From: Andi Kleen <ak@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Hugh Dickins" <hughd@google.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Kees Cook" <keescook@google.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@kernel.org>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Jürgen Groß" <jgross@suse.com>,
"Josh Poimboeuf" <jpoimboe@redhat.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Borislav Petkov" <bp@alien8.de>,
"Andrew Lutomirski" <luto@kernel.org>
Subject: Re: [PATCH 3/7] x86/mm/init: pass unconverted symbol addresses to free_init_pages()
Date: Sat, 4 Aug 2018 23:11:32 -0700 [thread overview]
Message-ID: <20180805061132.GD4238@tassilo.jf.intel.com> (raw)
In-Reply-To: <CA+55aFzd-F65GVBq8a-vTaU4G5UwddDcOdcd3SV9YVdB6qDGdg@mail.gmail.com>
> [ Goes around and rummages ]
>
> Oh, never mind, looking around reminded me why: we want to map the
> kernel text in the top 31 bits, so that we can use the faster
> -mcmodel=kernel because all symbols fit in sign-extended 32 bits.
>
> Maybe there was some other reason too, but I think that's it.
No that was the only reason.
Large code model would be extremely expensive, and PIC linked
kernel also had some issues. So we ended up with this set up.
-Andi
next prev parent reply other threads:[~2018-08-05 6:11 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-02 22:58 [PATCH 0/7] [v2] x86/mm/pti: close two Meltdown leaks with Global kernel mapping Dave Hansen
2018-08-02 22:58 ` [PATCH 1/7] x86/mm/pti: clear Global bit more aggressively Dave Hansen
2018-08-05 20:30 ` [tip:x86/pti] x86/mm/pti: Clear " tip-bot for Dave Hansen
2018-08-02 22:58 ` [PATCH 2/7] mm: allow non-direct-map arguments to free_reserved_area() Dave Hansen
2018-08-05 20:31 ` [tip:x86/pti] mm: Allow " tip-bot for Dave Hansen
2018-08-02 22:58 ` [PATCH 3/7] x86/mm/init: pass unconverted symbol addresses to free_init_pages() Dave Hansen
2018-08-04 0:18 ` Hugh Dickins
2018-08-04 17:31 ` Linus Torvalds
2018-08-04 18:23 ` Hugh Dickins
2018-08-05 6:11 ` Andi Kleen [this message]
2018-08-05 20:31 ` [tip:x86/pti] x86/mm/init: Pass " tip-bot for Dave Hansen
2018-08-02 22:58 ` [PATCH 4/7] x86/mm/init: add helper for freeing kernel image pages Dave Hansen
2018-08-05 20:32 ` [tip:x86/pti] x86/mm/init: Add " tip-bot for Dave Hansen
2018-08-02 22:58 ` [PATCH 5/7] x86/mm/init: remove freed kernel image areas from alias mapping Dave Hansen
2018-08-04 0:35 ` Hugh Dickins
2018-08-04 21:38 ` Andy Lutomirski
2018-08-06 15:17 ` Dave Hansen
2018-08-05 20:32 ` [tip:x86/pti] x86/mm/init: Remove " tip-bot for Dave Hansen
2018-08-06 20:21 ` [tip:x86/pti-urgent] " tip-bot for Dave Hansen
2018-08-02 22:58 ` [PATCH 6/7] x86/mm/pageattr: pass named flag instead of 0/1 Dave Hansen
2018-08-05 20:09 ` Thomas Gleixner
2018-08-06 15:09 ` Dave Hansen
2018-08-02 22:58 ` [PATCH 7/7] x86/mm/pageattr: Remove implicit NX behavior Dave Hansen
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