diff --git a/target/linux/generic/backport-5.10/005-v5.17-01-Kbuild-use-Wdeclaration-after-statement.patch b/target/linux/generic/backport-5.10/005-v5.17-01-Kbuild-use-Wdeclaration-after-statement.patch new file mode 100644 index 0000000000000..dd8a1b445df4c --- /dev/null +++ b/target/linux/generic/backport-5.10/005-v5.17-01-Kbuild-use-Wdeclaration-after-statement.patch @@ -0,0 +1,73 @@ +From 2fd7e7f9317d3048a14026816d081b08ba98ea8e Mon Sep 17 00:00:00 2001 +From: Mark Rutland +Date: Tue, 8 Mar 2022 22:56:13 +0100 +Subject: [PATCH 1/3] Kbuild: use -Wdeclaration-after-statement + +The kernel is moving from using `-std=gnu89` to `-std=gnu11`, permitting +the use of additional C11 features such as for-loop initial declarations. + +One contentious aspect of C99 is that it permits mixed declarations and +code, and for now at least, it seems preferable to enforce that +declarations must come first. + +These warnings were already enabled in the kernel itself, but not +for KBUILD_USERCFLAGS or the compat VDSO on arch/arm64, which uses +a separate set of CFLAGS. + +This patch fixes an existing violation in modpost.c, which is not +reported because of the missing flag in KBUILD_USERCFLAGS: + +| scripts/mod/modpost.c: In function ‘match’: +| scripts/mod/modpost.c:837:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] +| 837 | const char *endp = p + strlen(p) - 1; +| | ^~~~~ + +Signed-off-by: Mark Rutland +[arnd: don't add a duplicate flag to the default set, update changelog] +Signed-off-by: Arnd Bergmann +Reviewed-by: Nathan Chancellor +Reviewed-by: Nick Desaulniers +Tested-by: Sedat Dilek # LLVM/Clang v13.0.0 (x86-64) +Signed-off-by: Masahiro Yamada +--- + Makefile | 3 ++- + arch/arm64/kernel/vdso32/Makefile | 1 + + scripts/mod/modpost.c | 4 +++- + 3 files changed, 6 insertions(+), 2 deletions(-) + +--- a/Makefile ++++ b/Makefile +@@ -416,7 +416,8 @@ HOSTCXX = g++ + endif + + export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ +- -O2 -fomit-frame-pointer -std=gnu89 ++ -O2 -fomit-frame-pointer -std=gnu89 \ ++ -Wdeclaration-after-statement + export KBUILD_USERLDFLAGS := + + KBUILD_HOSTCFLAGS := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS) +--- a/arch/arm64/kernel/vdso32/Makefile ++++ b/arch/arm64/kernel/vdso32/Makefile +@@ -76,6 +76,7 @@ VDSO_CFLAGS += -Wall -Wundef -Wstrict-pr + -fno-strict-aliasing -fno-common \ + -Werror-implicit-function-declaration \ + -Wno-format-security \ ++ -Wdeclaration-after-statement \ + -std=gnu89 + VDSO_CFLAGS += -O2 + # Some useful compiler-dependent flags from top-level Makefile +--- a/scripts/mod/modpost.c ++++ b/scripts/mod/modpost.c +@@ -844,8 +844,10 @@ static int match(const char *sym, const + { + const char *p; + while (*pat) { ++ const char *endp; ++ + p = *pat++; +- const char *endp = p + strlen(p) - 1; ++ endp = p + strlen(p) - 1; + + /* "*foo*" */ + if (*p == '*' && *endp == '*') { diff --git a/target/linux/generic/backport-5.10/005-v5.17-02-Kbuild-move-to-std-gnu11.patch b/target/linux/generic/backport-5.10/005-v5.17-02-Kbuild-move-to-std-gnu11.patch new file mode 100644 index 0000000000000..7938fe502696d --- /dev/null +++ b/target/linux/generic/backport-5.10/005-v5.17-02-Kbuild-move-to-std-gnu11.patch @@ -0,0 +1,60 @@ +From b810c8e719ea082e47c7a8f7cf878bc84fa2455d Mon Sep 17 00:00:00 2001 +From: Arnd Bergmann +Date: Tue, 8 Mar 2022 22:56:14 +0100 +Subject: [PATCH 2/3] Kbuild: move to -std=gnu11 + +During a patch discussion, Linus brought up the option of changing +the C standard version from gnu89 to gnu99, which allows using variable +declaration inside of a for() loop. While the C99, C11 and later standards +introduce many other features, most of these are already available in +gnu89 as GNU extensions as well. + +An earlier attempt to do this when gcc-5 started defaulting to +-std=gnu11 failed because at the time that caused warnings about +designated initializers with older compilers. Now that