From: Richard Weinberger <richard@nod.at>
To: Borislav Petkov <bp@alien8.de>, Tony Luck <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
elliott@hpe.com, Brian Gerst <brgerst@gmail.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-nvdimm@ml01.01.org, x86@kernel.org
Subject: Re: [PATCH v10 3/4] x86, mce: Add __mcsafe_copy()
Date: Sun, 7 Feb 2016 21:54:06 +0100 [thread overview]
Message-ID: <56B7AEEE.5070504@nod.at> (raw)
In-Reply-To: <20160207165524.GF5862@pd.tnic>
Am 07.02.2016 um 17:55 schrieb Borislav Petkov:
> due to those
>
>> + _ASM_EXTABLE_FAULT(0b,30b)
>> + _ASM_EXTABLE_FAULT(1b,31b)
>> + _ASM_EXTABLE_FAULT(2b,32b)
>> + _ASM_EXTABLE_FAULT(3b,33b)
>> + _ASM_EXTABLE_FAULT(4b,34b)
>
> things below and that's because ex_handler_fault() is defined in
> arch/x86/mm/extable.c and UML doesn't include that file in the build. It
> takes kernel/extable.c and lib/extable.c only.
>
> Richi, what's the usual way to address that in UML? I.e., make an
> x86-only symbol visible to the UML build too? Define a dummy one, just
> so that it builds?
As discussed on IRC with Boris, UML offers only minimal extable support.
To get rid of the said #ifndef, UML would have to provide its own
extable.c (mostly copy&paste from arch/x86) and an advanced
struct exception_table_entry which includes the trap number.
This implies also that UML can no longer use uaccess.h from asm-generic
or has to add a new ifdef into uaccess.h to whiteout the minimal
struct exception_table_entry from there.
So, I'd vote to keep the #ifndef CONFIG_UML in memcpy_64.S.
As soon you need another #ifndef please ping me and I'll happily
bite the bullet and implement the advanced extable stuff for UML.
Deal?
Thanks,
//richard
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next prev parent reply other threads:[~2016-02-07 20:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-04 20:36 [PATCH v10 0/4] Machine check recovery when kernel accesses poison Tony Luck
2015-12-31 19:40 ` [PATCH v10 2/4] x86, mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries Tony Luck
2016-01-08 20:49 ` [PATCH v10 1/4] x86: Expand exception table to allow new handling options Tony Luck
2016-01-08 21:18 ` [PATCH v10 3/4] x86, mce: Add __mcsafe_copy() Tony Luck
2016-02-07 16:49 ` Borislav Petkov
2016-02-09 23:15 ` Luck, Tony
2016-02-10 10:58 ` Borislav Petkov
2016-02-10 19:39 ` Luck, Tony
2016-02-10 20:50 ` Borislav Petkov
2016-02-07 16:55 ` Borislav Petkov
2016-02-07 20:54 ` Richard Weinberger [this message]
2016-01-30 0:00 ` [PATCH v10 4/4] x86: Create a new synthetic cpu capability for machine check recovery Tony Luck
2016-02-07 17:10 ` Borislav Petkov
2016-02-09 23:38 ` Luck, Tony
2016-02-10 11:06 ` Borislav Petkov
2016-02-10 19:27 ` Luck, Tony
2016-02-11 11:55 ` Borislav Petkov
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