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Date:   Wed, 20 Oct 2021 22:03:19 +0800
From:   Jisheng Zhang <jszhang3@mail.ustc.edu.cn>
To:     kernel test robot <lkp@intel.com>
Cc:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        llvm@lists.linux.dev, kbuild-all@lists.01.org,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-kbuild@vger.kernel.org
Subject: Re: [PATCH 1/2] riscv: consolidate __ex_table construction
Message-ID: <20211020220319.41ad167f@xhacker>
In-Reply-To: <202110180820.HH9NB6vw-lkp@intel.com>
References: <20211017000443.4275747d@xhacker>
        <202110180820.HH9NB6vw-lkp@intel.com>
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On Mon, 18 Oct 2021 08:14:28 +0800
kernel test robot <lkp@intel.com> wrote:

> Hi Jisheng,
> 
> I love your patch! Yet something to improve:
> 
> [auto build test ERROR on linus/master]
> [also build test ERROR on v5.15-rc5 next-20211015]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
> 
> url:    https://github.com/0day-ci/linux/commits/Jisheng-Zhang/riscv-switch-to-relative-extable/20211017-001318
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 8fe31e0995f048d16b378b90926793a0aa4af1e5
> config: riscv-randconfig-r032-20211017 (attached as .config)
> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 746dd6a700931988dd9021d3d04718f1929885a5)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install riscv cross compiling tool for clang build
>         # apt-get install binutils-riscv64-linux-gnu
>         # https://github.com/0day-ci/linux/commit/23c273bf6ec4ca672a21dba701725087208dc784
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Jisheng-Zhang/riscv-switch-to-relative-extable/20211017-001318
>         git checkout 23c273bf6ec4ca672a21dba701725087208dc784
>         # save the attached .config to linux build tree
>         mkdir build_dir
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from kernel/futex.c:36:
>    In file included from include/linux/pagemap.h:11:
>    In file included from include/linux/highmem.h:10:
>    In file included from include/linux/hardirq.h:11:
>    In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:136:
>    include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
>                                                            ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from kernel/futex.c:36:
>    In file included from include/linux/pagemap.h:11:
>    In file included from include/linux/highmem.h:10:
>    In file included from include/linux/hardirq.h:11:
>    In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:136:
>    include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
>                                                            ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from kernel/futex.c:36:
>    In file included from include/linux/pagemap.h:11:
>    In file included from include/linux/highmem.h:10:
>    In file included from include/linux/hardirq.h:11:
>    In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:136:
>    include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^

The warnings like this are not caused by this patch, they existed for a long
time since NOMMU is supported. But no good solution so far.

>    include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
>                                                          ~~~~~~~~~~ ^
>    include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
>                                                          ~~~~~~~~~~ ^
>    include/asm-generic/io.h:1024:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
>                                                      ~~~~~~~~~~ ^
>    In file included from kernel/futex.c:43:
> >> arch/riscv/include/asm/futex.h:51:3: error: expected ')'  
>                    __futex_atomic_op("amoswap.w.aqrl %[ov],%z[op],%[u]",
>                    ^
>    arch/riscv/include/asm/futex.h:33:3: note: expanded from macro '__futex_atomic_op'
>                    _ASM_EXTABLE(1b, 3b)                            \
>                    ^

Errors like this are caused by my patch, I missed NOMMU. Fixed in V2.


Thanks