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From: Borislav Petkov <bp@suse.de>
To: "Bae, Chang Seok" <chang.seok.bae@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	"mingo@kernel.org" <mingo@kernel.org>,
	"luto@kernel.org" <luto@kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"Brown, Len" <len.brown@intel.com>,
	"Hansen, Dave" <dave.hansen@intel.com>,
	"hjl.tools@gmail.com" <hjl.tools@gmail.com>,
	"Dave.Martin@arm.com" <Dave.Martin@arm.com>,
	"jannh@google.com" <jannh@google.com>,
	"mpe@ellerman.id.au" <mpe@ellerman.id.au>,
	"carlos@redhat.com" <carlos@redhat.com>,
	"Luck, Tony" <tony.luck@intel.com>,
	"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
	"libc-alpha@sourceware.org" <libc-alpha@sourceware.org>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Yu, Fenghua" <fenghua.yu@intel.com>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>
Subject: Re: [PATCH v6 3/6] x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ
Date: Wed, 10 Mar 2021 18:43:10 +0100	[thread overview]
Message-ID: <20210310174310.GB25403@zn.tnic> (raw)
In-Reply-To: <F637CCE0-1744-478C-B2ED-65EA14B07938@intel.com>

On Wed, Mar 10, 2021 at 04:34:40PM +0000, Bae, Chang Seok wrote:
> Yeah, right. While this attempts to fix the issue, it involves the ABI change.
> Len and I think PATCH5 [1] is rather a backport candidate as it gives a more
> reasonable behavior.

Yap, patch 5 is more conservative, sure.

I guess I can take it out of the set and send it Linuswards now.

> > That source code needs some special markup to look like source code -
> > currently, the result looks bad.
> 
> How about this code:

No, build the docs by doing

make htmldocs

and look at the result.

Btw, you should always look at the result before sending it out.

> Rewrote like this:
> 
> AT_SYSINFO is used for locating the vsyscall entry point.  It is not exported
> on 64-bit mode.
> 
> AT_SYSINFO_EHDR is the start address of the page containing the vDSO.
> 
> AT_MINSIGSTKSZ denotes the minimum stack size required by the kernel to
> deliver a signal to user-space.  AT_MINSIGSTKSZ comprehends the space consumed
> by the kernel to accommodate the user context for the current hardware
> configuration.  It does not comprehend subsequent user-space stack
> consumption, which must be added by the user.  (e.g. Above, user-space adds
> SIGSTKSZ to AT_MINSIGSTKSZ.)

Better.

Thx.

-- 
Regards/Gruss,
    Boris.

SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg

  reply	other threads:[~2021-03-10 17:44 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-27 16:59 [PATCH v6 0/6] x86: Improve Minimum Alternate Stack Size Chang S. Bae
2021-02-27 16:59 ` [PATCH v6 1/6] uapi: Define the aux vector AT_MINSIGSTKSZ Chang S. Bae
2021-03-01 19:09   ` Borislav Petkov
2021-03-10 16:31     ` Bae, Chang Seok
2021-02-27 16:59 ` [PATCH v6 2/6] x86/signal: Introduce helpers to get the maximum signal frame size Chang S. Bae
2021-02-27 16:59 ` [PATCH v6 3/6] x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ Chang S. Bae
2021-03-05 10:43   ` Borislav Petkov
2021-03-10 16:34     ` Bae, Chang Seok
2021-03-10 17:43       ` Borislav Petkov [this message]
2021-03-10 18:01         ` Bae, Chang Seok
2021-02-27 16:59 ` [PATCH v6 4/6] selftest/sigaltstack: Use the AT_MINSIGSTKSZ aux vector if available Chang S. Bae
2021-02-27 16:59 ` [PATCH v6 5/6] x86/signal: Detect and prevent an alternate signal stack overflow Chang S. Bae
2021-02-27 16:59 ` [PATCH v6 6/6] selftest/x86/signal: Include test cases for validating sigaltstack Chang S. Bae

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