lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 10 Nov 2017 08:19:38 +0100 From: Takashi Iwai <tiwai@...e.de> To: Arnd Bergmann <arnd@...db.de> Cc: Baolin Wang <baolin.wang@...aro.org>, Jaroslav Kysela <perex@...ex.cz>, Fabian Frederick <fabf@...net.be>, Arvind Yadav <arvind.yadav.cs@...il.com>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, alsa-devel@...a-project.org, Vinod Koul <vinod.koul@...el.com>, hardik.t.shah@...el.com, guneshwor.o.singh@...el.com, Liam Girdwood <lgirdwood@...il.com>, SF Markus Elfring <elfring@...rs.sourceforge.net>, gudishax.kranthikumar@...el.com, Mark Brown <broonie@...nel.org>, Bhumika Goyal <bhumirks@...il.com>, Naveen M <naveen.m@...el.com>, jeeja.kp@...el.com, Takashi Sakamoto <o-takashi@...amocchi.jp>, subhransu.s.prusty@...el.com, Ingo Molnar <mingo@...nel.org>, Dan Carpenter <dan.carpenter@...cle.com> Subject: Re: [alsa-devel] [RFC PATCH v2 7/7] sound: core: Avoid using timespec for struct snd_timer_tread On Fri, 10 Nov 2017 00:20:10 +0100, Arnd Bergmann wrote: > > On Thu, Nov 9, 2017 at 7:11 PM, Takashi Iwai <tiwai@...e.de> wrote: > > On Thu, 09 Nov 2017 18:01:47 +0100, > > Arnd Bergmann wrote: > >> > >> On Thu, Nov 9, 2017 at 5:52 PM, Takashi Iwai <tiwai@...e.de> wrote: > >> > > >> > IOW, is there any macro indicating the 64bit user time_t? > >> > >> There is a macro defined by the C library, but so far we have not > >> started relying on it in kernel headers, because there is no guarantee > >> that this symbol is visible before sys/time.h has been included, > >> and there are some cases where it's possible to include a kernel > >> header before sys/time.h. > >> > >> In case of sound/asound.h, that should be no problem since we rely > >> on having seen the definition on 'struct timeval' already today, and > >> that must come from sys/time.h. Then we just need to make sure that > >> all C libraries define the same macro. > >> > >> Are you sure about the switch()/case problem? I thought that worked > >> in C99, the only problem would be using the macro outside of a > >> function, e.g. as initalizer for a variable > > > > Hmm, OK it seems working. > > > > But, honestly speaking, it's too scaring. I'm OK if it were only in > > the kernel local code. But it's the API/ABI definition, which is > > referred by user-space... > > > > A more solid condition would be really appreciated. > > I understand your concern here and agree it's really ugly. It did take us > many attempts to come up with this trick for other cases, so my initial > reaction would be to use the same thing everywhere since I know > it works, but we can use #ifdef instead if you prefer that. I think we > can use a single #ifdef variant to cover all cases, but I'd have to think > about the x32 and x86-32 some more here. With this trick, we can > make user space with new glibc use data structures that are compatible > with 64-bit kernels and avoid the additional translation helpers: > > enum { > SNDRV_PCM_MMAP_OFFSET_DATA = 0x00000000, > SNDRV_PCM_MMAP_OFFSET_CONTROL = 0x81000000, > #if (__BITS_PER_LONG == 64) || !defined(__USE_TIME_BITS64) Yeah, it's definitely better, more understandable! thanks, Takashi
Powered by blists - more mailing lists