[U-Boot] [PATCH v3 2/2] arm: work around assembler bug

[U-Boot] [PATCH v3 2/2] arm: work around assembler bug

[Allen Martin]

Disable sibling call optimization based on binutils version.  This is
to work around a bug in the assember in binutils versions < 2.22.
Branches to weak symbols can be incorrectly optimized in thumb mode to
a short branch (b.n instruction) that won't reach when the symbol gets
preempted.

http://sourceware.org/bugzilla/show_bug.cgi?id=12532

Signed-off-by: Allen Martin <amartin@nvidia.com>
---
changes for v3:
 -split shell line to improve readability
changes for v2:
 -changed GAS_BUG_12532 from yes/no to y/n to be consistent
 -added additional warning about code size increase
---
 arch/arm/config.mk |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 3f4453a..afa6769 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -87,3 +87,25 @@ endif
 ifndef CONFIG_NAND_SPL
 LDFLAGS_u-boot += -pie
 endif
+
+#
+# binutils versions < 2.22 have a bug in the assembler where branches
+# to weak symbols can be incorrectly optimized in thumb mode to a
+# short branch (b.n instruction) that won't reach when the symbol
+# gets preempted
+#
+# http://sourceware.org/bugzilla/show_bug.cgi?id=12532
+#
+ifeq ($(CONFIG_SYS_THUMB_BUILD),y)
+ifeq ($(GAS_BUG_12532),)
+export GAS_BUG_12532:=$(shell if [ $(call binutils-version) -lt 0222 ] ; \
+	then echo y; else echo n; fi)
+ifeq ($(GAS_BUG_12532),y)
+$(warning *** disabling sibling call optimzation because binutils version < 2.22)
+$(warning *** code size may be slightly larger)
+endif
+endif
+ifeq ($(GAS_BUG_12532),y)
+PLATFORM_RELFLAGS += -fno-optimize-sibling-calls
+endif
+endif
-- 
1.7.9.5

[U-Boot] [PATCH v3 1/2] tools, config.mk: add binutils-version

[Allen Martin]

Modeled after gcc-version, add function to get binutils version.

Signed-off-by: Allen Martin <amartin@nvidia.com>
---
 config.mk                 |    1 +
 tools/binutils-version.sh |   20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100755 tools/binutils-version.sh

diff --git a/config.mk b/config.mk
index 3dcea6a..919b77d 100644
--- a/config.mk
+++ b/config.mk
@@ -128,6 +128,7 @@ endif
 # cc-version
 # Usage gcc-ver := $(call cc-version)
 cc-version = $(shell $(SHELL) $(SRCTREE)/tools/gcc-version.sh $(CC))
+binutils-version = $(shell $(SHELL) $(SRCTREE)/tools/binutils-version.sh $(AS))
 
 #
 # Include the make variables (CC, etc...)
diff --git a/tools/binutils-version.sh b/tools/binutils-version.sh
new file mode 100755
index 0000000..d4d9eb4
--- /dev/null
+++ b/tools/binutils-version.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+#
+# binutils-version [-p] gas-command
+#
+# Prints the binutils version of `gas-command' in a canonical 4-digit form
+# such as `0222' for binutils 2.22
+#
+
+gas="$*"
+
+if [ ${#gas} -eq 0 ]; then
+	echo "Error: No assembler specified."
+	printf "Usage:\n\t$0 <gas-command>\n"
+	exit 1
+fi
+
+MAJOR=$($gas --version | head -1 | awk '{print $NF}' | cut -d . -f 1)
+MINOR=$($gas --version | head -1 | awk '{print $NF}' | cut -d . -f 2)
+
+printf "%02d%02d\\n" $MAJOR $MINOR
-- 
1.7.9.5

[U-Boot] [PATCH v3 2/2] arm: work around assembler bug

[Allen Martin]

Disable sibling call optimization based on binutils version.  This is
to work around a bug in the assember in binutils versions < 2.22.
Branches to weak symbols can be incorrectly optimized in thumb mode to
a short branch (b.n instruction) that won't reach when the symbol gets
preempted.

http://sourceware.org/bugzilla/show_bug.cgi?id=12532

Signed-off-by: Allen Martin <amartin@nvidia.com>
---
changes for v3:
 -removed warning print
changes for v2:
 -changed GAS_BUG_12532 from yes/no to y/n to be consistent
 -added additional warning about code size increase
---
 arch/arm/config.mk |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 3f4453a..afa6769 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -87,3 +87,25 @@ endif
 ifndef CONFIG_NAND_SPL
 LDFLAGS_u-boot += -pie
 endif
+
+#
+# binutils versions < 2.22 have a bug in the assembler where branches
+# to weak symbols can be incorrectly optimized in thumb mode to a
+# short branch (b.n instruction) that won't reach when the symbol
+# gets preempted
+#
+# http://sourceware.org/bugzilla/show_bug.cgi?id=12532
+#
+ifeq ($(CONFIG_SYS_THUMB_BUILD),y)
+ifeq ($(GAS_BUG_12532),)
+export GAS_BUG_12532:=$(shell if [ $(call binutils-version) -lt 0222 ] ; \
+	then echo y; else echo n; fi)
+ifeq ($(GAS_BUG_12532),y)
+$(warning *** disabling sibling call optimzation because binutils version < 2.22)
+$(warning *** code size may be slightly larger)
+endif
+endif
+ifeq ($(GAS_BUG_12532),y)
+PLATFORM_RELFLAGS += -fno-optimize-sibling-calls
+endif
+endif
-- 
1.7.9.5

[U-Boot] [PATCH v3 2/2] arm: work around assembler bug

[Allen Martin]

Sorry I screwed this patch up, please ignore, I'll resend in a minute

-Allen
-- 
nvpublic