[Buildroot] [PATCH 1/1] Add support for x32 ABI for x86-64 target.

* [Buildroot] [PATCH 1/1] Add support for x32 ABI for x86-64 target.
@ 2015-08-11 22:59 Guido Hatzsis
  2015-08-19 22:49 ` sergey kostanbaev
  0 siblings, 1 reply; 5+ messages in thread
From: Guido Hatzsis @ 2015-08-11 22:59 UTC (permalink / raw)
  To: buildroot

x32 uses 32-bit pointers on the x84-64 linux target. The kernel needs
to have CONFIG_X86_X32 enabled. For more information see:
https://en.wikipedia.org/wiki/X32_ABI

Signed-off-by: Guido Hatzsis <Guido.Hatzsis@yandex.com>
---
 arch/Config.in.x86                      | 30 ++++++++++++++++++++++++++++++
 package/Makefile.in                     |  5 +++++
 package/glibc/Config.in                 |  2 ++
 package/uclibc/Config.in                |  1 +
 toolchain/toolchain-buildroot/Config.in |  2 ++
 5 files changed, 40 insertions(+)

diff --git a/arch/Config.in.x86 b/arch/Config.in.x86
index 43f6abc..a312df1 100644
--- a/arch/Config.in.x86
+++ b/arch/Config.in.x86
@@ -268,3 +268,33 @@ config BR2_GCC_TARGET_ARCH
 	default "c3"		if BR2_x86_c3
 	default "c3-2"		if BR2_x86_c32
 	default "geode"		if BR2_x86_geode
+
+choice
+	prompt "Target ABI"
+	depends on BR2_x86_64
+	default BR2_X86_64_ABI_GCC
+	help
+	  Application Binary Interface to use. The Application Binary
+	  Interface describes the calling conventions (how arguments
+	  are passed to functions, how the return value is passed, how
+	  system calls are made, etc.).
+
+config BR2_X86_64_ABI_GNU
+	bool "gnu"
+	depends on BR2_x86_64
+	help
+      This is the gnu ABI for x86-64 which has 64-bits wide pointers.
+
+config BR2_X86_64_ABI_X32
+	bool "x32"
+	depends on BR2_x86_64
+	help
+      The X32 ABI is x86-64 with 32 bit pointers. It runs in x86-64 mode
+      but as it has 32-bit pointers only 4 GB of RAM can be addressed.
+      https://en.wikipedia.org/wiki/X32_ABI
+
+endchoice
+
+config BR2_GCC_TARGET_ABI
+    default "x32"      if BR2_X86_64_ABI_X32
+
diff --git a/package/Makefile.in b/package/Makefile.in
index 545694f..db2c0f0 100644
--- a/package/Makefile.in
+++ b/package/Makefile.in
@@ -70,6 +70,11 @@ ABI := $(ABI)hf
 endif
 endif
 
+# Only set the ABI for x86-64 x32.
+ifeq ($(BR2_X86_64_ABI_X32),y)
+ABI = x32
+endif
+
 # For FSL PowerPC there's SPE
 ifeq ($(BR2_powerpc_SPE),y)
 ABI = spe
diff --git a/package/glibc/Config.in b/package/glibc/Config.in
index 8cc8cce..a76f2c7 100644
--- a/package/glibc/Config.in
+++ b/package/glibc/Config.in
@@ -4,6 +4,7 @@ if BR2_TOOLCHAIN_BUILDROOT_EGLIBC
 config BR2_PACKAGE_EGLIBC
 	bool
 	default y
+	depends on !BR2_X86_64_ABI_X32
 
 choice
 	prompt "eglibc version"
@@ -29,6 +30,7 @@ if BR2_TOOLCHAIN_BUILDROOT_GLIBC
 config BR2_PACKAGE_GLIBC
 	bool
 	default y
+	depends on !BR2_X86_64_ABI_X32
 
 choice
 	prompt "glibc version"
diff --git a/package/uclibc/Config.in b/package/uclibc/Config.in
index bf40a13..b21a7fe 100644
--- a/package/uclibc/Config.in
+++ b/package/uclibc/Config.in
@@ -4,6 +4,7 @@ if BR2_TOOLCHAIN_BUILDROOT_UCLIBC
 config BR2_PACKAGE_UCLIBC
 	bool
 	default y
+	depends on !BR2_X86_64_ABI_X32
 
 comment "uClibc Options"
 
diff --git a/toolchain/toolchain-buildroot/Config.in b/toolchain/toolchain-buildroot/Config.in
index 13e2b15..828f753 100644
--- a/toolchain/toolchain-buildroot/Config.in
+++ b/toolchain/toolchain-buildroot/Config.in
@@ -34,6 +34,7 @@ config BR2_TOOLCHAIN_BUILDROOT_UCLIBC
 		   BR2_mips    || BR2_mipsel || BR2_mips64 || BR2_mips64el || \
 		   BR2_powerpc || BR2_sh2a   || BR2_sh4	   || BR2_sh4eb    || \
 		   BR2_sparc   || BR2_xtensa || BR2_x86_64
+	depends on !BR2_X86_64_ABI_X32
 	help
 	  This option selects uClibc as the C library for the
 	  cross-compilation toolchain.
@@ -51,6 +52,7 @@ config BR2_TOOLCHAIN_BUILDROOT_EGLIBC
 	depends on BR2_USE_MMU
 	depends on !BR2_STATIC_LIBS
 	depends on BR2_DEPRECATED_SINCE_2015_08
+	depends on !BR2_X86_64_ABI_X32
 	select BR2_TOOLCHAIN_USES_GLIBC
 	# our eglibc.mk enables RPC support
 	select BR2_TOOLCHAIN_HAS_NATIVE_RPC
-- 
2.5.0

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