From: Dave Hansen <dave.hansen@linux.intel.com>
To: Andy Lutomirski <luto@kernel.org>, Thomas Gleixner <tglx@linutronix.de>
Cc: Lars Wendler <wendler.lars@web.de>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Borislav Betkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Greg KH <gregkh@linuxfoundation.org>,
Laura Abbott <labbott@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>
Subject: Re: CONFIG_PAGE_TABLE_ISOLATION=y on x86_64 causes gcc to segfault when building x86_32 binaries
Date: Wed, 3 Jan 2018 14:27:17 -0800 [thread overview]
Message-ID: <e29cbd54-95f2-52ed-508e-12c1c2520bfb@linux.intel.com> (raw)
In-Reply-To: <CALCETrW8RD2vtcUjYoq07DEiLoXYxqXuxD7xujOtuF=UGjNYvw@mail.gmail.com>
On 01/03/2018 02:14 PM, Andy Lutomirski wrote:
> + /* Use %rsp as scratch reg. User ESP is stashed in r8 */
> + SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp
> +
> + /* Switch to the kernel stack */
> movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
The stack is unreadable at this point without the CR3 switch.
> What's the issue that this is fixing?
Users doing 32-bit SYSCALLs on the CPUs that support them double fault
since they end up with an %rsp that they can't access.
next prev parent reply other threads:[~2018-01-03 22:27 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20180103123723.1dd26828@abudhabi.paradoxon.rec>
2018-01-03 11:57 ` CONFIG_PAGE_TABLE_ISOLATION=y on x86_64 causes gcc to segfault when building x86_32 binaries Thomas Gleixner
2018-01-03 12:05 ` Thomas Gleixner
2018-01-03 13:30 ` Lars Wendler
2018-01-03 15:21 ` Thomas Gleixner
2018-01-03 15:42 ` Dave Hansen
2018-01-03 18:52 ` Thomas Gleixner
2018-01-03 22:12 ` Laura Abbott
2018-01-03 22:14 ` Andy Lutomirski
2018-01-03 22:22 ` Thomas Gleixner
2018-01-03 23:43 ` Andy Lutomirski
2018-01-03 22:27 ` Dave Hansen [this message]
2018-01-03 22:25 ` [tip:x86/pti] x86/pti: Switch to kernel CR3 at early in entry_SYSCALL_compat() tip-bot for Thomas Gleixner
2018-01-03 23:46 ` CONFIG_PAGE_TABLE_ISOLATION=y on x86_64 causes gcc to segfault when building x86_32 binaries Lars Wendler
2018-01-04 2:44 ` Boris Ostrovsky
2018-01-03 15:40 ` Borislav Petkov
2018-01-03 23:22 ` Lars Wendler
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