Linux-csky Archive on lore.kernel.org
 help / color / Atom feed
From: Guo Ren <guoren@kernel.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Anup Patel <anup@brainfault.org>,
	Greentime Hu <greentime.hu@sifive.com>,
	Zong Li <zong.li@sifive.com>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-csky@vger.kernel.org, Guo Ren <guoren@linux.alibaba.com>
Subject: Re: [PATCH] riscv: Fixup compile error BUILD_BUG_ON failed
Date: Sun, 28 Jun 2020 14:12:07 +0800
Message-ID: <CAJF2gTTCHMHp-+RoG8DoDhbJStzmOf5AK=Z3K26FUmd_hbgR=g@mail.gmail.com> (raw)
In-Reply-To: <20200628115945.335b92c517cb8a8fa87be759@kernel.org>

On Sun, Jun 28, 2020 at 10:59 AM Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> On Sat, 27 Jun 2020 16:20:02 +0000
> guoren@kernel.org wrote:
>
> > From: Guo Ren <guoren@linux.alibaba.com>
> >
> > Unfortunately, the current code couldn't be compiled, because
> > BUILD_BUG_ON needs a static defined value, not a dynamic
> > variable with a0 regs. Just use it inline as a solution.
> >
> >   CC      arch/riscv/kernel/patch.o
> > In file included from ./include/linux/kernel.h:11,
> >                  from ./include/linux/list.h:9,
> >                  from ./include/linux/preempt.h:11,
> >                  from ./include/linux/spinlock.h:51,
> >                  from arch/riscv/kernel/patch.c:6:
> > In function ‘fix_to_virt’,
> >     inlined from ‘patch_map’ at arch/riscv/kernel/patch.c:37:17:
> > ./include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_205’ declared with attribute error: BUILD_BUG_ON failed: idx >= __end_of_fixed_addresses
> >   _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> >                                       ^
> > ./include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’
> >     prefix ## suffix();    \
> >     ^~~~~~
> > ./include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’
> >   _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> >   ^~~~~~~~~~~~~~~~~~~
> > ./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
> >  #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
> >                                      ^~~~~~~~~~~~~~~~~~
> > ./include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
> >   BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
> >   ^~~~~~~~~~~~~~~~
> > ./include/asm-generic/fixmap.h:32:2: note: in expansion of macro ‘BUILD_BUG_ON’
> >   BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
> >   ^~~~~~~~~~~~
> >
> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > Cc: Masami Hiramatsu <mhiramat@kernel.org>
> > Cc: Zong Li <zong.li@sifive.com>
> > ---
> >  arch/riscv/kernel/patch.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c
> > index d4a64df..f8e84f2 100644
> > --- a/arch/riscv/kernel/patch.c
> > +++ b/arch/riscv/kernel/patch.c
> > @@ -20,7 +20,7 @@ struct patch_insn {
> >  };
> >
> >  #ifdef CONFIG_MMU
> > -static void *patch_map(void *addr, int fixmap)
> > +static inline void *patch_map(void *addr, int fixmap)
>
> Would we be better to use "__always_inline" as same as fix_to_virt?
Ok

> And also, could you add a comment why we need to make it inline?
I've mentioned in comment:
> > BUILD_BUG_ON needs a static defined value, not a dynamic
> > variable with a0 regs.

idx must be a const unsigned int or it will cause compile error with
BUILD_BUG_ON.

/*
 * 'index to address' translation. If anyone tries to use the idx
 * directly without translation, we catch the bug with a NULL-deference
 * kernel oops. Illegal ranges of incoming indices are caught too.
 */
static __always_inline unsigned long fix_to_virt(const unsigned int idx)
{
        BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
        return __fix_to_virt(idx);
}

-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/

  reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-27 16:20 guoren
2020-06-28  2:59 ` Masami Hiramatsu
2020-06-28  6:12   ` Guo Ren [this message]
2020-06-28 14:52     ` Masami Hiramatsu
2020-06-28 15:58       ` Guo Ren

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAJF2gTTCHMHp-+RoG8DoDhbJStzmOf5AK=Z3K26FUmd_hbgR=g@mail.gmail.com' \
    --to=guoren@kernel.org \
    --cc=anup@brainfault.org \
    --cc=greentime.hu@sifive.com \
    --cc=guoren@linux.alibaba.com \
    --cc=linux-csky@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=mhiramat@kernel.org \
    --cc=palmerdabbelt@google.com \
    --cc=paul.walmsley@sifive.com \
    --cc=zong.li@sifive.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-csky Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-csky/0 linux-csky/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-csky linux-csky/ https://lore.kernel.org/linux-csky \
		linux-csky@vger.kernel.org
	public-inbox-index linux-csky

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-csky


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git