x86/entry/64: Use a per-CPU trampoline stack for IDT entries
authorAndy Lutomirski <luto@kernel.org>
Mon, 4 Dec 2017 14:07:23 +0000 (15:07 +0100)
committerIngo Molnar <mingo@kernel.org>
Sun, 17 Dec 2017 13:27:38 +0000 (14:27 +0100)
commit7f2590a110b837af5679d08fc25c6227c5a8c497
treef94f6d9d657feaf40bda4f7597807b8beb3f0081
parent6d9256f0a89eaff97fca6006100bcaea8d1d8bdb
x86/entry/64: Use a per-CPU trampoline stack for IDT entries

Historically, IDT entries from usermode have always gone directly
to the running task's kernel stack.  Rearrange it so that we enter on
a per-CPU trampoline stack and then manually switch to the task's stack.
This touches a couple of extra cachelines, but it gives us a chance
to run some code before we touch the kernel stack.

The asm isn't exactly beautiful, but I think that fully refactoring
it can wait.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Link: https://lkml.kernel.org/r/20171204150606.225330557@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/entry/entry_64.S
arch/x86/entry/entry_64_compat.S
arch/x86/include/asm/switch_to.h
arch/x86/include/asm/traps.h
arch/x86/kernel/cpu/common.c
arch/x86/kernel/traps.c