Messages in this thread | | | Date | Fri, 11 Jun 2021 20:55:41 -0700 (PDT) | Subject | Re: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used | From | Palmer Dabbelt <> |
| |
On Thu, 03 Jun 2021 03:03:14 PDT (-0700), Damien Le Moal wrote: >> On 2021/06/03 18:35, kernel test robot wrote: >> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >> head: 324c92e5e0ee0e993bdb106fac407846ed677f6b >> commit: c6ca7616f7d5c2ce166280107ba74db1d528fcb7 clk: Add RISC-V Canaan Kendryte K210 clock driver >> date: 3 months ago >> config: riscv-randconfig-r033-20210603 (attached as .config) >> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project d8e0ae9a76a62bdc6117630d59bf9967ac9bb4ea) >> 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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c6ca7616f7d5c2ce166280107ba74db1d528fcb7 >> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >> git fetch --no-tags linus master >> git checkout c6ca7616f7d5c2ce166280107ba74db1d528fcb7 >> # save the attached .config to linux build tree >> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv >> >> If you fix the issue, kindly add following tag as appropriate >> Reported-by: kernel test robot <lkp@intel.com> >> >> All warnings (new ones prefixed by >>): >> >> In file included from drivers/clk/clk-k210.c:8: >> In file included from include/linux/io.h:13: >> In file included from arch/riscv/include/asm/io.h:149: >> include/asm-generic/io.h:556:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] >> return inb(addr); >> ^~~~~~~~~ >> arch/riscv/include/asm/io.h:55:76: note: expanded from macro 'inb' >> #define inb(c) ({ u8 __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) >> ~~~~~~~~~~ ^ >> arch/riscv/include/asm/mmio.h:87:48: note: expanded from macro 'readb_cpu' >> #define readb_cpu(c) ({ u8 __r = __raw_readb(c); __r; }) >> ^ >> In file included from drivers/clk/clk-k210.c:8: >> In file included from include/linux/io.h:13: >> In file included from arch/riscv/include/asm/io.h:149: >> include/asm-generic/io.h:564:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] >> return inw(addr); >> ^~~~~~~~~ >> arch/riscv/include/asm/io.h:56:76: note: expanded from macro 'inw' >> #define inw(c) ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) >> ~~~~~~~~~~ ^ >> arch/riscv/include/asm/mmio.h:88:76: note: expanded from macro 'readw_cpu' >> #define readw_cpu(c) ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; }) >> ^ >> 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 drivers/clk/clk-k210.c:8: >> In file included from include/linux/io.h:13: >> In file included from arch/riscv/include/asm/io.h:149: >> include/asm-generic/io.h:572:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] >> return inl(addr); >> ^~~~~~~~~ >> arch/riscv/include/asm/io.h:57:76: note: expanded from macro 'inl' >> #define inl(c) ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) >> ~~~~~~~~~~ ^ >> arch/riscv/include/asm/mmio.h:89:76: note: expanded from macro 'readl_cpu' >> #define readl_cpu(c) ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; }) >> ^ >> 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 drivers/clk/clk-k210.c:8: >> In file included from include/linux/io.h:13: >> In file included from arch/riscv/include/asm/io.h:149: >> include/asm-generic/io.h:580:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] >> outb(value, addr); >> ^~~~~~~~~~~~~~~~~ >> arch/riscv/include/asm/io.h:59:68: note: expanded from macro 'outb' >> #define outb(v,c) ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) >> ~~~~~~~~~~ ^ >> arch/riscv/include/asm/mmio.h:91:52: note: expanded from macro 'writeb_cpu' >> #define writeb_cpu(v, c) ((void)__raw_writeb((v), (c))) >> ^ >> In file included from drivers/clk/clk-k210.c:8: >> In file included from include/linux/io.h:13: >> In file included from arch/riscv/include/asm/io.h:149: >> include/asm-generic/io.h:588:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] >> outw(value, addr); >> ^~~~~~~~~~~~~~~~~ >> arch/riscv/include/asm/io.h:60:68: note: expanded from macro 'outw' >> #define outw(v,c) ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) >> ~~~~~~~~~~ ^ >> arch/riscv/include/asm/mmio.h:92:76: note: expanded from macro 'writew_cpu' >> #define writew_cpu(v, c) ((void)__raw_writew((__force u16)cpu_to_le16(v), (c))) >> ^ >> In file included from drivers/clk/clk-k210.c:8: >> In file included from include/linux/io.h:13: >> In file included from arch/riscv/include/asm/io.h:149: >> include/asm-generic/io.h:596:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] >> outl(value, addr); >> ^~~~~~~~~~~~~~~~~ >> arch/riscv/include/asm/io.h:61:68: note: expanded from macro 'outl' >> #define outl(v,c) ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) >> ~~~~~~~~~~ ^ >> arch/riscv/include/asm/mmio.h:93:76: note: expanded from macro 'writel_cpu' >> #define writel_cpu(v, c) ((void)__raw_writel((__force u32)cpu_to_le32(v), (c))) >> ^ >> In file included from drivers/clk/clk-k210.c:8: >> In file included from include/linux/io.h:13: >> In file included from arch/riscv/include/asm/io.h:149: >> include/asm-generic/io.h:1005:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] >> return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port; >> ~~~~~~~~~~ ^ >>>> drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used [-Wunused-but-set-variable] >> u32 reg; >> ^ >> 8 warnings generated. >> >> >> vim +/reg +717 drivers/clk/clk-k210.c >> >> 710 >> 711 static int k210_clk_set_parent(struct clk_hw *hw, u8 index) >> 712 { >> 713 struct k210_clk *kclk = to_k210_clk(hw); >> 714 struct k210_sysclk *ksc = kclk->ksc; >> 715 struct k210_clk_cfg *cfg = &k210_clk_cfgs[kclk->id]; >> 716 unsigned long flags; >> > 717 u32 reg; > > Palmer, > > I do not think this driver is the real cause of this error. Did something change > recently with risc-v mmio readl()/writel() ?
I have no idea what's going on here. When I try to re-build that config I don't get any warnings or errors. That said...
>> 718 >> 719 spin_lock_irqsave(&ksc->clk_lock, flags); >> 720 reg = readl(ksc->regs + cfg->mux_reg); >> 721 if (index) >> 722 reg |= BIT(cfg->mux_bit); >> 723 else >> 724 reg &= ~BIT(cfg->mux_bit); >> 725 spin_unlock_irqrestore(&ksc->clk_lock, flags);
Isn't reg unused here? That's one of the warnings.
The void* casting has been there for a while and looks like a real bug, but asm-generic adopted our {in,out}{bwlq} implementation so I'm just going to toss ours. I'm not quite sure why the generic ones aren't doing arithmetic on void*, but I'm not getting warnings.
>> 726 >> 727 return 0; >> 728 } >> 729 >> >> --- >> 0-DAY CI Kernel Test Service, Intel Corporation >> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org >> > > >-- >Damien Le Moal >Western Digital Research >
| |