gcc-5.1 is +the minimum compiler version used for building kernels, that is no +longer a concern. Similarly, the behavior of 'inline' functions changes +between gnu89 using gnu_inline behavior and gnu11 using standard c99+ +behavior, but this was taken care of by defining 'inline' to include +__attribute__((gnu_inline)) in order to allow building with clang a +while ago. + +Nathan Chancellor reported a new -Wdeclaration-after-statement +warning that appears in a system header on arm, this still needs a +workaround. + +The differences between gnu99, gnu11, gnu1x and gnu17 are fairly +minimal and mainly impact warnings at the -Wpedantic level that the +kernel never enables. Between these, gnu11 is the newest version +that is supported by all supported compiler versions, though it is +only the default on gcc-5, while all other supported versions of +gcc or clang default to gnu1x/gnu17. + +Link: https://lore.kernel.org/lkml/CAHk-=wiyCH7xeHcmiFJ-YgXUy2Jaj7pnkdKpcovt8fYbVFW3TA@mail.gmail.com/ +Link: https://github.com/ClangBuiltLinux/linux/issues/1603 +Suggested-by: Linus Torvalds +Acked-by: Marco Elver +Acked-by: Jani Nikula +Acked-by: David Sterba +Tested-by: Sedat Dilek +Reviewed-by: Alex Shi +Reviewed-by: Nick Desaulniers +Reviewed-by: Miguel Ojeda +Signed-off-by: Arnd Bergmann +Reviewed-by: Nathan Chancellor +Signed-off-by: Masahiro Yamada +--- + Makefile | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/Makefile ++++ b/Makefile +@@ -498,7 +498,7 @@ KBUILD_CFLAGS := -Wall -Wundef -Werror + -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE \ + -Werror=implicit-function-declaration -Werror=implicit-int \ + -Werror=return-type -Wno-format-security \ +- -std=gnu89 ++ -std=gnu11 + KBUILD_CPPFLAGS := -D__KERNEL__ + KBUILD_AFLAGS_KERNEL := + KBUILD_CFLAGS_KERNEL := diff --git a/target/linux/generic/backport-5.10/005-v5.17-03-Kbuild-use-std-gnu11-for-KBUILD_USERCFLAGS.patch b/target/linux/generic/backport-5.10/005-v5.17-03-Kbuild-use-std-gnu11-for-KBUILD_USERCFLAGS.patch new file mode 100644 index 0000000000000..34b5b653ae189 --- /dev/null +++ b/target/linux/generic/backport-5.10/005-v5.17-03-Kbuild-use-std-gnu11-for-KBUILD_USERCFLAGS.patch @@ -0,0 +1,42 @@ +From 40337d6f3d677aee7ad3052ae662d3f53dd4d5cb Mon Sep 17 00:00:00 2001 +From: Arnd Bergmann +Date: Tue, 8 Mar 2022 22:56:15 +0100 +Subject: [PATCH 3/3] Kbuild: use -std=gnu11 for KBUILD_USERCFLAGS + +As we change the C language standard for the kernel from gnu89 to +gnu11, it makes sense to also update the version for user space +compilation. + +Some users have older native compilers than what they use for +kernel builds, so I considered using gnu99 as the default version +for wider compatibility with gcc-4.6 and earlier. + +However, testing with older compilers showed that we already require +HOSTCC version 5.1 as well because a lot of host tools include +linux/compiler.h that uses __has_attribute(): + + CC tools/objtool/exec-cmd.o +In file included from tools/include/linux/compiler_types.h:36:0, + from tools/include/linux/compiler.h:5, + from exec-cmd.c:2: +tools/include/linux/compiler-gcc.h:19:5: error: "__has_attribute" is not defined [-Werror=undef] + +Signed-off-by: Arnd Bergmann +Reviewed-by: Nathan Chancellor +Reviewed-by: Nick Desaulniers +Tested-by: Sedat Dilek +Signed-off-by: Masahiro Yamada +--- + Makefile | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/Makefile ++++ b/Makefile +@@ -416,7 +416,7 @@ HOSTCXX = g++ + endif + + export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ +- -O2 -fomit-frame-pointer -std=gnu89 \ ++ -O2 -fomit-frame-pointer -std=gnu11 \ + -Wdeclaration-after-statement + export KBUILD_USERLDFLAGS := diff --git a/target/linux/generic/backport-5.15/005-v5.17-01-Kbuild-use-Wdeclaration-after-statement.patch b/target/linux/generic/backport-5.15/005-v5.17-01-Kbuild-use-Wdeclaration-after-statement.patch new file mode 100644 index 0000000000000..141a7a18c5c5e --- /dev/null +++ b/target/linux/generic/backport-5.15/005-v5.17-01-Kbuild-use-Wdeclaration-after-statement.patch @@ -0,0 +1,81 @@ +From 2fd7e7f9317d3048a14026816d081b08ba98ea8e Mon Sep 17 00:00:00 2001 +From: Mark Rutland +Date: Tue, 8 Mar 2022 22:56:13 +0100 +Subject: [PATCH 1/3] Kbuild: use -Wdeclaration-after-statement + +The kernel is moving from using `-std=gnu89` to `-std=gnu11`, permitting +the use of additional C11 features such as for-loop initial declarations. + +One contentious aspect of C99 is that it permits mixed declarations and +code, and for now at least, it seems preferable to enforce that +declarations must come first. + +These warnings were already enabled in the kernel itself, but not +for KBUILD_USERCFLAGS or the compat VDSO on arch/arm64, which uses +a separate set of CFLAGS. + +This patch fixes an existing violation in modpost.c, which is not +reported because of the missing flag in KBUILD_USERCFLAGS: + +| scripts/mod/modpost.c: In function ‘match’: +| scripts/mod/modpost.c:837:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] +| 837 | const char *endp = p + strlen(p) - 1; +| | ^~~~~ + +Signed-off-by: Mark Rutland +[arnd: don't add a duplicate flag to the default set, update changelog] +Signed-off-by: Arnd Bergmann +Reviewed-by: Nathan Chancellor +Reviewed-by: Nick Desaulniers +Tested-by: Sedat Dilek # LLVM/Clang v13.0.0 (x86-64) +Signed-off-by: Masahiro Yamada +--- + Makefile | 3 ++- + arch/arm64/kernel/vdso32/Makefile | 1 + + scripts/mod/modpost.c | 4 +++- + 3 files changed, 6 insertions(+), 2 deletions(-) + +diff --git a/Makefile b/Makefile +index b9e0b5c604af..cfe400032f96 100644 +--- a/Makefile ++++ b/Makefile +@@ -416,7 +416,8 @@ HOSTCXX = g++ + endif + + export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ +- -O2 -fomit-frame-pointer -std=gnu89 ++ -O2 -fomit-frame-pointer -std=gnu89 \ ++ -Wdeclaration-after-statement + export KBUILD_USERLDFLAGS := + + KBUILD_HOSTCFLAGS := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS) +diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile +index abad38c576e1..33cd7ed3f94f 100644 +--- a/arch/arm64/kernel/vdso32/Makefile ++++ b/arch/arm64/kernel/vdso32/Makefile +@@ -76,6 +76,7 @@ VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ + -fno-strict-aliasing -fno-common \ + -Werror-implicit-function-declaration \ + -Wno-format-security \ ++ -Wdeclaration-after-statement \ + -std=gnu89 + VDSO_CFLAGS += -O2 + # Some useful compiler-dependent flags from top-level Makefile +diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c +index 3c27a177b28b..d2b17ed27e6e 100644 +--- a/scripts/mod/modpost.c ++++ b/scripts/mod/modpost.c +@@ -844,8 +844,10 @@ static int match(const char *sym, const char * const pat[]) + { + const char *p; + while (*pat) { ++ const char *endp; ++ + p = *pat++; +- const char *endp = p + strlen(p) - 1; ++ endp = p + strlen(p) - 1; + + /* "*foo*" */ + if (*p == '*' && *endp == '*') { +-- +2.37.2 diff --git a/target/linux/generic/backport-5.15/005-v5.17-02-Kbuild-move-to-std-gnu11.patch b/target/linux/generic/backport-5.15/005-v5.17-02-Kbuild-move-to-std-gnu11.patch new file mode 100644 index 0000000000000..79bda0cd7e3ed --- /dev/null +++ b/target/linux/generic/backport-5.15/005-v5.17-02-Kbuild-move-to-std-gnu11.patch @@ -0,0 +1,64 @@ +From b810c8e719ea082e47c7a8f7cf878bc84fa2455d Mon Sep 17 00:00:00 2001 +From: Arnd Bergmann +Date: Tue, 8 Mar 2022 22:56:14 +0100 +Subject: [PATCH 2/3] Kbuild: move to -std=gnu11 + +During a patch discussion, Linus brought up the option of changing +the C standard version from gnu89 to gnu99, which allows using variable +declaration inside of a for() loop. While the C99, C11 and later standards +introduce many other features, most of these are already available in +gnu89 as GNU extensions as well. + +An earlier attempt to do this when gcc-5 started defaulting to +-std=gnu11 failed because at the time that caused warnings