Re: [Buildroot] [PATCH v3 1/1] configs/rock5b: Add patches to fix gcc12 warnings

["Yann E. MORIN" <yann.morin.1998@free.fr>]

Kilian, All,

On 2023-08-20 21:04 +0200, Kilian Zinnecker via buildroot spake thusly:
> This patch introduces patches for the custom kernel, as it is
> currently used for the Radxa Rock 5B. The patches fix two gcc
> compiler warnings, which result in a build error, if the kernel
> is used with gcc version 12.
> Since also the code of custom board drivers for WiFi support is
> affected, and no fixes are provided by the vendor, the custom WiFi
> support is disabled.
> 
> Signed-off-by: Kilian Zinnecker <kilian.zinnecker@mail.de>

Applied to master, thanks.

Regards,
Yann E. MORIN.

> ---
>  board/radxa/rock5b/linux.fragment             |  3 +
>  ...st-ether_addr-prototypes-to-silence-.patch | 64 +++++++++++++++++++
>  ...x-building-error-on-Werror-array-com.patch | 43 +++++++++++++
>  board/radxa/rock5b/readme.txt                 | 20 ++++++
>  configs/rock5b_defconfig                      |  1 +
>  5 files changed, 131 insertions(+)
>  create mode 100644 board/radxa/rock5b/patches/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch
>  create mode 100644 board/radxa/rock5b/patches/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch
> 
> diff --git a/board/radxa/rock5b/linux.fragment b/board/radxa/rock5b/linux.fragment
> index 811d42a79b..6d65cb7bb8 100644
> --- a/board/radxa/rock5b/linux.fragment
> +++ b/board/radxa/rock5b/linux.fragment
> @@ -1 +1,4 @@
>  CONFIG_R8169=y
> +# Disable Rockchip specific WiFi drivers, as the kernel
> +# code cannot be build with GCC 12 due to several Werrors
> +# CONFIG_WL_ROCKCHIP is not set
> diff --git a/board/radxa/rock5b/patches/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch b/board/radxa/rock5b/patches/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch
> new file mode 100644
> index 0000000000..5632c5a627
> --- /dev/null
> +++ b/board/radxa/rock5b/patches/0001-etherdevice-Adjust-ether_addr-prototypes-to-silence-.patch
> @@ -0,0 +1,64 @@
> +From 2618a0dae09ef37728dab89ff60418cbe25ae6bd Mon Sep 17 00:00:00 2001
> +From: Kees Cook <keescook@chromium.org>
> +Date: Sat, 12 Feb 2022 09:14:49 -0800
> +Subject: etherdevice: Adjust ether_addr* prototypes to silence
> + -Wstringop-overead
> +MIME-Version: 1.0
> +Content-Type: text/plain; charset=UTF-8
> +Content-Transfer-Encoding: 8bit
> +
> +With GCC 12, -Wstringop-overread was warning about an implicit cast from
> +char[6] to char[8]. However, the extra 2 bytes are always thrown away,
> +alignment doesn't matter, and the risk of hitting the edge of unallocated
> +memory has been accepted, so this prototype can just be converted to a
> +regular char *. Silences:
> +
> +net/core/dev.c: In function ‘bpf_prog_run_generic_xdp’: net/core/dev.c:4618:21: warning: ‘ether_addr_equal_64bits’ reading 8 bytes from a region of size 6 [-Wstringop-overread]
> + 4618 |         orig_host = ether_addr_equal_64bits(eth->h_dest, > skb->dev->dev_addr);
> +      |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +net/core/dev.c:4618:21: note: referencing argument 1 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
> +net/core/dev.c:4618:21: note: referencing argument 2 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
> +In file included from net/core/dev.c:91: include/linux/etherdevice.h:375:20: note: in a call to function ‘ether_addr_equal_64bits’
> +  375 | static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
> +      |                    ^~~~~~~~~~~~~~~~~~~~~~~
> +
> +Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
> +Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
> +Link: https://lore.kernel.org/netdev/20220212090811.uuzk6d76agw2vv73@pengutronix.de
> +Cc: Jakub Kicinski <kuba@kernel.org>
> +Cc: "David S. Miller" <davem@davemloft.net>
> +Cc: netdev@vger.kernel.org
> +Signed-off-by: Kees Cook <keescook@chromium.org>
> +Signed-off-by: David S. Miller <davem@davemloft.net>
> +Upstream: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2618a0dae09ef37728dab89ff60418cbe25ae6bd
> +Signed-off-by: Kilian Zinnecker <kilian.zinnecker@mail.de>
> +---
> + include/linux/etherdevice.h | 5 ++---
> + 1 file changed, 2 insertions(+), 3 deletions(-)
> +
> +diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
> +index 2ad71cc90b37d..92b10e67d5f87 100644
> +--- a/include/linux/etherdevice.h
> ++++ b/include/linux/etherdevice.h
> +@@ -134,7 +134,7 @@ static inline bool is_multicast_ether_addr(const u8 *addr)
> + #endif
> + }
> + 
