[arm64] linux-headers: Disable check for a 32-bit compiler

Closes: #943953 Cherry-pick these from upstream: * arm64: vdso32: Fix broken compat vDSO build warnings * arm64: Kconfig: Make CONFIG_COMPAT_VDSO a proper Kconfig option Then update our build config: * debian/bin/gencontrol.py: Optionally define CROSS_COMPILE_COMPAT make variable * Enable COMPAT_VDSO and set $(CROSS_COMPILE_COMPAT) instead of setting CROSS_COMPILE_COMPAT_VDSO
2026-06-11 13:27:06 +09:00 · 2019-11-01 16:18:25 +00:00
parent cea4f80f43
commit d06731909d
7 changed files with 182 additions and 5 deletions
--- a/debian/bin/gencontrol.py
+++ b/debian/bin/gencontrol.py
@@ -343,6 +343,7 @@ class Gencontrol(Base):
        ('kernel-arch', 'KERNEL_ARCH', False),
        ('cflags', 'KCFLAGS', True),
        ('override-host-type', 'OVERRIDE_HOST_TYPE', True),
+        ('cross-compile-compat', 'CROSS_COMPILE_COMPAT', True),
    )

    flavour_makeflags_build = (
--- a/debian/changelog
+++ b/debian/changelog
@@ -16,6 +16,14 @@ linux (5.3.7-2) UNRELEASED; urgency=medium
  * debian/templates/headers.postinst.in: Set executable for consistency
  * debian/README.source: Document code signing and how to test it
  * debian/tests/control: Mark python test as superficial
+  * [arm64] linux-headers: Disable check for a 32-bit compiler
+    (Closes: #943953):
+    - arm64: vdso32: Fix broken compat vDSO build warnings
+    - arm64: Kconfig: Make CONFIG_COMPAT_VDSO a proper Kconfig option
+    - debian/bin/gencontrol.py: Optionally define $(CROSS_COMPILE_COMPAT) make
+      variable
+    - Enable COMPAT_VDSO and set $(CROSS_COMPILE_COMPAT) instead of setting
+      CROSS_COMPILE_COMPAT_VDSO

  [ Bastian Blank ]
  * [amd64/cloud-amd64] Re-enable RTC drivers. (closes: #931341)
--- a/debian/config/arm64/config
+++ b/debian/config/arm64/config
@@ -15,6 +15,7 @@ CONFIG_KEXEC=y
 CONFIG_CRASH_DUMP=y
 CONFIG_XEN=y
 CONFIG_COMPAT=y
+CONFIG_COMPAT_VDSO=y
 CONFIG_ARMV8_DEPRECATED=y
 CONFIG_SWP_EMULATION=y
 CONFIG_CP15_BARRIER_EMULATION=y
@@ -1281,11 +1282,6 @@ CONFIG_CMA_SIZE_MBYTES=64
 ##
 CONFIG_ENERGY_MODEL=y

