From: Guenter Roeck <linux@roeck-us.net>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Richard Henderson <rth@twiddle.net>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matt Turner <mattst88@gmail.com>,
"James E . J . Bottomley" <James.Bottomley@hansenpartnership.com>,
Helge Deller <deller@gmx.de>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
alpha <linux-alpha@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Parisc List <linux-parisc@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
linux-sparse@vger.kernel.org
Subject: Re: [PATCH v2 1/4] compiler.h: Introduce absolute_pointer macro
Date: Wed, 15 Sep 2021 07:03:26 -0700 [thread overview]
Message-ID: <ab67dccf-cf29-523d-3cf7-7554c493dcd1@roeck-us.net> (raw)
In-Reply-To: <CAMuHMdXZcrjGAE5OOipKsYpEgk9AZ_hrWKh+v81FMBtQTBv2LA@mail.gmail.com>
On 9/15/21 12:13 AM, Geert Uytterhoeven wrote:
> Hi Günter,
>
> On Wed, Sep 15, 2021 at 5:52 AM Guenter Roeck <linux@roeck-us.net> wrote:
>> absolute_pointer() disassociates a pointer from its originating symbol
>> type and context. Use it to prevent compiler warnings/errors such as
>>
>> drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe':
>> ./arch/m68k/include/asm/string.h:72:25: error:
>> '__builtin_memcpy' reading 6 bytes from a region of size 0
>> [-Werror=stringop-overread]
>>
>> Such warnings may be reported by gcc 11.x for string and memory operations
>> on fixed addresses.
>>
>> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> ---
>> v2: No change
>>
>> include/linux/compiler.h | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
>> index b67261a1e3e9..3d5af56337bd 100644
>> --- a/include/linux/compiler.h
>> +++ b/include/linux/compiler.h
>> @@ -188,6 +188,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
>> (typeof(ptr)) (__ptr + (off)); })
>> #endif
>>
>> +#define absolute_pointer(val) RELOC_HIDE((void *)(val), 0)
>
> I guess we're not worried about "val" being evaluated multiple
> times inside RELOC_HIDE(), as this is mainly intended for constants?
>
No, we are not. It is quite similar to RELOC_HIDE() in that regard.
Guenter
next prev parent reply other threads:[~2021-09-15 14:03 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-15 3:52 [PATCH v2 0/4] Introduce and use absolute_pointer macro Guenter Roeck
2021-09-15 3:52 ` [PATCH v2 1/4] compiler.h: Introduce " Guenter Roeck
2021-09-15 7:07 ` Geert Uytterhoeven
2021-09-15 7:13 ` Geert Uytterhoeven
2021-09-15 14:03 ` Guenter Roeck [this message]
2021-09-15 3:52 ` [PATCH v2 2/4] net: i825xx: Use absolute_pointer for memcpy from fixed memory location Guenter Roeck
2021-09-15 7:08 ` Geert Uytterhoeven
2021-09-15 3:52 ` [PATCH v2 3/4] alpha: Move setup.h out of uapi Guenter Roeck
2021-09-15 3:52 ` [PATCH v2 4/4] alpha: Use absolute_pointer to define COMMAND_LINE Guenter Roeck
2021-09-15 19:18 ` [PATCH v2 0/4] Introduce and use absolute_pointer macro Linus Torvalds
2021-09-15 19:35 ` Guenter Roeck
2021-09-15 19:47 ` Linus Torvalds
2021-09-15 19:50 ` Linus Torvalds
2021-09-15 21:19 ` Linus Torvalds
2021-09-16 7:02 ` Anders Larsen
2021-09-16 16:25 ` Linus Torvalds
2021-09-15 20:30 ` Helge Deller
2021-09-15 22:33 ` Guenter Roeck
2021-09-16 18:35 ` Linus Torvalds
2021-09-18 9:51 ` Michael Cree
2021-09-18 13:11 ` Ulrich Teichert
2021-09-18 17:04 ` Linus Torvalds
2021-09-18 17:17 ` Thorsten Glaser
2021-09-18 17:21 ` Linus Torvalds
2021-09-18 17:28 ` Linus Torvalds
2021-09-18 20:26 ` Ulrich Teichert
2021-09-18 20:46 ` Linus Torvalds
2021-09-18 21:12 ` Linus Torvalds
2021-09-18 22:09 ` Linus Torvalds
2021-09-19 15:13 ` Dave Taht
2021-09-20 18:25 ` Ulrich Teichert
2021-09-20 18:46 ` Linus Torvalds
2021-09-20 18:59 ` Matt Turner
2021-09-20 19:45 ` Linus Torvalds
2021-09-21 19:13 ` Ulrich Teichert
2021-09-21 20:42 ` Linus Torvalds
2021-09-21 21:39 ` Linus Torvalds
2021-09-22 20:50 ` Ulrich Teichert
2021-09-16 19:47 ` Linus Torvalds
2021-09-16 0:34 ` Michael Cree
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