> +-static inline bool is_multicast_ether_addr_64bits(const u8 addr[6+2])
> ++static inline bool is_multicast_ether_addr_64bits(const u8 *addr)
> + {
> + #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
> + #ifdef __BIG_ENDIAN
> +@@ -372,8 +372,7 @@ static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2)
> +  * Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits.
> +  */
> + 
> +-static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
> +-					   const u8 addr2[6+2])
> ++static inline bool ether_addr_equal_64bits(const u8 *addr1, const u8 *addr2)
> + {
> + #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
> + 	u64 fold = (*(const u64 *)addr1) ^ (*(const u64 *)addr2);
> +-- 
> +cgit 
> +
> diff --git a/board/radxa/rock5b/patches/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch b/board/radxa/rock5b/patches/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch
> new file mode 100644
> index 0000000000..10de6c72d3
> --- /dev/null
> +++ b/board/radxa/rock5b/patches/0002-mm-page_alloc-fix-building-error-on-Werror-array-com.patch
> @@ -0,0 +1,43 @@
> +From ca831f29f8f25c97182e726429b38c0802200c8f Mon Sep 17 00:00:00 2001
> +From: Xiongwei Song <sxwjean@gmail.com>
> +Date: Fri, 14 Jan 2022 14:07:24 -0800
> +Subject: mm: page_alloc: fix building error on -Werror=array-compare
> +
> +Arthur Marsh reported we would hit the error below when building kernel
> +with gcc-12:
> +
> +  CC      mm/page_alloc.o
> +  mm/page_alloc.c: In function `mem_init_print_info':
> +  mm/page_alloc.c:8173:27: error: comparison between two arrays [-Werror=array-compare]
> +   8173 |                 if (start <= pos && pos < end && size > adj) \
> +        |
> +
> +In C++20, the comparision between arrays should be warned.
> +
> +Link: https://lkml.kernel.org/r/20211125130928.32465-1-sxwjean@me.com
> +Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
> +Reported-by: Arthur Marsh <arthur.marsh@internode.on.net>
> +Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> +Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> +Upstream: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ca831f29f8f25c97182e726429b38c0802200c8f
> +Signed-off-by: Kilian Zinnecker <kilian.zinnecker@mail.de>
> +---
> + mm/page_alloc.c | 2 +-
> + 1 file changed, 1 insertion(+), 1 deletion(-)
> +
> +diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> +index 806f317c2e7e2..c4ef450ac4428 100644
> +--- a/mm/page_alloc.c
> ++++ b/mm/page_alloc.c
> +@@ -8228,7 +8228,7 @@ void __init mem_init_print_info(void)
> + 	 */
> + #define adj_init_size(start, end, size, pos, adj) \
> + 	do { \
> +-		if (start <= pos && pos < end && size > adj) \
> ++		if (&start[0] <= &pos[0] && &pos[0] < &end[0] && size > adj) \
> + 			size -= adj; \
> + 	} while (0)
> + 
> +-- 
> +cgit 
> +
> diff --git a/board/radxa/rock5b/readme.txt b/board/radxa/rock5b/readme.txt
> index a88b9b46fa..f02f3d380e 100644
> --- a/board/radxa/rock5b/readme.txt
> +++ b/board/radxa/rock5b/readme.txt
> @@ -60,3 +60,23 @@ Enter 'root' as login user, and the prompt is ready.
>  wiki link:
>  ----------
>  https://forum.radxa.com/c/rock5
> +
> +Issues:
> +=======
> +
> +The custom Radxa kernel provides custom code to support WiFi. However,
> +that code does not compile with GCC 12, which is the current default
> +version in buildroot. Hence, the WiFi kernel drivers are disabled, until
> +the issues get fixed (if ever). If they are desperately needed, one may
> +apply the following workaround, as long as buildroot still supports GCC
> +version 11:
> +
> +1. Set GCC version 11, by adding the following line to
> +configs/rock5b_defconfig:
> +
> +BR2_GCC_VERSION_11_X=y
> +
> +2. Re-enable custom WiFi drivers by removing the following line from
> +board/radxa/rock5b/linux.fragment:
> +
> +# CONFIG_WL_ROCKCHIP is not set
> diff --git a/configs/rock5b_defconfig b/configs/rock5b_defconfig
> index 6e525d9676..eed656ef5f 100644
> --- a/configs/rock5b_defconfig
> +++ b/configs/rock5b_defconfig
> @@ -5,6 +5,7 @@ BR2_ROOTFS_POST_IMAGE_SCRIPT="board/radxa/rock5b/post-image.sh"
>  BR2_ROOTFS_POST_SCRIPT_ARGS=""
>  BR2_TARGET_GENERIC_HOSTNAME="rock5b"
>  BR2_TARGET_GENERIC_ISSUE="Welcome to the rock5b board"
> +BR2_GLOBAL_PATCH_DIR="board/radxa/rock5b/patches"
>  BR2_SYSTEM_DHCP="eth0"
>  BR2_LINUX_KERNEL=y
>  BR2_LINUX_KERNEL_CUSTOM_GIT=y
> -- 
> 2.34.1
> 
> _______________________________________________
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> buildroot@buildroot.org
> https://lists.buildroot.org/mailman/listinfo/buildroot

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