mbox series

[v3,0/2] Unify uapi bitsperlong.h

Message ID 1687443219-11946-1-git-send-email-yangtiezhu@loongson.cn
Headers
Series Unify uapi bitsperlong.h |

Message

Tiezhu Yang June 22, 2023, 2:13 p.m. UTC 
  v3:
  -- Check the definition of __BITS_PER_LONG first at
     the beginning of uapi/asm-generic/bitsperlong.h

v2:
  -- Check __CHAR_BIT__ and __SIZEOF_LONG__ rather than
     __aarch64__, __riscv, __loongarch__, thanks Ruoyao
  -- Update the code comment and commit message

v1:
  -- Rebase on 6.4-rc6
  -- Only unify uapi bitsperlong.h for arm64, riscv and loongarch
  -- Remove uapi bitsperlong.h of hexagon and microblaze in a new patch

Here is the RFC patch:
https://lore.kernel.org/linux-arch/1683615903-10862-1-git-send-email-yangtiezhu@loongson.cn/

Tiezhu Yang (2):
  asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch
  tools arch: Remove uapi bitsperlong.h of hexagon and microblaze

 arch/arm64/include/uapi/asm/bitsperlong.h          | 24 -------------------
 arch/loongarch/include/uapi/asm/bitsperlong.h      |  9 --------
 arch/riscv/include/uapi/asm/bitsperlong.h          | 14 -----------
 include/uapi/asm-generic/bitsperlong.h             | 13 ++++++++++-
 tools/arch/arm64/include/uapi/asm/bitsperlong.h    | 24 -------------------
 tools/arch/hexagon/include/uapi/asm/bitsperlong.h  | 27 ----------------------
 .../arch/loongarch/include/uapi/asm/bitsperlong.h  |  9 --------
 .../arch/microblaze/include/uapi/asm/bitsperlong.h |  2 --
 tools/arch/riscv/include/uapi/asm/bitsperlong.h    | 14 -----------
 tools/include/uapi/asm-generic/bitsperlong.h       | 14 ++++++++++-
 tools/include/uapi/asm/bitsperlong.h               |  6 -----
 11 files changed, 25 insertions(+), 131 deletions(-)
 delete mode 100644 arch/arm64/include/uapi/asm/bitsperlong.h
 delete mode 100644 arch/loongarch/include/uapi/asm/bitsperlong.h
 delete mode 100644 arch/riscv/include/uapi/asm/bitsperlong.h
 delete mode 100644 tools/arch/arm64/include/uapi/asm/bitsperlong.h
 delete mode 100644 tools/arch/hexagon/include/uapi/asm/bitsperlong.h
 delete mode 100644 tools/arch/loongarch/include/uapi/asm/bitsperlong.h
 delete mode 100644 tools/arch/microblaze/include/uapi/asm/bitsperlong.h
 delete mode 100644 tools/arch/riscv/include/uapi/asm/bitsperlong.h

Comments

Arnd Bergmann June 22, 2023, 3:09 p.m. UTC | #1 
On Thu, Jun 22, 2023, at 16:13, Tiezhu Yang wrote:
> v3:
>   -- Check the definition of __BITS_PER_LONG first at
>      the beginning of uapi/asm-generic/bitsperlong.h
>
> v2:
>   -- Check __CHAR_BIT__ and __SIZEOF_LONG__ rather than
>      __aarch64__, __riscv, __loongarch__, thanks Ruoyao
>   -- Update the code comment and commit message
>
> v1:
>   -- Rebase on 6.4-rc6
>   -- Only unify uapi bitsperlong.h for arm64, riscv and loongarch
>   -- Remove uapi bitsperlong.h of hexagon and microblaze in a new patch
>
> Here is the RFC patch:
> https://lore.kernel.org/linux-arch/1683615903-10862-1-git-send-email-yangtiezhu@loongson.cn/

I've applied these to the asm-generic tree now

Thanks,

   Arnd
Ian Rogers July 14, 2023, 6:34 p.m. UTC | #2 
On Thu, Jun 22, 2023 at 8:10 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Thu, Jun 22, 2023, at 16:13, Tiezhu Yang wrote:
> > v3:
> >   -- Check the definition of __BITS_PER_LONG first at
> >      the beginning of uapi/asm-generic/bitsperlong.h
> >

Thanks for doing this cleanup! I just wanted to report an issue I ran
into with building the Linux perf tool. The header guard in:
tools/include/asm-generic/bitsperlong.h
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/include/asm-generic/bitsperlong.h

Caused an issue with building:
tools/perf/util/cs-etm.c
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/util/cs-etm.c

