5.5-stable patches

added patches:
	kconfig-introduce-m32-flag-and-m64-flag.patch

diff --git a/queue-5.5/kconfig-introduce-m32-flag-and-m64-flag.patch b/queue-5.5/kconfig-introduce-m32-flag-and-m64-flag.patch
new file mode 100644 (file)
index 0000000..bfda048
--- /dev/null
+++ b/queue-5.5/kconfig-introduce-m32-flag-and-m64-flag.patch
@@ -0,0 +1,80 @@
+From 8cc4fd73501d9f1370c3eebb70cfe8cc9e24062b Mon Sep 17 00:00:00 2001
+From: Masahiro Yamada <masahiroy@kernel.org>
+Date: Tue, 10 Mar 2020 19:12:49 +0900
+Subject: kconfig: introduce m32-flag and m64-flag
+
+From: Masahiro Yamada <masahiroy@kernel.org>
+
+commit 8cc4fd73501d9f1370c3eebb70cfe8cc9e24062b upstream.
+
+When a compiler supports multiple architectures, some compiler features
+can be dependent on the target architecture.
+
+This is typical for Clang, which supports multiple LLVM backends.
+Even for GCC, we need to take care of biarch compiler cases.
+
+It is not a problem when we evaluate cc-option in Makefiles because
+cc-option is tested against the flag in question + $(KBUILD_CFLAGS).
+
+The cc-option in Kconfig, on the other hand, does not accumulate
+tested flags. Due to this simplification, it could potentially test
+cc-option against a different target.
+
+At first, Kconfig always evaluated cc-option against the host
+architecture.
+
+Since commit e8de12fb7cde ("kbuild: Check for unknown options with
+cc-option usage in Kconfig and clang"), in case of cross-compiling
+with Clang, the target triple is correctly passed to Kconfig.
+
+The case with biarch GCC (and native build with Clang) is still not
+handled properly. We need to pass some flags to specify the target
+machine bit.
+
+Due to the design, all the macros in Kconfig are expanded in the
+parse stage, where we do not know the target bit size yet.
+
+For example, arch/x86/Kconfig allows a user to toggle CONFIG_64BIT.
+If a compiler flag -foo depends on the machine bit, it must be tested
+twice, one with -m32 and the other with -m64.
+
+However, -m32/-m64 are not always recognized. So, this commits adds
+m64-flag and m32-flag macros. They expand to -m32, -m64, respectively
+if supported. Or, they expand to an empty string if unsupported.
+
+The typical usage is like this:
+
+  config FOO
+          bool
+          default $(cc-option,$(m64-flag) -foo) if 64BIT
+          default $(cc-option,$(m32-flag) -foo)
+
+This is clumsy, but there is no elegant way to handle this in the
+current static macro expansion.
+
+There was discussion for static functions vs dynamic functions.
+The consensus was to go as far as possible with the static functions.
+(https://lkml.org/lkml/2018/3/2/22)
+
+Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
+Tested-by: George Spelvin <lkml@sdf.org>
+Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ scripts/Kconfig.include |    7 +++++++
+ 1 file changed, 7 insertions(+)
+
+--- a/scripts/Kconfig.include
++++ b/scripts/Kconfig.include
+@@ -40,3 +40,10 @@ $(error-if,$(success, $(LD) -v | grep -q
+ 
+ # gcc version including patch level
+ gcc-version := $(shell,$(srctree)/scripts/gcc-version.sh $(CC))
++
++# machine bit flags
++#  $(m32-flag): -m32 if the compiler supports it, or an empty string otherwise.
++#  $(m64-flag): -m64 if the compiler supports it, or an empty string otherwise.
++cc-option-bit = $(if-success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null,$(1))
++m32-flag := $(cc-option-bit,-m32)
++m64-flag := $(cc-option-bit,-m64)

diff --git a/queue-5.5/series b/queue-5.5/series
index add91fd9aaa42df2982970ec60fde1597642a016..1cd822fadc52d83f803e3c4ec9f4327b0940db16 100644 (file)
--- a/queue-5.5/series
+++ b/queue-5.5/series
@@ -115,4 +115,5 @@ drm-i915-execlists-track-active-elements-during-dequeue.patch
 drm-i915-handle-all-mcr-ranges.patch
 staging-greybus-loopback_test-fix-potential-path-truncation.patch
 staging-greybus-loopback_test-fix-potential-path-truncations.patch
+kconfig-introduce-m32-flag-and-m64-flag.patch
 int128-fix-__uint128_t-compiler-test-in-kconfig.patch