From: Dave Hansen <dave.hansen@intel.com>
To: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC 6/7] x86/asm: Remap the TSS into the cpu entry area
Date: Mon, 13 Nov 2017 11:22:44 -0800 [thread overview]
Message-ID: <3e2bdf66-cbd4-4e78-ead1-e5c99d2a6d08@intel.com> (raw)
In-Reply-To: <5b424fefa9230917995d0584b40bc539a9bd9224.1510371795.git.luto@kernel.org>
On 11/10/2017 08:05 PM, Andy Lutomirski wrote:
> diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
> index fbc9b7f4e35e..8a9ba5553cab 100644
> --- a/arch/x86/include/asm/fixmap.h
> +++ b/arch/x86/include/asm/fixmap.h
> @@ -52,6 +52,13 @@ extern unsigned long __FIXADDR_TOP;
> struct cpu_entry_area
> {
> char gdt[PAGE_SIZE];
> +
> + /*
> + * The gdt is just below cpu_tss and thus serves (on x86_64) as a
> + * a read-only guard page for the SYSENTER stack at the bottom
> + * of the TSS region.
> + */
> + struct tss_struct tss;
> };
>
Aha, and here's the place that you need sizeof(tss_struct) to be nice
and page-aligned.
But why don't we just do:
char tss_space[PAGE_SIZE*something];
?
next prev parent reply other threads:[~2017-11-13 19:22 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-11 4:05 [RFC 0/7] Prep code for better stack switching Andy Lutomirski
2017-11-11 4:05 ` [RFC 1/7] x86/asm/64: Allocate and enable the SYSENTER stack Andy Lutomirski
2017-11-13 19:07 ` Dave Hansen
2017-11-14 2:17 ` Andy Lutomirski
2017-11-14 7:15 ` Ingo Molnar
2017-11-11 4:05 ` [RFC 2/7] x86/gdt: Put per-cpu GDT remaps in ascending order Andy Lutomirski
2017-11-11 4:05 ` [RFC 3/7] x86/fixmap: Generalize the GDT fixmap mechanism Andy Lutomirski
2017-11-11 4:05 ` [RFC 4/7] x86/asm: Fix assumptions that the HW TSS is at the beginning of cpu_tss Andy Lutomirski
2017-11-13 17:01 ` Dave Hansen
2017-11-26 13:48 ` [PATCH v2] x86/entry: " Ingo Molnar
2017-11-26 15:41 ` Andy Lutomirski
2017-11-26 15:58 ` Ingo Molnar
2017-11-26 16:00 ` Ingo Molnar
2017-11-26 16:05 ` Andy Lutomirski
2017-11-26 16:43 ` Ingo Molnar
2017-11-11 4:05 ` [RFC 5/7] x86/asm: Rearrange struct cpu_tss to enlarge SYSENTER_stack and fix alignment Andy Lutomirski
2017-11-11 4:11 ` Andy Lutomirski
2017-11-13 19:19 ` Dave Hansen
2017-11-11 4:05 ` [RFC 6/7] x86/asm: Remap the TSS into the cpu entry area Andy Lutomirski
2017-11-13 19:22 ` Dave Hansen [this message]
2017-11-13 19:36 ` Linus Torvalds
2017-11-14 2:25 ` Andy Lutomirski
2017-11-14 2:28 ` Linus Torvalds
2017-11-14 2:30 ` Andy Lutomirski
2017-11-14 2:27 ` Andy Lutomirski
2017-11-11 4:05 ` [RFC 7/7] x86/unwind/64: Add support for the SYSENTER stack Andy Lutomirski
2017-11-13 22:46 ` Josh Poimboeuf
2017-11-14 2:13 ` Andy Lutomirski
2017-11-11 10:58 ` [RFC 0/7] Prep code for better stack switching Borislav Petkov
2017-11-12 2:59 ` Andy Lutomirski
2017-11-12 4:25 ` Andy Lutomirski
2017-11-13 4:37 ` Andy Lutomirski
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