysdeps/arm/pt-machine.h
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@@ -28,8 +28,7 @@
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# define PT_EI __extern_always_inline
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#endif
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-#if defined(__thumb__)
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-#if defined(__USE_LDREXSTREX__)
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+#if defined(__thumb2__)
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PT_EI long int ldrex(int *spinlock)
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{
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long int ret;
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@@ -63,7 +62,7 @@ testandset (int *spinlock)
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return ret;
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}
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-#else /* __USE_LDREXSTREX__ */
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+#elif defined(__thumb__)
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/* This will not work on ARM1 or ARM2 because SWP is lacking on those
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machines. Unfortunately we have no way to detect this at compile
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@@ -88,7 +87,7 @@ PT_EI long int testandset (int *spinlock)
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: "0"(1), "r"(spinlock));
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return ret;
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}
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-#endif
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+
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#else /* __thumb__ */
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PT_EI long int testandset (int *spinlock);
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--
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2.6.4
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