about +designated initializers with older compilers. Now that gcc-5.1 is +the minimum compiler version used for building kernels, that is no +longer a concern. Similarly, the behavior of 'inline' functions changes +between gnu89 using gnu_inline behavior and gnu11 using standard c99+ +behavior, but this was taken care of by defining 'inline' to include +__attribute__((gnu_inline)) in order to allow building with clang a +while ago. + +Nathan Chancellor reported a new -Wdeclaration-after-statement +warning that appears in a system header on arm, this still needs a +workaround. + +The differences between gnu99, gnu11, gnu1x and gnu17 are fairly +minimal and mainly impact warnings at the -Wpedantic level that the +kernel never enables. Between these, gnu11 is the newest version +that is supported by all supported compiler versions, though it is +only the default on gcc-5, while all other supported versions of +gcc or clang default to gnu1x/gnu17. + +Link: https://lore.kernel.org/lkml/CAHk-=wiyCH7xeHcmiFJ-YgXUy2Jaj7pnkdKpcovt8fYbVFW3TA@mail.gmail.com/ +Link: https://github.com/ClangBuiltLinux/linux/issues/1603 +Suggested-by: Linus Torvalds +Acked-by: Marco Elver +Acked-by: Jani Nikula +Acked-by: David Sterba +Tested-by: Sedat Dilek +Reviewed-by: Alex Shi +Reviewed-by: Nick Desaulniers +Reviewed-by: Miguel Ojeda +Signed-off-by: Arnd Bergmann +Reviewed-by: Nathan Chancellor +Signed-off-by: Masahiro Yamada +--- + Makefile | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/Makefile b/Makefile +index cfe400032f96..fe86758acaaa 100644 +--- a/Makefile ++++ b/Makefile +@@ -498,7 +498,7 @@ KBUILD_CFLAGS := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \ + -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE \ + -Werror=implicit-function-declaration -Werror=implicit-int \ + -Werror=return-type -Wno-format-security \ +- -std=gnu89 ++ -std=gnu11 + KBUILD_CPPFLAGS := -D__KERNEL__ + KBUILD_AFLAGS_KERNEL := + KBUILD_CFLAGS_KERNEL := +-- +2.37.2 diff --git a/target/linux/generic/backport-5.15/005-v5.17-03-Kbuild-use-std-gnu11-for-KBUILD_USERCFLAGS.patch b/target/linux/generic/backport-5.15/005-v5.17-03-Kbuild-use-std-gnu11-for-KBUILD_USERCFLAGS.patch new file mode 100644 index 0000000000000..f60daa3800959 --- /dev/null +++ b/target/linux/generic/backport-5.15/005-v5.17-03-Kbuild-use-std-gnu11-for-KBUILD_USERCFLAGS.patch @@ -0,0 +1,47 @@ +From 40337d6f3d677aee7ad3052ae662d3f53dd4d5cb Mon Sep 17 00:00:00 2001 +From: Arnd Bergmann +Date: Tue, 8 Mar 2022 22:56:15 +0100 +Subject: [PATCH 3/3] Kbuild: use -std=gnu11 for KBUILD_USERCFLAGS + +As we change the C language standard for the kernel from gnu89 to +gnu11, it makes sense to also update the version for user space +compilation. + +Some users have older native compilers than what they use for +kernel builds, so I considered using gnu99 as the default version +for wider compatibility with gcc-4.6 and earlier. + +However, testing with older compilers showed that we already require +HOSTCC version 5.1 as well because a lot of host tools include +linux/compiler.h that uses __has_attribute(): + + CC tools/objtool/exec-cmd.o +In file included from tools/include/linux/compiler_types.h:36:0, + from tools/include/linux/compiler.h:5, + from exec-cmd.c:2: +tools/include/linux/compiler-gcc.h:19:5: error: "__has_attribute" is not defined [-Werror=undef] + +Signed-off-by: Arnd Bergmann +Reviewed-by: Nathan Chancellor +Reviewed-by: Nick Desaulniers +Tested-by: Sedat Dilek +Signed-off-by: Masahiro Yamada +--- + Makefile | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/Makefile b/Makefile +index fe86758acaaa..e569fccfb009 100644 +--- a/Makefile ++++ b/Makefile +@@ -416,7 +416,7 @@ HOSTCXX = g++ + endif + + export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ +- -O2 -fomit-frame-pointer -std=gnu89 \ ++ -O2 -fomit-frame-pointer -std=gnu11 \ + -Wdeclaration-after-statement + export KBUILD_USERLDFLAGS := + +-- +2.37.2