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| author | Andy Lutomirski <luto@kernel.org> | 2017-12-04 15:07:23 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-12-17 14:27:38 +0100 |
| commit | 7f2590a110b837af5679d08fc25c6227c5a8c497 (patch) | |
| tree | f94f6d9d657feaf40bda4f7597807b8beb3f0081 /arch/x86/kernel/cpu/common.c | |
| parent | 6d9256f0a89eaff97fca6006100bcaea8d1d8bdb (diff) | |
| download | lwn-7f2590a110b837af5679d08fc25c6227c5a8c497.tar.gz lwn-7f2590a110b837af5679d08fc25c6227c5a8c497.zip | |
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>
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index e5837bd6c672..57968880e39b 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1623,11 +1623,13 @@ void cpu_init(void) setup_cpu_entry_area(cpu); /* - * Initialize the TSS. Don't bother initializing sp0, as the initial - * task never enters user mode. + * Initialize the TSS. sp0 points to the entry trampoline stack + * regardless of what task is running. */ set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); load_TR_desc(); + load_sp0((unsigned long)&get_cpu_entry_area(cpu)->tss + + offsetofend(struct tss_struct, SYSENTER_stack)); load_mm_ldt(&init_mm); |