-##
-## file: lib/vdso/Kconfig
-##
-CONFIG_CROSS_COMPILE_COMPAT_VDSO="arm-linux-gnueabihf-"
-
 ##
 ## file: mm/Kconfig
 ##
--- a/debian/config/arm64/defines
+++ b/debian/config/arm64/defines
@@ -1,4 +1,5 @@
 [base]
+cross-compile-compat: arm-linux-gnueabihf-
 kernel-arch: arm64
 featuresets:
 none
--- a/debian/patches/bugfix/arm64/arm64-kconfig-make-config_compat_vdso-a-proper-kconf.patch
+++ b/debian/patches/bugfix/arm64/arm64-kconfig-make-config_compat_vdso-a-proper-kconf.patch
@@ -0,0 +1,71 @@
+From: Will Deacon <will@kernel.org>
+Date: Mon, 7 Oct 2019 13:03:12 +0100
+Subject: arm64: Kconfig: Make CONFIG_COMPAT_VDSO a proper Kconfig option
+Origin: https://git.kernel.org/linus/7c4791c9efca8c105a86022f7d5532aeaa819125
+Bug-Debian: https://bugs.debian.org/943953
+
+CONFIG_COMPAT_VDSO is defined by passing '-DCONFIG_COMPAT_VDSO' to the
+compiler when the generic compat vDSO code is in use. It's much cleaner
+and simpler to expose this as a proper Kconfig option (like x86 does),
+so do that and remove the bodge.
+
+Acked-by: Catalin Marinas <catalin.marinas@arm.com>
+Signed-off-by: Will Deacon <will@kernel.org>
+[bwh: Backported to 5.3: adjust context]
+---
+ arch/arm64/Kconfig  | 15 +++++++++++++--
+ arch/arm64/Makefile |  5 -----
+ 2 files changed, 13 insertions(+), 7 deletions(-)
+
+--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
+@@ -111,7 +111,6 @@ config ARM64
+ 	select GENERIC_STRNLEN_USER
+ 	select GENERIC_TIME_VSYSCALL
+ 	select GENERIC_GETTIMEOFDAY
+-	select GENERIC_COMPAT_VDSO if (!CPU_BIG_ENDIAN && COMPAT && "$(CROSS_COMPILE_COMPAT)" != "")
+ 	select HANDLE_DOMAIN_IRQ
+ 	select HARDIRQS_SW_RESEND
+ 	select HAVE_PCI
+@@ -1132,7 +1131,7 @@ menuconfig COMPAT
+ if COMPAT
+ 
+ config KUSER_HELPERS
+-	bool "Enable kuser helpers page for 32 bit applications"
+	bool "Enable kuser helpers page for 32-bit applications"
+ 	default y
+ 	help
+ 	  Warning: disabling this option may break 32-bit user programs.
+@@ -1158,6 +1157,18 @@ config KUSER_HELPERS
+ 	  Say N here only if you are absolutely certain that you do not
+ 	  need these helpers; otherwise, the safe option is to say Y.
+ 
+config COMPAT_VDSO
+	bool "Enable vDSO for 32-bit applications"
+	depends on !CPU_BIG_ENDIAN && "$(CROSS_COMPILE_COMPAT)" != ""
+	select GENERIC_COMPAT_VDSO
+	default y
+	help
+	  Place in the process address space of 32-bit applications an
+	  ELF shared object providing fast implementations of gettimeofday
+	  and clock_gettime.
+
+	  You must have a 32-bit build of glibc 2.22 or later for programs
+	  to seamlessly take advantage of this.
+ 
+ menuconfig ARMV8_DEPRECATED
+ 	bool "Emulate deprecated/obsolete ARMv8 instructions"
+--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
+@@ -50,11 +50,6 @@ endif
+ COMPATCC ?= $(CROSS_COMPILE_COMPAT)gcc
+ export COMPATCC
+ 
+-ifeq ($(CONFIG_GENERIC_COMPAT_VDSO), y)
+-  export CONFIG_COMPAT_VDSO := y
+-  compat_vdso := -DCONFIG_COMPAT_VDSO=1
+-endif
+-
+ KBUILD_CFLAGS	+= -mgeneral-regs-only $(lseinstr) $(brokengasinst) $(compat_vdso)
+ KBUILD_CFLAGS	+= -fno-asynchronous-unwind-tables
+ KBUILD_CFLAGS	+= $(call cc-disable-warning, psabi)
--- a/debian/patches/bugfix/arm64/arm64-vdso32-fix-broken-compat-vdso-build-warnings.patch
+++ b/debian/patches/bugfix/arm64/arm64-vdso32-fix-broken-compat-vdso-build-warnings.patch
@@ -0,0 +1,98 @@
+From: Vincenzo Frascino <vincenzo.frascino@arm.com>
+Date: Thu, 3 Oct 2019 18:48:33 +0100
+Subject: arm64: vdso32: Fix broken compat vDSO build warnings
+Origin: https://git.kernel.org/linus/e0de01aafc3dd7b73308106b056ead2d48391905
+Bug-Debian: https://bugs.debian.org/943953
+
+The .config file and the generated include/config/auto.conf can
+end up out of sync after a set of commands since
+CONFIG_CROSS_COMPILE_COMPAT_VDSO is not updated correctly.
+
+The sequence can be reproduced as follows:
+
