linux-kernel - Re: [PATCH]gx-suspmod.c use boot_cpu_data instead of current_cpu

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <a11ccc30707260055y46438459gd618265a4df02ff3@mail.gmail.com>
Date:	Thu, 26 Jul 2007 16:55:59 +0900
From:	"Hiroshi Miura" <miura@...cha.org>
To:	"Andrew Morton" <akpm@...ux-foundation.org>
Cc:	"Dave Young" <hidave.darkstar@...il.com>,
	"Dave Jones" <davej@...emonkey.org.uk>,
	linux-kernel@...r.kernel.org, cpufreq@....linux.org.uk
Subject: Re: [PATCH]gx-suspmod.c use boot_cpu_data instead of current_cpu_data

2007/7/25, Andrew Morton <akpm@...ux-foundation.org>:
> On Wed, 25 Jul 2007 14:19:05 +0000 Dave Young <hidave.darkstar@...il.com> wrote:
>
> > Hi,
> > in preemptible kernel will report BUG: using smp_processor_id() in preemptible, so use boot_cpu_data instead of current_cpu_data.
> >
> > Signed-off-by: Dave Young <hidave.darkstar@...il.com>
> >
> > ---
> > arch/i386/kernel/cpu/cpufreq/gx-suspmod.c |    4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff -pur linux/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c linux.new/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c
> > --- linux/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c   2007-07-25 14:11:06.000000000 +0000
> > +++ linux.new/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c       2007-07-25 13:57:29.000000000 +0000
> > @@ -181,8 +181,8 @@ static __init struct pci_dev *gx_detect_
> >       struct pci_dev *gx_pci = NULL;
> >
> >       /* check if CPU is a MediaGX or a Geode. */
> > -     if ((current_cpu_data.x86_vendor != X86_VENDOR_NSC) &&
> > -         (current_cpu_data.x86_vendor != X86_VENDOR_CYRIX)) {
> > +     if ((boot_cpu_data.x86_vendor != X86_VENDOR_NSC) &&
> > +         (boot_cpu_data.x86_vendor != X86_VENDOR_CYRIX)) {
> >               dprintk("error: no MediaGX/Geode processor found!\n");
> >               return NULL;
> >       }
>
> um, I suspect it really wants to get at the current CPU.  But putting a
> preempt_disable() around just that code is meaningless: the current CPU
> could change immediately before or after the code block. It needs deeper
> fixing, methinks.

I think we can  remove these part. It checks chipset 's pci id
(vendor id/device id) after this part as follows;

        /* detect which companion chip is used */
        while ((gx_pci = pci_get_device(PCI_ANY_ID, PCI_ANY_ID,
gx_pci)) != NULL) {
                if ((pci_match_id(gx_chipset_tbl, gx_pci)) != NULL)
                        return gx_pci;
        }

It drives cpu frequency  through chipset register, not CPU regsiter.
It may be enough to check chipset pci id.

Hiroshi

-- 
HIroshi Miura
NTT DATA Corp. and IPA OSS center
miura@...cha.org
（株）NTTデータ /（独）情報処理推進機構
三浦広志
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/