From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Rik van Riel <riel@redhat.com>,
daniel.gruss@iaik.tugraz.at, hughd@google.com,
keescook@google.com, linux-mm@kvack.org,
michael.schwarz@iaik.tugraz.at, moritz.lipp@iaik.tugraz.at,
richard.fellner@student.tugraz.at
Subject: Re: [patch V2 5/5] x86/kaiser: Add boottime disable switch
Date: Mon, 27 Nov 2017 22:43:08 +0100 [thread overview]
Message-ID: <20171127214308.hxzturumrucfnlpy@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20171127102241.oj225ycxkc7rfvft@hirez.programming.kicks-ass.net>
On Mon, Nov 27, 2017 at 11:22:41AM +0100, Peter Zijlstra wrote:
> Could be a simple as this.. but I've not tested.
>
>
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index f4f4ab8525bd..1be393a97421 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -1442,7 +1442,10 @@ void syscall_init(void)
> (entry_SYSCALL_64_trampoline - _entry_trampoline);
>
> wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS);
> - wrmsrl(MSR_LSTAR, SYSCALL64_entry_trampoline);
> + if (kaiser_enabled)
> + wrmsrl(MSR_LSTAR, SYSCALL64_entry_trampoline);
> + else
> + wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64);
>
> #ifdef CONFIG_IA32_EMULATION
> wrmsrl(MSR_CSTAR, (unsigned long)entry_SYSCALL_compat);
Seems to work:
root@ivb-ep:~# rdmsr --all 0xc0000082 | uniq
ffffffff81beb780
root@ivb-ep:~# grep ffffffff81beb780 /proc/kallsyms
ffffffff81beb780 T entry_SYSCALL_64
next prev parent reply other threads:[~2017-11-27 21:43 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-26 23:14 [patch V2 0/5] x86/kaiser: Boot time disabling and debug support Thomas Gleixner
2017-11-26 23:14 ` [patch V2 1/5] x86/kaiser: Respect disabled CPU features Thomas Gleixner
2017-11-27 9:57 ` Peter Zijlstra
2017-11-27 11:47 ` Thomas Gleixner
2017-11-27 12:31 ` Brian Gerst
2017-11-27 13:18 ` Thomas Gleixner
2017-11-27 18:11 ` Dave Hansen
2017-11-27 18:37 ` Kees Cook
2017-11-26 23:14 ` [patch V2 2/5] x86/kaiser: Simplify disabling of global pages Thomas Gleixner
2017-11-27 11:49 ` Thomas Gleixner
2017-11-27 18:15 ` Dave Hansen
2017-11-27 20:28 ` Thomas Gleixner
2017-11-26 23:14 ` [patch V2 3/5] x86/dump_pagetables: Check KAISER shadow page table for WX pages Thomas Gleixner
2017-11-27 18:17 ` Dave Hansen
2017-11-26 23:14 ` [patch V2 4/5] x86/mm/debug_pagetables: Allow dumping current pagetables Thomas Gleixner
2017-11-27 9:41 ` Peter Zijlstra
2017-11-27 10:06 ` [PATCH] vfs: Add PERM_* symbolic helpers for common file mode/permissions Ingo Molnar
2017-11-27 19:21 ` Linus Torvalds
2017-11-28 10:54 ` Ingo Molnar
2017-11-28 11:12 ` Ingo Molnar
2017-11-29 8:52 ` Michael Ellerman
2017-11-27 18:18 ` [patch V2 4/5] x86/mm/debug_pagetables: Allow dumping current pagetables Dave Hansen
2017-11-26 23:14 ` [patch V2 5/5] x86/kaiser: Add boottime disable switch Thomas Gleixner
2017-11-27 9:48 ` Peter Zijlstra
2017-11-27 10:22 ` Peter Zijlstra
2017-11-27 11:50 ` Thomas Gleixner
2017-11-27 12:49 ` Peter Zijlstra
2017-11-27 21:43 ` Peter Zijlstra [this message]
2017-11-27 18:22 ` Dave Hansen
2017-11-27 19:00 ` Thomas Gleixner
2017-11-27 19:18 ` Josh Poimboeuf
2017-11-27 20:47 ` Thomas Gleixner
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