+$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig
+[...]
+$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig
+[set CONFIG_CROSS_COMPILE_COMPAT_VDSO="arm-linux-gnueabihf-"]
+$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-
+
+Which results in:
+
+arch/arm64/Makefile:62: CROSS_COMPILE_COMPAT not defined or empty,
+the compat vDSO will not be built
+
+even though the compat vDSO has been built:
+
+$ file arch/arm64/kernel/vdso32/vdso.so
+arch/arm64/kernel/vdso32/vdso.so: ELF 32-bit LSB pie executable, ARM,
+EABI5 version 1 (SYSV), dynamically linked,
+BuildID[sha1]=c67f6c786f2d2d6f86c71f708595594aa25247f6, stripped
+
+A similar case that involves changing the configuration parameter
+multiple times can be reconducted to the same family of problems.
+
+Remove the use of CONFIG_CROSS_COMPILE_COMPAT_VDSO altogether and
+instead rely on the cross-compiler prefix coming from the environment
+via CROSS_COMPILE_COMPAT, much like we do for the rest of the kernel.
+
+Cc: Will Deacon <will@kernel.org>
+Cc: Catalin Marinas <catalin.marinas@arm.com>
+Reported-by: Will Deacon <will@kernel.org>
+Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
+Signed-off-by: Will Deacon <will@kernel.org>
+---
+ arch/arm64/Kconfig                |  2 +-
+ arch/arm64/Makefile               | 18 +++++-------------
+ arch/arm64/kernel/vdso32/Makefile |  2 --
+ 3 files changed, 6 insertions(+), 16 deletions(-)
+
+--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
+@@ -111,7 +111,7 @@ config ARM64
+ 	select GENERIC_STRNLEN_USER
+ 	select GENERIC_TIME_VSYSCALL
+ 	select GENERIC_GETTIMEOFDAY
+-	select GENERIC_COMPAT_VDSO if (!CPU_BIG_ENDIAN && COMPAT)
+	select GENERIC_COMPAT_VDSO if (!CPU_BIG_ENDIAN && COMPAT && "$(CROSS_COMPILE_COMPAT)" != "")
+ 	select HANDLE_DOMAIN_IRQ
+ 	select HARDIRQS_SW_RESEND
+ 	select HAVE_PCI
+--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
+@@ -47,20 +47,12 @@ $(warning Detected assembler with broken
+   endif
+ endif
+ 
+-ifeq ($(CONFIG_GENERIC_COMPAT_VDSO), y)
+-  CROSS_COMPILE_COMPAT ?= $(CONFIG_CROSS_COMPILE_COMPAT_VDSO:"%"=%)
+COMPATCC ?= $(CROSS_COMPILE_COMPAT)gcc
+export COMPATCC
+ 
+-  ifeq ($(CONFIG_CC_IS_CLANG), y)
+-    $(warning CROSS_COMPILE_COMPAT is clang, the compat vDSO will not be built)
+-  else ifeq ($(strip $(CROSS_COMPILE_COMPAT)),)
+-    $(warning CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will not be built)
+-  else ifeq ($(shell which $(CROSS_COMPILE_COMPAT)gcc 2> /dev/null),)
+-    $(error $(CROSS_COMPILE_COMPAT)gcc not found, check CROSS_COMPILE_COMPAT)
+-  else
+-    export CROSS_COMPILE_COMPAT
+-    export CONFIG_COMPAT_VDSO := y
+-    compat_vdso := -DCONFIG_COMPAT_VDSO=1
+-  endif
+ifeq ($(CONFIG_GENERIC_COMPAT_VDSO), y)
+  export CONFIG_COMPAT_VDSO := y
+  compat_vdso := -DCONFIG_COMPAT_VDSO=1
+ endif
+ 
+ KBUILD_CFLAGS	+= -mgeneral-regs-only $(lseinstr) $(brokengasinst) $(compat_vdso)
+--- a/arch/arm64/kernel/vdso32/Makefile
+++ b/arch/arm64/kernel/vdso32/Makefile
+@@ -8,8 +8,6 @@
+ ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32
+ include $(srctree)/lib/vdso/Makefile
+ 
+-COMPATCC := $(CROSS_COMPILE_COMPAT)gcc
+-
+ # Same as cc-*option, but using COMPATCC instead of CC
+ cc32-option = $(call try-run,\
+         $(COMPATCC) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -73,6 +73,8 @@ bugfix/arm64/arm64-acpi-Add-fixup-for-HPE-m400-quirks.patch
 bugfix/x86/x86-32-disable-3dnow-in-generic-config.patch
 bugfix/riscv64/riscv-Fix-memblock-reservation-for-device-tree-blob.patch
 bugfix/riscv64/RISC-V-Clear-load-reservations-while-restoring-hart-.patch
+bugfix/arm64/arm64-vdso32-fix-broken-compat-vdso-build-warnings.patch
+bugfix/arm64/arm64-kconfig-make-config_compat_vdso-a-proper-kconf.patch

 # Arch features
 features/mips/MIPS-Loongson-3-Add-Loongson-LS3A-RS780E-1-way-machi.patch