2021-06-03 09:37:13

by kernel test robot

[permalink] [raw]
Subject: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used

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 <[email protected]>

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;
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);
726
727 return 0;
728 }
729

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]


Attachments:
(No filename) (8.23 kB)
.config.gz (26.22 kB)
Download all attachments

2021-06-03 10:06:49

by Damien Le Moal

[permalink] [raw]
Subject: Re: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used

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 <[email protected]>
>
> 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() ?

> 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);
> 726
> 727 return 0;
> 728 }
> 729
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/[email protected]
>


--
Damien Le Moal
Western Digital Research

2021-06-12 03:57:10

by Palmer Dabbelt

[permalink] [raw]
Subject: Re: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used

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 <[email protected]>
>>
>> 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/[email protected]
>>
>
>
>--
>Damien Le Moal
>Western Digital Research
>

2021-06-12 13:26:54

by Jisheng Zhang

[permalink] [raw]
Subject: Re: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used

On Fri, 11 Jun 2021 20:55:41 -0700 (PDT)
Palmer Dabbelt <[email protected]> wrote:

> 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 <[email protected]>
> >>
> >> 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;

+ Christoph

This warning can only be reproduced with clang + W=1
The problem is that PCI_IOBASE isn't defined for NOMMU, so clang complains
null pointer arithmetic.


> >> ~~~~~~~~~~ ^
> >>>> drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used [-Wunused-but-set-variable]
> >> u32 reg;
> >> ^
> >> 8 warnings generated.

This warning can't be reproduced even with clang + W=1

> >>
> >>
> >> 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/[email protected]
> >>
> >
> >
> >--
> >Damien Le Moal
> >Western Digital Research
> >
>
> _______________________________________________
> linux-riscv mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-riscv


2021-06-14 02:10:38

by Damien Le Moal

[permalink] [raw]
Subject: Re: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used

On 2021/06/12 12:55, Palmer Dabbelt wrote:
> 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 <[email protected]>
>>>
>>> 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.

Yep. I just sent a patch to fix that. The writel() call to update the mux
register was missing (did not notice since the code basically use all default
parents and never change parents).

> The void* casting has been there for a while and looks like a real bug,

Which (void *) cast are you talking about ? The one for the asm generic
definition of PCI_IOBASE ? That one is used in the case of NOMMU build since it
is not defined by arch/riscv for NOMMU builds.

> 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.

I tried to compile the attached config with clang 12 and the compilation even
failed (on a frame buffer driver)... Have not tried W=1 build as Jisheng
mentioned. Anyway, if (void *) arithmetic is a problem with clang, I wonder how
anything can compile at all with it. That is used in a lot of places...

>
>>> 726
>>> 727 return 0;
>>> 728 }
>>> 729
>>>
>>> ---
>>> 0-DAY CI Kernel Test Service, Intel Corporation
>>> https://lists.01.org/hyperkitty/list/[email protected]
>>>
>>
>>
>> --
>> Damien Le Moal
>> Western Digital Research
>>
>


--
Damien Le Moal
Western Digital Research