The issue was that cs-etm.c would #include a system header, which
would transitively include a header with the same header guard. This
led to the tools/include/asm-generic/bitsperlong.h being ignored and
the compilation of tools/perf/util/cs-etm.c failing due to a missing
define. My local workaround is:

```
diff --git a/tools/include/asm-generic/bitsperlong.h
b/tools/include/asm-generic/bitsperlong.h
index 2093d56ddd11..88508a35cb45 100644
--- a/tools/include/asm-generic/bitsperlong.h
+++ b/tools/include/asm-generic/bitsperlong.h
@@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __ASM_GENERIC_BITS_PER_LONG
-#define __ASM_GENERIC_BITS_PER_LONG
+#ifndef __LINUX_TOOLS_ASM_GENERIC_BITS_PER_LONG
+#define __LINUX_TOOLS_ASM_GENERIC_BITS_PER_LONG
#include <uapi/asm-generic/bitsperlong.h>
@@ -21,4 +21,4 @@
#define small_const_nbits(nbits) \
(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0)
-#endif /* __ASM_GENERIC_BITS_PER_LONG */
+#endif /* __LINUX_TOOLS_ASM_GENERIC_BITS_PER_LONG */
```

I'm not sure if a wider fix is necessary for this, but I thought it
worthwhile to report that there are potential issues. I don't think we
can use #pragma once, as an alternative to header guards, to avoid
this kind of name collision.

Thanks,
Ian


> > v2:
> >   -- Check __CHAR_BIT__ and __SIZEOF_LONG__ rather than
> >      __aarch64__, __riscv, __loongarch__, thanks Ruoyao
> >   -- Update the code comment and commit message
> >
> > v1:
> >   -- Rebase on 6.4-rc6
> >   -- Only unify uapi bitsperlong.h for arm64, riscv and loongarch
> >   -- Remove uapi bitsperlong.h of hexagon and microblaze in a new patch
> >
> > Here is the RFC patch:
> > https://lore.kernel.org/linux-arch/1683615903-10862-1-git-send-email-yangtiezhu@loongson.cn/
>
> I've applied these to the asm-generic tree now
>
> Thanks,
>
>    Arnd
Arnd Bergmann July 14, 2023, 7:56 p.m. UTC | #3 
On Fri, Jul 14, 2023, at 20:34, Ian Rogers wrote:
> On Thu, Jun 22, 2023 at 8:10 AM Arnd Bergmann <arnd@arndb.de> wrote:
>>
>> On Thu, Jun 22, 2023, at 16:13, Tiezhu Yang wrote:
>> > v3:
>> >   -- Check the definition of __BITS_PER_LONG first at
>> >      the beginning of uapi/asm-generic/bitsperlong.h
>> >
>
> Thanks for doing this cleanup! I just wanted to report an issue I ran
> into with building the Linux perf tool. The header guard in:
> tools/include/asm-generic/bitsperlong.h
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/include/asm-generic/bitsperlong.h
>
> Caused an issue with building:
> tools/perf/util/cs-etm.c
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/util/cs-etm.c
>
> The issue was that cs-etm.c would #include a system header, which
> would transitively include a header with the same header guard. This
> led to the tools/include/asm-generic/bitsperlong.h being ignored and
> the compilation of tools/perf/util/cs-etm.c failing due to a missing
> define. My local workaround is:
>
> ```
> diff --git a/tools/include/asm-generic/bitsperlong.h
> b/tools/include/asm-generic/bitsperlong.h
> index 2093d56ddd11..88508a35cb45 100644
> --- a/tools/include/asm-generic/bitsperlong.h
> +++ b/tools/include/asm-generic/bitsperlong.h
> @@ -1,6 +1,6 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> -#ifndef __ASM_GENERIC_BITS_PER_LONG
> -#define __ASM_GENERIC_BITS_PER_LONG
> +#ifndef __LINUX_TOOLS_ASM_GENERIC_BITS_PER_LONG
> +#define __LINUX_TOOLS_ASM_GENERIC_BITS_PER_LONG
> #include <uapi/asm-generic/bitsperlong.h>
> @@ -21,4 +21,4 @@
> #define small_const_nbits(nbits) \
> (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0)
> -#endif /* __ASM_GENERIC_BITS_PER_LONG */
> +#endif /* __LINUX_TOOLS_ASM_GENERIC_BITS_PER_LONG */
> ```
>
> I'm not sure if a wider fix is necessary for this, but I thought it
> worthwhile to report that there are potential issues. I don't think we
> can use #pragma once, as an alternative to header guards, to avoid
> this kind of name collision.

Thanks for the report! I think the correct fix is to update
the tools/include/ headers to have the same change as the kernel
itself. I don't know why we end up including both, that sounds
like a separate issue but should normally be harmless as long
as the contents are the same.

      Arnd